396 lt-1 guys please read !!
Thread Starter
Burning Brakes
Joined: Feb 2003
Posts: 1,246
Likes: 1
From: SouthBend IN
396 lt-1 guys please read !!
My neighbor built a 396 lt-1 with 11.8-1 comp., ported stock heads and int. , with cam specs 236-244 @.050 with 650 lift. He was running the car on 93 octane and it spit out a head gasket. he pulled the motor and looked it over all was good so they dynoed it with a dual plane and carb as our engine shop can't hook up the computer ?? Anyway it was dynoed on 112 octane 34 deg timing and made 525 HP @6000 and 535 FT LBS TQ at 4250( the lowest the dyno reads).
His question is will this run on 93 octane and any recommendations for setting up his lt-1 edit ? ( timing,fuel, knock sensor....etc)
i don't know much about this but i told him i would post here and see what advice i could find for him.
i can give his direct e-mail address if anyone would like more info about the motor.
Thanks
Mike
His question is will this run on 93 octane and any recommendations for setting up his lt-1 edit ? ( timing,fuel, knock sensor....etc)
i don't know much about this but i told him i would post here and see what advice i could find for him.
i can give his direct e-mail address if anyone would like more info about the motor.
Thanks
Mike
Racer
Joined: Jun 2002
Posts: 428
Likes: 0
From: Dallas Tx
Re: 396 lt-1 guys please read !! (mike 1985)
Nice Race Gas motor, but the static compression ratio looks a little high for the street on 93 octane pump gas. Even with the reverse flow cooling, 11.0 is about tops. With perfect combustion chambers (ie, no hot spots) you might get a little higher, but as engine or outside air temps go up, you are living on the edge.
I've got totally thermal coated chambers, pistons, and valves, and when the outside temp gets above 90, the knock sensors get active on my 11.0 engine. I don't have quite as much cam as you do, so maybe you could get away with a couple tenths more. Dropping the compression to 11.0 should only cost you 15 hp or so.
I've got totally thermal coated chambers, pistons, and valves, and when the outside temp gets above 90, the knock sensors get active on my 11.0 engine. I don't have quite as much cam as you do, so maybe you could get away with a couple tenths more. Dropping the compression to 11.0 should only cost you 15 hp or so.
Thread Starter
Burning Brakes
Joined: Feb 2003
Posts: 1,246
Likes: 1
From: SouthBend IN
Re: 396 lt-1 guys please read !! (tkrussell)
thanks, that's what i've been telling him, but i have no experience with lt-1.
could you e-mail me your bin file ...i think. basically what your parameters are set at with your lt-1. If this is even possible?
thanks
Mike
could you e-mail me your bin file ...i think. basically what your parameters are set at with your lt-1. If this is even possible?
thanks
Mike
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: 396 lt-1 guys please read !! (mike 1985)
It is definately on the edge of needing race gas. I ran an 11.5:1 396 LT1 with a CC305 cam (220/230, .540/.540, 114) without issues on 93 octane. Not running a lot of timing with that setup, but a little more than 34 degrees(~38 reported). I know of one other guy who was running a 12.0:1 355 but he did use race gas.
He could try running a little less timing and premium gas for the street and then up the timing and run race gas for the joy trips at the track. IMO the increase in power is not worth running that high of compression for a street driven car. He is probably only gaining 5-10 horsepower at most above running the compression at 11:1.
Is he running stock thickness head gaskets (.046-.043 compressed) or is he running the Impala head gasket (.021 compressed). If he is running the Impala gasket, he would do himself a favor by using the Felprod LT1 .043 gasket. It would drop his compression down around 11.4.
He could try running a little less timing and premium gas for the street and then up the timing and run race gas for the joy trips at the track. IMO the increase in power is not worth running that high of compression for a street driven car. He is probably only gaining 5-10 horsepower at most above running the compression at 11:1.
Is he running stock thickness head gaskets (.046-.043 compressed) or is he running the Impala head gasket (.021 compressed). If he is running the Impala gasket, he would do himself a favor by using the Felprod LT1 .043 gasket. It would drop his compression down around 11.4.
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: 396 lt-1 guys please read !! (mike 1985)
I'm running 11.2 right now on 91 pump gas...on road course no less. No problems...yet. :)
I have pulled timing out of its entire range-only 2 degrees at hi rpm WOT though.
This is with a mild HOT cam with cranking compression of 225 psion the high cylinders! Pretty high from what I'm used to.
:)
I have pulled timing out of its entire range-only 2 degrees at hi rpm WOT though.
This is with a mild HOT cam with cranking compression of 225 psion the high cylinders! Pretty high from what I'm used to.
:)
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