So I have a turbo 3.1 running about 7-8 psi. If I run it hard I can see temps around 240 degrees F. It seems to run best with the temps over 200 and spools better. I have regular 5w-30.

What are upper limits for oil? Or, when does it start to burn up? I was thinking of going synthetic to help with spooling.

I use 15W 40 Mobil 1 exclusively in boosted engines. It can survive at temps that kill petroleum based oils, even over 300*F. With a turbo a good cold air intake system really helps. Run the air from the side vent in and the air charge temps should drop.

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87GT 3.4 Turbo- 0-60 5.2 seconds
2006 3800SC Series III swap in progress
Engine Controls, PCM goodies,
re-programming & odd electronics stuff
" I'M ON THE LOOSE WITHOUT THE JUICE "

My oil hit 255 today. (I was going 110 mph and it was 90+ degrees out). Normally runs 220 at 70mph cruise on a 90+ day and I run an oil cooler and a TH125c auto. I really need to move that temp gauge sensor to the oil cooler output side though. I can't see the temp drop from the cooler yet. (mounting issue)

[This message has been edited by Hudini (edited 07-09-2007).]

I notice that 220 is about normal but when I go crazy, just boosting thru the gears, it does jump to 240.

I have no oil cooler and, if I was racing or doing some performance driving, I guess I would need one. But, for now I appear to be okay.

I do have a CAI.

So around 300 is not good. If so I have a margin of safety.

How about the sythetics? If would be great to get some quicker spool ups.

I never measured oil temps in mine. I used a 160* stat, and it never whent over 180* (stop n go traffic, august heat). Mine would barely run with a 195* and only slightly better at 180*. I ALWAYS use synthetic in turbo engine because its very resistant to heat. Dont take a lot to coke up and destroy dino oil. I didnt have an oil cooler either btw.

Use synthetic oil! An oil cooler will help with your oil temperatures, but the real problem comes when you shut the engine down. The oil in the turbo bearings gets cooked by the residual heat in the turbo and reaches temperatures that'll break dino oil down.

Watch out for the oils that say synthetic on the label but are nothing more than processed dino oil. The real thing will cost $4 or more per quart - and it's worth it in your applicaiton.

if your turbo also has water cooling lines ,coking is not usually a problem .i also use mobil one in my turbo .but in a flat lifter motor you should use synthetic race oil because oils for modern production engines dont have enough zinc additive to prevent lifter wear .mostly ,this is a problem in fresh rebuilds .

Yes, I have a water cooled turbo. I made sure of this, being the location of the engine and lack of air circulation. Though I wonder for those running ultra low thermostats, if the engine is ever warming up.