what octane is required?
Thread Starter
Instructor
Joined: Mar 2006
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From: San Antonio Texas
what octane is required?
This past December I bought an 85 cpe with 140K. I have given it a complete tune up. Even changed the fuel pump this weekend. It runs great. No fouled plugs or start up smoke. I have no history on the car or manual. What is the octane recommended by GM? I have been putting in premium and just wondering if Regular, Midgrade or Premium is recommended?
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From: OBAMA IS HITLER
the c/r for early L98's yrs 85-89 was rated at 9.5:1.....late L98's 90/91 were 10.25:1.....LT1's all 10.5:1.
i would run 87-89 octane for early L98's, 89-91 octane for late L98's, 91-93 octane for LT1.
i would run 87-89 octane for early L98's, 89-91 octane for late L98's, 91-93 octane for LT1.
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Originally Posted by pearlvette
What is the octane recommended by GM?
Gary
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
87 octane is recommended for your 85.
premium is not recommended, unless you're into spending more money for infinitesimally worse fuel mileage and performance.
premium is not recommended, unless you're into spending more money for infinitesimally worse fuel mileage and performance.
Team Owner
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From: Athens AL
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CR for 85 is 9.0:1, so 87 octane is all that she should need.
Going to higher octane would only hurt performance.
Going to higher octane would only hurt performance.
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Le Mans Master
Joined: Oct 2003
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From: seattle WA
Definetly 87 octane-anything above that for your year-and alot more years is useless!!!!!!!! I've been running 87 in my 87 for almost 7 years
with no problems-actually, if you do your research on line-you'll find
sometimes a higher octane rating actually hurts your performance and mileage
with no problems-actually, if you do your research on line-you'll find
sometimes a higher octane rating actually hurts your performance and mileage
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Premium is not better gas, it's different gas. They should be sued for calling it premium, it's a marketing ploy to sell it to those who don't need it.
Team Owner
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From: Athens AL
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Originally Posted by Hot Rod 90
i stand corrected. the c/r for '85 was 9.0:1, same for '84. it got bumped to 9.5:1 for '86-89.
Le Mans Master
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From: Santa Teresa New Mexico
Originally Posted by CentralCoaster
Premium is not better gas, it's different gas. They should be sued for calling it premium, it's a marketing ploy to sell it to those who don't need it.
Burning Brakes
Joined: Jul 2005
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From: Gainesville, FL
Originally Posted by kopbet89c4
Premium gas smells like bananas in my area. Regular gas just stinks!
i'm obviously getting bum data, which irritates the living ---- out of me.
Advanced
Joined: Apr 2005
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From: Dickson Tennessee
Originally Posted by vader86
CR for 85 is 9.0:1, so 87 octane is all that she should need.
Going to higher octane would only hurt performance.
Going to higher octane would only hurt performance.
Team Owner
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From: Athens AL
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Originally Posted by tnrover
I don't mean to be a smart a.. But how does running higher octaine in a lower compression car hurt performance?
Plus, slow burning causes fuel mileage to drop.
Low octane burns fast, which is needed in lower compression motors.
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From: Poop land
Originally Posted by 4REGT4
ALRIGHT ALREADY!!! WE KNOW!!! - You know how Freud might interpret your obsession with these bananas!!?