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Ill cut all the BS and just give the built points!
APS TT, Built with L19's and HKS gasket. 10K miles on motor. 11-12psi 460ish WHP. Rev limit is 7.2K
- The car suffers from high coolant temps on tack (road course not drag)
- Coolant is 90% distilled water, 10% anti freeze with 1 bottle of water wetter.
- It has a low temp thermostat (tested in boiling water and it opens fully), I did have a 36mm koyo rad OEM fans, swapped to 53mm Koyo rad with slim mishmoto fans (set to come on full at 180F)
- AC deleted, Basic all ducting from grill to IC
- Mocal 25 row oil cooler, Oil temps are from 75C (stat temp) to 120C on track.
- Front splitter and under tray along with a vented CF bonnet.
- Swirl pot on turbo returns and nismo 1.2 Bar cap
Im suffering high coolant temps on track, on wet days when i can't rev out as high or use as much WOT, my coolant peaks around 210F-215F with 15 min sessions on dry days it can hit 230f in just a few laps!
I have had a small amount of coolant push out the APS expansion tank but that was after filling it to around half full at the track, (may have added too much?) It does not spray out or anything (Ive ran the car on track with no bonnet so would have seen this surly? )
Any help? Cant have head lift at 11-12psi on L19's and HKS can i? I don't over heat on the road or in traffic so not a fan issue. I have changed rads and bled the system a few times and stat does open so i don't think its air locked, changed rad caps etc.
I have no mayo in the oil and the car I dont think is burning coolant? No sweet smell or steam from exhaust?
are you giving the heat-soaked air a route to escape?
the cooling fans are not the solution ... after thinking about your issues I think they are the problem...
You will dissipate more heat from passive air flow than you will from any fan setup. Fans are used for 30mph and below...any speed higher and your passive air flow does the work.
In a round-about-kind-of-way if you're cooling fans are blocking, hindering, impeding, passive air flow from your radiator they are part of the problem.
If the fans are coming on at 180* then they are limiting your airflow when you are at speeds higher than 30mph. If you are doing 100mph and your fans are moving 10mph worth of passive air than you are restricting yourself.
Can you remove the fans all-together for a session and see how your temps do?
You got any pictures of the engine bay?
I've said this a million times but I'm not a fan (ha!!) of Mishi nor Koyo ... I run a 4"(100mm) C&R Racing (NASCAR hammy-down) and I've never had cooling issues. I reached 103* C during my dyno sessions a few weeks back. Granted, yes - I have never tracked(road course'd) my car...
you don't need 12psi of boost to pop your heads ... a bad tune can do that for you without effort!
I would consider switching to Evans coolant so you do not have to worry about steam pockets. I don't think you have a HG issue but you might if you don't control temps. Coolant expands significantly when hot so you want your overflow tank to be nearly empty when cold.
I use the thick Koyo and a pair of 12 inch SPAL puller fans (30102044) that sound like jet engines. Never had an issue pushing the car hard on the airstrip or in mountain runs. Fans appear to be a weak point in your set up. High revving around a track with a high number of turns (slow track) will be hard without a great cooling system.
I have looked into Evans but heard good and bad things about it. It raises temp in the motor but stops pocket boiling.. I'm not sure what's better?
I may test running no fans at all and see how that works on track to see if it is improving with more air flow.
What do you think about adding another oil cooler to aim for more like 100c oil temps rather than 120c?? Can't make it worse IMHO.
So you overheated with the bonnet/hood on??
I would do a leakdown / compression check first to make sure that headgasket is okay
I know for a fact that mishimoto fans suck .. go on YouTube and check for mishimoto fans generic fans vs SPL..
if the head gasket is good I would replace those with SPL High flows..
I moved my oil cooler to the passenger side and power steering cooler to the driver side away from the intercooler
I had to switch out front bumper designs to allow more airflow to keep my cool on track and a vented Hood
Last edited by vegasanthony; 06-12-2017 at 02:57 PM.
I would consider switching to Evans coolant so you do not have to worry about steam pockets. I don't think you have a HG issue but you might if you don't control temps. Coolant expands significantly when hot so you want your overflow tank to be nearly empty when cold.
