LS1 Question.
LS1 Question---HELP! A friend of mine has a 2004 GTO 6-speed
Here are the details:
Stock LS1 heads
Stock LS6 intake
K&N CAI
Z06 MAF
MTI Ported 75mm TB
SW 1-3/4" LTs with hi-flo cats
SW catback
NGK TR55 Plugs
ASP Underdrive Pulley
cam - .608/.612 238/242 115LSA
REV Springs
Hardened Pushrods
LS1 Edit dyno tune
Best Mustang Dyno was 333rwhp
Another friend has another 2004 GTO 6-speed with the exact same list with the exception of Kooks 1-7/8" LTs with hi-flo cats and Corsa catback. His Mustang dyno (on the same dyno on the same day with the cars both cold) was 380rwhp. I cannot believe that the different primary size of headers and the different catback made 47rwhp difference!
The most timing that could be put in the 333rwhp car because of detonation was 26 degrees as opposed to 29 degrees for the 380rwhp car.
The 333rwhp car traps 106 and the 380rwhp car traps 111.....Hell, the 380rwhp car trapped 105 bone stock!!!
Any ideas??? Its a hell of a puzzle to me.
EDIT- something else.....we had a dyno day in February, all of the GTOs that showed were stock from our group, including both of the aforementioned cars, the car that is now dynoing lower actually was the highest stock dyno at that time.
Here are the details:
Stock LS1 heads
Stock LS6 intake
K&N CAI
Z06 MAF
MTI Ported 75mm TB
SW 1-3/4" LTs with hi-flo cats
SW catback
NGK TR55 Plugs
ASP Underdrive Pulley
cam - .608/.612 238/242 115LSA
REV Springs
Hardened Pushrods
LS1 Edit dyno tune
Best Mustang Dyno was 333rwhp
Another friend has another 2004 GTO 6-speed with the exact same list with the exception of Kooks 1-7/8" LTs with hi-flo cats and Corsa catback. His Mustang dyno (on the same dyno on the same day with the cars both cold) was 380rwhp. I cannot believe that the different primary size of headers and the different catback made 47rwhp difference!
The most timing that could be put in the 333rwhp car because of detonation was 26 degrees as opposed to 29 degrees for the 380rwhp car.
The 333rwhp car traps 106 and the 380rwhp car traps 111.....Hell, the 380rwhp car trapped 105 bone stock!!!
Any ideas??? Its a hell of a puzzle to me.
EDIT- something else.....we had a dyno day in February, all of the GTOs that showed were stock from our group, including both of the aforementioned cars, the car that is now dynoing lower actually was the highest stock dyno at that time.
Last edited by HRJ; Oct 13, 2005 at 10:36 AM.
Originally Posted by HRJ
A friend of mine has a 2004 GTO 6-speed
Here are the details:
Stock LS1 heads
Stock LS6 intake
K&N CAI
Z06 MAF
MTI Ported 75mm TB
SW 1-3/4" LTs with hi-flo cats
SW catback
NGK TR55 Plugs
ASP Underdrive Pulley
cam - .608/.612 238/242 115LSA
REV Springs
Hardened Pushrods
LS1 Edit dyno tune by HPE
Best Mustang Dyno was 333rwhp
Another friend has another 2004 GTO 6-speed with the exact same list with the exception of Kooks 1-7/8" LTs with hi-flo cats and Corsa catback. His Mustang dyno (on the same dyno on the same day with the cars both cold) was 380rwhp. I cannot believe that the different primary size of headers and the different catback made 47rwhp difference!
The most timing that could be put in the 333rwhp car because of detonation was 26 degrees as opposed to 29 degrees for the 380rwhp car.
The 333rwhp car traps 106 and the 380rwhp car traps 111.....Hell, the 380rwhp car trapped 105 bone stock!!!
Any ideas??? Its a hell of a puzzle to me.
EDIT- something else.....we had a dyno day in February, all of the GTOs that showed were stock from our group, including both of the aforementioned cars, the car that is now dynoing lower actually was the highest stock dyno at that time.
