Highest CR on pump gas?
Bigger cam changes the timing of the cycle. if you close too early you leave a bunch on the table. To a point, the pressure is still there it just changed the rpms that it might happen at. As far as lift goes your heads will dictate that, and your springs will try to keep up.
Bigger cam changes the timing of the cycle. if you close too early you leave a bunch on the table. To a point, the pressure is still there it just changed the rpms that it might happen at. As far as lift goes your heads will dictate that, and your springs will try to keep up.
. 
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
TECH Apprentice
Joined: Jun 2012
Posts: 372
Likes: 0
From: Mississauga Ontario Canada
as very few N/A setups flow better than atmospheric pressures, or atleast to my knowledge they're arent, how could cam selection make a difference (other than valve lift and timing with the piston)?
Launching!
Joined: Jun 2005
Posts: 277
Likes: 0
From: SC
Google Pat Kelly compression calculator. It'll explain the details. Compression does not happen until the intake valve closes. The longer the duration on the cam, the later the intake valve closes, the lower the dynamic compression for a set combo. There are charts that tell you max safe dynamic compression for octane and temperature. Aluminum buys about a half point of headroom.
Static compression is just the ratio of the combustion chamber size with piston at BDC to chamber size with piston at TDC. Piston design, head chamber, bore, stroke, gasket thickness and bore, and deck clearance set that. Dynamic compression is your true running compression.
Static compression is just the ratio of the combustion chamber size with piston at BDC to chamber size with piston at TDC. Piston design, head chamber, bore, stroke, gasket thickness and bore, and deck clearance set that. Dynamic compression is your true running compression.
TECH Apprentice
Joined: Jun 2012
Posts: 372
Likes: 0
From: Mississauga Ontario Canada
Google Pat Kelly compression calculator. It'll explain the details. Compression does not happen until the intake valve closes. The longer the duration on the cam, the later the intake valve closes, the lower the dynamic compression for a set combo. There are charts that tell you max safe dynamic compression for octane and temperature. Aluminum buys about a half point of headroom.
Static compression is just the ratio of the combustion chamber size with piston at BDC to chamber size with piston at TDC. Piston design, head chamber, bore, stroke, gasket thickness and bore, and deck clearance set that. Dynamic compression is your true running compression.
Static compression is just the ratio of the combustion chamber size with piston at BDC to chamber size with piston at TDC. Piston design, head chamber, bore, stroke, gasket thickness and bore, and deck clearance set that. Dynamic compression is your true running compression.
Bumping this up!
Decided to just go with race gas and high compression, instead of risking using pump gas, I'll barely drive it so it'll be fine.
Thanks for your help guys!
Decided to just go with race gas and high compression, instead of risking using pump gas, I'll barely drive it so it'll be fine.
Thanks for your help guys!
TECH Resident
Joined: Jan 2009
Posts: 869
Likes: 0
From: In the moment...
Id like to have a little more compression in my stock bottom end motor without changing too much around. Could I just swap to a .026 head gasket and be fine or would I need to make some other changes at the same time? I was going to get the head surface milled down just a touch as well as change the gasket but I dont know what compression just changing gaskets would put me at.
Google Pat Kelly compression calculator. It'll explain the details. Compression does not happen until the intake valve closes. The longer the duration on the cam, the later the intake valve closes, the lower the dynamic compression for a set combo. There are charts that tell you max safe dynamic compression for octane and temperature. Aluminum buys about a half point of headroom.
Static compression is just the ratio of the combustion chamber size with piston at BDC to chamber size with piston at TDC. Piston design, head chamber, bore, stroke, gasket thickness and bore, and deck clearance set that. Dynamic compression is your true running compression.
Static compression is just the ratio of the combustion chamber size with piston at BDC to chamber size with piston at TDC. Piston design, head chamber, bore, stroke, gasket thickness and bore, and deck clearance set that. Dynamic compression is your true running compression.
Those calculations assume the engine is operating at 100% ve with no scavenging going on or anything like it. The whole thing just started so internet experts had another talking point to try to make themselves look smart.
Yes.
Running high compression on a street engine (pump gas) requires that you have proper engine quench (ideally .035" to .040"), optimal dynamic compression (about 9:1 w/the LT1/4)....this is where the camshaft specs come into play....and a spot-on tune.
12.5:1 static compression is very doable when your build has been done correctly!
KW
Running high compression on a street engine (pump gas) requires that you have proper engine quench (ideally .035" to .040"), optimal dynamic compression (about 9:1 w/the LT1/4)....this is where the camshaft specs come into play....and a spot-on tune.
12.5:1 static compression is very doable when your build has been done correctly!
KW
Last edited by KW Baraka; Jun 4, 2013 at 02:28 PM.