Oil for turbocharged cars on a stock motor *Warning*

[jaffaz32]

When researching recommendations for oil.

Members may say they are running a thicker oil for example w50.

This is more than likely on a built motor and not a stock motor with factory clearances.

I just wanted to make this a little more clearer because when researching you can very easily jump to the conclusion it's ok to just put in 15w50 on a stock motor.

 

[foundry3]

I run 10w30 Mobil VR1.

VR1 has added ZDP which is awesome for turbo bearings and added wear protection on your engine.

 

[peiserg]

I've been running 10 30 on my SOS stage 2 forged C32 build for years. That motor is built like a brick shithouse. It is the cat's ass.

 

[kingtal0n]

Oil viscosity needs to match the engine's clearances and use.

If I have a tight engine with .0008" bearing clearances, such as many nissan/toyota engines come OEM, I will need to use an 5W-30 or 10w-30 oil (as temperature goes up in our climate, we use thicker oil also, according to the FSM)

If I am building a new engine, and it has large clearances for racing and high rpm and minimal drag... the engine will not last as long as a tight OEM engine, and, it will use a thicker oil all the time, such as 20W-50.

As someone mentioned "ZDDP" there is some addition to oil I believe all oils contain, however, oils intended for regular passenger vehicles (like typical off the shelf oils such as mobil-1 for car engines) will have much less of this "ZDDP" which is an additive intended to protect your bearings (and other metal contact locations like tappets) and the reason they put LESS of it in "normal car oils" is because it will damage modern catalytic converters.

So if I were in your shoes, I Would find an oil that A: Has as much "ZDDP" in it as possible (if you have no cat), and B: Meets the viscosity necessary for my bearing clearances.
I would then take one more step and use an oil pressure gauge to verify that I am at least in the right ballpark (great oil pressure when the engine is full hot, with 220*F Oil, at idle, is a good sign)
Keep in mind that the oil pressure you see on the gauge does not reflect the flow of oil in the engine. You can see 65psi on the gauge, but if you are using a very thick oil (like 15W-40) in a tight engine like we just discussed, oil may be at a trickle by the time it hits the top of the engine.

 

[A.S. Motorsport]

When researching recommendations for oil.

Members may say they are running a thicker oil for example w50.

This is more than likely on a built motor and not a stock motor with factory clearances.

I just wanted to make this a little more clearer because when researching you can very easily jump to the conclusion it's ok to just put in 15w50 on a stock motor.

Do NOT put such thick oil in a stock NSX engine, I've seen NSX's damage cam's, heads, v-tec issues due to running 10W60 oil.
I would not go above 10w40 in a stock NSX engine, the oiling system (bearings spec, channels, etc) isn't meant for such thick oils.
If you're running in to heat issues there are a number of ways you can reduce heat.

In a purpose built motor there is much more flexibility.

 

[kookoo4nsx]

Unrelated I purchased a 25' boat with a 502 Mercruiser EFI. Stock 415 prop hp which is about 450 at the shaft. The guy I bought it from said he would change the oil for me before the deal closed. It ran great BUT the dumbass used 10-30. I was only showing 5-10 psi at idle and 25 at cruise.

My research showed the motor needed straight 40w oil. Pressure now reads 65 and only temporarily goes down to 25 when I beat on it.

Know your motor.

 

[stuntman]

Shell Rotella 5W40. I use it in my stock car and it's commonly used in E9X (V8) M3s that have tighter bearing tolerances than the NSX (and also run 10W60 from the factory).

 

[Stephen@NCAutoUSA]

Amsoil 5w40. But my engines not stock spec.