Question: what engine oil for 90 ZR1?

[italian job]

Owner manual says "only 10W-30". But it was almost 20 years ago....
And now, today? I suppose syntethic oil is a must.
Someone told me to use amsoil, but here we don't have amsoil.
Here we have mobil1, castrol, selenia, and more others.

Any suggestion about brand and viscosity grade?

A racing syntethic oil 5W-20 can be dangerous to use on LT5?

 

[Hib Halverson]

Owner manual says "only 10W-30". But it was almost 20 years ago....
And now, today? I suppose syntethic oil is a must.
Someone told me to use amsoil, but here we don't have amsoil.
Here we have mobil1, castrol, selenia, and more others.

Any suggestion about brand and viscosity grade?

A racing syntethic oil 5W-20 can be dangerous to use on LT5?

Mobil 1 10W30 is a good choice, however, an ester-based synthetic is probably better. I'm pretty sure Red Line Synthetic Oil is distributed in Italy. Red Line 10W30 is an excellent choice. If you can't find Red Line and Motul is available, it's also an oustanding ester-based engine oil. The 10W40 Motul sells would be a good choice.

1990-1992, GM recommended a 10W30 petroleum-based oil. 1993-1995, it recommended either a 5W30 or a 10W30 synthetic.

 

[italian job]

Thanks Hib
If I understand well the redline syntethic 1O W-30 is the best choice, right?

Yes here we have redline oil.
I found two types: one has blue label plastic bottle, and another is a "race type" and has a red plastic bottle
The blue has 10 W-30 viscosity
The red type has choice from 10 to 60 (the label on the bottle say only the number 10, or 20 or 30 etc. and not 10W-30)

You know what is better?

 

[Hib Halverson]

Do not use Red Line Race Oil (Red bottle) in a street driven ZR-1 having cat converters. Use the 10W30 Engine Oil (Blue label).

Sorry to take so long to answer. I haven't checked this thread in a while.

 

[italian job]

thanks for reply Hib; I filled the engine just yesterday, I used redline oil blue label bottle 5-W30. I asked to redline and they told me right choice was 5-W30 blue label. (but redline are zr1 expert? I don't know..)
catalyst on my zr1 are empty, I think previous owner made this job to gain a bit of aggressive sound.