Dumb question
Team Owner
Joined: Sep 2001
Posts: 62,067
Likes: 1,723
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Yes, but it'll cut timing which hurts mileage, among other things.
It should run best on midgrade fuel, but you have to use a scanner to be sure.
It should run best on midgrade fuel, but you have to use a scanner to be sure.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Not all cars are the same. Some will, some may not. The best way to find out about your car, is to take a drive with a recording scanner attached and check for knock counts or timing retard on play back. For your terrain and style of driving, you may be just fine.
RACE ON!!!
RACE ON!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Forget the scanner. Wait until the tank is nearly empty and put in 5 gallons or so. Even if it were to knock like crazy, you could still dilute it with better gas since you left plenty of room in the tank. I have my base timing set a 14° BTDC (stock is 6°) and I use 85 octane with no pinging. Admittedly, out cars are quite different.
RACE ON!!!
RACE ON!!!
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
The 1990 has 10.25:1 compression IIRC. That is not normally compatible with 87 octane gas. With your timing retarded the car won't run at it's potential.
My 1989, running near sea level, needs 89 octane to run properly and my compression ratio is 9.5:1.
My advice is to run premium like GM advises.
My 1989, running near sea level, needs 89 octane to run properly and my compression ratio is 9.5:1.
My advice is to run premium like GM advises.
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