gas? lt1
According to the owners manual ('94 Trans Am) premium is recommended but mid grade should be OK. I agree with the others though..... with an average of .10 difference from mid grade to premium or even 87 to premium the overall price difference, based on a 16 gal. tank would only be about a $3 savings per a full 16 gal fill up.
Originally Posted by sdm1234
because of problems later on down the road
I gave an INTELLIGENT reply earlier but most of you seem to have missed it, I guess simple logic escapes you especially backup up with facts like the 10:1 iron head LT1 under more load doing wonderfully with 87 octane. It is all in the tune not the stock engine.
I have always heard that on a stock engine the car is fine on 87 or 89. I usually run 89 in mine and can not tell a difference. The only time I run premium is at the track or if I am going to be driving in town a lot. I do mostly highway driving and cant see paying $3 or more per fill up for premium just to cruise at 75 mph.
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From: In the garage fixing LT1
Went to the track on Saturday with my stock LT1, zero mods. Tank was full of 87. I ran 14.3 with a .35 RT. It was warm weather, high humidity. Not sure how much better I would have done with 94. Maybe I'll try that next time. But yeah, I run 87 daily with no problems.
Joined: Oct 2005
Posts: 1,419
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From: Holland Twp/Milford, New Jersey
Originally Posted by 96capricemgr
If a heavy pig of a b-body is OK lugging the motor with 2.56s(wagons) and iron heads at 10:1 the aluminum head engine in a lighter car would be no problem whatsoever to make run on 87 octane.
Originally Posted by 96capricemgr
I gave an INTELLIGENT reply earlier but most of you seem to have missed it, I guess simple logic escapes you
wasn't so intelligent afterall, now was it?
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Originally Posted by 96capricemgr
The f-body was 10.4 the b-body was 10.0 but with iron heads and everyone knows aluminum allows higher compression.
For a retrofit application you will likely need reprogramming anyway so reprogram it for 87 octane and you will be fine.
If a heavy pig of a b-body is OK lugging the motor with 2.56s(wagons) and iron heads at 10:1 the aluminum head engine in a lighter car would be no problem whatsoever to make run on 87 octane.
I thought they f-bodies were 10.4 except the 97's which they bumped up to 10.5?
Originally Posted by sdm1234
aluminum head LT1's have higher compression, resulting in higher octane. weight has nothing to do with it... i don't care if u put the LT1 on a go-kart, or a motorcycle. it still needs the proper octane...
wasn't so intelligent afterall, now was it?
wasn't so intelligent afterall, now was it?
As I already covered it is widely accepted that aluminum allows more compression than iron without tuning issues and the number usually placed on that is one full point. The iron head motors are just .4 shy.
Weight has to do with LOAD, LOAD has EVERYTHING to do with timing and detonation resistance don't believe me go and take either your part throttle or WOT timing and use that column across the whole MAP range and let us know how that works for you.
Joined: Oct 2005
Posts: 1,419
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From: Holland Twp/Milford, New Jersey
with high compression heads + pistons, higher octane is not just an option for whatever kind of driving you do. i have a Gen I LT1 pushing out 600+ HP with the compression running so high, it requires avaiation fuel (108+ octane). just because i had it in my '23 Bucket T (2500 lbs) and never took it over 65 didn't mean i could put 87 octane in it. your logic sounds correct in your head, but the calculations just don't add up on paper.
sure... the lower octane may DETONATE and the PCM may allow timing adjustments, but as for combustion efficiency, you'll never see proper results...
please, don't challenge me on this subject. i know what i'm talking about.
sure... the lower octane may DETONATE and the PCM may allow timing adjustments, but as for combustion efficiency, you'll never see proper results...
please, don't challenge me on this subject. i know what i'm talking about.
after reading this i went and filled up my tank with premium while its cheap i normally ran 87. well i didnt notice a power difference but i did notice a noise difference. sounded smoother at wot it could be in my head though btw i have no knowledge on how octane ratings work.
Originally Posted by sdm1234
with high compression heads + pistons, higher octane is not just an option for whatever kind of driving you do. i have a Gen I LT1 pushing out 600+ HP with the compression running so high, it requires avaiation fuel (108+ octane). just because i had it in my '23 Bucket T (2500 lbs) and never took it over 65 didn't mean i could put 87 octane in it. your logic sounds correct in your head, but the calculations just don't add up on paper.
sure... the lower octane may DETONATE and the PCM may allow timing adjustments, but as for combustion efficiency, you'll never see proper results...
please, don't challenge me on this subject. i know what i'm talking about.
sure... the lower octane may DETONATE and the PCM may allow timing adjustments, but as for combustion efficiency, you'll never see proper results...
please, don't challenge me on this subject. i know what i'm talking about.
We are talking on a stock LT1 which is worlds apart from what you are talking about.
When I had just a mild cam I ran 87 octane yet with appropriate programming, never a ping audible and rarely when I was datalogging. With the AI setup though we pushed compression on a stock shortblock to 11.5:1 now she gets super, but going by your logic if the 10.4:1 stock motor needs 91 then I would need more than that wouldn't I??????
You may know carbed crap but I have a pretty good handle on the LT1 and it's injection and sofar you are not showing much knowledge there.
Again I am not saying everyone with with a stock motor and tuning should run 87 I am saying with proper tuning it WILL work perfectly.
Joined: Oct 2005
Posts: 1,419
Likes: 1
From: Holland Twp/Milford, New Jersey
Originally Posted by 96capricemgr
When I had just a mild cam I ran 87 octane yet with appropriate programming, never a ping audible and rarely when I was datalogging.
Originally Posted by 96capricemgr
We are talking on a stock LT1
stock gen II LT1... i'd say high octane; load or no load. period. please don't continue this discussion.
I was saying even on my cammed motor, stock it is fine as I have said over and over the IRON head motor at 10:1 was rated for 87 from the factory. It is widely accepted that aluminum allows up to one point more compression without detonation issues so where is the flaw in my logic. Seems to me you are the one being blindly rigid without an ounce of THOUGHT here.
I REALLY get sick of you ignorant f-body kids(reguardless of age) incapable of thought and will not back down because in doing so I just allow you to spread your ignorance.
DETAILS, EXACTLY what part of my argument as far as the iron head motor being factory speced for 87 so the aluminum one needs nothing but a tune to run it is flawed??? Not your different application and no facts answers sofar answer this directly, if you can't do that you prove my assertion of your ignorance.
I REALLY get sick of you ignorant f-body kids(reguardless of age) incapable of thought and will not back down because in doing so I just allow you to spread your ignorance.
DETAILS, EXACTLY what part of my argument as far as the iron head motor being factory speced for 87 so the aluminum one needs nothing but a tune to run it is flawed??? Not your different application and no facts answers sofar answer this directly, if you can't do that you prove my assertion of your ignorance.
I know both my LT1s and friends LT1s all run like **** on 87/89. Gas mileage goes down, performance drops, feel shaky, idle bad, take longer to start and ping like ************. They need 91, even says so in the owners manual and the fuel door.
Originally Posted by urbanhunter44
I know both my LT1s and friends LT1s all run like **** on 87/89. Gas mileage goes down, performance drops, feel shaky, idle bad, take longer to start and ping like ************. They need 91, even says so in the owners manual and the fuel door.
