Yeah, I'm a bit worried about this since I just installed a RB duct. I'm thinking I'll try a couple of counter measures. First, use a functional splitter which should contain the airflow around the front of the car and possibly reduce pressure under the car for better cooling. Second is to hang a "wing" under the duct down into the main cooling air flow. The plus of the duct is that it has a very "aerodynamic" back exteroir surface. The minus is that it breaks away from the flow too quickly and will generate the turbulance you mentioned. An upwards curved plate about 2" deep might be useful in preventing this. (In airplanes, this is called a "slot".

Humm, how to tell if these measures have any effect? A few years ago, I measured some pressure effects on my glider by using a spare airspeed indicator and a bunch of aquarium tubing. By moving the inlet and static tubes around to different locations, I could measure pressure differences. I don't think I have a spare ASI sitting around anymore, but the Goodbox has what seems to be a pretty sensitive PSIa gauge built in for manifold pressure. It would be interesting to see what happens if I lead the mp tube down to the radiator area and measure pressures in different locations @ 75 mph or so. If the differences between pressure at the top of the radiator vs the bottom can be seen, then perhaps the effectiveness of making changes could be measured too. Dunno, but likely the effects of uncontrolled variables will wash out any differences. Who knows? Will have to wait until spring for me anyway.

Back to my subwoofer installation.

 

Very true! He might be on to something here!

 

I was wondering about the affect of the ram air duct on our aerodynamics. I think before more testing is done the MS intake is what I will have to stick with on the VFAD.

 

I would argue that there is more benefit in achieving safe operating temperatures under high load engine and high ambient temps then chasing aero gains that are very difficult to validate. ESPECIALLY in a street car with low grip and low torque. Aero gains are directly related to several factors and street cars generally don't benefit them at all. The RX8's are so well balanced that a big giant wing will end up with more grip in the rear at the expense of front grip. You'll need a longer, high speed type corner for this additional grip to work for you. This may benefit you only for a few seconds a lap at some tracks. But duuudde, it looks really cool. Most drivers don't take full advantage of driving their cars nearer their full potential so jazz like that are bandaids (even if they do work). As an experienced driver coach I recommend drivers steering away from these to think they help them driver better. Same for suspenson and engine mods. DRIVERS take advantage of the cars potential. MODS allow the car to go faster (and then the driver still drives it less than its potential).

For what its worth, we are able with our cars to run WOT and sometimes HAVE to tape up the oil coolers and radiator to get temps more in align with where higher and safe power resides. Chassis dyno testing has shown us that more hp and trq is made when our oil is North of 215F measured at the oil filter w the RB adapter. About 4 hp more than 185F on a well controlled test environment. Oil Temp gains appeared to stop North of 220F (for us). For that matter, we find the biggest differences (and I've mentioned this before) when the trans and diff are nice and hot. If I had to guess about a stock RX8, 15 minutes should get the diff to a great operating temps. Therefore, there is no need to artificially put heat into a diff. If anything you will need differential cooling when you really start to push a modified car. Adding more grip (tires) will tax your suspension and drivetrain compoents which add heat.

Often on the tracks with higher terminal speeds we will tape up the radiator and one or both oil coolers to find out if we have temps to "give". The thought process is less drag/lift/better aero ala NASCAR cup cars. We've been able to do this a few places that have longer straights which cool both the oil and water much more than tigher turning and slower tracks. I think we taped the water and oil for Watkins Glen, Mosport, and VIR. I'll note that ambient temps at these particular events were average and no where near 90F plus. Street courses this season like St. Pete, Long Beach and Toronto saw our highest temps. As a general rule there is very poor air flow at these downtown street coursr venues which are flanked by concrete barriers. I have no data for this however the prevolent mindset is that these tracks hold higher temps. Some people offer that it is due to no breeze or wind. Perhaps the surface heat is retained and cools poorly. Dunno. These were also the tracks that had hotter cockpit temps (140F+ measured at the Motec disply just above the steering wheel). Coolsuit required all year long for 50 minute World Challenge races.

