ASH8

I think you should start your own thread on information that is not relevant to the thread title.

Please don't assume we are all ignorant, some of your comments are condescending.

The majority of members here have been playing with "semantics" for years there is no exclusivity.

Yes, I could have told you 6 years ago that Mazda did a great job of their air filter and intake in general...that why mine is OEM.

Most members also have limited "testing"equipment, I only have an OBD Reader, so I (we) rely on what our car PCM tells us, I posted the information that my Coolant Temps lowered after my Mod (as you graciously suggest). Mazda OBD does do monitor oil Temps.

09 Engines make more power...really...perhaps you should back up that statement with some facts, I am sure Mazda would like to hear this as they "officially" say there is NO change in HP.

One needs to "test" their findings and share results..

EricMeyer

I think Denny has it right. A friend of mine got an early 09 engine from Mazda for the Pro Formula Mazda Series (Denny and Jimbo I think you know who this is). I just sent him an email. I beleive (as Denny eludes to) that the fuel injectors were the difference. I was thinking he said something small---5 chassis hp give or take. Will share when he gets me some info. Don't recall. Don't have an 09 motor. And as far as what Mazda publishes if you beleive everything you read then I have some beachfront in Indiana for you. Any of you remember the 240 hp number Mazda through out for the Renny? No where near that chassis or engine hp. Many manufacturers report crazy numbers for their own marketing purposes---I digress.

Ash---might you be able to share your water temps in a before and after test and we can make some correlations to what the oil temps are doing? I realize what the ECU can and can't pull out of it---perhaps we base findings by looking more closely at the water temp data. You can't log info on your PDA can you? Read only? Interesting little thread given we can't read oil temps. Perhaps a few pieces of racers tape on the back of your vents using the same route you described above. Just an idea.

E

9krpmrx8

iTrader: (46)

I have noticed lately as my Mobil1 0W-40 get closer to the 3,000 mark that my oil pressure has been down a bit (like 5psi). I'm headed up to my parents this weekend to use a real garage/shop so I will track data (pen and paper on the drive up, do the Mazmart RE-medy mod, then track data on the way back)

I am interested what my UOA will be on this sample of 0W-40.

hoss -05

iTrader: (4)

As am I 9k.

TooManyIDs

Correct me if I missed something, but based on the reading, the ideal solution appears to be:

Eric,
What kind of oil thermostats are you using?

Brettus

iTrader: (2)

A small point ;
there may be some advantage in sealing up around the area where air can bypass the oil cooler via the bumper opening . There is quite a gap there on my car due to the greddy intercooler pipework - can't remember how well this area is sealed off in a stock NA car ....

hoss -05

iTrader: (4)

My 05 was still sealed fairly well last night when I felt in the gap with my hands.

ASH8

REALLY....YES, the Factory already seals the radiator with foam...in ALL RX-8's...

Brettus

iTrader: (2)

hoss -05

iTrader: (4)

lol i know that sounded bad...... O well.

EricMeyer

-Open up the inlets to allow for as much air flow TO, THROUGH and out of the oil coolers. So, YES to your comment.
-Seal around the water radiator (top, bottom and sides) with a foam type product. There is some inexpensive gray colored foam that people use to seal around window mounted air conditioners in their homes. It's usually about 2" x 2" square and comes in 3 foots lengths. $8 or so at the hardware store. Buy extra. On this same note some people make a radiator block out plate for the top of the rad. This is behind the top of the front bumper. It is the area that air could escape out the top prior to the air reaching the front side of the radiator. Every little bit helps. A simple duct tape job will do the trick just fine. Keep in mind that we are (and I think this is your objective) to help your car run less hot water and oil temps. We don't want to run the car too cool, we want to keep it from running too hot.
-We had to add an oil themo because we do not run the stock oil lines and oil coolers. One of the things I learned very early on about this engine was just how critical heat management is. Too high of temps results in ka-boom. 240F oil in a piston car isn't a huge deal but terrible in a rotary. For this reason we chose to run a bit of an overkill approach to cooling these engines. Larger oil coolers and larger oil lines (-10) allow more oil flow and heat dissipation. I blew two piston motors in my early racing career due to high temps and have taken a more aggressive approach to heat management than some people. Fall and winter driving revealed to us 150 F oil temps----much too low. We added an oil thermo and she runs 185 minimum after she warms up. The larger oil coolers and sealed larger radiator allows us to run the car very hard from about 6,000 to 8,500 rpm at WOT for hours on end and stay well below 200 oil and water. Usually between 180 and 190 for both oil and water at race pace.


