what octane is appropriate for the TPI?
what octane is appropriate for the TPI?
Was really low on gas ..engine was dying on my way home. Used some of my go kart gas, which is 87 octane so I can get to the station.
I barely poured like a dollars worth, stopped bc I realized it was 87.
I want this engine to last around 2-4 years, but only driving once a week and maybe some car meets. As for my driving style, like to rev high sometimes
, but not excessively.
Is 87 fine for this engine use or should I go with higher?
I barely poured like a dollars worth, stopped bc I realized it was 87.
I want this engine to last around 2-4 years, but only driving once a week and maybe some car meets. As for my driving style, like to rev high sometimes
, but not excessively.Is 87 fine for this engine use or should I go with higher?
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Joined: Mar 2003
Posts: 851
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From: vacaville,ca
Car: 1988 camaro z28,1997 camaro lt1
Engine: 355 afr 195 heads,tpis big mouth
Transmission: 700r-4 built by me 3-4 z pack
Axle/Gears: 3.42
Re: what octane is appropriate for the TPI?
89 octane is what it requires but you can run 87 safety as long as your timing is stock°6
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Joined: Jan 2000
Posts: 3,178
Likes: 48
From: Tracy, CA
Car: '87 IROC
Engine: LB9
Transmission: TH700R4
Re: what octane is appropriate for the TPI?
The 1987 owner's manual states that TPI engines should use premium unleaded fuel with an octane rating of at least 91.
87 octane can be used but there will be reduced acceleration performance.
87 octane can be used but there will be reduced acceleration performance.
Re: what octane is appropriate for the TPI?
I never got any pinging or knock on my LB9 with 87 according to my data logs. I actually got much better mileage using 87 compared to 91.
If you aren't daily driving it and only using it once a week, by all means use 91.
If you aren't daily driving it and only using it once a week, by all means use 91.
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From: Northern part of The Netherlands
Car: '88 Firebird Formula 350
Engine: 350 (5.7 TPI)
Transmission: auto 700R4
Axle/Gears: BW 9-bolt L.S.
Re: what octane is appropriate for the TPI?
Here in Europe, I use 102 octane (RON) in my '88 TPI.... available at some stations as Competition 102.
Contains no ethanol, and that's the most important aspect in my case, as I hardly drive my car these days anymore...
Contains no ethanol, and that's the most important aspect in my case, as I hardly drive my car these days anymore...
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Joined: Apr 2000
Posts: 3,938
Likes: 99
From: Huntsville AL
Car: 88GTA
Engine: 5.7TPI
Transmission: Auto
Axle/Gears: 3.27
Re: what octane is appropriate for the TPI?
Best I can do on the non ethanol is 91. I usually run this. Less pressure buildup in tank.
I can get 110 racing fuel for 7 bucks a gallon, no need though.
I can get 110 racing fuel for 7 bucks a gallon, no need though.
Joined: Nov 2010
Posts: 5,892
Likes: 84
From: Mantua NJ
Car: 1 Owner 1986 TA with a WS6 package
Engine: 5.0 EFI
Transmission: THM700R4
Axle/Gears: 277 Posi Speedo
Joined: Oct 2001
Posts: 12,214
Likes: 1,140
From: Il
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: what octane is appropriate for the TPI?
When I used to dd mine, I would run 87 until Friday b4 work, then it was 93 for the track and weekend activities. Don't think it helped much if any with a stock motor.
Supreme Member

Joined: Aug 2002
Posts: 1,169
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From: ARIZONA
Car: 92 Trans Am Conv
Engine: LB9
Transmission: T5
Axle/Gears: 3.08
Re: what octane is appropriate for the TPI?
I run 91 at all times and get knock. My car would greatly benefit from 93. The oem timing logic is a bit odd.
Joined: Dec 2000
Posts: 1,954
Likes: 68
From: NC
Car: 1987 Iroc
Engine: 357 Single plane and a Ysi vortech
Transmission: T56
Axle/Gears: 3.50 9"
Re: what octane is appropriate for the TPI?
I have ran 87-93 and don't see any difference with stock timing and ECM.
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Joined: May 2015
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From: Temecula, CA
Car: 1989 Pontiac Formula 350
Engine: L98
Transmission: 700R4
Axle/Gears: BorgWarner 3.27 Posi
Supreme Member

Joined: Aug 2002
Posts: 1,169
Likes: 41
From: ARIZONA
Car: 92 Trans Am Conv
Engine: LB9
Transmission: T5
Axle/Gears: 3.08
Re: what octane is appropriate for the TPI?
I watch KR 100% of the time with the dash light flashing at me, so I definitely know when I have it.
BUT every car and environment is totally different. Not too many places more taxing than AZ on a car. If I had this car in WA it would be knock free on 92 (maybe even on 89octane 90% of the time.)
BUT every car and environment is totally different. Not too many places more taxing than AZ on a car. If I had this car in WA it would be knock free on 92 (maybe even on 89octane 90% of the time.)
Joined: Dec 2000
Posts: 1,954
Likes: 68
From: NC
Car: 1987 Iroc
Engine: 357 Single plane and a Ysi vortech
Transmission: T56
Axle/Gears: 3.50 9"
Re: what octane is appropriate for the TPI?
I was on my old car, but only ran 93 in it, of course. The current car is an 85 Iroc that I haven't logged and is bone stock. No audible spark knock, and 6 * timing.
Supreme Member

Joined: Aug 2002
Posts: 1,169
Likes: 41
From: ARIZONA
Car: 92 Trans Am Conv
Engine: LB9
Transmission: T5
Axle/Gears: 3.08
Re: what octane is appropriate for the TPI?
Listening for knock is not accurate. And using two different cars introduces a variable rendering it useless for info regarding octane effect.
Joined: Dec 2000
Posts: 1,954
Likes: 68
From: NC
Car: 1987 Iroc
Engine: 357 Single plane and a Ysi vortech
Transmission: T56
Axle/Gears: 3.50 9"
Re: what octane is appropriate for the TPI?
I was only giving examples of times when, of course, running a higher octane is needed. I had a MSD knock light on the dash in it..... It would only lightly flash before audible pinging started anyway.
BUT, since you obviously are looking an argument. Why don't you log 87 and 93 in the SAME stock car with stock base timing and see what happens?
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Joined: Aug 2002
Posts: 1,169
Likes: 41
From: ARIZONA
Car: 92 Trans Am Conv
Engine: LB9
Transmission: T5
Axle/Gears: 3.08
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Joined: Mar 2016
Posts: 108
Likes: 1
From: Jackson, New Jersey
Car: 1989 Trans Am GTA
Engine: 5.7L 350 TPI (Deleted Cats)
Transmission: 700r4
Axle/Gears: Original 3.27
Re: what octane is appropriate for the TPI?
I never really experimented with different octanes (Its only had one fill up in the past 7 years) but i run sunoco 93 and runs like a top. On my dads daily he runs 87, but when he treats it with 93 it runs a little better, as well as an increase in gas mileage. By around 3 mpg's. But all thats ever been in my L98 in sunoco 94 octane (when it was still around) and 93




