This mod is for those of us in hot climates. People in areas where it gets really cold may want to consider the fact that this may have an effect on warm-up.

Coolant runs through the throttle body to help get everything warmed up, but when the car is warmed up, this means that the intake air must run through a ~180 degree heater before entering the engine. This means lots of heat soak for people in hot climates.

You're not going to notice a huge difference in power with this cheap mod, but you won't get as much heat soak, and for about 5 dollars you can't really complain. :p

Here's a parts list. The brass hose splicers I used could've been a bit smaller on one end (5/16*3/8 as opposed to the 3/8*3/8 I used).

2x..3/8*3/8 barbed brass hose splicers
2x...Hose clamps
1x.....~6" 3/8 inc inner diameter heater hose (I got 10ft for 7 bucks at a local auto parts store)

Instructions are simple. Take off your intake first, or you won't be able to get to the hose on the bottom of the throttle body. Pull the 2 coolant hoses off the throttle body. Splice in your 6" heater hose, clamp it down, and VOILA!!!

Interesting mod. I live in Texas and it's a freakin' sauna here. I might try it. Thanks paradigm. :)

Any time. :)




I also should've said that instead of the parts I used you can use a single piece of metal pipe with an outer diameter of about 3/8 inch, but as much as I looked I couldn't find any pipe to use, also the pipe wouldn't have the barbed ends like the brass splicers I used have.


As soon as I get my hands on the CANScan software I'll try to get some intake air temp readings, and compare them to a car that doesn't have this done. :)

It's unlikely you'll see any difference reading off the car's data channels. I'm pretty sure that the stock IAT sensor is located on the same unit with the MAF sensor, which is in front of the throttle body.

You'd need to install another sensor somewhere in the upper intake manifold to get a reading downstream from where your mod changes things.

It's not a reading he is trying to affect. This is a mod that I've done to every car I own. the premise is that since the coolant (strange term in this scenario) is running through the throttlebody, it heats up the throttlebody. Since air runs through the throttlebody, it heats up the air. The whole point is to get a little cooler air into the engine. Will you feel it? Maybe, maybe not. But it is essentially a "free" mod.

It's not a reading he is trying to affect. This is a mod that I've done to every car I own. the premise is that since the coolant (strange term in this scenario) is running through the throttlebody, it heats up the throttlebody. Since air runs through the throttlebody, it heats up the air. The whole point is to get a little cooler air into the engine. Will you feel it? Maybe, maybe not. But it is essentially a "free" mod.


I understand all that, I was responding more to the later part of the post where he talks about logging comparison data on with/without cars to try to quantify the effect of the mod. My only point was that a sensor upstream of the mod point will not produce any data significant to determining what effect is there.


P.S. how much coolant gets spilled in the course of this mod? I'm swapping out my springs/sways this weekend, and I might do this too while I'm in there....

I think what bgreene was refering to was how paradigm said he was gonna take readings from his intake temps and from a stock TB'ed RX8. Bgreene was just saying that he thought the intake temp readings would be readings from before the TB, so if there is a difference in temps, it would NOT be correct data to use in proving the difference this mod made.

Nate

damn, too late

I remember I read once about using a similar mod. Some Firebird owners build a second separate cooling circuit using the windshield washer pump, a separate reservoir filled with water and ice, to overcool the TB. They would run this mix at the track, between runs, to cool the TB. Their claim of increase performance was based on colder air being more dense so they would get extra mass in the cylinders. Kinda makes sense but from what I read about the Renesis, even if you remove the air filter power is the same, so extra air is not needed. But it is a free mod :o) I'm in NJ, so it is not for me.

Cool idea. Moving this to the DIY forum. :D

Since i dont have to work today and i'm bored.. Why the heck not.
it's quite warm In AZ. I'll try this out.

I took the TB off and looked on the backside of it. There was a gray ring of crap where the valve meets the TB sides. I'm guessing that it was the lube that Mazda uses for the venturi pivot points. I cleaned the TB w/ carb cleaner. Sorry I didn't take a pic.

Can someone confirm this?

I haven't had a chance to drive the car in the heat yet so I can't say anything about the mod. I'll post thoughts about it later.

Sorry to bring this back from the dead and all... but I figured I'd give some input from a "colder" area.

I did this mod, first of all a 3/8" barb is a tad "tight" with the stock hose. I didn't use any new coolant hose, I merely pulled the stock hose out of its bracketing, cut it, and have it connected near the alternator. This moved it completely away from the tb, shorter overall, cleaner, etc. The 3/8" by 3/8" brass adapter was NOT easy to fit into the stock hose. I forced it in and it's okay now, but I think 5/16" would be a much better fit. Just my input...

As far as warmup goes, it's completely unchanged. Since the cold start warmup is controlled by the PCM, I didn't expect it to change at all. It still revs up to 2k rpms and all on cold starts until it is warm, so I don't see how this mod becomes an issue in cold climates. Unless I'm missing something? I mean, the coolant is cold on startup anyways, so how does it help warm things up? Maybe I'm missing something, I'm not sure. I know on older cars they use a thermowax system for the cold start, but since ours is PCM controlled I don't see how it makes a difference.

Either way, I've been starting the car up in 20-30º weather without an issue. Cranks and fires immediately, no idle issues, nothing. Just thought I'd let people know this mod isn't a big deal at all. Also thought I'd give my input on the 5/16" adapter possibly being a better fit than 3/8".

so it doesn't affect the cold startup?

None that I've noticed. Been starting my car up in 20-30º weather for over a week now, no issues.

Like I said, I don't see how it WOULD effect cold start/warmup since it's PCM controlled for the accelerated warmup. But I might be missing something and someone can correct me if I'm wrong.

Interesting. TB mod doesn't affect start-up (above). I wonder if the heater is there for another reason.

In airplanes, the carburetors have heaters installed to prevent icing. Could the coolant to the throttle body be acting in the same capacity? Could a cold, humid morning result in icing around the throttle body plate if the TB isn't heated?

I'm speculating here...
thoughts?

I went through some of my friend's auto-tech books from his school to try and figure out what the purpose might be. So far I'm still really not sure.

One thing one of the books talked about goes along with what you (samsong) said. It said that sometimes coolant running through the TB is a way to melt frost/ice that might have formed along the inside of the throttle body/tb plate(s). But this doesn't really make sense. The coolant is COLD when you start up, just as cold as the frost/ice. So how is this supposed to help melt it or keep it from forming? Doesn't seem logical to me, but maybe I'm wrong.

The book also mentioned that coolant is sometimes used in carburetors and some fuel injection setups to help heat the fuel mixture as it goes into the engine, providing a more efficient burn. I guess I can buy that, though I don't think it matters. However, that only works if the coolant is AFTER the fuel injection on EFI cars. The coolant in our TB is prior to the fuel mixture, so this doesn't mean jack for us.

And that's all I could find. I still want to know why Mazda did this! I can't find a purpose in it, it's confusing me :(

Thanks for your thoughts.

Clarify: The carb heaters on the planes are on all the time, though...it's to keep it from icing during normal operation (not just start-up).

I would think the ice would form when the low-pressure around the throttle causes the watervapor to condense (ever watched an airplane at take-off and see "clouds" form on the tops of the wings?). Maybe that condensation could also freeze to a cold TB and build-up during other than WOT operation.

Again...just my speculation.

You will notice the greatest diffrence from this mod in the summer. Just try and touch the throttle body after you have been driving hard for 20 miuntes or so before and after the mod. The tb goes from scolding to warm in the summer months.

ok guys... i live in miami & i could defenitely benefit from this mod. the only problem is that i'm not the most mechanically inclined person out there. i could defenitely follow a DIY on this but it just seems a little too vague to follow. also, the pictures didn't seem to help me much either... no offense to paradigm at all... actually, i'm glad i came across ur post. could any of u guys help me out a bit on this??

I'll take some better pics some day for you. For mine, though, I cut the hose to make it shorter and moved it to the other side of the alternator since I saw it pointless to ADD hose and wrap it around the TB.

It's really not complicated, just take my advice earlier in this thread, 3/8" barb is too big for the stock hose that goes into the TB, 5/16" would work MUCH better.

bump

Oh yah pictures. Okay I took some.

So the pipe/nipples that are left after the rerouting I capped. Don't need to, I just preferred not to have debri or anything get in there in case I ever decide to revert it back to stock.

Pic of the first cap where the hose used to go.

http://home.comcast.net/~ddub114/tbmod/1.jpg

Pic of the second cap where the hose used to come out of. Was kind of hard to see so I added an arrow to guide you :)

http://home.comcast.net/~ddub114/tbmod/2.jpg

Close up of the barb and where I moved the hoses/made the connection.

http://home.comcast.net/~ddub114/tbmod/3.jpg

And standing back a bit further so you can see everything.

http://home.comcast.net/~ddub114/tbmod/4.jpg






EDIT:
Why wont the img tags work in the DIY section :(

ur the man dDub... thanks a lot!

ok dDub, I finally got this done... only took about 5 min. the 5/16" barb fit like a glove! my only concern is that i didn't cap the throttle body ends where the hoses were attached. i cut the bottom hose off to avoid having to disconnect my intake. i can always cap the top opening. but, i won't be able to get to the bottom one until i get around to disconnecting the intake for w/e reason. so, i'm wondering if there would be any problem with debris getting in there somehow...
also, i'll let everyone know how this works out for me here in miami temps...

Glad to know I was right about the 5/16" I had a feeling it'd fit nicely :)

Don't worry too much about capping it, you really don't have to. It doesn't go into anything now, before it was only the coolant anyways. Plus not a whole lot really can get in there. I mainly did it because I had them laying around and said what the heck.

Thanks for your thoughts.

Clarify: The carb heaters on the planes are on all the time, though...it's to keep it from icing during normal operation (not just start-up).