There is a trick little water pump that Paul has with a much improved impeller. Easy to install yourself. Good insurance.

If you have heat issues I would suggest a vented hood. The air flow is very poor out of a stock RX8 radiator. There is a whole bunch of "stuff" packaged behind the rad and in front of the motor. This doesn't help air flow. Think about this a second------where does the air go once it passes through the radiator? Well it stumbles, trips, stalls, builds high pressure and tries to find its way out here and there. There is a great path TO the radiator, a less effective path THROUGH the rad. and a terrible exit path. Here is something you could do if you REALLY wanted to decrease your water temps and let the water thermo control the temps:

-Purchase a larger radiator and foam/seal all around it. Try and find a dual pass rad----tanks on the side. A dual pass (as opposed to single pass) exposes the water LONGER to air flow. From the top to bottom of a stock radiator is about 18" +/- of water path that receives air flow. A dual pass from side to side (and then back to the other side) is approx twice that of a single pass. Think about that one.
-Dump the stock fans and purchase a fan that has less surface or less "wall" area so that air can flow more easily through the current areas that somewhat block off straight air flow. Look at your fans again and you'll see this. I beleive the function of the current shrouded fans that you see many V-8 drag cars use is to keep the car cool when it's stationairy (not moving). These drag cars make a ton of heat over a 1/4 mile and then they shut the motors down. There is no "cool down lap" to help the cars return their high temps to normal. You can also buy products that turn a fan on at different temperatures. Keeping the car from getting hot in the first place is a smart approach vs. having to deal with a bunch of heat. Our system is controllable and we have the fan come on earlier so the heat never goes the route of a runaway train.
-Vented hood. Help the air flow out of the rad and exit the hood. Make a nice path for it.
-Relocate your battery and remove the battery tray because this structure impedes air flow.
-I'll suggest you'll get better air flow through the rad when you dump the big, giant stock airbox and use a MazdaSpeed/AEM style intake. We want that air to flow unrestricted in, through and out the radiator. There is a lot of surface area restiction in several of those items behind the rad.

I think you'll find that any of these will lower your high(er) temps. Remember to record a lot of good data both before and after to confirm your assumptions and that you're headed in the right direction. A chassis dyno is a nice little proving ground because you can generate heat quickly, hear/see the fans come on and not have to worry about watching the road ahead. A chassis dyno does more than just measure power-----it's great way to see that all your new little changes work properly before you go to the track.

Happy rotorings,

ASH8

Actually for A Road Car, the RX-8 Bonnet or Hood Holes is a BAD Idea, unless you are doing a LOT of idling at traffic lights.

There are Very few car makers today who install REAL hood scoops/holes that work (inter-coolers excepted), why...

Well as the Factories say with extensive wind tunnel testing, putting holes in your hood your are changing air pressure zones around the car..

Most of us know that it is best to get as much air through your radiator as possible, not through the Hood to cool your coolant.

In RX-8's like many other road cars the heat is designed to go out under the rear of the car.

Guys here have experimented with also gapping their hood (an inch) at the vent cowl (wipers)...fine at idling and if you want fumes in through your cabin.

Most have shown that ANY holes in the hood does not help reduce coolant temps when driving..

Naturally when stopped or at idle engine heat escapes through holes..

ALL Old school and Rice....

9krpmrx8

iTrader: (46)

Good info Eric, as always the more input the better. I will be foaming up my radiator this weekend because the factory foam is a mess.

EricMeyer

Ash,

You are incorrect on several points. The proper function of a vented hood (or any other inlet/diffuser/exit air flowing device) is to make an efficient path for air at speed to follow/flow. These hood items do not function when the car is at a standstill. I believe you may be referring to radiating heat as opposed to improved heat reduction using an improved airflow design. Agreed that the removal of radiated heat does very little to reduce fluid temps. For purposes of helping those reading this who have high heat issues with the somewhat high heat sensitive Renesis, an airflow design into, through and exit out of the radiator and then through the hood would be most/more efficient. This is more easily allowed in the RX8 due to the packaging of our smaller engine (low and to the rear) and the angle and forward location of the radiator. Keep in mind there is a lot of obtrusive componets that need removed or located to optimize this concept: battery relocate, air box, all the fancy cosmetic plastic dressings on top of the motor) however improved heat managment will be the result. Another ease of air flow out the hood of our cars is direction of the air flow exiting the radiator (aimed up to the center of the hood if you will). Essentially this air is already "pointed" at the bottom of the hood/bonnet and ready for exit here. Compare and contrast this to horizontal mounted radiators on other cars which require the air to massively "bend" to exit the hood. Air doesn't like to bend. This makes our cars more ideal candidates that other cars to increase the effectiveness of the radiator location and reduces the probability of water temps getting out of control which also gives the benefit of bringing or reducing higher heat in the oil system. These are all proven concepts and generally accepted in seveal forms of racing circles. You need only to make a trip to a track and get into a conversation with a mechanic to confirm this. Start your line of questioning with "have you ever had any overheating issues" and you'll open a can of worms and hear about all the problems and solutions the car/team/owner/mechanic has encountered. They are often sore and expensive subject but you'll get a ton of info.

