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Overheating issue on track

Joined
3 April 2012
Messages
521
Location
Saint Paul MN
I was hoping some of you more experienced track guys could help me out. I was at the track this past weekend, I got a total of 6, 20 minute sessions (1 hour between each session). For the first 4 sessions I took it pretty easy, driving about 6/10's of my ability, and for the final 2 runs I drove closer to 9/10's of my ability. Towards the end of my 5th and 6th sessions, I noticed my temp gauge went up to about 3/4 of the way, at this point I immediately let off and drove her back to the pits to cool off. My temp gauge has never moved above the 1/2 way point, and always stays there once there, so this had me a little concerned. It is also important to note that prior to my 5th session, my car had been running (idling) for about an hour with the AC on, and I did not shut off the AC until the second that I left the pits to get onto the track.


92 NSX, no engine mods. 70k miles, coolant hoses replaced 5 years ago, no coolant loss from overflow, no visible coolant in oil.
Outside temp was about 85-90 degrees
I have put about 200 miles on my car since, without any issue or overheating.

I will be changing the coolant this week, and doing a closer inspection for any coolant loss. Is there anything else I should be looking at?

Thanks guys!
 
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Run some water wetter. Are you open to running a vented hood?

I dont think Water Wetter is a good option for me, as I live in climate that is below 0 degrees for most of the year :/

A vented hood sounds like a good option, and if it is "required" that makes it a lot easier to get the wifey's buy off on it, lol.
 
If you see more track fun times.. you really need to consider an external temp gauge. The dash idiot gauge is not the most telling. 3/4ths is already very HOT. IIRC correctly that's already above 230F.

I monitor my ECT diligently and a fluctuation from the operating temp range of 76C - 98C doesn't even blip the OEM gauge. It moves an incrementally small amount - which is good as to not alarm the daily street driver. However at the track once mine hits 95C I back off the rpms and my alarms start going off.
 
RYU is something that reads the OEM coolant temp sensor over OBD2 adequate? Or should I install a sensor in the spot recommended by SoS?
 
RYU is something that reads the OEM coolant temp sensor over OBD2 adequate? Or should I install a sensor in the spot recommended by SoS?
An OBD2 digital readout scanner that's been calibrated properly is much better than the dash gauge. That's why I was mentioning in another thread that the OBD2 has its advantages. Use a Bluetooth OBD2 reader and the Torque App to get started. It's a little laggy but will do the job for starters.

I have an HKS F-Con iS that's the only unit I know about that reads off the Honda OBD1 sensors. I read my ECT from the OEM sensor.
 
You shouldn't need water wetter if your coolant system is up to par. I would check the radiator to make sure it isn't blocked by debris or anything. Check your system to make sure you have all the air out of it as well. I've run hot with my NSX in complete stock mode. It is usually the last 1000rpms that would push it to run hot.

As for water wetter; it contains anti-oxidants, anti-corrosion and metal inhibitors just like regular coolant, but without the Ethylene glycol. That is why Redline suggest you run distilled water with it. It does not react well with some coolants. I've seen some horrible "gunking" sensations with it. It is good for when you can't run coolant at a track or drag strip. It still isn't better than coolant since the boiling point is raised with coolant, and that is what you really need. Bobtheoilguy.com has some good info on this topic.

ProEFI will run most OEM sensors from what I was told, but since my car is a 92' I decided to just replace all sensors while I was at it with new ones from ProEFI. After Pikes Peak International I am getting mine installed, and give you a write up on it. Should have a before install dyno tuned map and an after install dyno tune map to show.
 
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Take a very close look at your coolant bottle if you are still running the OEM unit. They can develop a hairline crack around the filler and when the coolant gets hot and the pressure rises the crack allows the pressure to bleed off. You need pressure to raise the boiling point of the coolant and keep temps under control. Without the proper amount of pressure in the system you will develope air pockets in the coolant system. Check and bleed the coolant system after the car sits for a while if you get any air you may have a bad coolant bottle. Any air in the coolant system will cause the coolant temps to rise slowly at first then fluctuate up and down.

This is a common failure that shows up at the track since you have to push the car hard and stress the coolant system for it to show up.

Dave
 
^ this is what i was going to say too.