I would think the ice would form when the low-pressure around the throttle causes the watervapor to condense (ever watched an airplane at take-off and see "clouds" form on the tops of the wings?). Maybe that condensation could also freeze to a cold TB and build-up during other than WOT operation.

Again...just my speculation.

Carb heat? - check.

This should answer some questions....

http://www.eaa32.org/Articles/CarbHeat.html

Carb heat? - check.

This should answer some questions....

http://www.eaa32.org/Articles/CarbHeat.html
The problem w/relating this article to our car is that is it is about carbs, of which we have none and so the idea of..."Temperatures in the carburetor can drop 60° to 70°F (refrigerator effect) as a result of fuel vaporization and the carburetor venturi effect." doesn't occur.

Perhaps our throttle body heating is done to prevent icing still or perhaps it is only for emmisions reasons or ?????. Would be nice to really know so as to avoid some unknown change/problem that could/will show up after doing this.

i'd doubt that ice could form in the rather warm engine bay, but in my mind condensation forming is a real possibility with the large pressure drop across the throttle.

FWIW, the inlet to the gas turbines at my power plant are heated at temperatures below 40-45 degrees (depending on humidity) to prevent ice forming. :Eyecrazy:

First, carb heat on airplanes is not "always on." It reduces HP signifigantly, so the pilot only turns it on when needed. You don't cruise around when it's 95 degress out superheating your intake air.

As it relates to our cars: Any time air goes from high pressure (ambient) to low pressure (vaccum in a manifold), the temperature drops and the water comes out. Thus the air can loose a lot of temperature when it goes past the throttle plate at idle. Given the right conditions, the air can drop to freezing, water can come out and condense, and ice can block off the throttle, leading to bad idle or the engine dying.

My 1990 Eagle talon had exactly the same thing, and I think all cars today do.

no problems whatsoever guys...

Would there be a problem installing an in line brass valve that could be truned on and off rather than bypassing the whole system?

or just insert a stainless steel ball in each hose end to block flow so the stealership tech doesn't hit you with a warranty violation

or just insert a stainless steel ball in each hose end to block flow so the stealership tech doesn't hit you with a warranty violation
Who goes to the stealership? :p: Only reason I'd go is to have something fixed under warranty, and if I do that I'll put things back to stock first.

Have not set foot back on that lot once since I bought the rx8 :)

I performed this mod and had no problems until today and it was my own fault. I used a two sided brass barb 5/16's I believe and just rerouted the hose.

Well today I noticed some steam coming up from under my hood and could smell anti freeze. I quickly popped my hood and found my modded coolant line had come undone. Why? Because I re-used the stock hose connecters and not the screw type hose clamps. :nono:

Luckily, I had two smaller ones in my tool box and quickly fixed the problem.

Motto of this story, use screw type hose clamps when performing this mod! :)

I recently change to the 5/16 barbs and used the screw clamps. The stock ones are too weak in this type of setup.

Luckly you had this happen locally to you instead of a long trip. That would've sucked!

i've had this done for a while now & have had no issues yet...

i've had this done for a while now & have had no issues yet...
this will be one of the first things i do after i get my 2 free oil changes from the dealer....oh well...i can wait 5000 more miles...

or just insert a stainless steel ball in each hose end to block flow so the stealership tech doesn't hit you with a warranty violation
Wouldn't this be bad, blocking the coolant flow? Or is this line just tapped from a main line?

Anyone thought of running a second cooling system up to those mounts and cool the intake down? Like those CPU water pumps on computers. Kinda like an intercooler. Someone with the time needs to give it a shot. If I had the time, I would. Get to working guys!

Did bypass yesterday. I can tell a difference already. It does not seem to run weaker after extended periods of time. A must do.

Did bypass yesterday. I can tell a difference already. It does not seem to run weaker after extended periods of time. A must do.

That is exactly the same effect I have noticed in my car after doing this. It makes a big difference on hot days. On really hot days, it used to drive fine for a while, and then after a certain period of time, it would bog down and drive sluggishly. It doesn't do that now. I am just worried what the service guys will say about it.

I wouldn't worry about it. did u guys cap off the ends or leave them open?

I left the ends of the TB open. When i do connect it back I run a pipe cleaner through and then use compressed air to blow out the dust.

I purchased another section of hose from Autozone and attached both ends back up to the throttle body so it looks stock from above.

I am worried about the service guys like I am worried about yesterdays trash. There is no reason to take it to the shop, ever. Dealerships do not have the OK to touch my car. I would rather let the local high school shop class look at my car. This is a simple car, very simple. You can do everything on this car.

I purchased another section of hose from Autozone and attached both ends back up to the throttle body so it looks stock from above.

i guess i can use this approach for safe measure w/ my dealer. i don't plan on reconnecting at all as long as i'm in miami's scorching heat.

I am worried about the service guys like I am worried about yesterdays trash. There is no reason to take it to the shop, ever. Dealerships do not have the OK to touch my car. I would rather let the local high school shop class look at my car. This is a simple car, very simple. You can do everything on this car.

If you're willing to buy the parts.

It's hard to get new plugs, starter, battery, brake rotors, heat shields, etc for free unless you let the dealer install them.

I'd also love to know how you're uploading the flash in your car, since many, many of us here would pay a pretty penny to be able to do that at home ourselves
:)

Just did this today!!! It took me about 1 hour and I did it at the same time I changed my oil (http:///#) and today was the first time I used the K&N oil filter (http:///#) and Royal Purple synthetic oil (http:///#)! I have to say that when the car warmed up the throttle was super smooth! Normally I get hesitation and after it's warm it will start to idle irratically and drop down to about 750 rpms. When it did this it would almost feel like it was going to stall and as soon as I would get on the gas it would just slug its way forward. I noticed a huge change today. I'll test it out when the temps are a little warmer but so far I'm liking what I saw. It actually felt like it did the first 6 months again today!

Now if I see mpg gains from this I don't know what I'll do with myself... :fingersx: (you do know that I'm sorta kidding right? RIGHT!) I've been getting around 12-13 mpgs lately and that is just painful these days. If my problem with mpgs was related I would be ecstatic

Thanks guys now it's time for me to go take a little break... :smokepoke

Well here's my update... I will start with the mpg last fill up (first one since I performed the mod) I got 12.138 mpgs!!! :eek: That's not getting better but then that's what I expected anyone but there was always that hope.

Engine is running smoother, the hp loss I was experiencing after warm up, and the hesitation are all gone!!! I haven't had those problems at all since. That is definately a step in the right direction. I guess I need to unperform the mod and head back to the dealer for the mpg problems. :(

I had 18-19mpg with mostly city driving before AND after the mod. I saw no difference in mileage.

I did this a much easier way, but many people will probably think I'm crazy.

I just dropped a 1 1/2" drywall screw in the top of the TB. This is wide enough that it can't go into the TB, and also wide enough that the rubber hose "grabs" it, creating a good seal. It's long enough that it can't go upwards and make it around the bend if it ever came loose.

Literally: I took off the upper hose, dropped in the screw, pushed the hose back on.

It's been there for three weeks and hasn't moved a millimeter, and it's clearly blocking the flow.

I did this a much easier way, but many people will probably think I'm crazy.

I just dropped a 1 1/2" drywall screw in the top of the TB. This is wide enough that it can't go into the TB, and also wide enough that the rubber hose "grabs" it, creating a good seal. It's long enough that it can't go upwards and make it around the bend if it ever came loose.

Literally: I took off the upper hose, dropped in the screw, pushed the hose back on.

It's been there for three weeks and hasn't moved a millimeter, and it's clearly blocking the flow.Ooooohhhh me likey the way you thinky. I actually think I am going to install a bypass valve with an on/off switch. I was thinking about this since I am going to have to reinstall it today anyway so I might as well go ahead and muss with doing it the right way from the start. I'll try to take a pic for you guys to see. I may also find myself driving back to Spokane from time to time in the winter and don't want to take the time to undo it everytime. Think the dealer will give me any grief if I explain to the the problems I was having and why I did it?

OK I went down and bought a bypass valve so I can shut the flow off to the throttle when I want and to turn it back on when I need to. Anyone know if the upper or lower coolant hose is the coolant feed in hose? I do kinda need to know which one I am needing to throw my valve on.

Anyone with the technical service manual? Please help!

Put it back to stock because I'm planning on taking it to the dealer this week and I decided to clean out the throttle body at the same time with carb cleaner... I think I killed the O2 sensor... :eek: The car would start and then stall out immediately. I started to get freaked! I mean really freaked out!!!! I could keep the car running while I was spraying in the carb cleaner but as soon as I would stop it would die. I figured that this was due to the MAF sensor which I think is located on the intake hose right before it gets to the throttle body.

So after I had sprayed like a quarter of the can of carb cleaner I decided it should be clean enough to put everything back together and see if it would stay running. It did! Suddenly I wasn't as freaked out. It was idling and continued to run with no major issues. Then I decided to give it a couple of runs through the neighborhood with some redlines (normal driving conditions) and some putting around to see how responsive or lack thereof it would be. Everything seemed pretty smooth and it was actually feeling smoother than it has in a while... then I got to a light and realized that the car was idling at about 1.5k rpms! Yes, that's higher than normal. It would eventually go down to 1k rpms and just about the time it would hit the typical 850 or 750 rpms it would shoot up to either 1.5k or 1.25k for about a second and then drop back down. I'm not going to say anything but I am going to clean the coolant off the engine and just see what he dealer comes up with. I'll let you know.

OK I have an update on my crappy mpg I will update this in a couple of threads since they are related to this. I had done the DIY throttle body bypass and since I was taking the car into the dealer this week I decided to put it back to stock. I didn't let the car cool down enough and sprayed coolant all over the interior of the engine compartment getting in the throttle body, the intake hose and generally just about everywhere except into the intake itself fortunately! I put everything back together after cleaning the throttle body and the intake out with carb cleaner.

