High-temp oil for turbo car

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Posting this at my wife's request: She has a very-highly-modified 1986 Buick Grand National. It's parked for the winter, but a driver in warm weather. The engine is a fire-breathing Stage II stroker (272ci) V6 that put over 700HP down at the wheels (easily 800+ at the crank). As you might expect of a turbo engine making better than 3hp/ci, it's pretty brutal on oil. We have done what we can (big oil cooler, oversized Chevy MDT oil filter, big oil pan), but even with all this, it still sees oil temps over 300 degrees and has topped 350. (Pre-cooler, it pinned the gauge at over 400!)

I think the current fill is 5W-50, I think Castrol Syntec, that being the only 5W-50 we could find on anything like a regular basis. What's in the car was the last of what we had, so we will need to switch. Any suggestions? Mobil or Rotella 5W-40 would seem like it might work...?
 
This is where an ester oil comes into the picture, I'd grab the redline with highest HTHS.

With those mods to support the oil longevity, and temperatures, IMO, the car is not designed to make such power. I doubt you would notice a difference dialing it back a few hundred for most uses.
 
There is a Mobil 1 5w-50 that you should be able to get through Mercedes, Lexus, and possibly Porsche dealerships. I'd use that over Syntec 5w-50 or any xw-40 on the shelf, honestly.

There is also Castrol TWS 10w-60, which definitely is available in large quantities through any BMW dealership.

Both of those oils are race-bred and designed to take very, very high temps -- more than any oil you'll find on the shelf.



EDIT: I second the suggestion to consider Red Line, but it usually isn't available in stores. If you're going to consider online or phone ordering, also look at RLI and Motul 300V.

EDIT 2: OP, have you considered a liquid heat exchanger for the oil?
 
How about M1/Bradd Penn/Valvoline Racing/etc. 15w-50?

No sense going for a 5w or 10w oil when the car is only being driven in warm weather.
 
for anything that high output you have to go Dominator.

A real race oil that actually wins races.

FWIW I run it in a very expensive blown Chevy BB stroker in a go-fast boat. Excellent results per oil analysis.
 
Originally Posted By: Jarlaxle
very-highly-modified 1986 Buick Grand National.


My favorite car of all time!
20.gif


Spare no expense on that beast! Redline,Amsoil,or Royal Purple 50 weight.
 
Those are oil temps that engines are not supposed to operate at so I'd use Redline xW-50 because of the high thermal stability, low volatility, and high HTHS viscosity. I would not use any oil that is mostly Group III.
 
Wow,does this even have any emissions hardware still installed? By rights,visual inspection is still required even in (Calif standards) New England.
 
Originally Posted By: SteveSRT8
for anything that high output you have to go Dominator.

A real race oil that actually wins races.

FWIW I run it in a very expensive blown Chevy BB stroker in a go-fast boat. Excellent results per oil analysis.


Yes, this or Redline.
 
You might want to look at VW502.00 spec synthetic oils. They for formulated for turbo engines. Examples:
- 5W40 Syntec/Edge
- 0W40 Mobil 1
 
Originally Posted By: d00df00d

EDIT 2: OP, have you considered a liquid heat exchanger for the oil?


This is a good suggestion. I know that it were mine, I'd be investigating ways to lower the oil temp.



How is the car driven normally? What are the bearing clearances like? Those temps seem a bit high if you're out of the throttle a lot. Also, what are your hot oil pressure readings?

While I'll freely admit that my experience with big power turbo cars is quite limited, as I'm sure your aware, that engine isn't making 700hp all the time and I would expect the heat to be a bit more manageable while off the loud pedal.

EDIT: As for an oil recommendation, I'd say, Red Line, RLI or Amsoil. Any of these places you can call and get a knowledgeable person to help you purchase the correct product from their line.
 
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I third or fourth the RedLine, Amsoil suggestion. These are two companies with a lot of races under their belts, with highly modified engines under extreme environmental pressure.
 
No one else mentioned that you wife is super cool for having such a killer car.

Synthetic, definitely. T6 or Amsoil would be my call.
 
Isn't Shell Rotella T6 a Group III+ product? I think this case is one of the few in which it is appropriate to seek a product that is made with group IV/V base stocks because the conditions are so extreme.
 
Originally Posted By: d00df00d
Isn't Shell Rotella T6 a Group III+ product? I think this case is one of the few in which it is appropriate to seek a product that is made with group IV/V base stocks because the conditions are so extreme.



I would agree. T6 might work on short OCIs, depending on how this car is driven. Methinks something like Redline or 300V is a good bet.

Maybe give Bill at RLI a call and see what he thinks? Their 5w40 might work well.
 
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