Is this overkill for a stock RX8? You bet. Is it technically correct? You bet. Would I modify my street car with several of the aformentioned modifications? No---only if you had high heat rentention issues most likely due to high ambient geographic summer temps, close drafting/poor clean air flow racing, using the stock oil and water cooling components and lastly (and most importantly) having a high(er) heat producing engine than stock. All of these beg better cooling and the measures I have provided are proven and have been used in several racing cars for dozens of years. If you refute these proven time established concepts than you may want to re-examine your belief systems my rotary friends. Below I have offered a few resources that are wonderful reads. Most of these I've offered are "easier" to read meaning you don't need a PHD in Astrophysics to comprehend them. Hard reading but great reading. Lots of cool pictures to help explain what is most likely a "new" concept to those just jumping into high performance car theory.

Personal note (and not a crush or slam by any means) Many people are limited in their thinking regarding "stock" production cars. Most of them (myself included) comprehend solutions based on what we can see and touch within the production car market. You can see this with the type of questions on this (and other) forums. We all had to start somewhere. Some of us keep learning, some have limited time or interest. There is a ton of info out there. F1 cars have 4 wheels, an engine and oil coolers just like an RX8. Need I say more? One needs only to look into more of the performance market to see the aforementioned concepts are work. A great example of this is those wonderful girlfriends and spouses we love who have little interest in cars and find it difficult to tell the difference between a Ford and a Ferrari (exceptions excluded ladies). How the heck can people understand shock tuning when you wonder if the local car wash will damage your paint? Most people only see what they have been exposed to. Hang out with a grown-up whose father drove and ran in drag racing and that person can school the normal layman a hundred times over. Talk to the circle track guys (dirt or pavement) about suspension and you guys will get blown away. They laugh at the thought of driving on a predictable dry, smooth surface. These guys make things hook up on dirt with big motors driving sideways at speed. Very smart guys even though most of them are named Bubba and drink Old Milwaukee (joke).

Large vented hoods in the popular U.S. Competition Dodge Viper, Ford GT, rally cars, touring cars, ALMS GT cars, and most notably the Japanese Super-GT series which allow liberal use of Aerodyamics will reveal unlimited examples of vented hoods. These work at speed (usually designed for average speeds where the car operates more frequently and less functional at low and very high speeds. This is similar to changing wing angles at higher speed tracks or reducing the radiator inlets for COT cars on the SuperSpeedways. Want to see something cool? Look at the size of radiator inlets on the front noses of Sprint Cup cars and keep in mind how high strung those big motors are running at near red-line for hours on end. Really cool (and simple) stuff.

See: http://supergt.net/en/ for some sexy design examples.

Keen race fans will know that often a racing rule set dictates what can and can not be done with Aero (and other) and therefore a person should read into the rules before jumping to conclusions about a car or series. You want to learn something about race cars? Read a ruleset. Very eye opening. Explains a ton. Hardly anyone does it. Several teams I know (and even more drivers) don't refer to these often enough. A great example of that is in our American Grand-Am and World Challenge Series. You would think that people would run larger rear downforce wings and one misconception is "wings don't work on these cars (my car) or don't do much". You can find these type of posts on this and other forums---"should I get a wing, how big and will it work on my XYZ blah, blah car with 20" pirelli Pxr9 tires?" To the contrary---the Grand-Am racing racing rule sets dictate the use of (or not) the size and location of these wings and rear wings are very functional (which some of us know, others debate and a few could care less about). BTW, the spec wing for the G-Am rolex series is a Crawford wing and if you run a wing it has to be a Crawford. Air ducting to the radiator, ducting size, exit and a ton of other cool topics can be found here --Neat stuff:

http://admin.grand-am.com/assets/dprulesforweb1.pdf

OK, so know we have gone from a simple oil cooler exit (Ash's trick vents) to some basics of cooling and aero and back again to our wonderful RX-8's of which I have owned 5 (soon to be 6) and have pulled off every item down to the bare subframe more than once. Bare metal. Only steel. No aluminum or other. So I think and hope I'm somewhat qualified to post information on this forum. I've also owned or designed 6 different radiators and 4 different oil coolers. Hopefully these posts have helped an interested few of you organize improved cooling via sealing, vents, size or other (there are more) into perspective. This topic is in dire need of an entirely different thread and has small benefit to street cars operating in street environments (albeit the foaming/sealing the radiator(s) which is a no-brainer).

