How thick is too thick?
How thick is too thick? I'm putting my parts together to support my TT kit. I've got a stock bottom-end '98 C5 LS1 MN6. I'll be running Alky kit but would like to lower compression as well. This isn't going to be seeing track and I'm not too concerned with a little low end loss.
From what I can see on the summit racing calculator, 317 heads on stock bottom end with a GM 6.0 gasket will net me ~9.4:1.
Is that going to get me in a "safe" neighborhood or do I need to go lower?
If so, does anyone have a pn for a thicker gasket that will work?
Is there a set of heads that others are using that would offer a lower compression ratio with larger chamber volume?
Thanks guys, I usually post in C/F but the FI knowledge seems to be higher here.
From what I can see on the summit racing calculator, 317 heads on stock bottom end with a GM 6.0 gasket will net me ~9.4:1.
Is that going to get me in a "safe" neighborhood or do I need to go lower?
If so, does anyone have a pn for a thicker gasket that will work?
Is there a set of heads that others are using that would offer a lower compression ratio with larger chamber volume?
Thanks guys, I usually post in C/F but the FI knowledge seems to be higher here.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
I'm putting my parts together to support my TT kit. I've got a stock bottom-end '98 C5 LS1 MN6. I'll be running Alky kit but would like to lower compression as well. This isn't going to be seeing track and I'm not too concerned with a little low end loss.
From what I can see on the summit racing calculator, 317 heads on stock bottom end with a GM 6.0 gasket will net me ~9.4:1.
Is that going to get me in a "safe" neighborhood or do I need to go lower?
If so, does anyone have a pn for a thicker gasket that will work?
Is there a set of heads that others are using that would offer a lower compression ratio with larger chamber volume?
Thanks guys, I usually post in C/F but the FI knowledge seems to be higher here.
From what I can see on the summit racing calculator, 317 heads on stock bottom end with a GM 6.0 gasket will net me ~9.4:1.
Is that going to get me in a "safe" neighborhood or do I need to go lower?
If so, does anyone have a pn for a thicker gasket that will work?
Is there a set of heads that others are using that would offer a lower compression ratio with larger chamber volume?
Thanks guys, I usually post in C/F but the FI knowledge seems to be higher here.
So really, no idea if you need to go lower, or could quite happily remain high.
But a little lower will always add a safety margin for negligible loss
Thanks guys!
Yes, I realize I havent included ALL the details. My basic question was whether or not I'd be giving myself an adequate margin of safety with the thinking. I'll be on pump gas. Trying to run ~10 psi. I'm really trying to baby this stock bottom end as it's currently a daily driver and I'd like to get some mileage out of it before I re-open it for another project. From what I gather guys are having luck with that level of boost on a stock bottom end with a solid tune and meth. If I can get 600 rwhp on that amount of boost I'll hang there. If not, ill turn it up and if it goes......I'll have another garage project!
Yes, I realize I havent included ALL the details. My basic question was whether or not I'd be giving myself an adequate margin of safety with the thinking. I'll be on pump gas. Trying to run ~10 psi. I'm really trying to baby this stock bottom end as it's currently a daily driver and I'd like to get some mileage out of it before I re-open it for another project. From what I gather guys are having luck with that level of boost on a stock bottom end with a solid tune and meth. If I can get 600 rwhp on that amount of boost I'll hang there. If not, ill turn it up and if it goes......I'll have another garage project!
With good intercooling and tune you should be fine to run that boost on pump gas. Guys run alot more than that on 93 lol Just watch the tune and take your time to see what it wants
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Your splitting hairs IMO. 1/2 point of compression either way isn't going to make a huge difference. It's like a 2% gain/loss in power NA. Generally the less compression you run the more power potential you'll have with limited octane. Less CR also provides a broader tuning window. So IMO error on the low side, esp. if your new to the turbo game.
I don’t care how the engine acts out of boost personally. My 8.6:1 JY 5.3 went 8’s in the quarter mile and 0-60 in 1.3 seconds... not exactly a "low compression dog".
I don’t care how the engine acts out of boost personally. My 8.6:1 JY 5.3 went 8’s in the quarter mile and 0-60 in 1.3 seconds... not exactly a "low compression dog".
Last edited by Forcefed86; May 13, 2015 at 09:43 AM.
Sounds good. Yeah I'd like to get lower on the CR, but I think I'm out of options short of getting into piston dimension. I dont want to run a gasket any thicker than .060. I might be able to squeeze a little more out with a port/polish job on the 317's. I get that I am probably overthinking it, but I'm sure you guys can all remember back to your first FI diy, just want to get it right.