I think you just ran it too hard for too long. I am able to do like 8 laps before I want to come back into the pits and cool down both the oil and the water. If your water is getting that hot imagine the oil temps.... I suggest getting an after market gauge for oil and water temp. OEM ones are pretty much useless like RYU said.

its a good idea to check the hoses under the car too. If the oem ones are slacked at all they'll rub on the oem plastic under cover. if your under cover is beat up theres a possibility the your rubbing a hole in one. I would check these regularly when tracking.

There is so much water line in the NSX thats you shuold run at external light. I have a water temp sensor and a water pressure dummy light. that triggers under 6psi. Once the system is warm and pressurized the dummy light on my dash turns off, if it ever comes back on while im on the track it means that I have lost pressure in the system. (very bad thing) and its critical that i get off line (as not to soak the track) and shut the car down.




another thing is if you have silicone hoses DO NOT run the OEM clamps. get some good t-bolt clamps in the correct sizing. the silicone hoses have a thinner wall that the oem ones and the clamps wont tighten around them as much as they need too if your running a high pressure water cap.
 
another thing is if you have silicone hoses DO NOT run the OEM clamps. get some good t-bolt clamps in the correct sizing. the silicone hoses have a thinner wall that the oem ones and the clamps wont tighten around them as much as they need too if your running a high pressure water cap.
water pressure.. great idea!

I remember those silicone hoses haha! can laugh about it now. Not so much fun dealing at trackside.
 
water pressure.. great idea!

I remember those silicone hoses haha! can laugh about it now. Not so much fun dealing at trackside.

Oh my god, that was such a fucking nightmare- being covered in hot sticky glycol and brake dust all day was as fun as it sounds. So glad everyone was there to lend a hand!
 
As a veteran of several horrible cooling issues with my NSX on the track, I agree you should check your coolant bottle and connections first. One trick is to crack the bottle cap WHEN COLD and you should hear a hiss as the pressure is released from the system. No hiss means there is a leak in the system and it cannot pressurize to control the temps. If you have a stock engine (no FI, high-comp, etc.), the car should be able to manage most 20 minute sessions just fine. 3/4 mark on the gauge is very hot and usually indicates a failure of the system somewhere. In my case, it was the head gasket. :(
 
I ran at Willow Springs this past weekend, radiator is a Mishimoto with less than 20kmi on it, all hoses and coolant were just replaced.

It was a HOT weekend, and once outside temps got over 105 degrees F, my coolant temp would start to creep up. Gauge has never moved from the halfway point before this weekend... my first sign of an issue was I could hear a gurgling sound behind me (assume coolant boiling), looked at the gauge and it was halfway between normal and red. Pulled off to look for issues, coolant was still full, no leaks. Ran the rest of the weekend with the heat on full blast (I think one of the instructors that went with me for a ride was ready to pass out by the end), and still had to shortshift to keep gauge from creeping up.

I was very careful to bleed all air when I added coolant after replacing the hoses, so I dont think that is the issue. Has anyone solved a running hot issue at the track with the vented hood? Or an added oil cooler? Or maybe improved radiator ducting?
 
It was a HOT weekend, and once outside temps got over 105 degrees F, my coolant temp would start to creep up. Gauge has never moved from the halfway point before this weekend... my first sign of an issue was I could hear a gurgling sound behind me (assume coolant boiling), looked at the gauge and it was halfway between normal and red. Pulled off to look for issues, coolant was still full, no leaks. Ran the rest of the weekend with the heat on full blast (I think one of the instructors that went with me for a ride was ready to pass out by the end), and still had to shortshift to keep gauge from creeping up.

I was very careful to bleed all air when I added coolant after replacing the hoses, so I dont think that is the issue. Has anyone solved a running hot issue at the track with the vented hood? Or an added oil cooler? Or maybe improved radiator ducting?

The gurgling sound you hear is likely air in the system or a leaking coolant bottle but with 105*F it will be very difficult for the OEM coolant system to maintain anywhere near a normal operating temp, I am not sure that is going to happen. Everything you have listed to try will help and will extend your run time till you overheat but the OEM coolant system while good is not going to be able to handle that heat load for very long. It is difficult enough to run 20-30 min sessions with ambient temps above 85*F at full song, 105*F is just going to be torcher. You could also remove the fan and shroud for maximum cooling while the vehicle is moving but if you do this you will have to manage your cool down and idle heat issues on your own and I think if I was to take that step I would want a very accurate coolant temp sensor to work from and not the OEM unit.