The car seemed to be idling a bit high but seemed to be ok. I took it out for a test run with some redline runs and some cruise around town driving conditions to see how it was running. I get to a light and notice my car is idling at 1.5k rpms which is higher than normal after it's warmed up. It did slowly go back down to normal or 850 rpms but shot right back up and did the hunting idle thing. After a 10 min run with no change I go back home and give up for the night (at least she's running right I didn't kill anything.)

The next day I go over to Zoom44's to use his Hymee tool since a CEL was thrown and I could get the codes from him. We get number one code as MAF=low input... that tells me what I suspected which was the MAF was either dirty or damaged. We bust out the carb cleaner spray it down real good and put it back in. We clear the codes and start it up. No codes!!! Idle is perfect just like new. We drive it around and no issue. I was just about 60% in the gas tank (yes the Hymee tool tells you that too) and I had 73 miles since last fill up! Yes my mileage has been that bad. I have gone 25 miles since Monday night and I have used less than 1/8th of a tank!!!!! :wow: I didn't actually expect to see mpg (and most likely hp) gain from this.

I think mines been dirty for a long time and has been slowly getting dirtier until we come to today and the sudden change in my cars gas mileage. Maybe some of the other people having gas mileage issues could check this out since I wasn't throwing CELs before and I have taken it into the dealership for mpg issues a number of times!

I will keep everyone updated on my next fill-ups to see if this continues.

is there any way i can clean the inside of the throttle body? i didn't cap the ends til several thousand miles later...
compressed air?? any suggestions??

ok.. sort of answered my own question...
http://www.lake-link.com/dodge/trucktips/tip.cfm?TruckTipID=16

i'm wondering now if those that have experienced power loss due to dirty MAF's have checked their TB's along w/ the inlet tube? it seems everyone is cleaning the tube & MAF but there could be buildup in the TB as well...

ok.. sort of answered my own question...
http://www.lake-link.com/dodge/trucktips/tip.cfm?TruckTipID=16

i'm wondering now if those that have experienced power loss due to dirty MAF's have checked their TB's along w/ the inlet tube? it seems everyone is cleaning the tube & MAF but there could be buildup in the TB as well...My tb was dirty as well as the intake tube and MAF sensor. I was already cleaning the tb with carb cleaner. Consider though that I have 40+k miles on my car too.

I did this Mod this morning. I bought a 3/8" brass barb splice from Home depot. I went to three different auto parts store trying to find any brass splice barbs....to no avail. Anyway The 3/8" barb is very tight but it sure won't ever leak. I placed worm gear clamps over each end of the barb to. I drove the car around for ~ 5 minutes and the coolant line was very hot but the TB was pretty cool still.....nice.

Currently I have electrical tape covering the TB's upper hose connection point.

I do suggest getting 5/16" Splice Barb (Brass) if you can find one.....I could not find one.

Also when I disconnected the coolant lines from the TB this morning I did not loose any coolant....must drained all down during the night.

In order to do this you also need to remove all of the accordian intake tube and the rubber tube connected to the Metal TB's housing.

Nice easy Mod.

ld suggest putting a rag in the accordian tube and in the throttle body openings just in case you get some coolant spray;)

ld suggest putting a rag in the accordian tube and in the throttle body (#) openings just in case you get some coolant (#) spray;)Good suggestion. I should've thought of it myself. I also should've just waited until it cooled down. Do you think I should replace the spilled coolant? :nono:

never hurts to top it off...

So are you just rerouting the coolant elsewhere or is the line plugged and the hose is fed outside of it's normal route? Me no get this mod..... I can tune the Int-x but cant figure this out.. haha

Anyway. If someone could explain it I would appreciate it.

So are you just rerouting the coolant elsewhere or is the line plugged and the hose is fed outside of it's normal route? Me no get this mod..... I can tune the Int-x but cant figure this out.. haha

Anyway. If someone could explain it I would appreciate it.It's just as it sounds... don't quote me for certain as to which is the Feed and Drain line but the concept works the same and I think this is accurate but I won't know for a little bit longer and no one answered my question... Bueller... Bueller... anyways, it seems that the line coming from underneath the throttle body is the feed line and the one on top of the throttle body is the drain line. If you disconnect both and hook them together as recommended you would have a connection that goes from feed to drain but doesn't do it through the throttle body but really goes through the hose for no reason.

Here's my recommendation... take a on/off valve and intercept the feed line so that you can shut it off in the higher temp days, track day, or whenever your fancy strikes... but if you find yourself driving through a cold mountain pass (we have plenty of those around my parts) then you can switch it back on and have no problems with condensation in the throttle body. Just a suggestion... like waiting until the car has cooled down completely before starting the mod. ;)

So are you just rerouting the coolant elsewhere or is the line plugged and the hose is fed outside of it's normal route? Me no get this mod..... I can tune the Int-x but cant figure this out.. haha

Anyway. If someone could explain it I would appreciate it.It's just as it sounds... don't quote me for certain as to which is the Feed and Drain line but the concept works the same and I think this is accurate but I won't know for a little bit longer and no one answered my question... Bueller... Bueller... anyways, it seems that the line coming from underneath the throttle body (http:///#) is the feed line and the one on top of the throttle body (#) is the drain line. If you disconnect both and hook them together as recommended you would have a connection that goes from feed to drain but doesn't do it through the throttle body but really goes through the hose for no reason.

Here's my recommendation... take a on/off valve and intercept the feed line so that you can shut it off in the higher temp days, track day, or whenever your fancy strikes... but if you find yourself driving (http:///#) through a cold mountain pass (we have plenty of those around my parts) then you can switch it back on and have no problems with condensation in the throttle body. Just a suggestion... like waiting until the car (http:///#) has cooled down completely before starting the mod. ;)

i have a question......
would there be a way to further cool our bypassed TB??
perhaps we can fill the plugged TB w/ coolant or water wetter... would that make any significant temperature changes?

just did the throttle body bypass mod on my RX8... took me about an hour and a half, but consider I did this with only a screwdriver and in a hotel parking lot (yes I live in a hotel - work related but yay i dont pay for it!)

I let the car cool down for the most part when i started it was a bit hot to the touch, but by the time I figured everything out it was cool, when I disconnected the coolant lines that run thru the throttle body I got no spray or leaking :) the toughest part was the underside "feed" line, for the life of me I coulndt get it off the right way so I just cut the tube. I got the top one off the right way, i need to get a large nipple or something to cover it and make it look nice instead of just some big metal hole.

Havent taken it for a spin yet, but once i secured everything and put my intake back together I fired up the car to check for leaks did a few revs to 9K to warm it up (and just to hear the sweetness of my rotary and the RP supercat I have) mmmm

No leaks, I did notice that the metal throttle body stayed cool as a cucumber the whole time even after the rest of the engine was nice and toasty. The only other thing I can say now is DAMN my fingers hurt :(

i have a question......
would there be a way to further cool our bypassed TB??
perhaps we can fill the plugged TB w/ coolant (#) or water wetter... would that make any significant temperature changes?You don't want to cool it any further since the throttle body may get condensation under cooling conditions. This really is enough unless you have a turbo. Then I would recommend an intercooler to cool down the air coming in.

I used a polyethlene barbed tube 5/16".

Any problem with using this?

I used a polyethlene barbed tube 5/16".

Any problem with using this?

nah... that's cool

I just did this and I figured I would reiterate some of the points made earlier because even though I read the entire thread I made some mistakes. :wallbash:

1) Make sure you let it cool first. I sprayed myself with hot coolant and that wasn't fun.
2) I decided to cut the longer stock line and just put a coupler between the two stock tubes over next to the alternator toward the passenger side. It just seemed to make more sense to do this, especially if you know you won't need to go back to stock configuration.
3) With that said you definitely want the 5/16" coupler for the stock hoses! I couldn't find one and went with 3/8". It is on but it is not as secure as I would like and I am going to be changing that as soon as I find a 5/16". The stock hose clamps barely go over the tube on the 3/8" coupler. I would definitely use screw type clamps with a 5/16" coupler though to get the best seal.
4) I had 3/8" rubber caps lying around so I put them on the throttle body holes and secured them with hose clamps. I was worried about corrosion inside the throttle body.
5) I don't think making the throttle body any cooler is necessary. By doing this mod the temp of the TB already drops nearly 100 degrees when driving around.

I
5) I don't think making the throttle body any cooler is necessary. By doing this mod the temp of the TB already drops nearly 100 degrees when driving around.


you said it's not necessary but you also said the temp drops by over 100 degrees, that HAS to be good for the incoming air... im kinda confused by that statement

He has no proof on temperture.

However I drove an hour from 80 degrees to 105. Then I joined the club meet and we went up the mountain. After anther hour we stopped and compared TB.

You can touch mine. We tried to toch the other throttle bodies. They were scalding hot. You touch you get burned. Difference is several degrees, 100, I don't know, but enough to make a huge difference.

I would say we get 1 1/2 HP or more from this. Plus a massive decrease in heat exhaustion, which means very little loss in power at extreme tempertures.

You can touch mine. We tried to toch the other throttle bodies. They were scalding hot. You touch you get burned. Difference is several degrees, 100, I don't know, but enough to make a huge difference.

I would say we get 1 1/2 HP or more from this. Plus a massive decrease in heat exhaustion, which means very little loss in power at extreme tempertures.

I agree the difference in temperature is amazing. 1.5HP that is not bad, not bad at all.

The point about further cooling is well taken - obviously, if you could cool it further, it would result in more "gains".

However, just filling the TB with a liquid (any liquid) is not going to help - full, empty, the body will be at the same temperature, if you think about it.

If there was a way to circulate a liquid that was cooler than ambient thru it, you would have further gain, but there isn't.

S

The point about further cooling is well taken - obviously, if you could cool it further, it would result in more "gains".