Dual pass radiator C&R radiator pix link info:

Here is what your looking at. 3" thick rad. Dual pass (water enters the upper right, travels horizontal, drops, travels back horizontal. Total radiator area avail for cooling is over 2X over the stock design which also enters the top, but drops straight down and then exits. See rad pics below in a link to FB. We also use a big Spal fan that pulls air that a 747 engine. This (and most of you may already know this) comes into play at a preset temperature. We set our fan at 190F to prevent water temps from going runaway early. Race water temps usually under 200F. Usually 190'ish. It is much easier to manage high temps to keep or prevent them from going hot then to wait until they are hot. Hotter temps take longer for a system to cool so prevention has been our design and testing methodology and I'm glad to report that they've been working for us (which is one of the reasons I enjoy sharing on this forum---in hopes that others may benefit by TRYING something different should their project require it). Sometimes I wonder if this message comes through. I know some people on these damn forums are just argumentative in nature or defensive. C'est Levie.

OK, keep in mind that we have to plan for front end / front bumper contact which can totally reduce cooling (see pic from Watkins Glen below). Removal or damage of the stock plastic undertray will also spike temps. If you have been thinking you've discovered America or the Wheel by removing this item---fail. Now that I think about it we have put racer tape all over the black plastic bellypan over all the little rectangular vent holes on the bottom. We also run without the black plastic wheel well inner fender covers. This will help big time for the oil coolers to work. SpeedSource original cars (I shared before in earlier posts) originally were designed WITHOUT these. If you want to argue that this doesn't work don't do it here. Go tell speedsource it doesnt work and they will put to their numerous Rolex championships and Daytona 24 wins. Again, forum people should take opportunities to be openminded and learn before refuting something that is working for another (race, street, drag, oval, other). This isn't rocket science kids. It's a freakin car. Note before naysayers start arguing with me over the exposed rears of the oil coolers that we have never had rocks, sticks, or roadkill fly up and damage our radiators. Never an oil related (or heat oil related) issue. Never. Every. They do get the fins bent but we treat them as consumables and replace them each year. Opening the back side is key. No custom rock guards. Open helps big time. As mentioned in previous posts, removal of any restriction behind a radiator---oil or water is critical. This belief is not arguable. It is so well known in the racing communities that only idiots think it doesn't work. The stock airbox was the first thing to go on our car because of its air blocking tendancy. Same for the stock fan configuration. Look at the stock fans. Look at the black plastic body that parallels the radiator plain. Look at how much strutural fan material there is in that design that disrupts air from flowing through the rad. This hurts cooling. Tape up the back side of your radiator and measure how quick your fan comes on and you'll see what I mean. Where did I learn about the fans? Am I smart? Hell no. I'm a freakin' dumbace with a huge open mind who listens to guys who have won championships and know how to build cars out of a stack of tubing. One of the first things my fried Pete told me was "look at that fan, it totally restricts air flow. you need a better one". I got one. It worked. End of story. We know have 3 spares. 3 years with the same rad and fan design and it works. No overheating. Full data acquisition to tell anyone exactly what temp the water or oil was at that spot on the track down to the second. Data rules.

Rad and cooling pics link: http://www.facebook.com/album.php?ai...3&id=796362043

Sharp eyes will see the additional of two outboard tanks (which are hollow) we made so this rad fits tightly in place. Very, very, very little air can escape the top, sides or bottom. We also use custom aluminum ducting to give all the air entering the front openings (top and bottom of the new nose) no place to escape except the rad. Grand-Am rule sets dictate that you have to use the stock belly ducting so we modified the radiator to perform a custom belly pan function. We also taped up any and every hole of the stock bellypan and used window foam for anything else larger than tape. Don't forget to look under the front core support area because air tries to escape everywhere (even an upward direction).

Other: I have the drawing for C&R rad if anyone wants it emailed to them.

Lastly, water and oil temperatures have a symbiotic relationship. Runaway oil temps bring the water with them. Runaway water temps bring the oil with them. Aggressively addressing one of them will help to reduce runaway of the other. Think about that for a second if you haven't before. So even if you have great oil or great water temps and the other is running away, any additional cooling gestures will start working for you when either or both start taking off. Thermostats will keep temps from getting too low. And as all/most all the of the engine builders, tuners and advanced tinkerers know, these rotary engines don't like a ton of heat. One of the first questions very smart engine builders will ask you if you bring them a rotary operating challenge is this: "what kind of temps are you seeing?".

Hope this helps. No need to argue these points and tell me I'm wrong. It works for us and I'm sharing it. I strongly beleive these concepts work for a street car as well. Expensive mods but we need them for our envirnoment. If you've run out of stuff to try and for some reason have problems that others on this forum do not, you might want to give things a try.

Cheers and see you guys at a future SCCA Pro Racing World Challenge event. Last year we finished second in points and this year we intend on winning both the Championship and the Fan Manufacturers Championship for Mazda. Want to help? Show up and share waving of the Mazda Flag and be a part of something special. Look for the 46 year old guy with the big rig who is showing rotary enthusiast the engine bay/motec data/videos/suspension, etc. I'm usualy pretty easy to find.

