My '04 350 overheated while on track today. When the temp needle rose to the last hash mark, the rev limiter (at least it felt like the rev limiter) began to cut in at around 5k revs. As soon as the engine cooled off a bit after a lap or so of more casual pace, the car ran fine. Until it heated up again, then the same thing happened.

Yes, I should have been more observant of the temp. No doubt about it. I am now. I wasn't then, so enough on that.

My question is: did the engine management kick in the rev limiter to protect the engine when the temp got high enough?

 

Yes. ECM function is similar for input from sensors such as engine coolant temperature sensor. ECM will cut fuel. The actuator is the fuel injector. The ECM will not allow the motor to run past 1,500 RPM. Applicable codes are :
P0117
P0118
P0125

 

We use Red Line water wetter in our radiator. There is also a larger radiator available but we haven't put one in yet. We also use Red Line synthetic oil, maybe some heat is taken off in that way too.

 

Sounds like you may need to invest in an aftermarket oil cooler.

 

Looks like Davidv answered your question....

What cooling mods do you have?

Aftermarket radiator, oil coolers, oils..etc.??

The Redline water wetter is a great suggestion, i have used that stuff before and it helps!

-J

 

out here in the heat!!! Welcome. What part of AZ?

 

Whatever was going on, it allowed the car to rev to about 5k. I wasn't limited to 1,500.

Stillen aluminum radiator, Stillen oil cooler, Stillen power steering cooler. The motor is stage 2 Stillen supercharged.

 

The M45 and MP62 units are notorious for heat soak. Keeping it cool on a road course is going to very hard.

Does the unit have an intercooler? If not the intake heat will heat up the rest of the system.

 

Yes, it's intercooled.

Just prior to the track day problem, I had the coolant changed by a shop I trust. I therefore assumed the cooling system was filled to capacity. Nothing was leaking at the track, so I dismissed low coolant as the problem. But, now that things are cool and I could easily check the coolant level, I found the radiator took 1/2 gallon of water.

Is the system being down 1/2 gallon enough to cause the overheating? Also, there doesn't appear to be an overflow tank. Does that make any sense or am I just missing it despite having looked fairly carefully?

 

you might want to invest few bucks in a REAL water and oil temperature gauge... keep running until the ecu kicks in isn't a brilliant idea if you want your engine to survive for a while. at least you can diagnose the issue and understand what needs better cooling.

 

In my original post I already admonished myself for failing to pay attention. It happened. I already said it won't happen again.

Now how about we figure why it overheated, starting with whether being down a 1/2 gallon on coolant will do it.

 

Is it possible they didnt properly bleed the coolant system of air? I hope so else your losing coolant somewhere internal.... But you would have seen white smoke.

I'm going with not properly burped just off what you said.

 

if you have the stock radiator cap it opens at 0.9 bar... that could be a reason.. for what I have seen the stock needle doesn't move a hair at boiling point... so your fluid was boiling and generating pressure big time.

I never lost 1/2 gallon.. but 1/4 yes, during the summer, than I changed the "mix" using 80% water, 2 bottle of water wetter and rest regolar coolant and 1.3 bar nismo radiator cap... and almost no water loss.

I forgot.. I also added a 19 row setrab oil cooler and I haven't disconnected the stock oil to water heater/cooler.

 

I'll try it. Thanks.

 

I ran a couple more sessions today. Topping up the radiator helped, but it still overheated so the problem is something more complex. Dang.

I have a 1 bar cap. It's not the 1.3 that was suggested, but it's better than the .9 OE cap. I'll try the water wetter, as well, before I start on more expensive stuff. What a pain in the neck it's going to be trying something, then going to the track to see if it works. If it didn't work, then try something else and wait for the next event to see if it worked, etc.

 

My guess is the oil temp is creeping up before the water temp ever does. The extra compression and higher intake temps are allowing the oil temp to creep up. How big is your oil cooler? Thought about a remote oil filter and an accusump system to add more quarts to the overall setup?

 

There is your problem. I see VERY few FI'd 350Zs on the tracks that can manage the heat. I don't have any special solution that hasn't been mentioned (or you don't already have), but you are in good company. Ask Steve, since you seem to have a good repertoire with them.

 

I think they are right about the heat soak issues and the FI package. Tracking a hot setup like that may require several custom mods to cut the heat issues. Once you've checked off the basic items, consult Stillen for problems they could have run into when testing.

 

What coolant/water setup are you running? You should invest in evans, since it's used in racing. I would also suggest the racing radiator cap.