However, just filling the TB with a liquid (any liquid) is not going to help - full, empty, the body will be at the same temperature, if you think about it.

If there was a way to circulate a liquid that was cooler than ambient thru it, you would have further gain, but there isn't.

S


sure there is -- would just require extensive modification, long story short maybe tapping the AC line and circulating the refrigerant thru the throttle body so the air would pass thru a 40 degree surface before entering the engine... but all the trouble and problems this would cause wouldnt be worth it im assuming because honestly how much gain is there to be had by passing air thru a cold chamber for the smallest fraction of a second.

would the TB see any corrosion w/o any coolant running through it???
would simply filling it w/ coolant would defenitely be worthless???

if you had just straight water sitting in the TB, im sure it would start corroding, I capped off the top metal nipple with a little rubber cap to make sure nothing gets down in there. The other end I left open just because it's such a pain in the ass to get to. I'm not that worried about it, any moisture that MIGHT be in there would easily be evaporated off with the really hot engine bay temps.

thanks. i'm capped at both top & bottom... so, i guess i'm good to go...

Glenn (Razz1) came over to my house the other night and helped me perform this mod as well as the oil bypass mod and the difference is noticable. Espeacilly after I performed the oil mod. I would definitely recommend performing both of these updates as I am very happy that I did this..

Thankx again for your help Glenn. These are great mods that everyone should do to their car.

oil mod??? turbo??

beers :beer:

The breather at the oil hose exit....

The breather at the oil hose exit....

got it... i thought i missed something..

thx.

beers :beer:

What are you folks using to cap the hole in the intake accordian tubing with?

What are you folks using to cap the hole in the intake accordian tubing with?

a 3/8" rubber cap
found at any autoparts

I also used some bonding silicon adhesive on all three of my caps.

glad to see everyone is enjoying both of these mods... i know i am!
it's really made a difference in these miami temps...

I changed the oil on my 2005 Ford Explorer 4X4 today. While I was under the hood I checked out the throttle body. The 4.0L V6 engine does not have any coolant lines attached to the throttle body.

What are you folks using to cap the hole in the intake accordian tubing with?


I found a package with about 20 rubber nipple caps of various colors at O'Reilly's auto parts. Believed they were made by Moroso, so you will probably get 5-10 extra horsepower by using them! :)

Has anyone tried introducing a valve switch in the feed line as was mentioned above? I would love this mod for 90 degree track days, but probably need the warming in winter here. Has it been confirmed that the bottom line is the feed?

So why do people think the RX-8 needs to have hot coolant pumped through it in cold climates when the Ford Explorer's throttle body does not have any hot coolant going throught it.

Maybe the Ford explorer gets all of its intake air from under the hood. I don't know.

I assume Mazda went to the trouble of routing coolant to the TB for a reason and with all the flooding issues, I don't want to have idle problems and stalling when starting out on winter mornings. Once the engine is warmed up and running at 800rpm, it may have issues with condensation and poor fuel mixing when sucking in air that is -15F.

My 300ZX's throttle bodies did not have coolant lines on them (1992 model) and I lived in New Hampshire with that car for ~ 3 years....never had an issue...and that car was a complete cold air intake system.

Also it is mentioned "Starting out on cold winter mornings"..you coolant is freezing cold then after sitting all night, thus your throttle body is -15F too.

Sorry RX8Maine....I too am trying to figure out why MAzda did this....

all I know is that I live in Dallas/Fort Worth, texas and right now we are hitting 106 degree temps in the daytime, it's hotter then german sheiza porn here (LoL)

I don't know if my butt could feel any improvements with the TB bypass mod but I'm happy i did it. With 106 degree temps the last thing I want is my intake air to run thru one more ring of scorching hot temps. I'm not worried about the winter time here, it gets cold but not super-freezing-ass cold.

^^ I'm hoping you don't actually know what "German sheise porn" is, because referring to it as "hot" is disturbing.:nono:

^^ I'm hoping you don't actually know what "German sheise porn" is, because referring to it as "hot" is disturbing.:nono:


oh but i DO know what german sheiza porn is... and it was more of a joke :-p

Its "sheise". If you use a "Z", it becomes "sheitza", which is something else.
Still disgusting....

Also it is mentioned "Starting out on cold winter mornings"..you coolant is freezing cold then after sitting all night, thus your throttle body is -15F too.


That's why I specifically referred to 800 rpms. That seems to be the slowest possible speed for the renesis to run smoothly when warm. It doesn't even try to turn that slowly until it has fully warmed up.

This mod is great on F-body's, the throttle body bypass is dynoed to get 6-8 hp on camaros and firebirds.

Just to add my 2 cents :mdrmed:

This mod is great on F-body's, the throttle body bypass is dynoed to get 6-8 hp on camaros and firebirds.

Just to add my 2 cents :mdrmed:

Cool, are those F-Body throttle bodies big like the RX8's? or larger?

i'm worried that it runs through the throttle body to cool it off when the motor gets really hot. The trottle body is close to the intake manifold. I live in the maritimes so i don't know how it would affect my 8.

The engine bay definately heats up the throttle body as well, a lot, why not take a tube (bigger than 3/8" to get flow volume)with a horn or flare at the front, to the front of the car and catch the (still warm but much cooler than engine bay temperatures) air and just let it blow trough the body and out again, just loose pipe down to ground. Then it works as a small forced induction idea forcing cooler air from front through body, the faster you go the better it works. Then with startup it wont change any thing.

cost will also be very small

worth the try, I will do it some time.

Philip

One thought on this mod. Like mentioned before, the coolant is cold on startup so making the mod probably does not effect that, sooo, why the coolant through the TB after it warms up? Ever heard of carburater freeze or venturi freeze? I don't know if it is the same on TBs but I imagine when the TB is partially closed the air is constricted forcing it to speed up. This reduces the air temp at that point and during mild conditions, that is, not 0 degrees but like around 30s, 40s, the moisture in the air can freeze to the TB or venturi. Had it happen once in my carburated car and had to pull over and wiat for the ice to melt. Carb heat, where heated air from a heat exchanger off of the exhaust, is common on aircraft for that reason. Why would it go through all of the time, maybe it is a cheap version instead of having to add it to programming and add extra moving parts. The car has to be a great value for what you get for a reason.

No gas in an EFI TB, so no venturi. Therefor, no icing.
Plus, no IAC valve like the OBD-II cars, so no wax ball or something similar to soften.
Its just a brass butterfly and nothing else.

Still, there is no real benefit to this mod since the IM is plastic.

A possible thought. Could the coolant through the throttle body be for emissions purposes.

Constant air temperature to easily control emissions via the ECU over all ranges of outside temperatures and acceleration changes.

MM,

When the throttle is "shut" at idle, there is a big pressure drop across the throttle plate. 20-ish inches of Hg, right?

This is a big enough change in pressure to cause water to condense and freeze in some very specific cases. I agree it's a rare case, but the engineers have to design for the rare corner cases too.

As for using the water to keep the air the same temp, two problems here:

The MAF is what cares about air temp and it has it's own temp sensor and it's in front of the TB

Look at the size of the water hose going to the TB. No way you can flow enough water into here to heat up the couple hundred CFM that the engine sucks in.

To add a little tidbit of info on this mod, the coolant flow through the TB is to prevent any icing in the throttle body. it will help on any car but you could (and I mean probbly not ever) but could get some icing under the right conditions.

...I was looking at my engine bay and I followed both hoses. the hose coming from the top of the TB led to the H2O pump area and the other one to block/housing by the firewall. now, I'm thinking about removing the 2 hoses and plugging the corresponding holes (water pump & block/housing). has anybody done this? I'm guessing that you won't need to circulate coolant any more since you are not trying to heat/cool the TB anymore and I don't think plugging the said holes is gonna hinder anything... any thoughts?

To add a little tidbit of info on this mod, the coolant flow through the TB is to prevent any icing in the throttle body. it will help on any car but you could (and I mean probbly not ever) but could get some icing under the right conditions.

Correct, I would not suggest this mod for those who live in northern climates, your throttle may ice up & stick open.

I also used some bonding silicon adhesive on all three of my caps.Three? Where are the three?
I removed the 2 hoses that connect to the throttle body, and connected them together.
That leaves me w/ two caps to cover. Did I miss something?

They are confusing the two coolant lines for the three air lines in the intake bellows.
I gave up on this thread a while ago...

OK, I think I get it now.
davefzr did the throttle body mod and he added a breather for his oil line.
He had 2 caps from the throttle body, but because he did the breather, he was left w/ a hole in the intake bellow.
I don't have to worry about that 3rd hole because I added a oil catch can instead.

OK, I think I get it now.
davefzr did the throttle body mod and he added a breather for his oil line.
He had 2 caps from the throttle body, but because he did the breather, he was left w/ a hole in the intake bellow.
I don't have to worry about that 3rd hole because I added a oil catch can instead.^what he said...

so instead of re-connecting the coolant lines, I capped the two coolant outlet/inlet using a rubber bypass plug and a clamp. I don't know if it's gonna be enough to withstand the heat and pressure tho'...

so instead of re-connecting the coolant lines, I capped the two coolant outlet/inlet using a rubber bypass plug and a clamp. I don't know if it's gonna be enough to withstand the heat and pressure tho'...I think that's a better option if you're not worried about going back to stock.
I didn't do it since I still have a little time left on my warranty. I might go back if they come out with another flash/recall.
Reaching those outlets doesn't look easy though.

I think that's a better option if you're not worried about going back to stock.
I didn't do it since I still have a little time left on my warranty. I might go back if they come out with another flash/recall.
Reaching those outlets doesn't look easy though.

hahaha! no it's not... unless you have super kinny arm, it's next to impossible for you to remove the clamp, pull the hose, install the plug and re-clamp it. I bouhgt a monkey and trained it to do it for me :mdrmed:

^^^^ yeah no f@ckin joke @ all.........So after seeing my intake temps reach 100+ on a 70 degree day I decided to go on ahead and try out this mod, it is beyond a PIA to get to that coolant hose on the bottom of the throttle body even w/intake removed...I ended up just cutting the damn hose...