E

World Challenge schedule: http://www.world-challenge.com/event/season.php?y=2011

 

its funny that there are some dumbasses here they totally removed the undertray and "wonder" why their car over heats .... lmao

oh btw I agreed with your removing restriction behind the cooler for better performance. There is a guy ASH on this forum who talks about it all the time + he did suggest that even for street cars its better to open up the back of the oil cooler piece for better air flow. But I was thinking of getting this from Autoexe for quite a while, and the 2nd pic is used to direct airflow for better brake cooling.





Im gonna wait and see how my 8 is doing @ this year's English Town run. I just installed Knight Sports Rad that has N-Flow design + installed set of Ohlins. I had Ron Davis/Mazmart rad before and it was ok at the track. lets see if this one will be able to keep me running longer.


oh if you guys ever come to the East Coast Im sure I will be there waving the Flag

 

Eric,

Do you have an approximate cost for your radiator and fan setup? Sounds like a winner! I can't do it this year, but I might at some point in the future. And I'm sure there are others who would love to see temps like that.

 

Guys --like Eric says --his is a purpose built car. Lots of R&D, lots of learning over the years.
The cost of his setup may be a little more than you think--and remember he doesnt have the a/c condensor and he has better oil coolers. So you may not see the same results.
Now no doubt your temps would be better and probably just as good--since he operates at high rpm and power on all the time and we dont.
I think what he is saying is --just get back to the basics-- you cant cool without airflow through the radiator, stay ahead of your temps and pass every Mustang you can

Has anyone been monitoring the oil temps TO the coolers---not the pan or adaptor.
OD

 

The oil cooler vent mod is extremely easy to do. I am contemplating about taking it tot he next level and cutting a proper size square in the fender liner and riveting a decent metal mesh to protect the oil coolers from debris.

 

^^^ Nice, I would love to see it...

 

NOW THAT"S FUNNY!!!!!!! Made my frikking day



You have no idea ERic, how many times over the last 6 years I have written that. Here and elsewhere. People have simply stopped asking.

RX-8 owner - "My Mazda makes this weird noise"

Mazda Service Writer - " Its normal"

Owner - "OK"

owner types on RX8Club " My 8 makes a noise and the dealer says it's normal. Is it?"

 

I have actually found this product to be well worth the money:

http://www.jscspeed.com/catalog/Mazd...azda_RX_8.html

I had it powder coated black, and chose this after my undercover was destroyed at the track. It improves air flow from the radiator, reflects ground radiation heat, and is a lot stronger than our plastic pos.

 

So you think all those vents help to force air through the radiator like the under tray should? Seems to me to look like it would vent air under neath and out, not through the radiator. The drain hole issue was fixed, but only by adding another large hole in the other side. This product too has been discussed to death. What did you use for uprights? The factory plastic ones? What was the weight of this? For some reason I remember it being heavy. I also hope you didn't pay $400.00 for it since another vendor has it for $299.00 shipped.

 

no just a quick google search for it. I have 75% of the vents were removed. I fabricated my own uprights, actually had to shortly after the front air dam was broken. Used aluminum wire to to make them and also to reinforce the broken plastic. Weighed about 12lbs. Not a real issue but a bit more than stock. I have replaced 3 stock under cover trays. My front air dam was broken an instead of replacing yet another part I used aluminum wire to fix it.

How did they angle the tray? vents out? or vents in? mine is vents in. It isn't really all that hard to form it to the proper shape,but I actually sent the specs to a company that will make parts for you. It cost me about 350 to have one custom cut. Its currently back off and out to be powder coated, when I get around to putting it back on I will take photos. the car won't be tracked again until the end of april maybe may once our weather is done being a PITA.

I am talking to the same company about making an aluminum front air dam. I pretty much have to use stock shaped and formed pieces to not get a DQ, and I am tired of replacing these plastic ones that break from such minor hits.

 

I know its easy butttttt ------

first off, Im lazy *cough*sometimes*cough*

but most important is ...

ITS JDM y0!

 

but if it gets hit, instead of just *rip* the plastic, it might just rip the head of the bolt underneath. then you gonna be SOL.

 

Its taken a pretty serious beating which is why its back getting cleaned up and recoated. Which is only a 15-20 dollar fix instead of another couple hundred for a new one. At worst if i bottom out it will be bent, but its never damaged the vehicle.