I use the thick Koyo and a pair of 12 inch SPAL puller fans (30102044) that sound like jet engines. Never had an issue pushing the car hard on the airstrip or in mountain runs. Fans appear to be a weak point in your set up. High revving around a track with a high number of turns (slow track) will be hard without a great cooling system.
I am a firm believer in evans. I read the same things about it increasing temps.... but I talked to more than a couple people/shops with experience running it. all were positive.
I would say the only concern is that some tracks don't allow it. that said, they may now have a track approved forumula
the way the APS turbos are fed with coolant, if you run a water based coolant, eventually you will get localized hotspots and it will downward spiral into over heating.
We had some hot temps lately 90-95... I had my car out. I have a temp gauge right were the turbos feed back into the heater core outlet. never gets above 200. I see pretty consistent 195-199 temps.
I have switched my S2000 and my evo over to evans as well.
I have looked into Evans but heard good and bad things about it. It raises temp in the motor but stops pocket boiling.. I'm not sure what's better?
I know what's better! That's why I recommended Evans! Agree with Zivman, also sold on it when fan failed and temps approached 300. That was last year and still running great (after fan replaced).
Steam pocket and temps can skyrocket. Yes water is a better heat conductor but the risk of melting metal parts is just too high. Evans will run hotter so you need a better cooling system but it will be much safer because it does not produce steam.
I was worried about potential higher temps with Evans too but 2000 miles with Evans so far (Mishimoto radiator and stock fans) and coolant temps have been on par with the readings I'd get with water in the cooling system. Outside temperature's have averaged 100+ degrees the last few weeks and we're supposed to hit 120 next week.
Wasn't at the track but the last couple days in Arizona have averaged just over 115, my car hasn't skipped a beat though.
Cooling system consists of a Mishimoto radiator, stock radiator fans, and Evans water-less coolant.
The rest of the setup includes a built motor (block was previously machined for HR head gaskets but running HKS gaskets), PowerLab single GT35R, CJM return fuel system, E54 for fuel, etc.
Wasn't at the track but the last couple days in Arizona have averaged just over 115, my car hasn't skipped a beat though.
Cooling system consists of a Mishimoto radiator, stock radiator fans, and Evans water-less coolant.
The rest of the setup includes a built motor (block was previously machined for HR head gaskets but running HKS gaskets), PowerLab single GT35R, CJM return fuel system, E54 for fuel, etc.
So hard, My car never has an issue on the road. Just like that. Oil is around 100-105C and coolant around 200F max. On track is a different ball game!
Car passed its HG test, I fitted another 25 row oil cooler (2 x 25 row -12AN oil coolers now) and cut a large hole in the front bumper plus drilled more holes in the front crash support. LOTS more air flow to the rad that bypasses the IC..... Over heating basically solved!
Still running a little hot peaking around 220f after 4-5 laps but loads better than before!
ill add my 2 cents being from Arizona with a polished built engine... (which is INSANELY radiantly hot.) air flow to the radiator is the #1 thing you have to make sure is perfect.
If I don't have airflow OVER TOP of the fmic to the radiator, the car would overheat on the freeway , not even under boost. I trim back the underside of the nose hole bumper center opening, and DUCT it to the radiator above the fmic, don't just leave it open.
The bumper usually needs bigger openings.. all openings also need to be solidly ducted to the radiator...as casual openings without guiding side panels inside the bumper to block the airflow from just escaping below the car, etc will kill your cooling.
Air goes to the easiest spot to flow, and the radiator is NOT it unless you force the flow.
using a track day hood with a slot cut across the area just behind the radiator can help also, as well as a small gurney flap on the top of the radiator trailing edge, or the hood slot as well. This will disrupt flow over the hood, but i doubt that's the big fish to fry here.
so recap, solidly directed air from any hole straight to the radiator fmic is a must.
Use some cardstock or cardboard in order to make templates as your bumper can crush in on it and make quicker work of finding the req shapes, then trim the final planes out of whatever material you're comfortable with that will withstand the front air pressure.
You will see the biggest change w this. made a huge difference in temps for me, and now that I plan to start doing hpde days, I plan to get much more involved w this issue.
06-11-2017, 07:24 AM
Overheating Built TT car... Only on track.
Fingers crossed I dont!
