Biggest cam on a MAX compression PP/CNCed LS2/LS6
02-12-2006, 01:44 AM
#1
On The Tree
Thread Starter
iTrader: (3)
Join Date: Feb 2005
Location: Brooklyn, New York
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
Biggest cam on a MAX compression PP/CNCed LS2/LS6 head With all these great deals on the PP/CNCed LS2/LS6 heads (from vendors like TSP, Patriot, Livernois) I was thinkin about doing a heads/cam swap...before I dream any further, I got a few question for the experts/vendors
1a).-What is the highest compression ratio that I can run with these heads while running on 91/93octane....
1b)- would I be able to use a higher compression ratio if I used 93 instead of 91 and how much of a a)WHP / b)compression ratio gain would we be looking at here?
2) What kind of a head gasket would I be using here?
3) What would be the biggest cam I can run with these heads and where would it peak? (I'm aware there might be a P/V clearance issue here thats why I'm asking this question).....should I get a custom grind?
4) Down the road, if I ever planned on using nitrous, would I be able to run it with this compression ratio
5) Do these heads differ from vendor to vendor or are all of them basically the same? Would anyone know which is the better 1?(I'm not trying to start a war here so lets be nice
)
6) Would a 3" X-pipe dumped at the axle be too big for this setup?
7) (silly question) What amount of horespower can you predict I will put down(at the wheels/All Motor) with an LS6 intake, LTheaders, 3" X-pipe, PP throttle body, tune and this setup (I'm thinkin optimistically 440-450rwhp on a dynojet and a 6 speed).
I know there's a search button but I'm hoping I can get a straight answer from a few of the vendors and hopefully some of you guys can chime in....Hopefully this thread will answer questions that others might be wondering about. Huge thanks to anyone who can help me out here!
1a).-What is the highest compression ratio that I can run with these heads while running on 91/93octane....
1b)- would I be able to use a higher compression ratio if I used 93 instead of 91 and how much of a a)WHP / b)compression ratio gain would we be looking at here?
2) What kind of a head gasket would I be using here?
3) What would be the biggest cam I can run with these heads and where would it peak? (I'm aware there might be a P/V clearance issue here thats why I'm asking this question).....should I get a custom grind?
4) Down the road, if I ever planned on using nitrous, would I be able to run it with this compression ratio
5) Do these heads differ from vendor to vendor or are all of them basically the same? Would anyone know which is the better 1?(I'm not trying to start a war here so lets be nice
)6) Would a 3" X-pipe dumped at the axle be too big for this setup?
7) (silly question) What amount of horespower can you predict I will put down(at the wheels/All Motor) with an LS6 intake, LTheaders, 3" X-pipe, PP throttle body, tune and this setup (I'm thinkin optimistically 440-450rwhp on a dynojet and a 6 speed).
I know there's a search button but I'm hoping I can get a straight answer from a few of the vendors and hopefully some of you guys can chime in....Hopefully this thread will answer questions that others might be wondering about. Huge thanks to anyone who can help me out here!
Last edited by Tkami129; 02-12-2006 at 03:02 PM.
02-12-2006, 06:37 AM
#2
TECH Senior Member
Originally Posted by Tkami129
With all these great deals on the PP/CNCed LS2/LS6 heads (from vendors like TSP, Patriot, Livernois) I was thinkin about doing a heads/cam swap...before I dream any further, I got a few question for the experts/vendors
1a).-What is the highest compression ratio that I can run with these heads while running on 91/93octane....LS1's like 11.0>11.2 ratio best
1b)- would I be able to use a higher compression ratio if I used 93 instead of 91 and how much of a a)WHP / b)compression ratio gain would we be looking at here? Yes, to be realistic 11.5 is reasonable, every point in SCR is worth~4% increase in HP.
2) What kind of a head gasket would I be using here? To maximise quench .040>.045 MLS
3) What would be the biggest cam I can run with these heads and where would it peak? (I'm aware there might be a P/V clearance issue here thats why I'm asking this question).....should I get a custom grind? Custom would be best IMO since you can do the heads and decide on SCR, then design a cam paying serious attention to DCR
4) Down the road, if I ever planned on using nitrous, would I be able to run it with this compression ratio, Nitrous loves high compression, but higher octane will be needed.
5) Do these heads differ from vendor to vendor or are all of them basically the same? Would anyone know which is the better 1?(I'm not trying to start a war here so lets be nice ) They each have their CNC programs so they will be differences (port volumes etc..)
6) Would a 3" X-pipe dumped at the axle be too big for this setup? No
7) (silly question) What amount of horespower can you predict I will put down(at the wheels/All Motor) with an LS6 intake, LTheaders, 3" X-pipe, PP throttle body, tune and this setup (I'm thinkin optimistically 440-450rwhp on a dynojet and a 6 speed). If that is what you want then match the parts to reach that figure
I know there's a search button but I'm hoping I can get a straight answer from a few of the vendors and hopefully some of you guys can chime in....Hopefully this thread will answer questions that others might be wondering about. Huge thanks to anyone who can help me out here!
1a).-What is the highest compression ratio that I can run with these heads while running on 91/93octane....LS1's like 11.0>11.2 ratio best
1b)- would I be able to use a higher compression ratio if I used 93 instead of 91 and how much of a a)WHP / b)compression ratio gain would we be looking at here? Yes, to be realistic 11.5 is reasonable, every point in SCR is worth~4% increase in HP.
