Couple of Q's
04-18-2017, 11:27 AM
#1
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Join Date: Feb 2017
Posts: 20
Couple of Q's
Hello,
I was curious how much hp would i gain if i increased one compression point on my heads. Next how much would anybody suggest porting my intake and exhaust on my 94 camaro. same car for compression increase.
I was curious how much hp would i gain if i increased one compression point on my heads. Next how much would anybody suggest porting my intake and exhaust on my 94 camaro. same car for compression increase.
04-18-2017, 02:56 PM
#3
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Join Date: Jul 2005
Location: Okemos, MI
Posts: 9,479
Re: Couple of Q's
I see that you're new here. Welcome to the site! 
Assuming based on your handle that you have a Z28 (you should add a signature to your profile), the stock compression ratio on your LT1 engine is 10.4:1. By "increased one compression point," do you mean going to 10.5:1?
Assuming you do, there are a few ways to accomplish this. The most likely are:
1. milling the heads
2. installing a different set of heads altogether with a small combustion chamber volume
3. installing domed pistons.
The amount of horsepower you'd stand to gain would vary greatly depending on which of the above options you chose, and the details surrounding that choice. In each case, you'd want to get the PCM tuned for the new setup, and the quality and priorities of that tune would also play a role.
Regarding porting your intake and exhaust -- do you mean porting the intake and exhaust ports in the heads? Or do you mean porting the throttle body and/or intake manifold? I've never heard of porting any part of the exhaust other than the head ports.
With enough money and fabrication skills, you can fit anything in anything. A big-block Chevy in a fourth-gen Camaro would require a lot of both. For a lot less work and probably less money too, you could buy an LSX454 making more power than a big block could ever dream of, and then all you're doing is an LS swap, which is well documented.
I get the impression that you're new to modifying cars for more horsepower, and you're asking about a few things you've heard about. If that's the case, I'd suggest you might be going about this backwards.
Assuming based on your handle that you have a Z28 (you should add a signature to your profile), the stock compression ratio on your LT1 engine is 10.4:1. By "increased one compression point," do you mean going to 10.5:1?
Assuming you do, there are a few ways to accomplish this. The most likely are:
1. milling the heads
2. installing a different set of heads altogether with a small combustion chamber volume
3. installing domed pistons.
The amount of horsepower you'd stand to gain would vary greatly depending on which of the above options you chose, and the details surrounding that choice. In each case, you'd want to get the PCM tuned for the new setup, and the quality and priorities of that tune would also play a role.
Regarding porting your intake and exhaust -- do you mean porting the intake and exhaust ports in the heads? Or do you mean porting the throttle body and/or intake manifold? I've never heard of porting any part of the exhaust other than the head ports.
With enough money and fabrication skills, you can fit anything in anything. A big-block Chevy in a fourth-gen Camaro would require a lot of both. For a lot less work and probably less money too, you could buy an LSX454 making more power than a big block could ever dream of, and then all you're doing is an LS swap, which is well documented.
I get the impression that you're new to modifying cars for more horsepower, and you're asking about a few things you've heard about. If that's the case, I'd suggest you might be going about this backwards.
04-19-2017, 01:24 AM
#4
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,648
Re: Couple of Q's
Keeping everything else unchanged and simply going from stock 10.5:1 static compression ratio to 11.5:1 might net you 10 HP at the flywheel. But running a more aggressive cam that can take advantage of the increased SCR can provide a more dramatic gain. But it's all about cam selection. Note that an aggressive cam may not do much at all for low RPM torque, but provides meaningful gains at high RPM. Depends how you want to use the car.
Used to be a good website featuring "Zinna the big block Camaro".... a 454 ci BBC in a 4th Gen Camaro. Great photos of the things that needed to be done to make it work. But the site seems to have disappeared.
Real question is "what is your HP goal"? You can make 500 HP at the flywheel with your LT1 engine using well ported stock heads and a well matched cam. Want even more? Gotta start beefing up the rotating assembly and using a power adder - supercharger, turbo charger, or nitrous. I'm relatively familiar with a 97 30th SS convertible that was running 1,125 HP at the flywheel, and 9.0x-second 1/4-mile at 3,800# race weight. Current record for an LT1 is 8.039-seconds @ 173.63 MPH.
The usual question.... "how fast do you want to go, and what's your budget?"
Used to be a good website featuring "Zinna the big block Camaro".... a 454 ci BBC in a 4th Gen Camaro. Great photos of the things that needed to be done to make it work. But the site seems to have disappeared.
Real question is "what is your HP goal"? You can make 500 HP at the flywheel with your LT1 engine using well ported stock heads and a well matched cam. Want even more? Gotta start beefing up the rotating assembly and using a power adder - supercharger, turbo charger, or nitrous. I'm relatively familiar with a 97 30th SS convertible that was running 1,125 HP at the flywheel, and 9.0x-second 1/4-mile at 3,800# race weight. Current record for an LT1 is 8.039-seconds @ 173.63 MPH.
The usual question.... "how fast do you want to go, and what's your budget?"
04-19-2017, 01:31 AM
#5
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,648
Re: Couple of Q's
512 ci BBC in a 4th Gen. Took the picture about 15 years ago.
https://www.camaroz28.com/forums/mem...re-slp28-6388/
https://www.camaroz28.com/forums/mem...re-slp28-6388/
04-19-2017, 11:48 AM
#6
Registered User
Thread Starter
Join Date: Feb 2017
Posts: 20
Re: Couple of Q's
Eventually looking to do all of it. Next year going for mechanics certificate. 16 yrs old just enough to go around for small improvments. Figured if a guy ported his heads it would be cheap and would get gains. Yeas porting exhaust outake on heads by the way.