Well did this with the intention of alleviating some rough idle issues and it has helped so for that im trying to contribute back to the thread where i got the info from.

:lol: I forgot this thread was created. I'm going to put this to rest now that I have a thermometer to show this mod is stupid.

Thanks for the detailed walk through with pics. I kept mine reversible. Looking forward to seeing somebody actually measure results...

What results are they going to measure ?

said it once, will say it again .... nothing is preventing the air from getting heatsoaked by the UIM/LIM so this "mod" is moot.

More posts moved from the DIY to the discussion thread.


Results have already been measured, and this does nothing.

The coolant is at ~180F running through a short section of the intake.

Anyone that thinks it's a beneficial mod is ignoring the 230F+ of the components all around the rest of the intake pipe or even higher heat of the exhaust manifold sitting a very short distance from the lower intake manifold.

On Sunday I will have quite a few RX-8's around so as they show up I will measure throttle body temps while they are hot and post them up. Some are bypassed (that circuit is thru my turbo now), and some are stock. My guess is that all of the throttle bodies will measure at 200-230F (give or take a few degrees). This mod is pointless.

I was referring to what 9k is doing.

2 Cents, Instead of using the bypass I just used the autobahn88 kit and connected the TB line from the coolant pump, directly to the rear housing as it got rid of a coolant line, and made things neater. my IAT are 3 degrees above ambient considering we have nothing on are car that measure the IAT post TB, this is a mod that we will never know if it works or doesn't, but for me at least it was a free mod so why wouldn't you do it :dunno:

Because you live in Buffalo and don't want your TB to freeze up :)

I would like to see these results. Not that I would reroute mine back to the TB. I really like not having to mess with the coolant to remove the UIM.


Where do you plan to measure from? Booster line nipple? Maybe you can get one from the service ports on the LIM too. That would be interesting.

Yeah, because i'm driving my car in the winter :lol: My 8 is lucky to even see spring or fall.

I look forward to seeing the results from your unbiased test lol.

http://photos.motoiq.com/MotoIQ/Proj...IMG_9870-L.jpg

Per motoiq. Valve allows you to return to stock functionality on the colder days.

Suggestion,

Bypass or not bypass, but do not block off. That water came from someplace, if you block off the line, whatever was getting cooled by that water is now not getting any flow.

I agree. This might be an option for those who feel that the wise thing to do is block off the inlet with an object lol (i think i read that somewhere here)

Unless you use two of them to create a "bypass loop"

probably far more trouble than it is worth as you would need to incorporate some Y splits in the line and such. Anyone actually know what comes after the TB in the coolant line network?

The line returns to the rear iron, passenger side. I wouldn't block it....

^ thanks. Yea i wouldn't ever block it. I think there was a thread similar to this where people were blocking it by dropping a bolt in the inlet to the TB coolant passage. *smh*

Autobahn hoses are flexible enough I was able to just route my inlet hose to the rear iron. Less clutter on the block, no disrupted flow, no obnoxious connectors and splices.

no issues in Buffalo winters?

To quote myself.

LOL muuuuust be nice

Just looked at my build matrix, I took deliver in March of 2012 with 23K ODO, and put it away this fall with 32K ODO.

Its become quite a spoiled thing since I purchased it.

Bumping this for my pal 9k :lol:

As we were just discussing in the racing forum, the likely best benefit is to block the whole thing. The hose is routed to take hot coolant from the rear iron, run it through the TB, and back around to the water pump inlet. In short, hot coolant is recirculating back around into the engine rather going to the radiator and being cooled down. The line is fairly small though so it is not a huge problem.

However, the heater core is set up the same way and is continuously recirculating hot coolant from the rear iron through the heater core and back to the water pump inlet regardless of whether the heater is on or not. This is a pretty good size line. In really hot climates it might help to have a valve to block this flow, but the system should be clean with fresh coolant before doing so. Opening it up once in a while to flush flow through might be needed. Letting it lay stagnant could create a corrosion or sludge issue, less so if you maintain the coolant well. Replacing a heater core is a major job, so don't take the mod lightly.

could you even take it one (granted more involved) step further and instead of blocking it off...run the line through a small rad? only as a solution to keeping coolant stagnant in the line while cooling it a bit before the pump?

Posted From RX8Club.com Android App

I forgot that the factory heater hose has a restrictor orifice in it. Not sure if anyone ever verified how big the orifice is.

I've thought about this option more than once...

It would slow down warmup unless you controlled it via a thermostat at some temp but certainly would increase the amount of heat that you could shed from the system.

And to add to this, one time we installed a reman and it overheated almost instantly after a couple of minutes of idling. We had installed ne heater and coolant hoses and forgot the restrict-or in the line that goes to the AST. We installed it and all was good, I still don't understand why though.

But blocking it (rear drivers side heater hose) off for fun runs and track days in hot weather seems like a good idea..

in that case, the valve i referenced above is a viable option for those who wish to just block the line with the option to return the flow pattern back to stock

where exactly is the restrictor ?

HEATER. Fits: Mazda | Jim Ellis Mazda

its called 'oriface, heater hose'

And then there is a little one in the hose that goes to the top of the coolant reservoir.

Weird, it's not listed here though in that line separately.

