wavehogger

I should clarify myself here. It's not just air temps that are triggering this because I've had it happen on many occasions when the air temp outside wasn't hot, but was actually was cool. If you're running it hard long enough, keeping the revs up and the oil temp gets up past 220 more closer to 240-250, you will feel a power loss as the ECU cuts back the HP, especially in the lower RPM's, it's a dog. A regional rep at Nissan discussed this with me. The power comes back way up past 5K but it still isn't all there. This isn't just specific to the 370z either. I have friends with late model cars that are also very temperature sensitive and even the magazines have commented at times on modern cars pulling power back as they get hot. They ECU is attempting to protect the engine when the internal temps are getting high, since it knows there is more stress on everything. Manufacturers want to prevent failure and of course not have to spend $$ to fix things. Though if Nissan had been smart they would have just put coolers in all the 370z's to help with all the heat this motor creates. But not that many owners will ever get the temps up that high so they figured it's not worth the money.

And of course this isn't the only reason the power drops. I know the basics about how hot air effects combustion and that cooler are creates a denser burn putting more oxygen into the cylinder when it explodes. So yes, there will be a loss of power when the air gets hotter and hotter which happens even if the external air is cool since it has to travel through the intakes, manifold etc. And since the engine is getting hot inside the air will get hotter as it passes through and arrives in the cylinder to be burned. So of course all engines, even carbureted, which I've had many, will have some power loss when everything starts getting hot. And in carbureted motors you'll get detonation if it gets too hot and can blow stuff up easier because you don't have an ECU to say hold up buddy you're about to do some damage. But all this just happens to be compounded with modern days cars whose temps rise fast when they are smaller engines revving higher to create power more efficiently, especially if they are forced induction. So the Z is suffering from both normal power heat loss and the ECU cutting back power. I'm not sure if my original statement was taken out of context without this information meaning the car can't perform at 100% all the time without a cooler. I mean it won't perform at 100% when the temps are up around 240-250 because of multiple reasons, one being the ECU and the other the laws of physics.

So basically, to maintain the most possible HP from the Z an oil cooler will delay the above two processes when the heat is starting to build up giving you a bit more power, until you finally heat soak the entire system. That is what I meant by running at 100% performance for the given conditions that will present themselves.