Happy 2010 and happy rotoring as always.

Eric

Interesting reading and or cooling resources for the techies:

RaceCar Engineering Magazine: www.racecar-engineering.com This is a wonderful U.K. magazine with tons of technical info and pictures. Incredibly eye-opening with windtunnel, F1 engine, suspension, LeMan's technology, NASCAR COT aero and everything inbetween. A bit expensive for a magazine subscription but well worth it.

A quick google for this web site currently reveals the new Honda GT-500/Super-GT which it says might be the NSX replacment.

Go here: http://www.racecar-engineering.com/n...the-track.html

Simon McBeath's COMPETITION CAR AERODYNAMICS. A hard read but you'll learn more about car aero than a million lifetimes of surfing this forum (or internet). Note: There is very, very, very little racing aerodynamic info on the web. Very, very little. Nil.

Anything from Carroll Smith. TUNE TO WIN is a technical book that is well written and easy to read. There is a great chapter on............get this.....Cooling and Internal Aerodynamics which explains proper oil cooler (heat exhanger) air flow designs. Cool stuff. His DRIVE TO WIN is a must have for competitive driving. Advanced concepts not for beginners or novices IMO.

Meyer out

olddragger

iTrader: (3)

Thanks Eric--- good read.
There is a big difference between a professional approach and a laymans approach using oem components that are modified by the backyard builder --like me.
I can be dangerous with a hole saw.
Mazda's design in it's entirety with the rad's air flow redirection downward was a manufacturing cop out. No doubt.
Billy (head of mazdaspeeds north A's nephew) told me mazda experimented with the classic hood vent immediately behind the radiator--but dropped it due to water/snow concerns etc.
OD

EricMeyer

You don't give your McGyver self enough credit. I've seen your hole saw work and you're not allowed to hold a handtool and be within 100 ft. of my cars

See you at Road Atl for NASA March event. Will have our new #45 car. Engine to arrive next week. First time on track in March. I'm thinking 1:33's at Road Atl once it gets sorted out. Perhaps faster. Dunno. Note oil heat exchanger location above rad.

http://gallery.me.com/meyermotorspor...r=black&sel=45

ASH8

Mate, I suggest you modify your postings..it is too hard to read and way a too long a rant..
I though I was bad..

Yes, I was referring to radiant engine heat at idle or stop lights..

Most of the race slots are for engine induction air as you know and
in most cases tube ducted.

I repeat, the more air through your actual radiator the better.

The USA should get with it..

DTM Racing..
Mercedes don't use them...OH they don't go fast enough do they..

olddragger

iTrader: (3)

Eric-pics of the 45 car are amazing ! My head is going around and around.
1-The side exhaust will be an automatic photo spread dude.
2 cage wielding and reinforcement is artistic.
3-- which way is that rear diff fan going to turn-- hehe
4- system set up and data collection is really top notch man--going to start a franchise?
5-- OK fess up-- what are you doing with the intake?? no variable intake tuning are ya?
6- can you put high speed vents in the rear window or are they not allowed?
make a cheater vent by splitting the rear window with a center support beam--two piece rear window.
7- is the rear spoiler to the frame?
wish i could be there--i would let yall tie my hands up?
Hope yall can keep up with me at Rd Atlanta in March---hehe.
OD

ASH8

Yes, good luck Eric with your GREAT-8....you have done a Fantastic job...we will all be rooting for you ...even Down Under...

bse50

Sorry to quote you after you called yourself out but i have something to say regarding cooling mods for mixed street\track use.
My car presently has a Mazmart water pump and opened up oil coolers vents plus a very slightly (7mm) tilted hood and open front metal grilles (metal ones). Airflow through the hood is caused by the removal of the stock air box (i'm using a mazdaspeed cai), i still have the stock battery tray.
The most important mod done was indeed the one to the oil coolers.
After this brief introduction here's some data recorded through my gauges:
During our mild\hot summer (25\40°C) with the oil coolers mod the average temps decreased by 3°C and i rarely see temps above 90°C while daily driving. 85°C while cruising.
During track days the average temps are still around the 90°C mark.
Before this mod, in similar conditions, my track and cruising temps were a bit higher. from 2 to 5°c depending on the humidity.

