Lower compression heads for LS2?
04-03-2012, 12:29 PM
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Lower compression heads for LS2? Looking into buying heads, not so much for a horsepower gain but rather to lower the compression for my whipple. I know a thicker head gasket will bring it down a point or so but I think I would like to go lower than that.
Would ported 225's lower the compression much, or at all with a 65cc combustion chamber? or can I go to 235 with a 70cc head on a stock bore?
Options I've been looking at are the patriot 68cc heads, but have heard many mixed things on patriot heads, my next option would be trick flow or afr.
Aybody deal with total engine airflow?
They offer 225's with a 70cc chamber.
When I reinstall my whipple I will be relying on my meth kit for both cooling and detination due to pump gas with 10.9-1 compression. I would rather have the meth be for heat safety factor only. which I could monitor easily if the meth unit ever failed. I don't want to spend an arm and a leg for 225 heads, because I may onday go bigger with the engine, so I would prefer something I can take with me on a larger bore.
Really looking for suggestions.
Would ported 225's lower the compression much, or at all with a 65cc combustion chamber? or can I go to 235 with a 70cc head on a stock bore?
Options I've been looking at are the patriot 68cc heads, but have heard many mixed things on patriot heads, my next option would be trick flow or afr.
Aybody deal with total engine airflow?
They offer 225's with a 70cc chamber.
When I reinstall my whipple I will be relying on my meth kit for both cooling and detination due to pump gas with 10.9-1 compression. I would rather have the meth be for heat safety factor only. which I could monitor easily if the meth unit ever failed. I don't want to spend an arm and a leg for 225 heads, because I may onday go bigger with the engine, so I would prefer something I can take with me on a larger bore.
Really looking for suggestions.
04-08-2012, 08:21 AM
#3
Among these, the Cadillac LSA or Corvette ZR1 heads should stand out as they are already used on F/A applications. One need only to look at the results produced by both of these motors to see that it would be a step in the right directions.
The downside is that there are some hardware changes that will be necessary due to the intake valve geometry and the intake port layout. A camshaft change would also be beneficial since the valve I/E ratio is quite different with the newer generation heads.
These changes, to me, are insignificant when compared to the output you'll get, especially with a Whipple.
04-08-2012, 11:22 AM
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Can't switch to square port heads without changing the lower manifold so I would assume that he is trying to find a cathedral port head with larger combustion chambers.
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04-09-2012, 06:31 AM
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I would look into the 317 Lq4 6.0 heads, they are for 4 inch bore and have 72cc chamber. They are the same as ls6 heads but with a bigger chamber so they flow really good. They make good FI heads. Best part is they are dirt cheap.
04-09-2012, 04:31 PM
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Are they cathedral port?
Last edited by tommycompton; 04-09-2012 at 04:39 PM.
04-10-2012, 02:19 PM
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did you buy the car with the whipple? I'm thinking 317 for a cheaper option or foot the bill and get the AFR mongoose heads with 68cc chamber. Hmmm.
04-10-2012, 03:21 PM
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ya the car came with some pretty sweet mods
Mods are as follows:
Dragon Pro Street M1000 intercooled supercharger kit using the Whipple 3.3L supercharger
Dragon Pro Street DX1 cam
Ported GM 317 casting heads with Manley valves, dual springs & titanium retainers
CTS-VR lifters
Dragon Pro Street ported oil pump
Upgraded timing set
Ceramic coated American Racing Headers
Spec stage 3+ clutch with aluminum flywheel
Dragon Pro Street built T56 trans with upgraded internals
B&M short throw shifter
Gforce passenger side half shaft
160 deg thermostat
I really like the car! There were some issues with the car when i got it but most of them are fixed now(ISSUES WERE NOT THE PREVIOUS OWNERS DOINGS) Im still getting light detnation on 91octane. It's still having a an issue when reved past 5K but ive got some stuff to look at.
