Impending Detonation Doom?
Thread Starter
Pro
Joined: Jul 2006
Posts: 557
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From: chiefland fl
Impending Detonation Doom?
Hey guys, I am currently building a '76 350 4 bolt for my '84 Corvette
I have a set of 041 heads that have been done over nicely with 202's and hardened seats, big springs, the works, the cc's are around 62, and they flow like 170, i purchased speed pro h631cp-30's I will use an RPM air gap intake with a demon 750 carb and a lunati voodoo cam.
accell HEI dist.
my machinest says i will detonate without aluminum heads and computer control, i live in Chiefland FL which is like,,hootersville!
his place is in back of an antique store. lol. he said i need lower compression pistons, the ones i bought say 9.73:1 with 64cc heads
so i should be somewhere between there and 10:1? i want to run 93 pump gas. i hope i will be ok with a cooler plug, good cooling around 180 degrees with BIG FANS and a custom hood design with cold air intake.
I value any of your comments, because you are like brothers to me!
I have a set of 041 heads that have been done over nicely with 202's and hardened seats, big springs, the works, the cc's are around 62, and they flow like 170, i purchased speed pro h631cp-30's I will use an RPM air gap intake with a demon 750 carb and a lunati voodoo cam.
accell HEI dist.
my machinest says i will detonate without aluminum heads and computer control, i live in Chiefland FL which is like,,hootersville!
his place is in back of an antique store. lol. he said i need lower compression pistons, the ones i bought say 9.73:1 with 64cc heads
so i should be somewhere between there and 10:1? i want to run 93 pump gas. i hope i will be ok with a cooler plug, good cooling around 180 degrees with BIG FANS and a custom hood design with cold air intake.
I value any of your comments, because you are like brothers to me!
Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
aluminum heads arent the best fix for detonation control.
you also dont have to have electronic engine control either.
with consevative ign. cuving, and slightly richer that ideal fuel mixture,
and the cooler plugs, you could problably sucessfully avoid detonation with your setup.
and yes, ensuring that cool air is entering the engine, rather than hot underhood air, could
make a difference too.
a good quench setup would certainly help you a lot.
but things would be easier with a little less compression.
i would rather have a bit lower C.R. than try to avoid detonation through tuning compromises...
you also dont have to have electronic engine control either.
with consevative ign. cuving, and slightly richer that ideal fuel mixture,
and the cooler plugs, you could problably sucessfully avoid detonation with your setup.
and yes, ensuring that cool air is entering the engine, rather than hot underhood air, could
make a difference too.
a good quench setup would certainly help you a lot.
but things would be easier with a little less compression.
i would rather have a bit lower C.R. than try to avoid detonation through tuning compromises...
Last edited by BigLee; Mar 20, 2007 at 01:28 PM.
Thread Starter
Pro
Joined: Jul 2006
Posts: 557
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From: chiefland fl
thanx for weighing in BigLee, those pistons are special order, i dont think i can swap them out for another, at the time they were the lowest compression i could find at the local parts store where my wife bought the gift card for my B-day on the 17th of this month.
Melting Slicks
Joined: Dec 2006
Posts: 3,374
Likes: 86
From: Corbin KY
I had this same problem with a Buick 455 that I built for my GS a few years back. I would have noticable detonation on 94 octane (highest available around here) driving around on the street. At the track I would use racing fuel and the problem would go away.
As mentioned above you can richen the car up and or retard the timing to get rid of it BUT in my case I fould that 92 Octane and 1 can of octane booster per tank would 99.5% eliminate the problem unless it was a 90+ degree day outside. I am no Chemist and have no idea WHY this fixed the problem because 1 can of octane booster does not bring 92 octane to over 94 octane BUT it worked. If i failed to put the can in the rattle returned.
Phil
As mentioned above you can richen the car up and or retard the timing to get rid of it BUT in my case I fould that 92 Octane and 1 can of octane booster per tank would 99.5% eliminate the problem unless it was a 90+ degree day outside. I am no Chemist and have no idea WHY this fixed the problem because 1 can of octane booster does not bring 92 octane to over 94 octane BUT it worked. If i failed to put the can in the rattle returned.
Phil
Thread Starter
Pro
Joined: Jul 2006
Posts: 557
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From: chiefland fl
thanx, running an additive is a good idea anyways, im guessing i should go ahead with the build, i would rather deal with this than a dismal low compression car! and when i hit the lotto, go with the commander elect sys and stealth ram!
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Thread Starter
Pro
Joined: Jul 2006
Posts: 557
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From: chiefland fl
doesn't look like the heads have been ported, haven't made up my mind on which voodoo yet, maybe the 60104 duration 276 and 504 lift, i want it to make a difference. the heads can handle it with no prob.