2) What kind of a head gasket would I be using here? To maximise quench .040>.045 MLS
3) What would be the biggest cam I can run with these heads and where would it peak? (I'm aware there might be a P/V clearance issue here thats why I'm asking this question).....should I get a custom grind? Custom would be best IMO since you can do the heads and decide on SCR, then design a cam paying serious attention to DCR
4) Down the road, if I ever planned on using nitrous, would I be able to run it with this compression ratio, Nitrous loves high compression, but higher octane will be needed.
5) Do these heads differ from vendor to vendor or are all of them basically the same? Would anyone know which is the better 1?(I'm not trying to start a war here so lets be nice
) They each have their CNC programs so they will be differences (port volumes etc..)6) Would a 3" X-pipe dumped at the axle be too big for this setup? No
7) (silly question) What amount of horespower can you predict I will put down(at the wheels/All Motor) with an LS6 intake, LTheaders, 3" X-pipe, PP throttle body, tune and this setup (I'm thinkin optimistically 440-450rwhp on a dynojet and a 6 speed). If that is what you want then match the parts to reach that figure
I know there's a search button but I'm hoping I can get a straight answer from a few of the vendors and hopefully some of you guys can chime in....Hopefully this thread will answer questions that others might be wondering about. Huge thanks to anyone who can help me out here!
02-12-2006, 07:56 AM
#3
10 Second Club
iTrader: (5)
Join Date: Nov 2003
Location: Ft. Lauderdale, FL
Posts: 1,649
Likes: 0
Received 0 Likes
on
0 Posts
Biggest issue trying to go max compression a big is PTV.
Start by finding a head that start out with the smallest chamber without milling to minimize PTV lost. The tighter the quench the more compression you can run safely. I would recommend a .040 gasket for a stock bottom end that usually have pistons .006 to .009 out of hole. That will but the quench around .032 for a piston .008 out of hole.
You MUST take the time and effort to measure to ensure adequate clearances.
If you fly cut it will give you a little more options.
Bob
Start by finding a head that start out with the smallest chamber without milling to minimize PTV lost. The tighter the quench the more compression you can run safely. I would recommend a .040 gasket for a stock bottom end that usually have pistons .006 to .009 out of hole. That will but the quench around .032 for a piston .008 out of hole.
You MUST take the time and effort to measure to ensure adequate clearances.
If you fly cut it will give you a little more options.
Bob
02-12-2006, 02:53 PM
#4
On The Tree
Thread Starter
iTrader: (3)
Join Date: Feb 2005
Location: Brooklyn, New York
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by PREDATOR-Z
..........
1)what do you mean by SCR? does that stand for Static Compression Ratio?
2)Whats "Quench"? and what do you mean by .040>.045MLS (all I know is it relates to the head gasket)
3)You mean every point as in 10.5 to 11.5 (not 10.5 to 10.6) results in a ~4%increase in HP, right?
4)Whats DCR? I'm not even gonna try and guess that one
5)my question regards the estimated output was exacltly just that, what would the car put down with those parts combined and not what parts I would need to put down 440-450rwhp..
SlickVert-I really dont want to do any piston flycutting cause thats just more room for error and I'm basically a 21 year old amatuer trying to complete a heads/cam swap with out leaving room for error by flycutting(i did consider it though)......and what do you mean by "pistons .006 to .009 out of hole"
Last question, what's the amount that the heads should be milled to achive a 11.2:1 compression ratio?
I'm sorry for my naiveness but I'm just trying to learn here and get the best of the aftermarket...I really appreciate the replys so far and hopefully there'll be more....
02-12-2006, 03:18 PM
#5
Launching!
iTrader: (1)
Join Date: Jul 2003
Location: Omaha, Nebraska
Posts: 256
Likes: 0
Received 0 Likes
on
0 Posts
Take it for what you will, I put a set of the ported PRC LS6 heads from texas speed milled down .17 and installed a torquer v2 cam with it. They said that was about the max they could be milled without any piston to valve clearance issues. They said the ave compression ratio should be 11.2:1 assuming I use GM head gaskets. I clayed the pistons to verify and everything was fine... but it was close.
02-13-2006, 07:44 PM
#6
On The Tree
Thread Starter
iTrader: (3)
Join Date: Feb 2005
Location: Brooklyn, New York
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 954RR
Take it for what you will, I put a set of the ported PRC LS6 heads from texas speed milled down .17 and installed a torquer v2 cam with it. They said that was about the max they could be milled without any piston to valve clearance issues. They said the ave compression ratio should be 11.2:1 assuming I use GM head gaskets. I clayed the pistons to verify and everything was fine... but it was close.
02-13-2006, 08:16 PM
#7
TECH Junkie
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
My PRC LS6 ers will be here tommorrow, Im going for "the area under the curve" with a 228/228 114 + 4 bumstick stock 10.5 CR...My cam specs unmilled put my DCR at 8.3....It did very well with stock heads so Im excited to see what I get with these jewels.
Trending Topics
02-13-2006, 09:32 PM
#8
On The Tree
Thread Starter
iTrader: (3)
Join Date: Feb 2005
Location: Brooklyn, New York
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by cantdrv65
My PRC LS6 ers will be here tommorrow, Im going for "the area under the curve" with a 228/228 114 + 4 bumstick stock 10.5 CR...My cam specs unmilled put my DCR at 8.3....It did very well with stock heads so Im excited to see what I get with these jewels.
02-13-2006, 10:02 PM
#9
TECH Regular
iTrader: (16)
Join Date: Jun 2004
Location: michigan
Posts: 483
Likes: 0
Received 0 Likes
on
0 Posts
dcr means dynamic compression ratio. it changes by cam choice and valve events.
quench is the distance from the top of the piston at top dead center to the deck of the cyl head.
quench is the distance from the top of the piston at top dead center to the deck of the cyl head.
