Thread: Coolant Temperature and Power

One other disadvantage in addition to all those pointed out is higher combustion temps can lead to NOx emissions in excess of those which the emissions control can handle, particularly at idle lower revs (~2500 rpm). Like Ben with a Koyo, half 50% coolant mix, a bottle of Water Wetter and the rest distilled water, I find my op temps consistently close to 180 deg. I never see the fans operate unless the A/C is activated under the right conditions as in above chart.

I run a thin mix with mostly water partly because if I leak on the track or in a track garage, it would be much easier to clean up. I've even checked the engine, radiator neck, etc, with my thermal laser just to see what gets hotter than is picked up by sensors, and it bears out the same story. One curious thing I found was my wheels actually get up to almost 200 deg in front with tire temps in the 170's and rotor temps low 200's. Never expected that until I just about burned my hand on the front wheel after 60 minutes on course.

Yup I can see that being the case, but I'm not planning on running anything higher then stock. I'm more of looking to run the same temps as stock, instead of trying to keep it at 185 all the time and running the fans just about all the time hehe.

...and by 230 deg F oil temps, you risk thermal breakdown of the oil depending on its TBN (Total Base Number, a relative number that describes how much base there is in your oil relative to the amount of acids that have built up).

250 and above almost any oil is going to shear and you'll be done. Clearly oil temps can easily exceed coolant temps, so 220 deg F coolant your oil could easily be +10 deg F above that.

Something additional you may want to consider for your turbo-based motors and track use vs. general use for high temperatures:

MY350Z.COM Forums - View Single Post - VQ Oil Analysis and Info

Ester based oils tend to resist shear better and are popular for racing oils, but they suck at moisture content, cold-start and overall long term wear, etc. Something that seems to have traction in the FI 350Z world is switching to a very different oil for track vs. street use.

Sorry if a little OT but given the oil issues we've seen and FI motors overheating on the track, Will's stuff at the above link is pure gold. He really knows his stuff.

If I was running FI particularly I'd be getting a UOA done regularly to see what's going on there. My lowly NA motor I am less concerned using a good oil, but I will do the UOA for my VQ35DE because of the downside of wrong oil choices and hard use, high temps.

Oil temps are definitely important, eventually I'll look into an oil temp gauge and coolers.

This is part of the reason we have to change our oil more religiously, turbo puts some good heat to the oil hehe.