The problem with the oil cooler mods is highway cruising at 130km\h in our humid winter (let's say 10°C). Both my water and oil temps don't go past 70°C, sometimes they sit at around 68°C which i feel is a bit too cold (the e-shaft bypass pellet opens at 65°C..).
Before the mod i saw temperatures around the 80°C (77\78°c) mark while highway cruising, 85 or so while daily driving in our horrible traffic. The traffic driving temperature didn't change much because the larger holes affect the flow (making it worse) while going slow thus reducing the coolers' efficiency.

So, without going too far away and driving back to an in topic discussion...
The mod works but is not a panacea. It can indeed lower the temperatures too much in my opinion in some circumstances and weathers. In the end this is something worth considering for the guys that live in very hot climates. strapping some black tape there during cold winters could be a solution for the ones who live in variable climates like me.

What do you guys think about this?

EricMeyer

I little converstion action to U.S. values (IN BOLD) . Also, note on bottom.


The improved cooling with lower wide open throttle (WOT) track temps but too low of WOT temps in cool weather is exactly the reason we added an oil themostat. Helping air flow for the coolers reduces the high temps but lowers the low temps (too low for proper oil operating range). 185-190 F oil and water is what several racing rotary engine builders have suggested to me is an ideal and safe range. Without an oil thermo (for us) I would wail on the car during testing (8,600 rpm max and/or shift points +/-), watch the temp alarms and pull into the pits to have the guys tape up the oil coolers (or pull tape off). Keep in mind that these lower oil temps contributed to pull the water temps down (which are regulated by the water thermo). Again, the oil and water acts as a temperature equilizer or sorts. With our BEFORE two big oil coolers, -10 AN lines, no fender vents, inlet vents that guide as much air directly to and through both oil coolers, and a big *** dual pass sealed up radiator with about nothing behind it except for the battery, we could not get enough operating oil temp into our system----even with FULL TAPE of the oil coolers. This was in 50 F weather. Water temps were about 180 F if I recall. Oil approx 150-160 depending on how much tape and how high of rpm we ran. BTW, this was a fuel testing effort where we rented BeaveRun and run for about 75 minutes straight before running out of fuel. We did this for 2 days totalling about 12 hours of WOT or near WOT driving. Had we had front cool air brake ducts operational for this event we would experienced the same lower (and undesirable) front brake temperatures. This is sort of off the subject but really ties in nicely to this same subject: proper brake operating temperature. I will start a new thread for this under the RACING portion of this forum seen here:

https://www.rx8club.com/showthread.p...53#post3373453

I believe BSE50's results echoes why Ash swaps out his fender vent solution (because cold weather driving oil temps are too low for generally accepted adequate oil temps). FWIW, these results are exactly what I'd expect to see if anyone else did this same modification.

Question to guys here in the US that track their cars:

1. Are BSE50's BEFORE track temps about the same as those you guys see?

2. Is anyone also tried an oil thermostat for a street and track operation?



Good post.

Questions for BSE50:

1. Is the oil cooler design (and water) any different for you then those models in the U.S.? I'm under the impression that your RX-8 may be on Italian design and may/may not be different than ours.

2. What is your typical rpm redline/shift point for your track driving?

TooManyIDs

bse50,
My track experience has been in Corvettes and not a real racer like Eric, very much the mixed use you mentioned (see my signature for where I play).

When I added an oil cooler to my 2002 Z06, it was with a thermostat to keep temperatures from getting too cold. If I recall, that took me from peak track oil temps of 305 F to around 270. Not as low as I wanted to go, but I didn't know if the thermostat was too much of a restriction to flow or if the cooler was just too small for the job.

It would have taken more money to experiment with both, and simply out of budget for what was primarily a street car.

dannobre

iTrader: (3)

WOW 305F oil temps What kind of oil were you running?

TooManyIDs

Stock fill for the Z06, Mobil 1 5W-30 Full Synthetic and I kept it changed far more than it probably needed (based on oil analysis from others playing on the track).

Changed every 3 months regardless of miles, sometimes as little as 800, often not too much more (wasn't a daily driver). Wasteful, probably so. ****, yes.

bse50

1. My car is what your full-optional rx8 is there: leather interiors, twin oil coolers, xenon lights etc. Same parts whatsoever. We only had those in italy!

2. Around 8700rpm or as soon as i hear the beep and i'm not in a turn!