Another option is to separate the engine oil cooling from the engine coolant system. Now the two systems are joined by the water to oil cooler located just above the oil filter, and the two system feed each other. This is great for bringing both oil and coolant up to operating temperatures together. Once you start to heat soak the coolant system it looses its ability to remove enough heat from the oil system and oil temps rise, this raises the demand on the coolant system even higher. If you add an adequate external oil cooler, separating the two heat loads should extend the coolant systems operation further before heat soak occurs. Once seperated care will need to be taken to monitor oil temps separate from coolant temps as without the water to oil cooler the oil will take much longer to get to operating temperature. Ideally for a street/track car a solenoid operated bypass of the coolant system would be best so once the engine coolant and oil temps were up to normal operating temps the two system could be isolated, for a track car completely separate systems with a large oil radiator would be best.

Dave
 
sounds like you have a leaking coolant reservoir....is it oem? I always run the heat on track..low fan..windows down...just increases the efficiency of the coolant system
 
I ran at Willow Springs this past weekend, radiator is a Mishimoto with less than 20kmi on it, all hoses and coolant were just replaced.

It was a HOT weekend, and once outside temps got over 105 degrees F, my coolant temp would start to creep up. Gauge has never moved from the halfway point before this weekend... my first sign of an issue was I could hear a gurgling sound behind me (assume coolant boiling), looked at the gauge and it was halfway between normal and red. Pulled off to look for issues, coolant was still full, no leaks. Ran the rest of the weekend with the heat on full blast (I think one of the instructors that went with me for a ride was ready to pass out by the end), and still had to shortshift to keep gauge from creeping up.

I was very careful to bleed all air when I added coolant after replacing the hoses, so I dont think that is the issue. Has anyone solved a running hot issue at the track with the vented hood? Or an added oil cooler? Or maybe improved radiator ducting?
Could you clarify if you have a vented hood (or not)?
 
Forgot to mention that I replaced the coolant reservoir with a new OEM along with the hoses.

I currently have a stock hood... when I mention converting to a vented hood I mean the type r setup.

Gurgling/boiling sound went away as soon as I turned the interior heater on and the temp began to drop. Just took a quick look at my car and it appears that there is enough room to run a radiator with a core about an inch thicker than my mishimoto unit. Does anyone manufacture a larger radiator? Maybe I'll try building one... would be a good excuse to buy that TIG welder I've been wanting :)

I'm sure a liquid to air oil cooler would help things, but I'm a fan of having the coolant work with the oil, plus it would add a bit of plumbing and complexity (compared to a larger radiator), though on the plus side it would be easier to add an accusump.
 
The vented hood helps quite a bit. Though the Mishimoto isn't the best it might just be enough. Take a look at the link in my sig. We went thru quite a bit of radiator testing here in SoCal and have ran Spring Mtn. So far so good.

What did you think of the Driving Ambition Dual Pass Racing Radiator vs. the one you chose?
 
I was hoping some of you more experienced track guys could help me out. I was at the track this past weekend, I got a total of 6, 20 minute sessions (1 hour between each session). For the first 4 sessions I took it pretty easy, driving about 6/10's of my ability, and for the final 2 runs I drove closer to 9/10's of my ability. Towards the end of my 5th and 6th sessions, I noticed my temp gauge went up to about 3/4 of the way, at this point I immediately let off and drove her back to the pits to cool off. My temp gauge has never moved above the 1/2 way point, and always stays there once there, so this had me a little concerned. It is also important to note that prior to my 5th session, my car had been running (idling) for about an hour with the AC on, and I did not shut off the AC until the second that I left the pits to get onto the track.


92 NSX, no engine mods. 70k miles, coolant hoses replaced 5 years ago, no coolant loss from overflow, no visible coolant in oil.
Outside temp was about 85-90 degrees
I have put about 200 miles on my car since, without any issue or overheating.

I will be changing the coolant this week, and doing a closer inspection for any coolant loss. Is there anything else I should be looking at?

Thanks guys!

Exactly what happened to me and my 1992 this past weekend. This car gets HOT quickly! I really do not like the idea of changing the hood though.
 
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I always overheat on track. Had sos build me bigger radiator with custom fan shroud and dual fan setup. Problem solved. This with 700 hp
 
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