Which octane gas does the '87 lb9 305 tpi vin F call for? I don't have the book for it. Someone told me it was 87 octane, but I know its compression ratio is 9.3, and I thought that would need a higher octane fuel. Any insight is appreciated!

 

you only need as much octane as necessary to prevent detonation. if it runs on 87 w/o spark knock then burn 87. higher octane fuel burns slower and less efficiently, not to mention costs more.

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85 IROC 350 11:1keith blacks,.555lift erson roller cam,1.6 crane roller rockers,edelbrock intake,holley 4150 750dbl pumper, nitrous oxide,full length heddman headers,true dual exhaust, 11"stall converter, 700R4, 3.73 locker, certified engine and electrical systems mechanic

 

Hey thanks for the reply.
The only thing is I have no idea what engine knock sounds like, and I don't want to find out the hard way I was just wondering what was recommemded for use in this engine?
anybody?

 

All of the TPI motors were designed to run on 91 octane. Due to production differences, some were able to run on 87, but most require 91. You may not hear the knock because the knock sensor will detect it and retard the timing before you're ears can hear it. Unless you are in a pinch, run what the owner's manual calls for.

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89 Transam GTA, 350TPI, auto, 3.27 rear, dual cats, gray.
Magnaflow cat-back,
K&N open element,
Best E.T. 14.63@95mph

 

thanks TransamGTA350, thats exactly what I needed to know.

 

I've been running 93 octane in my 86 TPI since i have owned it...it was ok, i guess. Didnt hurt it one bit. Then, i tried the 89 octane, and it seems to run a bit better now...better mileage, and i feel a bit more power when i step on it. I asked around about difference, and why all of a sudden am i feeling a power increase when i havent made anymore mods, and i have been told that they like to mix all all sorts of s*** in the 93 octane gas for some reason, and not in the 89. For now, i am sticking with 89, since my car has been performing better than with the 93. Plus, its cheaper too Good luck.

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1986 WS6-Equipped 5.0 TPI Trans Am
Random Tech High-Flow Cat
Two Chamber Flowmaster Muffler
Megs Custom 4.5" Stainless Steel Rolled Tips
1999 Grand Am GT In-Dash CD Player w/Equalizer(fits like '86 original)
5% Tint On Rear, 35% On Sides
http://www.pitt.edu/~zyhst/trans86/

OTHER RIDE:
1998 C5 6Spd. Corvette Coupe
Silver w/Gray Leather Int.
12/14 Options
Stock(for now)
Best 1/4th: 13.5 @ 104.4MPH