Mods are as follows:
Dragon Pro Street M1000 intercooled supercharger kit using the Whipple 3.3L supercharger
Dragon Pro Street DX1 cam
Ported GM 317 casting heads with Manley valves, dual springs & titanium retainers
CTS-VR lifters
Dragon Pro Street ported oil pump
Upgraded timing set
Ceramic coated American Racing Headers
Spec stage 3+ clutch with aluminum flywheel
Dragon Pro Street built T56 trans with upgraded internals
B&M short throw shifter
Gforce passenger side half shaft
160 deg thermostat
I really like the car! There were some issues with the car when i got it but most of them are fixed now(ISSUES WERE NOT THE PREVIOUS OWNERS DOINGS) Im still getting light detnation on 91octane. It's still having a an issue when reved past 5K but ive got some stuff to look at.
04-10-2012, 04:50 PM
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I saw some post between you guys talking about the setup.
I’m only running 42# injectors, I think their pretty low, the previous owner said they were maxed out in Denver when had it tuned he made 500HP(without water meth) I’m 2000’ lower in elevation then he is. When I got it the car was logging fault codes for Knock sensors, after further investigation the harness was cut. No big deal we got that fixed. The belt was pretty worn out and the tensioner was SHOT so I bought a Kartech manual tensioner that seems to work pretty well, it don't slip any near what it did before but the belt does need replaced. First pull on the dyno it made 293HP
My tuner did some adjusting and we got it up to 417HP but were still about 100HP low. I’ve got something’s to check but I won't be able to right away. I would think as hard as it pulled there isn’t nothing mechanical wrong with it but im going to check anyways. As far as the tune goes I’m not real sure.
What did your car make after everything was set up?
If you want ill PM you if you want to know more, i just don't want to derail your thread.
Beautiful car by the way!!!
I’m only running 42# injectors, I think their pretty low, the previous owner said they were maxed out in Denver when had it tuned he made 500HP(without water meth) I’m 2000’ lower in elevation then he is. When I got it the car was logging fault codes for Knock sensors, after further investigation the harness was cut. No big deal we got that fixed. The belt was pretty worn out and the tensioner was SHOT so I bought a Kartech manual tensioner that seems to work pretty well, it don't slip any near what it did before but the belt does need replaced. First pull on the dyno it made 293HP
My tuner did some adjusting and we got it up to 417HP but were still about 100HP low. I’ve got something’s to check but I won't be able to right away. I would think as hard as it pulled there isn’t nothing mechanical wrong with it but im going to check anyways. As far as the tune goes I’m not real sure.What did your car make after everything was set up?
If you want ill PM you if you want to know more, i just don't want to derail your thread.
Beautiful car by the way!!!
04-11-2012, 10:53 AM
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Thanks man.
Sounds like yours is the makings of a beast.
I never did get to put down numbers, I took it off because it would detonate without using race gas, and that wasn't an option. I later got a methanol kit but have yet to put the whipple back on, I am now contemplating heads before I reinstall it. I just picked up a progressive controller for my meth, and also picked up a tensioner from east coast superchargers.
Us whipple guys need to stick together, let me know when you get it all worked out, I am very interested in your results.
I believe you have a larger pulley on yours than I do, I may end up getting the same.
I'll probably pull the trigger on heads in about a month or so.
Do you know how much boost you are pushing?
Sounds like yours is the makings of a beast.
I never did get to put down numbers, I took it off because it would detonate without using race gas, and that wasn't an option. I later got a methanol kit but have yet to put the whipple back on, I am now contemplating heads before I reinstall it. I just picked up a progressive controller for my meth, and also picked up a tensioner from east coast superchargers.
Us whipple guys need to stick together, let me know when you get it all worked out, I am very interested in your results.
I believe you have a larger pulley on yours than I do, I may end up getting the same.
I'll probably pull the trigger on heads in about a month or so.
Do you know how much boost you are pushing?