15-277

http://www.jimellismazdaparts.com/im...ze/2F17035.jpg

Probably because it is considered part of the hose ...........

I am just curious why it is not listed the same way on the other hose, the restrictor is listed separately on that hose.

They show the one for the heater though with a part indicator. Plus it was easy to check mine right now since the engine is out and I'm working on it ...

Nada, both hoses are straight through, no restrictor between the coolant tank and either the water pump or radiator, at least on the USDM version.

Just checked all my heater hoses too. If there's a restrictor in there it must not be much of one because I can blow through them all like they are wide open.

Am I the first person to have actually ever checked? All of these particular hoses are OE factory. I've only ever changed the main large diameter radiator hoses. This may need further input from other owners.



Mine has that one, maybe this is the one Brettus is referring to? It flows from the thermostat discharge side. This hose is not an issue IMO. Seems to be the only restrictor on my car.

The only time it's ever gotten hot coolant temp was making a bunch of back-back runs on the dyno and I figured out later this was caused by the oil temp going through the roof because they had the fan shoved into the center front bumper cover opening only. I don't track or street drive much though.




.
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If you are referring to the hose that goes to the top of the header tank (15-277 in the diagram above) then yes, there is definitely a brass restrictor in that hose (on JDM versions anyway).

Wasn't there a restrictor in the heater hose on early models Then it was removed around 05 and only put in to solve the miac when people complained about it? What tear is your car tema?

I'm not 100% sure about the rear heater hose but I think mine has one there too. There is definitely one in the hose that goes to the top of the AST (15-277) and when we started the car without it, it overheated rather quickly at idle. The hose was replaced with just normal heater hose and the owner did not know the OEM one had a restrictor. So we cut the restrictor out of the OEM hose and installed and all was well. Made no sense to me why but the car has been running fine ever since.

Apparently, without the restriction, a LOT of water goes through the heater core and not through the motor. I am really considering adding more restriction.

Ball valve with a couple hose barbs...open it up on those frosty mornings...close it up for track duty.

That ^^ may be a brilliant solution... Given the number of frosty mornings in Florida, it could stay pretty closed. But then again, global warming has it pretty cold here in the morning....

scroll up to post #64 ;)

Heh Heh Heh,

I crossed up a heater core thread with the throttle body thread. Looks like a common solution though.. I have my throttle body bypassed. Seemed like the right thing to do. I did not plug, I bypassed.

The valve approach mentioned is incredibly attractive for the heater hose. I want to look at it and the fluid routing a bit more, but it really looks interesting.

Thanks,

yes, mine has that one. My early 2005 model 6-port *does not* have any other orifice in any of the other hoses

apparently they quit using the one in the heater hose from the factory as posted above and discussed in the thread linked below? Have never heard any noise in mine, but do use the higher viscosity Evans NPG-R waterless coolant and underdrive pullies

https://www.rx8club.com/rx-8-discuss...n-miac-181950/

couldn't find any TSB on it though ...


.

apparently there is an orifice on the coolant tank outlet to the water pump that is internal to the tank



https://www.rx8club.com/attachment.p...1&d=1401343688


https://www.rx8club.com/attachment.p...1&d=1401343689


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From GA RX8 Club, if the first words did not give it away.... after re-reading some of this..

Yall know and probably get tired of me talking about cooling the rotary engine.
I have tried many, many different things toward trying to get to that goal. The last "package" that I had including a different fan controller ( works VERY well) mazmart pump and thermostat for the cooler months and then adding a small secondary radiator for the really hot months--like over 90F. Those set ups have really worked well for me. Cooling is stable and within parameters. Engine still warms up normally.
Well it was a pita to reinstall the secondary cooler and clear the air out of the cooling system every year so I was thinking about a system in which i wouldnt have to be doing that.
Solution----remote fluid thermostat from Derale! $55 from summit racing. This is hooked up to the heater hose between the heater and the radiator. It allows a small amount of coolant to flow through at all times ( approx 5%), it has only 3/8 inch fittings ( the heater coolant system does need a little resistance) and it begins to open at 170F and is fully open at 200F. PERFECT. Now just install it once and leave it alone--no more summer/winter cooling systems!
Now it is sweet, spot on and this fool doesnt have to fool with it anymore!

And

So my stable year round cooling package now consists of ( and I dont think all of these items are needed)
1-Mazmart w/p and thermostat--thermostat drilled with one 1/8 inch hole ( i will not go into all those reasons)
2- flex a lite fan controller that activates BOTH ( this is important)fans at 185F
3- a very small open fin design Summit racing cooler 21x 7 mounted directly on the front bumper support ( the back side of the cooler does not have to be open to the air--if it is--ok but it doesnt have to be, but the face of the cooler needs to be in the airflow. That front bumper support is also a HUGE heat sink. Dont forget to open up your grill a little
4- derale fluid thermostat that starts opening at 170F--look it up and read the details.
5- coolant bend of water /coolant 70 W 30 C
6- oem radiator cap
7- oem radiator
8- pull the a/c condensor away from the radiator approx 1 inch this allows the fans to pull air better
9- proper radiator hoses --the biggest bottom radiator hose you can get. full supply to the water pump is critical.