I meant fine as far as safe, yes you are definitely going to lose power in hot conditions, in part because of the higher intake temperatures but high engine temps don't help either. Cooler is better overall, no doubt.

Oh for sure.

My experience has been that our engines will definitely back off the power purposely when temps get above an acceptable level. Part of the engineering dance to deliver the power level we have (which is easy to lose sight of... remember the venerable R34 GT-R or the Supra RZ? Yeah we make 50+ more HP than they did. Just think about that for a bit.) while maintaining reliability and hitting certain cost points (not having racing radiators and giant oil coolers from the factory, etc).

Well with our engines the temps/timing issue is all about the language you use. It's very adaptable, and it seems to tune timing in both directions until it gets to an optimal point of "just before bad knock." So it's not really fair to say something like "When my water goes over 190 the engine pulls timing on me and I lose power". An equivalent statement that's more correct in its implications would be to say "The car adds timing and makes self-tuning gains when I manage to get the water down to 190". It's not really going by temp, it's going by knock-sensor. Adding more octane rating helps, any kind of cooling always helps. But you'll find you're chasing an unreasonable goal if you never want this engine to "pull timing". It's always pulling timing relative to something, but that something might be unreasonably cold conditions :)

Which is why I always run 100-octane (RON) on the track - it gives the WCU the best chance of maximising torque (and hence power).

We can get 106 Octane (RON) ELF racing fuel (Formula 1 stuff), but it is $A6/litre .... our Formula Ford racers swear by this stuff as it gives them a 2mph advantage at the endof any logn-sih straight and that in FF is a mssice advantage.

However, I am too tight to spend 6 bucks/litre on track day fuel in what is actually my daily driver ..

Yeah what I've commonly been able to find at tracks around here for higher-end unleaded fuel is Sunoco 260-GTX (which is 103 RON, or 98 using the normal average we see on commercial gas pumps in the US). I usually put a few gallons in once during the weekend just because whatever (too lazy to drive to the gas station and/or hoping it helps clean the system or offset some heat).

Once or twice I've filled up on the stuff, but it just costs too much and I can't really tell the difference on-track definitively. How tired/focused I am, how my tire/suspension setup is doing, and whether I've really got my lines down or not all have like 1000% more impact on my lap times than whether I'm running the best gas or not, at this stage :)

Great thread!

I have a track event this weekend and the forcast high is 90 degrees so I am going to log timing to see how it changes as it heats up.

Starting tire pressure will be...15 PSI? lol

Will uprev do that?

I believe you can set when the fans come with uprev.

Yep. You can reset the temp that kicks on the fan. It makes a huge difference.

On the street maybe, doesn't seem to make any difference on the track since you are almost always above the set point.

Cant you also just buy an upgrade thermostat and get the same effect as uprev tuning? Im not the expert by any means I am just throwing that out there for discussion. Thanks for a GREAT thread!!! Sub'd

I just started AUTO X and have been to 2 events and an all day driving school.. Love it. I think for me personally this is where to start learning about driving the car a little harder than street and actually getting a good feel for pedal pressure and breaking and steering so that when you do spin out it is in a parking lot and the most you hit is a cone.

Just my 2 bits.

My driver training day I ran the hell out of my Z for about an hour and some change straight without going over 240 oil temp and no brake problems.. no fuel problems either at 3/4 tank. TWICE. the only think that hurt me that day was the one run with traction control on. after that I was golden.

Once you're above the temp where the thermostat is fully open, I can't imagine it making much of a difference.

Pretty much what Chuck said. By changing the thermostat the radiator will be fully flowing at a lower temperature, but the electric fan still wont kick on until 213F. At highway speed you have enough airflow to make the fan largely irrelevant, but at lower speeds it might be useful to have them kick on a little earlier.

I assume this was auto-x style course instruction? Usually the pace of those is such that you don't really have a temperature issue unless you do back to back to back runs, plus the 2012's have the factory oil heat exchanger at least.