Good to have a real auto enthusiast here. It’s hard to find high speed freaks like me around here. Glad I found you. I will share with you ways to overcome your cooling issue. First, Here are the very important links to some of my work. I will post the part with cooling fan temp PCM modification soon :
Installing the largest possible radiator for your 370Z - Part 1
Installing the largest possible street racing radiator for your 370Z - part 2 FINAL
I am a high speed driver as well. My favorite part when it comes to highly spirited driving is doing super high speed. 130 mph is nothing if the 370Z is properly and professionally modified (Of course it is not that cheap ). I used to own a 2009 GT3-RS and 130 mph was like lunch everyday. Loved that car every minute of it, until my damn brother severely wrecked the car 2 years ago.... Yikes......... Anyway, this is the ultimate and reliable way to cool down your engine considerably.
The fact is this VVEL cylinder heads act like a heat pump. Very nice design but thermally very inefficient .They generate a tremendous amount of heat that you would not believe. These below are the true weaknesses of the VQ37VHR oil and water cooling system , and that's why the engine temp itself runs very hot, and thus the super hot oil temp :
1)) Factory radiator is flimsy and very thin. The whole cooling capacity is only 9-1/8 quarts. After the engine fully warms up for 30 minutes and especially at 85F+ ambient temps with highly spirited driving, this radiator could never cool the engine down below 217F.
2)) No factory oil cooler
3)) Engine Oil capacity is very little. Only 5-1/8 quart
Well, I think Nissan engineers know well this design will allow the engine oil overheat to 285F in no time under high speed / load / rpm driving . But this is the best that they could do in order to keep down the cost of the car.
So, :
1)) You need to have the Mocal thermostatic oil adapter and a 25 row oil cooler ( Setrab is the best ) installed.
2)) You need to modify to this dual row large radiator as shown in the 2 links above
3)) Using Uprev – tuner version and reprogram the fan duty cycle so that the fan will turn on at lower temperatures. This is VERY important since factory setting will NOT allow you to fully utilize this large radiator capability. Please see these links for stock fan setting and modified fan setting, respectively :
http://i1061.photobucket.com/albums/...ckradiator.png
http://i1061.photobucket.com/albums/...fansetting.png
4)) Install a Greddy oil pan ( My future project soon… )
Notice : Step 3 is VERY vital. If you retain the factory fan setting, you will not be able to utilize this radiator to its fullest capability. This is where it gets the coolant temp down to about 195F , and thus considerably cools the oil down way further. A must for twin turbo 500whp package
Step 4 is also very important. Not only this Greddy oil pan adds another 2 quarts of oil, which further cools down your oil temp, there are baffle plates that will help to minimize or eliminate the oil starvation. Believe me on this when you start rpm the car at about 7000+ while pulling a 1.3 to 1.4G turns .... and this VQ37VHR does NOT come with a secondary scavenging oil pump.
After everything that I have done above ( Except with the Greddy oil pan ). I did drive at a 5 mile real hard driving on HWY 9 ( Rpm from 5500 to 7600 rpm constant ) at about 88F – 90F ambient, my oil temp NEVER got passed 215F. In comparison with just the 25 row oil cooler alone before, I was up to about 250F all the time. And with no oil cooler, it went up to a dangerous level of 280F+, almost put my car in limb mode…..
Remember : Heat kills your engine. How do you think the Carrera 4, GT3, Carrerra Turbo can survive that heat in super high speed and high RPM ? The reason would be because they have 9+ quarts of oil and a 25+ quarts cooling capacity. You can verify these specs yourself. The VQ37VHR engine is not quite as stout as Porsche and may not last as long under severe and high speed drivings, but it is plenty strong and will last for a while if you keep it cool enough .
Good luck.