 

well you are in TX so ur 8 never sees snow/salt ...

can't do that in NYC, I replaced the bolts underneath like 2 yrs ago and now its all rusty again ... I don't even drive it @ winter that much.

with all the rust, a strong hit might pull the head away then Im gonna be #@$)*

not to mention, NYC roads are shittiest of the worst of the shittiest of the worst ... so a plastic piece might actually last longer than a harder piece.

 

yeah our roads suck though. Don't count on yours being the only horrible ones. I have seen a lot of parts bent, and broken out here just daily driving. We don't have the road heaving you do, or the salt issue. But we get more rain than a lot of places in the country. Thats why I have parts coated to prevent rust from the flooding, humidity exposure we get.

 

i guess u never tried having all 2 front shocks joint broke in 1/2 + the rear 2 just bent ... thats how bad NYC roads are

off topic : what happen to our tax dollars? fix the roads please? jesus !

 

its actually why you have all those toll roads. But I can tell you where they go in NYC. Its the fault of all your unions. They are sucking your taxes dry. If they said "were not paying pensions to unions anymore" your roads would be fixed. Your toll roads and bridges are supposed to support your roads, but instead they are supporting your unions.

 

I think it was around $700 US with the fan. It bolts into the same lower mounting points and runs a different fitting to the surge tank (all different than stock). The external tanks were added later to comply with the Grand-Am rules. It works with the stock belly pan when the additional tanks are added.

Contact C&R Radiator and David Bridges. He can share our latest revised drawing. If your style is to throw down a VISA and figure it out later, be careful. I doubt this is a 100% plug and play without a mod or two.

davidb@crracing.com

 

Eric or anyone really ---if all the releif vents are closed wont air pressure build to high at high speed? Now I am talking about folks that may go out and do this without removing the restrictions behind the radiator.
For us street /sometimes track folks--the radiator heat is redirected to escape at the bottom of the car--by removing that redirection/restriction you are allowing all that heat to go into the engine bay. At high speed that is not a problem at all, but during cruising around town and DD when the summer temps hit---it may be without a vented hood?
There is a reason the S2 model modified the the pcm box and put a fail safe in that when the pcm gets to 230F it turns the fans on whether the car is running or not. That PCM gets hot guys---yall ever felt that thing? Too much underhood heat is bad for a lot of stuff.
With radiator heat going into the bay and no where to go from there it may make things a little too warm for a DD car?
You modify one thing and it always affects another. Think it through.
That is why I did my secondary radiator set up way back wonder. I didnt want to deal with all of that.

Ok after all this----get back to the exhaust ports hot spots? Any way to cool them suckers. Does evans do a better job?

 

/\ In that blurb about why TCs are no good Pettit explain that they inprove the cooling around the exhaust ports . Anybody looked into what they actually do ?

 

Yeah, the PCM gets "quite hot", especially summer days. I've been thinking what to do with it. this is why I have the RB flash which turns the fan on at 87 Celsius. much better than stock 97 and 101.

You will see "higher" temps with Evan but thats because Evans remove/carry heat much better than H2O + EG, sad thing is its going to be really expensive and PITA to use/install

u need to flush your system with stuff like Sierra at least 2-3 times with heater on to remove all H2O. any H2O remain in your system will lower Evans efficiency. the worst is you can't top your tank off with anything else, only Evans.


I wonder if a 4 to 1 header will be able to keep the heat away from each other better. as far as I know only Knight Sports make this kind of header. RB had a prototype but they said they didn't make it because they don't see any improvements on the dyno + its PITA to make/weld it.

 

the header wont make the egt drop unless its acting like a heat sync. in which case u would need it to be finned. surface area is what cools things down. so you would need to create more surface area to radiate the heat. in turn this would make a hotter exhaust up front so u would also need a heat shield and to make certain its being vented.

your better off cooling the motor, and running a vented hood. my hood has 3 small cowlings over the right rear and u can put your hand over them on any given day to feel the heat being vented. this leads me to believe that while driving, since heats a fluid that takes the path of least resistance and up, that while driving cooling is improved even more. this actually has worked since i have seen an 8-10 degree drop during normal driving conditions. once in a while i get really lucky and it peaks to 15 deg cooler.

remember our hoods are insulated and trap heat. the hood i saw on Mazda's rx8 was vented on the edge of the rotary shape. i think they just didn't want us to have to deal with cleaning the vents. plus they covered all the engine parts. why would u cover the battery and protect the alternator then go add insulation to a sealed hood?