LT1-LT4 Modifications 1993-97 Gen II Small Block V8

compression and boost question with a cometics head gasket

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Old Oct 14, 2011 | 02:41 PM
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Default compression and boost question with a cometics head gasket

i blew my head gasket out so i am going to redo my heads and use arp studs and cometics gaskets....

i can go up to a .60 gasket thickness, so i was wondering if lowering the compression would let me run any more boost? i am running 8lbs now and i have a good valve train and a thicker gasket with studs would i be good to run any more boost? or does it not work like that

thanks
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Old Oct 14, 2011 | 06:46 PM
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it does work like that, but with a gasket you may drop .1 or .2 at the most off your static compression ratio so you can go up to 10 lbs safely with a stock bottom end i wouldnt be hesitant to run 15 lbs with a turbo car. are you intercooled? add water meth and id run 20 lbs on a stock bottom end.

then again im ballsy, but my motor is forged and stroked i have a 10.7 compression and i run 15 lbs on a supercharger all day, but i also have water meth (80% meth) and run 93 octane. no intercooler here, maybe someday.
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Old Oct 15, 2011 | 12:06 AM
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yea its intercooled.... but there is no way a stock lt1 can hold 15 lbs of boost... 8 is the limit for me right now.. 9 if i dont care about blowing it....

you crazy
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Old Oct 15, 2011 | 04:49 AM
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Originally Posted by popethe5th
it does work like that, but with a gasket you may drop .1 or .2 at the most off your static compression ratio so you can go up to 10 lbs safely with a stock bottom end i wouldnt be hesitant to run 15 lbs with a turbo car. are you intercooled? add water meth and id run 20 lbs on a stock bottom end.
Dude would you please stop giving 'advice'. It is blatantly obvious you have ZERO idea WTF you're talking about.

Just STFU and learn. You are talking just to hear yourself.
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Old Oct 15, 2011 | 06:56 AM
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I would not go putting head studs in a block bored with bolts. They stress the block differently and that is why blocks are bored with deck plates and the intended fasteners.
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Old Oct 15, 2011 | 07:19 AM
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Originally Posted by 96capricemgr
I would not go putting head studs in a block bored with bolts. They stress the block differently and that is why blocks are bored with deck plates and the intended fasteners.
Agreed.
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Old Oct 15, 2011 | 08:06 AM
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Originally Posted by popethe5th
it does work like that, but with a gasket you may drop .1 or .2 at the most off your static compression ratio so you can go up to 10 lbs safely with a stock bottom end i wouldnt be hesitant to run 15 lbs with a turbo car. are you intercooled? add water meth and id run 20 lbs on a stock bottom end.

then again im ballsy, but my motor is forged and stroked i have a 10.7 compression and i run 15 lbs on a supercharger all day, but i also have water meth (80% meth) and run 93 octane. no intercooler here, maybe someday.
Man your joke posts lately have been hilarious!
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Old Oct 15, 2011 | 08:23 AM
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ok i was just thinking for boost the studs will help hold it down under pressure... but ill stuck with arp bolts then....

i was talking with a guy and he was saying how it takes usually takes extreme heat to blow a head gasket and since i never ran hot, he thinks that i blew a hole in the head... or however you say that... cracked it?

i can see this as possible because i was running a how plug when i was gonna switch over to the nkg 6 i was just test driving it.... also do you guys think my piston rings are fine? cause im pretty sure detonation can kill them too...

im still learning about the internals of motors and all that goes with them so no hatin
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Old Oct 15, 2011 | 01:00 PM
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You're better off sticking with a thinner head gasket and keeping the quench clearance (piston to head distance) down as close to .035" as possible. the tiny decrease in CR from a thicker gasket will be overshadowed by the higher tendency toward detonation you'll create with the larger quench clearance.
Tight quench creates more mixture motion, a faster more efficient burn, and therefore less need for ignition advance.
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Old Oct 15, 2011 | 02:16 PM
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Originally Posted by bowtienut
You're better off sticking with a thinner head gasket and keeping the quench clearance (piston to head distance) down as close to .035" as possible. the tiny decrease in CR from a thicker gasket will be overshadowed by the higher tendency toward detonation you'll create with the larger quench clearance.
Tight quench creates more mixture motion, a faster more efficient burn, and therefore less need for ignition advance.
ur smart
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Old Oct 15, 2011 | 05:36 PM
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Originally Posted by bowtienut
You're better off sticking with a thinner head gasket and keeping the quench clearance (piston to head distance) down as close to .035" as possible. the tiny decrease in CR from a thicker gasket will be overshadowed by the higher tendency toward detonation you'll create with the larger quench clearance.
Tight quench creates more mixture motion, a faster more efficient burn, and therefore less need for ignition advance.
This is a good train of thought for N/A. But with power adder apps it pushes the tuning window much too narrow...
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Old Oct 15, 2011 | 06:56 PM
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Originally Posted by gregrob
This is a good train of thought for N/A. But with power adder apps it pushes the tuning window much too narrow...
I think it still applies for him. 8 psi is pretty mild; probably no more cylinder pressure than a lot of the good running NA setups.
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Old Oct 16, 2011 | 11:34 AM
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Tell me how I am wrong, I'm not saying I know crap about anything but a thicker headgasket will effectively decrease compression ratio making it safer for the boost he is running?
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Old Oct 16, 2011 | 11:57 AM
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Originally Posted by popethe5th
Tell me how I am wrong, I'm not saying I know crap about anything but a thicker headgasket will effectively decrease compression ratio making it safer for the boost he is running?
yea... not 20lbs.... plus if your saying you dont know crap about anything then dont say anything
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Old Oct 16, 2011 | 11:59 AM
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Originally Posted by popethe5th
Tell me how I am wrong, I'm not saying I know crap about anything but a thicker headgasket will effectively decrease compression ratio making it safer for the boost he is running?
Your wrong because your can't put 20 PSI on a stock bottom end with a THICKER head gasket.......Maybe with LT4 KM with your LS1 PCM it might be possible......
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Old Oct 16, 2011 | 12:00 PM
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anywayy... so thicker or thinner? seems to be a dissagreement
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Old Oct 16, 2011 | 12:18 PM
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Whatever you do don't run 20 pounds through it


Oh wait....
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Old Oct 16, 2011 | 12:59 PM
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Originally Posted by 95batmobile
anywayy... so thicker or thinner? seems to be a dissagreement
What's your CR? Stock LT1?
You're better off staying with a thinner gasket and limiting the boost.
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Old Oct 16, 2011 | 05:55 PM
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its gonna be a unported head but its gonna have everything beefed up on it.... springs rockers valves ect
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Old Oct 16, 2011 | 06:30 PM
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"stock" heads but "beefed up valves"???????????????????????

Do you mean stock castings reworked and ported or genui9nely stock castings with aftermarket valves? Ported stock castings can be a GREAT option for most builds. Putting aftermarket valves in an otherwise untouched head is just pissing money into the wind.
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