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Hello all, recently purchased a 2010 R3 and took it for a track day at Willow Springs Raceway. Before taking it to the track, I had new tires put on (225/40/19 Hankook RS-4) as well as new brake pads and rotors (Carbotech XP8 and blank centric rotors). The car handled well, but it could not stay cool enough to run a full lap.
The ambient temperature was 85-91F with low humidity as this is in Southern California. The car would hover around 200F water temps while in the pits and it would quickly climb to 220F+ on the track. After about half a lap or so, it would climb to high 220s and it peaked at 232F which I then started to cool it off. It wasn't possible for me to run a full lap without it climbing quickly to 230. I tried running the heater on full blast, but that only helped marginally. On the street, the car does fine. It hovers around 205-208 in traffic and peaked at 214 when I was doing a canyon run recently.
My question is if this is normal for the stock cooling system. Is there air in my system that's causing it to not be as efficient? The coolant was flushed about 4k miles ago (previous owner claims). I'm thinking I'll do the coolant bleeding procedure (throttle body line) and run the car on the highway for a bit to see if temps are lower.
What are some mods I can add to reduce the peak coolant temps? Currently at the top my list is a S2 Koyo rad, but is this rad enough to allow the car to run laps at the track on a hot day?
I'm also aware of the fan relay kits and lower temp thermostats (oil and coolant), but my understanding is that these help with street driving and won't help much at the track when they're all open/at full speed anyway.
Doesn't sound normal, I've run similar temps without a ton of trouble. Do you still have the plastic undertray under the rad and engine? You definitely need that to keep air going through the rad.
A rad upgrade will help for sure, hard to tell how much.
Is the rest of the car healthy? Ignition, catalytic converter, oil coolers.
I still have the plastic undertray and it looked fine last time I looked at it briefly. When you say you run similar temps, do you mean you're consistently at 220-230 on the track? Ignition should be fine since the previous owner replaced it less than 5k miles ago, but he did go with some O'reillys stuff so that probably should be switched out. I also got a misfire on cylinder 1 (rotor 1 I presume) on the way back from the track. Have a magnaflow high flow cat and custom 3" exhaust. Not sure about oil coolers, is there a way to check? Coolant is generic Zerex Asian vehicle I think.
I meant similar ambient temps. I've rarely ventured above 220 with a stock cooling system, the times I've been close to 230 was 1 track day in 95F+ high humidity.
A few things: get that Zerex stuff out of there ASAP. Only Mazda FL22 coolant, others may contain 2-EHA which over time will eat seals. If the previous owner ran it for a long time you may have a perforated seal leading to exhaust in the coolant system and overheating. Worth a look if the coolant bubbles in the reservoir.
Don't expect that Magnaflow cat to live long, rotaries destroy basic aftermarket metal cats pretty quickly. You want a high quality one like HJC or Mazda OEM.
Just looked up the Zerex contents and it specifically states that there isn’t any 2-EHA, so I don’t think it’s a problem. I get the need to use the OEM coolant though.
As for the cat, I’m not too worried about it. I’ve thought about getting a RB Resonated pipe, but that’s not on the top of my priority list (also in California, so I’d rather not get in trouble).
Alright. A bad cat will kill your engine if it clogs, so keep an eye on it.
If you haven't already, rx8help.com has good summaries for new owners. That rotor 1 misfire might be worth looking into, no good reason for a misfire when you're not even pushing it. Did you have a compression test done when you bought it?
do a coolant system pressure check, including the cap & tank. Both which are known to develop leaking issues with time, but there could be another issue elsewhere
200 in the pit can be fixed easily. Run fans high speed all the time (even during warmup) with wiring if you don’t have a tuner. That will give some margin for running on the track, which will get used up, but you might be able to get a lap done.
But:
A. 2500 ft elevation
B. low or almost no humidity to speak of
C. Full power 85% plus of the time
D. 90 degrees plus ambient
E. Inadequate cooling design from factory
Sounds like your car is working as designed.