This DIY needs more pictures. A number of people have come up with some alternate concepts, but have not said what the results were or showed pics.

yes please more pictures and detailed description. Ive been wanting to do this myself for months, but the pictures for the install are no good! Anybody wanna help on this?

yes please more pictures and detailed description. Ive been wanting to do this myself for months, but the pictures for the install are no good! Anybody wanna help on this?

Already done:

http://rotaryinsider.com/rx8-59.html

^^^Nice write up. I found that removing the throttle body(4 x 10mm nuts) all together made this task much easier. While I was at, I clean that bugger cause it was coated in black, gunky stuff. It removes easily with some carb cleaner and a rag.

it was all like you said... but i spilled some antifreeze when i disconected the hose. Should have relesed the prechure...

I just did this mod today........however I used the stock clamp for the bottom clamp since i sucked too bad to reach down there anyways............do you think it would come undone? I'm kinda scared..........

I re-did this a few weeks ago when I drained my coolant and installed the Sohn OMP adaptor. but instead of connecting the coolant lines together, I capped both outlets with arubber vacuum cap and a hose clamp. I removed the upper intake manifold to gain access to the one by the firewall. I'm not worried about the rubber bursting under pressure since I'm using evans NPG-R.

I just re-routed my coolant to the flux capacitor !!! :rollingla

Just to clear up the reason why some manufactures run coolant through the throttle body. It is for emissions, The same reason cars run a min 195 degree thermostat. The less dense air means less fuel, less fuel means more complete fuel mixture burns. More complete fuel mixture burns mean less emissions coming from the tail pipe. For those that don't know, the rotary engine was always bad on fuel mileage and emissions, Emissions was the reason the RX-7 was not sold here for years. If you take the coolant out of the throttle body it is kinda like the old trick of putting a lower thermostat in, Colder air=dense air. Dense air=more air, More air=more fuel, more fuel=more power. more fuel also = less mpg, more emissions. So please stop with the stupid BS of icing T-body plates.

Just to clear up the reason why some manufactures run coolant through the throttle body. It is for emissions, The same reason cars run a min 195 degree thermostat. The less dense air means less fuel, less fuel means more complete fuel mixture burns. More complete fuel mixture burns mean less emissions coming from the tail pipe. For those that don't know, the rotary engine was always bad on fuel mileage and emissions, Emissions was the reason the RX-7 was not sold here for years. If you take the coolant out of the throttle body it is kinda like the old trick of putting a lower thermostat in, Colder air=dense air. Dense air=more air, More air=more fuel, more fuel=more power. more fuel also = less mpg, more emissions. So please stop with the stupid BS of icing T-body plates.

As someone previously noted, the amount of heat transfer from a small coolant line into hundreds of CFM of air is minimal. They are not trying to heat the air, they are trying to warm the throttle body. To begin with, the shape of the throttle body does not promote efficient heat transfer into the air. Does not make sense as an emmissions measure either. The fuel/air ratio is precisely controlled by the ECU. Trying to create a leaner mixture by such an imprecise method as running coolant through the throttle body, makes no sense when the ECU already controls the mixture precisely. And, btw, would immediately compensate for any minor heating the throttle body heating would do. And also consider that the engineers deliberately designed a fresh-air intake -- for the express purpose of getting COLDER/DENSER air into the engine! The effect of the VFAD on intake temperature easily outweighs the effect of throttle body heating by a factor of a thousand times. And, limiting power as you suggest, even if it worked that way, would not limit emmissions. The driver would just push down the pedal a bit more to get the desired power.

Before you call BS on the icing issue, take time to read some of the references.

Yep - emissions reasons are BS. Higher combustion temps yeild higher emissions (well, NOx / SOx anyway, CO comes down with combustion temp...). Read any combustion textbook. Also, absolutely not enough heat transfer area to conduct heat to the air (the TB is not designed like a radiator). The "coolant" was there to keep the TB hot.

It took you guys 2 years to come up wityh this BS. It is emissions related, ask anyone with a history in Vehicle performance.... Sorry im just a Master Technician, i have no idea what im talking about. Collage training, Factory training and accually working on cars everyday shouldnt make my opinion any more valid, Just the simple fact that I understand how a car works does. But if you guys want to debate it for another couple of years go ahead, I find it amusing.

It took you guys 2 years to come up wityh this BS. It is emissions related, ask anyone with a history in Vehicle performance.... Sorry im just a Master Technician, i have no idea what im talking about. Collage training, Factory training and accually working on cars everyday shouldnt make my opinion any more valid, Just the simple fact that I understand how a car works does. But if you guys want to debate it for another couple of years go ahead, I find it amusing.

The days of carburetted engines are long gone. There is only one reason for the coolant going through the throttle body these days - it's to prevent the throttle body being blocked due to a mix of condensation, humidity and cold temperatures.

Carburation? No one said anything about a carb. Anyway, Ill let you all debate on this for another couple of years. I stand by my explaination, because it is right. By the way the heat of the engine compartment would thaw out a throttle body if it was to freeze anyway, but they dont. Thats just ignorance.

Here's an alternative explanation of what the coolant line may be for -- activation of the FIAV (fast idle air valve). I don't know if this has been mentioned. I will still stand by my assertion that the purpose is NOT to warm the incoming air, because that is just physically impossible given the amount of flow and the surfaces involved.

Anyway, this FIAV thing makes a lot of sense.

http://www.stealth316.com/2-3s-tb.htm

So, it would seem that blocking the line isn't going to give you performance boost, but might give you idle problems.

What say you, Master Technician? ;)

That's for Piston engines. Our's is controlled by the ECU.

Just to clear up the reason why some manufactures run coolant through the throttle body. It is for emissions, The same reason cars run a min 195 degree thermostat. The less dense air means less fuel, less fuel means more complete fuel mixture burns. More complete fuel mixture burns mean less emissions coming from the tail pipe. For those that don't know, the rotary engine was always bad on fuel mileage and emissions, Emissions was the reason the RX-7 was not sold here for years. If you take the coolant out of the throttle body it is kinda like the old trick of putting a lower thermostat in, Colder air=dense air. Dense air=more air, More air=more fuel, more fuel=more power. more fuel also = less mpg, more emissions. So please stop with the stupid BS of icing T-body plates.
that makes more sense than anything else cause the car is not always sold in old climax and there is no way the throttle is going to freeze here in florida

all cars are controled by ecu or pcm now. fuel injection requires a computer. Aisian auto manufactures are big on coolant heating the incoming air charge by heating the throttle body. this is an easy inexpensive way to save on fuel milage and to help with emissions. idle air valve is controled by a stepper motor ever heard of an IAC? it is PCM controled the pcm uses IAT, MAF, ETC, O2 sensors to adjust the fuel injector pulse width to be as lean as possible without causing damage and keep idle up. The RX-7 used 40% more fuel at idle then the 8, and the 8 get crap for gas milage, so anything will help. Its not hard to understand if you think about it. Im not guessing here by the way like most of you guys.

And by the way if your thottle body freezes up the car wont even start, so the cold coolant wont be able to warm up to thaw out your "frozen" throttle body. Another thing if you have a problem with water getting on the throttle body where it could possibly freeze you have worse problems than just a frozen throttle body. The reason airplanes used this is because in upper atmosphere things are cold, especially traveling a couple hundred MPH or so, plus there is alot of condensation in the air up there so things can freeze. Like i said use your brain its common sense people.

Throttle bodies don't "freeze up". That is a carburettor behavior because of the presence of fuel. Since there is no significant drop in temperature across the TB (venturi effect), the only real reason for heating the intake charge is emissions.
Also, the RX-8 doesn't have an IAC.

Nubo-
Here's an alternative explanation of what the coolant line may be for -- activation of the FIAV (fast idle air valve). I don't know if this has been mentioned. I will still stand by my assertion that the purpose is NOT to warm the incoming air, because that is just physically impossible given the amount of flow and the surfaces involved.

Anyway, this FIAV thing makes a lot of sense.
http://www.stealth316.com/2-3s-tb.htm

So, it would seem that blocking the line isn't going to give you performance boost, but might give you idle problems.

What say you, Master Technician?


all cars are controled by ecu or pcm now. fuel injection requires a computer. Aisian auto manufactures are big on coolant heating the incoming air charge by heating the throttle body. this is an easy inexpensive way to save on fuel milage and to help with emissions. idle air valve is controled by a stepper motor ever heard of an IAC? it is PCM controled the pcm uses IAT, MAF, ETC, O2 sensors to adjust the fuel injector pulse width to be as lean as possible without causing damage and keep idle up. The RX-7 used 40% more fuel at idle then the 8, and the 8 get crap for gas milage, so anything will help. Its not hard to understand if you think about it. Im not guessing here by the way like most of you guys.



all cars are controled by ecu or pcm now. fuel injection requires a computer. Aisian auto manufactures are big on coolant heating the incoming air charge by heating the throttle body. this is an easy inexpensive way to save on fuel milage and to help with emissions. idle air valve is controled by a stepper motor ever heard of an IAC? it is PCM controled the pcm uses IAT, MAF, ETC, O2 sensors to adjust the fuel injector pulse width to be as lean as possible without causing damage and keep idle up. The RX-7 used 40% more fuel at idle then the 8, and the 8 get crap for gas milage, so anything will help. Its not hard to understand if you think about it. Im not guessing here by the way like most of you guys.


So if the "theory" of what RxJaye and Nubo are saying are correct than...

1. Would you not see a difference in idle rpm after the throttle mod?

2. Also, would you not see an overall difference in gas usage before and after this mod?

Since a number of people have done this mod, they can give information about the above 2.

Everyone that has done this mod, what do you think?

