highest CR for pump gas
06-23-2006, 08:29 PM
#4
I'm at like 11.1. It all depends what cam you have. Typically, the "bigger" the cam, the higher static compression ratio you can run. Bigger cams tend to have a lower dynamic compression ratio, which is far more important in determining what kind of gas you can run (its also more important for making power...static compression is just a variable in the dynamic compression formula).
06-23-2006, 08:31 PM
#5
It depends on the timing you're running, polished chambers? Stock-style piston? A lot of variables go into achieving maximum quench without hot spots and detonation. If you're running 16-18 degrees full timing like us FI guys, then yeah, I would imagine you could get away with much higher compression, but with the 24+ that a lot of NA guys run, I wouldn't suggest chancing much above 11:1 static on a 4.8-6.0L. 1:1 compression is worth only about 4% more power, not significant enough to have to back off timing due to knock.
06-23-2006, 08:44 PM
#6
Banned
Thread Starter
iTrader: (7)
Join Date: Oct 2003
Location: Pittsburgh!!!!!!!! Pa
Posts: 4,893
Likes: 0
Received 0 Likes
on
0 Posts
im using the stock flat top pistons. i have a LQ9 shortblock and currently at 8.12/11.1 but was wanting to maximize my combo more. so i was thinking of some TSP LS6 CNC heads either mill them .020 or run a .040 gasket along with a 90/90 setup was hoping ot be around 11.5:1. i run the tsp tv2 112 now
i want power through the curve along with peak numbers. i want to see 4xx/4xx NA and hopefully 5xx/5xx on juice. i want to hit 11.5 et with ease if i go faster great but no cage here
i want power through the curve along with peak numbers. i want to see 4xx/4xx NA and hopefully 5xx/5xx on juice. i want to hit 11.5 et with ease if i go faster great but no cage here
06-23-2006, 08:46 PM
#7
Another good point, that's how I could get away with running 11:1 with Edelbrock aluminum heads on my 464ci Pontiac in my 67 firebird without detonation, and still able to run 34-36 degrees timing. Running a cam with a fair amount of valve overlap, cools the chamber and bleeds pressure off. Running a low LSA and higher @ .050" duration helps.
Trending Topics
06-23-2006, 10:29 PM
#13
TECH Addict
iTrader: (18)
Join Date: Jun 2004
Location: WI
Posts: 2,247
Likes: 0
Received 0 Likes
on
0 Posts
I'm running 11.5 SCR and about 8.6 DCR on 93 octane. Runs just fine for the most part. Theres some KR I'm seeing at WOT although I'm curring dropping my timing some to get rid of that but it not nearly as bad as I thought it would be.
LQ9 + 243s + Cometics .040 gaskets
LQ9 + 243s + Cometics .040 gaskets
06-24-2006, 03:11 AM
#14
Banned
Thread Starter
iTrader: (7)
Join Date: Oct 2003
Location: Pittsburgh!!!!!!!! Pa
Posts: 4,893
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Zick
I'm running 11.5 SCR and about 8.6 DCR on 93 octane. Runs just fine for the most part. Theres some KR I'm seeing at WOT although I'm curring dropping my timing some to get rid of that but it not nearly as bad as I thought it would be.
LQ9 + 243s + Cometics .040 gaskets
LQ9 + 243s + Cometics .040 gaskets
KR could be in your tune
06-24-2006, 09:07 AM
#15
TECH Addict
iTrader: (18)
Join Date: Jun 2004
Location: WI
Posts: 2,247
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Quik
i have 2 of the 3 there. so basically run cometics and im where i need to be?
KR could be in your tune
KR could be in your tune
Oh I guarentee that its just my tune. I was still running about 30* of timing at WOT from my last setup.
I've got it down to 25* now at WOT and no KR. Still about 3* here and there in the low range but I'll have that taken care of soon.