Here are the details:
Stock LS1 heads
Stock LS6 intake
K&N CAI
Z06 MAF
MTI Ported 75mm TB
SW 1-3/4" LTs with hi-flo cats
SW catback
NGK TR55 Plugs
ASP Underdrive Pulley
cam - .608/.612 238/242 115LSA
REV Springs
Hardened Pushrods
LS1 Edit dyno tune by HPE
Best Mustang Dyno was 333rwhp
Another friend has another 2004 GTO 6-speed with the exact same list with the exception of Kooks 1-7/8" LTs with hi-flo cats and Corsa catback. His Mustang dyno (on the same dyno on the same day with the cars both cold) was 380rwhp. I cannot believe that the different primary size of headers and the different catback made 47rwhp difference!
The most timing that could be put in the 333rwhp car because of detonation was 26 degrees as opposed to 29 degrees for the 380rwhp car.
The 333rwhp car traps 106 and the 380rwhp car traps 111.....Hell, the 380rwhp car trapped 105 bone stock!!!
Any ideas??? Its a hell of a puzzle to me.
EDIT- something else.....we had a dyno day in February, all of the GTOs that showed were stock from our group, including both of the aforementioned cars, the car that is now dynoing lower actually was the highest stock dyno at that time.
Originally Posted by AUGTO
I too have that cam and a similar set-up. I dynoed @ 339 on thier Mustang dyno. I recently re-tuned and saw a 34rwhp gain and 39rwtq gain. Could need a re-tune possibly.
Originally Posted by AUGTO
Where's his timing running?
My new tuner found timing to be low, around 23* from my GP tune.
He uses HP tuners.
My new tuner found timing to be low, around 23* from my GP tune.
He uses HP tuners.
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Originally Posted by redtail2426
those heads are only designed to run 22-24* of timing.running near the point of detonation isnt always best.
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what size collectors are on the SW headers? They come 2 1/2 inch unless you order 3 inch. most will say stay away for the 2 1/2's, but I just made 400rw with them and a cam. I think this may account for some of that gain.
Originally Posted by mcamp001
what size collectors are on the SW headers? They come 2 1/2 inch unless you order 3 inch. most will say stay away for the 2 1/2's, but I just made 400rw with them and a cam. I think this may account for some of that gain.
Teching In
Joined: Sep 2005
Posts: 25
Likes: 0
From: Central North Carolina
I would suggest degreeing the cam to make sure it is exact (not likely to be way off, but it does happen), then regardless, having it re-tuned as well as possible.
If that does not get you another 30-40 HP (I think it will) I'd suggest changing the cam to something with a bit more intake duration and less exhaust duration. Its been years, but I saw this happen on carburated street race engines in the late 70s - if you had really good of headers, etc., buta near stock or small intake manifold, and some overlap combined with a big exhaust duration and lift, it would scavenge some intake charge traveling out the exhaust at some RPMs. I would think a modern engine, or the dyno sensers, would pick this up, but . . . .
If that does not get you another 30-40 HP (I think it will) I'd suggest changing the cam to something with a bit more intake duration and less exhaust duration. Its been years, but I saw this happen on carburated street race engines in the late 70s - if you had really good of headers, etc., buta near stock or small intake manifold, and some overlap combined with a big exhaust duration and lift, it would scavenge some intake charge traveling out the exhaust at some RPMs. I would think a modern engine, or the dyno sensers, would pick this up, but . . . .
Originally Posted by Rhino21149
I would suggest degreeing the cam to make sure it is exact (not likely to be way off, but it does happen), then regardless, having it re-tuned as well as possible.
If that does not get you another 30-40 HP (I think it will) I'd suggest changing the cam to something with a bit more intake duration and less exhaust duration. Its been years, but I saw this happen on carburated street race engines in the late 70s - if you had really good of headers, etc., buta near stock or small intake manifold, and some overlap combined with a big exhaust duration and lift, it would scavenge some intake charge traveling out the exhaust at some RPMs. I would think a modern engine, or the dyno sensers, would pick this up, but . . . .
If that does not get you another 30-40 HP (I think it will) I'd suggest changing the cam to something with a bit more intake duration and less exhaust duration. Its been years, but I saw this happen on carburated street race engines in the late 70s - if you had really good of headers, etc., buta near stock or small intake manifold, and some overlap combined with a big exhaust duration and lift, it would scavenge some intake charge traveling out the exhaust at some RPMs. I would think a modern engine, or the dyno sensers, would pick this up, but . . . .