So if the "theory" of what RxJaye and Nubo are saying are correct than...

1. Would you not see a difference in idle rpm after the throttle mod?

2. Also, would you not see an overall difference in gas usage before and after this mod?

Since a number of people have done this mod, they can give information about the above 2.

Everyone that has done this mod, what do you think?

1. No decernable difference
2. No difference

I forget the Rx8 has ETC and doesnt need IAC for idle. But you should have no idle issues since it is pcm controlled. There will be fuel milage concerns but very minute. More noticable if you put a lower thermostat in.

can someone point me to where the bottom hose is again? if I'm facing the engine, is it the one kinda' buried beneath the throttle body to the left a litte? Obviously the top was a piece of cake, just want to make sure I'm yanking the correct hose from the bottom. (pretty sure I may have the right one, it's the only one connected and has the same heat blanket type covering as the top, just would like to verify first) Thanks!!

can someone point me to where the bottom hose is again? if I'm facing the engine, is it the one kinda' buried beneath the throttle body to the left a litte? Obviously the top was a piece of cake, just want to make sure I'm yanking the correct hose from the bottom. (pretty sure I may have the right one, it's the only one connected and has the same heat blanket type covering as the top, just would like to verify first) Thanks!!

I would tell you to search, but you're already posting in the thread with the info you seek.. so I guess I'll point you to the right post ... on this very page:

http://www.rx8club.com/showpost.php?p=1785177&postcount=121

kickass, I had the right one, just making sure :) car's too hot to play anyway, so I'll be finishing this up this evening, thanks again :thumbup:

Has it really gotten so bad that people ask for direction in an existing thread that already has ALL of the answers?
I've run into this a couple of times this week already and its frightening.
Is it something in the water?
It is bad enough when newbs post new threads about obviously available stuff, but for an established forum member to screw up that bad means there is something else at play.

Maybe its just hand-holding...

don't worry so much, even if you pick the wrong one, what's the worse that could happen? :)

Throttle bodies don't "freeze up". That is a carburettor behavior because of the presence of fuel. Since there is no significant drop in temperature across the TB (venturi effect), the only real reason for heating the intake charge is emissions.
Also, the RX-8 doesn't have an IAC.

Throttle bodies can ice up. Just let some air out of a dive tank and see how cold the valve can get. Carburetors are more likely to experience icing because the phase change from liquid to gas takes heat energy out of the surrounding air in addition to venturi cooling. Fuel injected aircraft have "alternate air for freezing tb and air filters. As mentioned many times, the drop in pressure also causes a drop in temperature. This is most likely to occur at lower power settings at temps just above freezing. Most jet engines have a limitation that states " if the static air temperature is 8 degrees C, or less, in visible moisture, Cowl anti icing must
be turned on." There is no fuel any near the cowl(intake) of a jet engine. It is less likely to occur in a car since throttle position is constantly changing. Aircraft throttle plates tend to be set and stay there for a long period of time. I have had a piston engine develop ice. It got my attention as the engine sputtered as it swallowed chunks of Ice. The outside temp over Miami was about 5 C at 10,000 ft.

I wouldn't worry about it in our cars since they are at wide open throttle on a regular basis.

MM, To answer your question about all of the "dumb" questions lately, It's the heat causing the "dumbness"...around here..

as for Mr Corbitts comments: I had a Bug whose carb would ice over. That was in Chicago with humidity. I rarely get to WOT the car. I run out of road too quickly.

The majority of us that did this mod live in hot arid environments.
I see intake temp of 120-170 degrees and coolant temps of 205-212.

just trying to keep as much heat out of the intake air that I can.

Throttle bodies can ice up. Just let some air out of a dive tank and see how cold the valve can get.

Now, scale the manifold of a dive bottle up to the volume of an automotive throttle body and calculate how much flow is happening there.

I doubt any normal driving scenario will yield a 3000 PSI difference across the TB.
That would be one hell of a turbo.

It is bad enough when newbs post new threads about obviously available stuff, but for an established forum member to screw up that bad means there is something else at play.

or maybe I've never done this type of mod before, have no clue which hose, and couldn't tell from the pics I was looking at. thanks for the help, much appreciated :rolleyes:

^^^ BTW it is easier to unplug the stepper motor and remove the TB to take the bottom hose off. Use a 10mm socket for the 4 bolts.

To clean up the engine bay I went so as to remove one of the hoses.
The hose that was removed was the one that connects to the rear rotor end place (iron).

Take the front one that connects to the coolant inlet ( follow the hose back to where it connects) and attach it to where the rear was connected.

While doing this you will spill coolant on the block. If you don't want the smell when the car warms up, use some rags. Don't forget to remove them.
I'll have to post pics sometime.

I got it done no problem, although i had the worst luck with dropping stuff into the engine bay last night while working on it which added about 20 minutes to a 5 minute job :banghead:

Reading this with interest... the post that got me here was from "Old Rotor" and he claims that this simple mod allows him to run 87 in warm/hot weather.
http://www.rx8club.com/showthread.php?t=121249
This info seems ignored in this thread but it might be used for the final explanation... if there is one.
My car has identical issues with Old Rotor, hence I'll do this DIY asap... and hope for the same happy ending ;o)

Would there be any way at all this mod could have a possible,remote,other-wordly effect on gas mileage? I noticed after doing this and prior to my engine being swapped that after doing this mod I gained about 60 extra miles out a single gas tank. I was averaging about 200-210, after doing this (and nothing else) I'm now sitting at 210 with over a 1/4 tank left. This is also the case with the new engine but I suspect that may be because it's new :dunno: I do have an AEM intake installed as well, but it's benn on there a long time and as I mentioned, nothing else had changed when I originally noticed the improvement.

Not too likely.....

The mod might affect the IAT but it is after the air has been measured, and the fuel is already dialed-in - so too late to effect the ratio.

S

that's what I figured, just trying to figure out why my car has suddenly started to get better mileage, and this is the only thing that has changed....weird. :eek:

^^^I read somewhere on this forum, that warmer weather = better mileage and that cooler weather = more power. Maybe that explains it....but probably the explanation lies with your right foot!

lol, a 1/4 fuel tank indicator could actually mean almost empty from what I've seen so far, it's definitely not linear many times

I just did this mod...took about 30 minutes...I only had a coupler, 1/4 and used the original clamps...I also had a 3/8's but i just couldn't get it to fit in all the way...I just pushed the lines under the throttle body and then capped the nipples on the throttle body with some vacuum caps I had laying around

Does coolant come out when you disconnect the hose?

Yes, coolant comes out when you disconnect the hose.

And as 09 says, dry it up if you don't want to smell it for a while. For a couple of days I was inspecting for leaks due to the smell.

I did both this change and the MazSport fan control. No leaks yet.

Further photos for those that may need them.

First shot is upper throttle body with coolant port capped and clamped.

Second shot is where I trimmed back the coolant lines and looped them into each other. They are at the red wire tie binding the rubber hoses together. I only trimmed back the upper hose, which I retained on the off chance I move to cold county.

The third shot shows how I routed the wiring for the relays to the MazSport fan controllers. I routed them across the tower brace and in through the existing entry into the fuse box, as opposed to across the front of the car and into a new hole MazSort suggested.

And don't mind the dirt it has been a little dusty here lately.

Jeff, Between the TB mod and the Fan mod any noticeable changes?
Like , Throt response, takeoff from stoplights...

Quick update - I did the mod using the screw, and my pinging on 87 gas is gone, just like "Old Rotor" mentioned... The only explanation I can think of is turbulent flow of coolant is not possible anymore, and that would have been the cause for the noise.
Monitoring coolant temps: 95 to 102C, depending of driving style and ambient temps.

I found the link that MM posted great!
http://rotaryinsider.com/rx8-59.html

But can someone tell me where I can find the the bottom TB hose in the first pic so I can trace it to the bottom of the TB?
I'm pointing to the top hose right?

http://img352.imageshack.us/img352/9755/p8270823ks2.jpg

This is the top hose right?

http://img166.imageshack.us/img166/9950/p8270822ou2.jpg

Gos to the top of the TB

http://img166.imageshack.us/img166/2982/p8270824xu1.jpg

But I can't find where to trace the bottom hose so I can use the 5/16" barb and hose clamps

Thanks,
-Gil

You didn't remove the intake tube. Things become much clearer once you take that off. You also can get by without cutting the hose in case you want to put it back on in the winter. In THIS (http://www.rx8club.com/attachment.php?attachmentid=105316&d=1186341710)photo you can see the TB hose next to the oil fill tube.

Thanks bro I'll do that. I'm on my way to homedepot now to buy my parts and will post pic's in a bit :)

OK I just got back from homedepot and they don't have any 5/16'' barbs so I got a 1/4'' and a 1/8'' brass pipe nipple. Think these are too small?
I should have went to lowes

it's hard to find the correct size. You can get one size too big and jam that sucker in deep enough that it can't leak.

Still working on it. Eating dinner now. I'll post pic's when its fin.

Wow it was not that hard at all. E.T.; was about 20min. Looks kinda funny but oh well. I did not cut the hoses so if I need to undo this mod I can still put it back :)

Don't think you guys need pix but if you do let me know and the 1/8'' brass pipe nipple worked great!

I found the correct 5/16" barb at Ace hardware. The local Home Despot didn't have that size. Not even a hook for it.

Dave, didn't see your post earlier. This change seemed to help hot weather drivability. I mean better idle, and better throttle response on those really hot days.

For those that live in colder country, can you tell me how cold it needs to get before putting this back in place is a good idea? In case I take my 8 on the road in the winter.