Somewhere, someone is going to find an internal factory document that states Mazda engineered the cooling system of this car to SAE standard reference, thinking that was the standard US/ World climate conditions, and would be useful to use as a target statistic when computing cooling capacity. (60 degrees F, sea level (29.92inhg)). Probably some new engineer group fresh from school, and the boss did not check their math.
Because those are pretty much the conditions you need to keep the cooling system as delivered at thermostat temp at full power on a continuous and robust basis, without temperatures creeping eventually to overheat.
Just kidding, but it wouldn't surprise me.
Last edited by kevink0000; 10-14-2023 at 06:37 AM.
200 in the pits isn't an issue for me. I was mostly worried about going over 230 as I didn't want to blow any coolant seals. Thanks for pointing out those conditions. You're probably right about the car operating as normal. In traffic I'm around 205-210 with AC on. The next move is probably a Koyo Rad.
I have a track day coming up in November and the ambient temps will be 60-70, same track. Hopefully the car stays cool enough that I can run some laps, will update this thread.
200 in the pits isn't an issue for me. I was mostly worried about going over 230 as I didn't want to blow any coolant seals. Thanks for pointing out those conditions. You're probably right about the car operating as normal. In traffic I'm around 205-210 with AC on. The next move is probably a Koyo Rad.
I have a track day coming up in November and the ambient temps will be 60-70, same track. Hopefully the car stays cool enough that I can run some laps, will update this thread.
The Koyo will likely do nothing for you, unfortunately.
200 in the pits means you’re already too hot before you even get under power.
The fans are set too high from factory.
If you want to keep your good compression, run it cooler at all times. Heat and compression are mutually exclusive.
There are plenty of threads on cooling improvements.
I personally have found only a large second radiator makes any appreciable difference.
Most people here follow the general consensus and buy $400 dollar radiators and $400 fans, and get almost immeasurable change.
Under $200 and an afternoon to put a second radiator in parallel. I used an aluminum Toyota AW11 radiator.
The Koyo will likely do nothing for you, unfortunately.
200 in the pits means you’re already too hot before you even get under power.
The fans are set too high from factory.
If you want to keep your good compression, run it cooler at all times. Heat and compression are mutually exclusive.
There are plenty of threads on cooling improvements.
I personally have found only a large second radiator makes any appreciable difference.
Most people here follow the general consensus and buy $400 dollar radiators and $400 fans, and get almost immeasurable change.
Under $200 and an afternoon to put a second radiator in parallel. I used an aluminum Toyota AW11 radiator.
HTH.
I have seen your posts about the second radiator, but it doesn’t seem possible. Do you have pictures of how that would even fit? How would plumbing work? Not the most mechanically savvy person here.
Not the best pictures. This may give you an idea. For this car I used a Toyota MR2 AW11 radiator in a pretty severe laydown. That's a flattened Racing Beat screen in front of it. Air can move past it on the sides and top and bottom. No fan currently, I tried one, but got worse results. Stock fans still in place.
For my other RX8, I used a RZR850 (I think) 3 row mounted to the factory condenser screen. I used better hoses and fittings on that one, but I am not sure there is a difference.
For this car I used universal flex hose with internal spring form, later I will probably re-do it to a less cobby job. I wanted to get it finished so I was pretty ham-handed.
I used copper household plumbing fittings in 2" size, (or maybe 2.25") from Ace hardware. I flared them enough to keep the hoses from popping off.
I tried both series and parallel on this car, and found parallel worked better. The other 8 had only parallel and it worked almost as well as this setup which has a larger radiator.
I can use full power as long as I want in any temps, even 118+ degrees with AC off. With AC on, cooling is still compromised and I have to watch what I am doing, temps will still rise under some conditions in the summer here in Arizona.
Last edited by kevink0000; 10-17-2023 at 07:58 PM.
10-12-2023, 03:30 PM
Cooling issues at the track (2010 R3)
