Boost with this compression
04-28-2009, 01:06 PM
#1
Launching!
Thread Starter
iTrader: (12)
Join Date: Apr 2009
Posts: 233
Likes: 0
Received 0 Likes
on
0 Posts
Boost with this compression My 418 stroker is currently making 11:1 compression NA running pump gas. So question is anybody running 93 with boost on this high of compression if so how much 4-5psi? Or on the other side how much boost are you running with C16 and high compression like this.
04-28-2009, 03:12 PM
#2
You can do it.
I'm running 10.9:1 compression (stock LS2). I run 7.5 PSI, but I also inject methanol. I was able to run the same boost on 93 alone, but had to knock the timing back to 9 degrees! Meth allows me to run 15 degreees very safely. Been doing this for 16,000 miles.
With lower boost, you wouldn't have to turn the timing back as much as I did.
I'm running 10.9:1 compression (stock LS2). I run 7.5 PSI, but I also inject methanol. I was able to run the same boost on 93 alone, but had to knock the timing back to 9 degrees! Meth allows me to run 15 degreees very safely. Been doing this for 16,000 miles.
With lower boost, you wouldn't have to turn the timing back as much as I did.
04-28-2009, 10:20 PM
#5
Launching!
Thread Starter
iTrader: (12)
Join Date: Apr 2009
Posts: 233
Likes: 0
Received 0 Likes
on
0 Posts
They are LS6 heads custom ported if I'm lucky the combustion chamber is volume is 64cc (so I have room to go up). I have some pictures from a previous owner of the motor with the heads off looks like there is some dish in the piston hard to tell. By my calculations a 64cc chamber with a -8cc piston dish would put me in the 11.0:1 range.
Take a look at the motor pics see what the pistons looks like to you also provides quite a bit of detail on the rest of the motor. I really would like to do a nice FI system with this car but right now all roads are pointing towards a big nitrous motor if I can't get the compression down.
pictures and specs
https://ls1tech.com/forums/vehicles-...treet-car.html
Take a look at the motor pics see what the pistons looks like to you also provides quite a bit of detail on the rest of the motor. I really would like to do a nice FI system with this car but right now all roads are pointing towards a big nitrous motor if I can't get the compression down.
pictures and specs
https://ls1tech.com/forums/vehicles-...treet-car.html
Last edited by laughatrice; 04-28-2009 at 10:28 PM.
04-28-2009, 11:02 PM
#6
TECH Addict
iTrader: (41)
Join Date: Jun 2005
Location: Jefferson City, MO
Posts: 2,329
Likes: 0
Received 0 Likes
on
0 Posts
A friend of mine is running some pretty good boost with a 11.2CR... He sprays meth now...
https://ls1tech.com/forums/dynamomet...p-91-meth.html
https://ls1tech.com/forums/dynamomet...p-91-meth.html
04-29-2009, 12:35 PM
#7
Launching!
Thread Starter
iTrader: (12)
Join Date: Apr 2009
Posts: 233
Likes: 0
Received 0 Likes
on
0 Posts
I'm a little concerned about the 11:1. I'm probably going try and sell my LS6 heads and get some LS2 72cc chambers. I'm probably going to loose some hp in the swap but should get it all back in the boost.
Right now my 243 solid roller heads which were ported by GTP a few years back flowed upwards of 338cfm. Any ideas for some good heads to get the compression down?
Right now my 243 solid roller heads which were ported by GTP a few years back flowed upwards of 338cfm. Any ideas for some good heads to get the compression down?
Trending Topics
04-29-2009, 03:39 PM
#8
On DiabloSport's dyno: 554HP/573TQ at the wheels.
I have a stock set of 317's in the shed that I want to put on to lower my compression, so I can up the boost. In my experience, the little bit of power you loose lowering compression is more than made up for by the extra boost you can run.
You don't need ported heads to make alot of power with boost, it does help though. If going with ported heads on a budget, I would go with Patriot's LQ9 (317) heads.
I have a stock set of 317's in the shed that I want to put on to lower my compression, so I can up the boost. In my experience, the little bit of power you loose lowering compression is more than made up for by the extra boost you can run.
You don't need ported heads to make alot of power with boost, it does help though. If going with ported heads on a budget, I would go with Patriot's LQ9 (317) heads.
04-29-2009, 04:18 PM
#9
Launching!
Thread Starter
iTrader: (12)
Join Date: Apr 2009
Posts: 233
Likes: 0
Received 0 Likes
on
0 Posts
The patriot LQ9 are one of my options either that or a setup from AFR price difference is huge. I'm probably going to yank the solid roller cam in exchange for a custom hydraulic. If I get my compression low enough I'd really like to run 14psi so I'm slightly concerned about the patriot heads being up to the task. I've seen a few 700hp+ builds with patriot heads that seemed to work out.
I keep waiting for a good set of 317's to go up for sale.
I keep waiting for a good set of 317's to go up for sale.
05-01-2009, 04:30 AM
#10
The patriot LQ9 are one of my options either that or a setup from AFR price difference is huge. I'm probably going to yank the solid roller cam in exchange for a custom hydraulic. If I get my compression low enough I'd really like to run 14psi so I'm slightly concerned about the patriot heads being up to the task. I've seen a few 700hp+ builds with patriot heads that seemed to work out.
I keep waiting for a good set of 317's to go up for sale.
I keep waiting for a good set of 317's to go up for sale.