+1^
I parked in the shade cars temp was showing 101 and did not move. Also the fans where not running as hard and no bog down on rpms well parked with the A/C on.
Temps are way down now that I have don this mod and A/C was on for the rest of the day for the drive home. Have not had a day like this for a long time. I norm dont drive with the A/C on but my temps where not going over 118 like befor! Also seams to cool down way faster.
I recomend every one in the hot are of the us do this mod.
http://img504.imageshack.us/img504/2466/p8280839bq3.jpg
:)

Forgive me if this is a stupid question, (and I fear that it is, but don't know any better so I must ask):

If I were to install the Mazdaspeed CAI, is this mod something that can/should still be done? (Probably at the same time I'm doing the CAI, right?)

I bought the MS CAI, but haven't installed it yet. (Just moved and my garage is totally trashed). Just not sure if putting the CAI in changes anything. We have just moved to Mississippi, and it's REALLY hot here. Thinking this would be good for me if it is still viable with the MS CAI.

Thanks to anyone who can offer some advice. Does anyone here have the MS CAI who's done this? Any feedback?

Take care, everyone, and thanks again.

Michael

The MS CAI will just replace your stock air box.

This mod will help keep your TB cooler IMO, and it takes about 5 min to do.
If you know your 8 (and I know mine) you will feel a jump on the gas peddle :) also keeps your car cooler IMO. My fans don't come on and off and on and off like befor, but run at a nor pace then high when need to. Also when useing AC and comeing to a light or stop, no bog down on RPM's or jumping odd idle that every one states is nor when AC in on.

The MS CAI will just replace your stock air box.

This mod will help keep your TB cooler IMO, and it takes about 5 min to do.
If you know your 8 (and I know mine) you will feel a jump on the gas peddle :) also keeps your car cooler IMO. My fans don't come on and off and on and off like befor, but run at a nor pace then high when need to. Also when useing AC and comeing to a light or stop, no bog down on RPM's or jumping odd idle that every one states is nor when AC in on.

Dominion,

Thanks for the reply. I'm sort of too far down that road at this point, as I've purchased the MS CAI recently (don't remember what I paid, but it wasn't cheap at all). I was just wondering if I could do this mod along with putting in the CAI.

Michael :)

Yes you can.

I actually just did this "mod" today... With the temperature's in Houston being 90 + humid, I feel heat soak as soon as I start the engine. Once I did it I felt stupid for not doing it first though...

I could ~kinda~ feel it, nothing spectacular but the air just "feels" a little cooler than what it used too be. I wanna say most of this is fault too that K&N intake. If I'm not moving, than the RB duct isn't doing anything and my engine gets too breath it's heat.

would this mod being acceptable in maryland? we definitely have our hot days (and i suppose MM did this while still living in md.) but we also have days that can hit 20F in the winter.

with fall, days away and many temps dropping to record lows so early in the season... I ask at what outside temp should the bypass be changed back to avoid condensation or other problems?Any suggestions or what have some of you others done since doing this mod when temps fall off?

i couldn't resist any longer. a mod that costs $10 dollars and will alleviate my sluggish throttle response after extended driving, how could i pass that up?!

purchased the 5/16 barb and hose clamps from local ace hardware. got the vacuum caps at pep boys, they didn't have the set of 3 black 5/16 caps so i had to buy the assorted version so i have white 5/16 caps booyah! +50hp for white vacuum caps.

in my infinite wisdom when i was putting the throttle body back on i overtorqued one of the (4) 10mm bolts and the end of the bolt snapped off. so now i have 3 bolts holding the throttle body to intake manifold. should i be worried about this? im really scared about using traditional screw extractor because the diameter of the bolt is not too big already, i only have 1 drill bit thats smaller than the bolt. i took it for a short test drive and everything seemed fine.

ill post again after i do some extended driving....i beat my poor 8 to from OC to LA quite alot so ill see how it fares under those conditions.

Sorry im just a Master Technician, i have no idea what im talking about. Collage training,and accually working on cars everyday shouldnt make my opinion any more valid, does.

Guess you did not have any spelling training? At even at COLLAGE? no ACCUALLY training either?

I believe the coolant line is there for more than one reason. My 91 Nissan 240SX also has the same setup, sadly it runs longer though the intake manifold, not just the throttle body so it cannot be removed w/o fabbing a custom manifold.

The reason it is there is probably to keep the thottle body within certain temp range while the vehicle is in operation. NOT to warm it up on cold weather starts. With the coolant running though the throttle (which has electrical and plastic parts) it is certain to be within the coolant temp range and NOT too HOT because of the weather or heat from the engine bay. It sure won't keep the throttle body cold but it will also prevent too much heat from being trapped in the throttle body at certain rare conditions.

I believe the coolant line is there for more than one reason. My 91 Nissan 240SX also has the same setup, sadly it runs longer though the intake manifold, not just the throttle body so it cannot be removed w/o fabbing a custom manifold.

The reason it is there is probably to keep the thottle body within certain temp range while the vehicle is in operation. NOT to warm it up on cold weather starts. With the coolant running though the throttle (which has electrical and plastic parts) it is certain to be within the coolant temp range and NOT too HOT because of the weather or heat from the engine bay. It sure won't keep the throttle body cold but it will also prevent too much heat from being trapped in the throttle body at certain rare conditions.

It is there to prevent Icing. "Carburetor Icing" can occur at temps as high as 70F. Unlike aircraft, cars are at partial throttle 90% of the time. This is when the greatest chance of icing can occur.

There's no Carb in the 91 240SX nor RX-8. With the engine running there's much less chance of the throttle freezing up even in snow fall.

It is there to prevent Icing. "Carburetor Icing" can occur at temps as high as 70F. Unlike aircraft, cars are at partial throttle 90% of the time. This is when the greatest chance of icing can occur.

"Carburetor Icing" cannot occur in an FI throttlebody.
FI TBs are not designed to create the venturi effect needed to atomize fuel, which is the cause of icing.
It has nothing to do with temperature directly, but the dewpoint and air velocity changes across surfaces cooled by fuel.

"Carburetor Icing" cannot occur in an FI throttlebody.
FI TBs are not designed to create the venturi effect needed to atomize fuel, which is the cause of icing.
It has nothing to do with temperature directly, but the dewpoint and air velocity changes across surfaces cooled by fuel.

"carburetor Icing" is a term. Fuel injected piston aircraft engines have an "alternate air" intake which takes warm air from the engine compartment to melt ice that forms in the throttle body. it also bypasses the air filter which can ice over in the right conditions.
Venturi Icing can occur in your throttle body if it is not heated. With the butterfly valve mostly closed you have a vacuum on one side. The air traveling from a region of high pressure to a region of low pressure will remove heat energy from the air. This is the principle of your a/c system. (vapor cycle machine) Large aircraft use an air cycle machine which is a glorified turbo. It is not uncommon on a 95F day to have ice rattling in the duct. Jet engines require the intake of the engine to be heated when there is visible moisture and the temp is at 8C or colder. Otherwise icing can occur on that large opening.

p.s. Bernoulli's law P1V1/T1=P2V2/T2

P=Pressure, V=Volume, T=Temperature

Very nice. Good homework. Nice formulae.

The TB on the RX-8 will not ice. It doesn't matter what the dew point is.
Try it some time.
The RX-8, as great as it is, is NOT an airplane.

Thread Revival

I just did this mod.

Without cutting the tubing as Im in Montreal and it gets VERY cold.
I honnestly dont think it will affect anything at all, but just in case I left the full length there in case I want to return to stock.

I honnestly was quite impressed with the results.

Im not claiming any power or anything, but I definatly felt an engine/throttle response difference.

Decided to try out 87 Octane as my tank was almost empty and I had to gas up.
And still felt perfectly nice and smooth with 87 and it was quite hot out today.

All in all, cheap and easy.

p.s. for us canadians, in Montreal anyways, it took me 3 hours to find all the parts needed and 5 Canadian tires + a few home depots.

There is no such thing as a 5/16 male/male barb here. sheesh.
Ended up using 3/8, a bit big, but still fits.

Oh and one more thing, damn Canadian tires dont sell packs of the same vacum caps. They have a 4$ pack with ONE of every size. That meant I had to buy TWO packs at 4$ a pop, stoopid canucks eh ? :)

Side Effect Caused by this Mod

I did this mod the simple way that TeamRX8 suggested, with the screw inserted into the coolant hose and put back on (works great by the way). I did this mod last winter and all has been well, engine seemed more responsive and all.

Here is the problem - on very hot days this summer after driving about 1.5 hours (I have a long commute), I noticed my car kept going into limp mode from detonation issues and I could not figure out why. I kept thinking all the traditional things, but what this wound up being, was this mod - let me explain.

I noticed that in the winter through not too hot months, the Throttle Body (TB) was actually cooler by having the coolant flow stopped. But on very hot days after long drives, the TB was getting extremely hot, even with my hood vent mod in place to keep the underhood temps down. This got me thinking, could it be this mod?

When I removed the screw and allowed the coolant to flow again, on many very hot days that I have driven since restoring the coolant flow, this detonation issue causing engine hesitation has NOT happened again (all the while running the same premium fuel and MMO premix)

What I have surmised, is that on very hot days and long drives, the coolant actually keep the TB cooler than it would be otherwise (although it does the opposite on cooler days), and thus it is heating the air entering the engine too much causing detonation issues.

If you live in a hot climate and/or are having detonation issues in hot weather and have this mod, you may want to reverse this mod to see if it cures the issue.

One last thing, if you use Team's method (it takes 30 second to put in and 30 seconds to remove) instead of permanently moving your hose configuration, this is easy to put in place for most of the year (cooler months) and removing during the hot months.

Hopefully this will helps others that may have come across the same issue.

bump

I just did this mod. I've done it on every car I've owned since the late 80's. I live in a warm climate so I'm not worried about any problems with it. I perused this thread so forgive me if what I'm saying has already been said.