Originally Posted by redtail2426
either the lower hp car is not running right......
Originally Posted by redtail2426
.....or the guy with 380 has something he isnt telling you about.
Teching In
Joined: Sep 2005
Posts: 25
Likes: 0
From: Central North Carolina
I realize degreeing a cam should not make a difference, but unless the tuning is way off (unlikely) I can't think of anything else could be causing this. And it is not that hard to check.
IF the cam is made to spec degreeing won't do anything. But my son and I got a cam from a respectable name brand through a good retailer about two years ago for the stock block in our 98 Z28: the thing ran like a pig and we struggled for weeks before finally deciding to have a shop check the cam: sure enough, it five degrees off. In fact we were ultimately convinced it was not even the advertised lift: just some screw up somewhere. We were just glad that it had not resulted in any valve-poiston clearance problems.
The retailer replaced it no questions asked and we degreed it putting it in and had just what we expected after that.
IF the cam is made to spec degreeing won't do anything. But my son and I got a cam from a respectable name brand through a good retailer about two years ago for the stock block in our 98 Z28: the thing ran like a pig and we struggled for weeks before finally deciding to have a shop check the cam: sure enough, it five degrees off. In fact we were ultimately convinced it was not even the advertised lift: just some screw up somewhere. We were just glad that it had not resulted in any valve-poiston clearance problems.
The retailer replaced it no questions asked and we degreed it putting it in and had just what we expected after that.
I really think the problem lies in the exhaust. There is a huge difference in the SW headers and the Kooks. The collector design is no comparison. Kooks are made to make power, SW are made to fit on the car. I also firmly believe this is the reason his car is having the timing issues. If he upgraded to the Kooks setup, I almost promise power would pick up, and I'd be able to put more timing in the tune. 47 hp seems like a lot, but I've seen people pick up 25 rwhp switching to Kooks headers before on other cars, and adding timing/leaning out the a/f mixture will probably give you another 10-20.
Chuck
Chuck
I used to think that there was little difference between the SW and Kooks headers...that was until I saw uninstalled sets of SW and Kooks side by side...the Kooks collector design is far superior. That is where I too would guess the majority of the issue is.
!LS1 11 Second Club
Joined: Apr 2003
Posts: 7,133
Likes: 2
From: Miami
Originally Posted by Chuck@HPE
I really think the problem lies in the exhaust. There is a huge difference in the SW headers and the Kooks. The collector design is no comparison. Kooks are made to make power, SW are made to fit on the car. I also firmly believe this is the reason his car is having the timing issues. If he upgraded to the Kooks setup, I almost promise power would pick up, and I'd be able to put more timing in the tune. 47 hp seems like a lot, but I've seen people pick up 25 rwhp switching to Kooks headers before on other cars, and adding timing/leaning out the a/f mixture will probably give you another 10-20.
Chuck
Chuck
I picked up 35 rwhp (425 to 460) going from SLP LT's and an LS6 intake to QTP HVMC LT's and a FAST 90 (purchased FAST intake from HPE actually), so I know what a good header can do, but he GTO in question just seams weak. Seems like cam is off or your Mustang dyno is damn stingy- but then again, his MPH sucks.
Last edited by SouthFL.02.SS; Oct 12, 2005 at 04:51 PM.
"All Motor 9 Second club member"
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From: On the Bumper!
Well FWIW, I put down 436 rwhp on the dynojet with FLP LT headers. When I swapped to the Kooks 1 7/8 headers (both thru y-pipe and single cut-out) AND added a 12 bolt rearend with higher 3.73 gears, the car made 459 rwhp. That was with the same tune and only a day apart on the same dyno. I should have lost about 15-18 rwhp with the addition of the 12 bolt. That would have been a at least a 33 rwhp gain with Kooks by themselves. I was pleased to say the least.
There is definitely a performance difference between the various headers out there and the Kooks are superior IMHO.
I would have never guessed it, but I have seen similiar results from others since I installed mine.
My guess is that the headers are making the difference. There's one way to find out
Good luck to ya!
There is definitely a performance difference between the various headers out there and the Kooks are superior IMHO.
I would have never guessed it, but I have seen similiar results from others since I installed mine.
My guess is that the headers are making the difference. There's one way to find out
Good luck to ya!