Do this when the engine is cold. Open the radiator cap to make sure there isn't any pressure in the system then put the cap back on. For those who had difficulty with the bottom hose, there is no need to remove the TB. Once the airbox and accordian hose to the TB has been removed and a couple of wires unplugged you can view the lower hose connection to the TB. With a pair of needle nose pliers you can pinch and slide the spring hose clamp off the TB. Then with a large flat blade screw driver place the screwdriver blade vertically against the end of the lower hose where it butts against the TB and gently twist the screwdriver blade and push the hose to the left (viewed from the front) with the blade of the screwdriver till its off the barb. I didn't add any hose. When you disconnect the lower hose from the TB and its loose, you can pull it from behind the alternator. Just grab it on the passenger side behind the alternator and pull it through. Then you have enough slack to connect it with a male/male hose barb to the other hose now off the top of the TB. Run the engine till warm and check for leaks, the new connection is now more readily visible since its out where you can see it. The whole thing took about 30 minutes.

just did it, very easy.

did a little research, mazda didnt do this for cold starts or engine warm up at all. Almost every manufacturer has to do this for emissions, unless the car is ulev before hand.
warmer air entering into the combustion chamber makes for a more fulfilled flame front propagation.......so at low RPMs this helps maintain emissions. but if your like me and constantly stay above 3g then flame front is no issue. just like high idle at cold start to get the cat to warm up faster.

its all gov crap.

now keep in mind older cars did this for a completely different reason than emissions.

The best way to do this, is to actually unbolt the throttle body. Makes getting to the lower hose simple.

I was tracing the coolant lines for this. I can see the feed line coming off the thermostat tree on the passenger side front, but trying to trace the line going back to the block is tough. It looks like it is the line right next to the rear engine lift point on the passenger side also. Is that correct?

I'd like to make just one hose with no bard/clamp fittings to worry about leaking.

You are right - gonna have to take the UIM off to get a real clean shot at the rear one.

On Nesters 8 - I capped them - didn't seem to cause any problems.

I was tracing the coolant lines for this. I can see the feed line coming off the thermostat tree on the passenger side front, but trying to trace the line going back to the block is tough. It looks like it is the line right next to the rear engine lift point on the passenger side also. Is that correct?

I'd like to make just one hose with no bard/clamp fittings to worry about leaking.

Yes, the other By Pass Hose goes on the rear Rotor (iron) Housing on the Passenger side like you said, so really you need a relatively short hose to join the two points.

You could probably use (cut) one of the two original hoses to make a neat fit.

Please let us know.

Ash

Please let us know.

Ash


Will do. I might do Kane's method and just cap them off, unless there is a benefit from sending coolant to the rear iron? Might be next weekend though, still have to swap brake pads and fix my clutch bracket in time for my track day coming up. I was thinking it would be bad to blow the coolant lines, where I patched them together with hose clamps, while on the track.

Ok so long story short does/ Would this void or have a possiblity of voiding our 8 year, 100K mile Powertrain Warranty??? Because I'm thinking about doing this Mod but I do NOT want to void that warranty. Heck with my Luck ill be needing a new engine in 20,000 miles lol

Ok so long story short does/ Would this void or have a possiblity of voiding our 8 year, 100K mile Powertrain Warranty??? Because I'm thinking about doing this Mod but I do NOT want to void that warranty. Heck with my Luck ill be needing a new engine in 20,000 miles lol

you do not have a 8 year 100k power train warranty.. power train on the 05 i think is 5 yr 60k miles.. could be just 4 / 50.

the 8 / 100 is the engine core alone..

as to the mod, i doubt anyone would notice, it is a very stealth mod.

beers :beer:

Right thats what I meant, not Powertrain dur... wow that made me sound like I know nothing about the car, lol alright man thanks :)

Side Effect Caused by this Mod

I did this mod the simple way that TeamRX8 suggested, with the screw inserted into the coolant hose and put back on (works great by the way). I did this mod last winter and all has been well, engine seemed more responsive and all.

Here is the problem - on very hot days this summer after driving about 1.5 hours (I have a long commute), I noticed my car kept going into limp mode from detonation issues and I could not figure out why. I kept thinking all the traditional things, but what this wound up being, was this mod - let me explain.

I noticed that in the winter through not too hot months, the Throttle Body (TB) was actually cooler by having the coolant flow stopped. But on very hot days after long drives, the TB was getting extremely hot, even with my hood vent mod in place to keep the underhood temps down. This got me thinking, could it be this mod?

When I removed the screw and allowed the coolant to flow again, on many very hot days that I have driven since restoring the coolant flow, this detonation issue causing engine hesitation has NOT happened again (all the while running the same premium fuel and MMO premix)

What I have surmised, is that on very hot days and long drives, the coolant actually keep the TB cooler than it would be otherwise (although it does the opposite on cooler days), and thus it is heating the air entering the engine too much causing detonation issues.

If you live in a hot climate and/or are having detonation issues in hot weather and have this mod, you may want to reverse this mod to see if it cures the issue.

One last thing, if you use Team's method (it takes 30 second to put in and 30 seconds to remove) instead of permanently moving your hose configuration, this is easy to put in place for most of the year (cooler months) and removing during the hot months.

Hopefully this will helps others that may have come across the same issue.

That's funny my tests show the TB to be cooler after driving long period of times.

Open hood touch TB. No mod you get burned. With mod almost but no burn.

Plus never had detenation on track days with TB mod.

So I did the throttle body bypass mod today and it is SIMPLE. But for those of you who are not so mechanically inclined here is a very detailed DIY (Make sure the coolant is cold and the car has been sitting for a while before doing this mod. Also you may want to remove the rad cap to release the pressure in the coolant system):

1. Remove top coolant hose from throttle body.
2. Remove the intake tubing and the 4 throttle body bolts.
3. Remove the wire harness on the throttle body and the last hose holding it to the car will be the bottom coolant line.
4. Remove the lower coolant line from the throttle body also.
5. You can then remove the throttle body and cap the coolant nipples. (Optional)

6. You can now pull the two coolant lines to the passenger (right) side of the alternater.
7. The top hose can be cut shorter so it fits nicely with the bottom coolant hose (about 6-7 inches cut off).
8. Now you can install the 5/16 brass barb into the lines along with the hose clamps.
9. You can then tuck the hose into a nice, out of the way, clean looking location.

hey i think this might be a dumb question but here goes...is it possible to bypass the maf sensor?.....


my car idle goes up and down i kinda sound like the timing is not right but if i take out the maf sensor and start it the car idles fine but i have to really rev it on the start up...

10. Replace the throttlebody and the intake tubing. Remember to hook up the wire harness and tighten the hose clamp on the intake tube. DO NOT tighten the throttle body bolts too much or you will strip them or even snap a head off!

This mod so far has not made any real noticable changes. Although this week has been cool and rainy up here on the prairies and it was only about 18C outside (64F for you American fellas).

The last picture is all the tools I used for the job and the left over materials from the car. Believe it or not it actually took me longer to write this up then to start and complete this mod.


Beers! :40oz:
Jesse A.

I wouldn't, as long as its not stalling on you it is fine if it is bouncing a little bit. The MAF is needed to tell your ECU how much fuel to inject relative to the amount of air coming into the engine. Put it back on ASAP

Just as a FYI, the feed coolant line is the one that is difficult to get to. The return line is the one at the top. So putting a screw to block the return line is not going to help you at all. Plus it's a much better idea to keep the system looped

Just as a FYI, the feed coolant line is the one that is difficult to get to. The return line is the one at the top. So putting a screw to block the return line is not going to help you at all. Plus it's a much better idea to keep the system looped

Yep, the feed (coolant) line is down by the thermostat RH side of car (Passenger LH Drive).

Thanks for the detailed info RotaryMachineRx .. and you have a VERY clean engine.. I plan on doing this mod tomorrow now..

I spent 1.5 hours to do this mod. I seriously doubt it will make any real difference unless you are running in some super hot condition. I did do my lines in a way that I can loop it back easily, I guess I can always mess with it to see if it helps. The next time I run my car, I will hook up the datalogger to see what I can find

i did this mod when i installed my BNR upgraded Greddy turbocharger. ran the feed line to one side and return to the other side of the turbo and capped off the TB ports.

I don't have enough data to backup the performance gain yet (no time to sort through the data), but there is definitely a noticeable different in the temperature of the throttle body. Another RX-8 and mine did 15 minutes straight, his TB was basically too hot to touch while you could place a hand on mine. I don't know how they translate in time, but it can't hurt right. I did route mine in a way that I could always swap back to stock easily

I've had this mod done on the car since I bought it (used in 2008). I drove it all winter with no problems, but had no real gains in the summer. In fact, I was running a little hot while autocrossing. . . but I can't confirm or deny that it had anything to do with it.

I did this mod before, but when my engine was swapped they undid it :cussing: . I rarely had the coolant light come on before even on 100+ degree days....now it comes on once the weather hits 90+ unless I shift to be in lower rpm's or let off the engine load. I will do this mod again before next summer. Its starting to cool down so its pointless for the time being.

well, when you mention it like that. I've never had my coolant light come on. Even on 100 degree days. (yes, it gets to be 100 in Ohio about once or twice a summer)

The f-ing coolant light comes on whenever it wants, seems to like to stay on when I am tracking it too

I've put about 8,000 miles on since the mod. All i did was put a sheetrock screw into the TB, and put the hose back on top, works ingeniously actually aha.

No problems, runs perfect. I can put my hand on the TB afterwards a longer drive, copared to the scolding surrounding areas.

:scratchhe

I've put about 8,000 miles on since the mod. All i did was put a sheetrock screw into the TB, and put the hose back on top, works ingeniously actually aha.

No problems, runs perfect. I can put my hand on the TB afterwards a longer drive, copared to the scolding surrounding areas.

That's the return line, so coolant is still flowing through your TB. Also all the extra pressure can't be good for the clamps

Thanks for the detailed info RotaryMachineRx .. and you have a VERY clean engine.. I plan on doing this mod tomorrow now..

no problem and thanks