Complex cam question
Thread Starter
Safety Car
Joined: Aug 2004
Posts: 4,067
Likes: 62
From: Houston Texas
Complex cam question
I am going with a very small blower cam on my LS3 (GT2-3 or Andy's Stage 2). My goal is to keep low end tq. and stock like driveability. The GT2-3 has and intake of 207 with a .571 lift, Andy's has a 214 dur. but only a .559 lift. Is the 6 one way 1/2 dozen the other as far as CFM into the chamber at 10psi? I am sure there is a formula to figure this out but I wanted to see if anyone had a round about answer.
I am leaning toward the GT2-3 because I want the smaller duration with the higher lift because it has more tq.
GT2-3 207/220 .571 .579 118.5 LSA
Andy's 214/228 .559 .571 117 LSA
I am leaning toward the GT2-3 because I want the smaller duration with the higher lift because it has more tq.
GT2-3 207/220 .571 .579 118.5 LSA
Andy's 214/228 .559 .571 117 LSA
Melting Slicks
Joined: May 2008
Posts: 2,121
Likes: 2
From: CT
I am going with a very small blower cam on my LS3 (GT2-3 or Andy's Stage 2). My goal is to keep low end tq. and stock like driveability. The GT2-3 has and intake of 207 with a .571 lift, Andy's has a 214 dur. but only a .559 lift. Is the 6 one way 1/2 dozen the other as far as CFM into the chamber at 10psi? I am sure there is a formula to figure this out but I wanted to see if anyone had a round about answer.
I am leaning toward the GT2-3 because I want the smaller duration with the higher lift because it has more tq.
GT2-3 207/220 .571 .579 118.5 LSA
Andy's 214/228 .559 .571 117 LSA
I am leaning toward the GT2-3 because I want the smaller duration with the higher lift because it has more tq.
GT2-3 207/220 .571 .579 118.5 LSA
Andy's 214/228 .559 .571 117 LSA
Drifting
Joined: Jul 2003
Posts: 1,796
Likes: 1
From: Annandale VA
No. The higher ratio rockers will change the lift, but have a negligible effect on duration. Also, the relative duration (difference between intake and exhaust) will not change at all. As was previously pointed out, FI engines benefit from increased flow on the exhaust side.
Melting Slicks
Joined: Jun 2006
Posts: 2,690
Likes: 1
From: Northern Calif
Hitman not disagreeing with you at all, but for the sake of the thread I have the stock specs of cam ls2: 204 211 .525 .525 lsa 118
with 1.8 ra approx would translate to 206 213 .582 .582 lsa 118
with 1.8 ra approx would translate to 206 213 .582 .582 lsa 118
Drifting
Joined: Jul 2003
Posts: 1,796
Likes: 1
From: Annandale VA
Le Mans Master
Joined: Dec 2005
Posts: 6,994
Likes: 1,677
From: Southeast TX
What blower are going to add? If it's a radix, there wouldn't be much difference between the cams you mentioned and the stock cam. If it's a radix, I wouldn't spend the time and money to do the swap. I have no experience with the centrifugals.
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Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
I am going with a very small blower cam on my LS3 (GT2-3 or Andy's Stage 2). My goal is to keep low end tq. and stock like driveability. The GT2-3 has and intake of 207 with a .571 lift, Andy's has a 214 dur. but only a .559 lift. Is the 6 one way 1/2 dozen the other as far as CFM into the chamber at 10psi? I am sure there is a formula to figure this out but I wanted to see if anyone had a round about answer.
I am leaning toward the GT2-3 because I want the smaller duration with the higher lift because it has more tq.
GT2-3 207/220 .571 .579 118.5 LSA
Andy's 214/228 .559 .571 117 LSA
I am leaning toward the GT2-3 because I want the smaller duration with the higher lift because it has more tq.
GT2-3 207/220 .571 .579 118.5 LSA
Andy's 214/228 .559 .571 117 LSA
Thread Starter
Safety Car
Joined: Aug 2004
Posts: 4,067
Likes: 62
From: Houston Texas
That lift is too much for me on the GT-11 but I am strongly thinking about going with a cam that is the best of both worlds the Thunder Racing blower cam.
214/230 .601 .579 117 LSA
I has the high intake lift that I want and the long duration on the exhaust and still on the 117 should idle like stock after a little tuning.
214/230 .601 .579 117 LSA
I has the high intake lift that I want and the long duration on the exhaust and still on the 117 should idle like stock after a little tuning.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
That lift is too much for me on the GT-11 but I am strongly thinking about going with a cam that is the best of both worlds the Thunder Racing blower cam.
214/230 .601 .579 117 LSA
I has the high intake lift that I want and the long duration on the exhaust and still on the 117 should idle like stock after a little tuning.
214/230 .601 .579 117 LSA
I has the high intake lift that I want and the long duration on the exhaust and still on the 117 should idle like stock after a little tuning.
However, in my opinion, going with a shorter duration cam on a NA car would be a waste of money because it would be too close to the factory cam.
If you are planning to add a blower, then the shorter duration cam would probably be a better choice.
My suggestion to you is to do more research on cam's that are in the 218-224 duration intake and 228-234 exhaust range with .590~ lift.
Last edited by Mez; Feb 19, 2009 at 07:52 PM.
Race Director
Joined: Jan 2000
Posts: 12,375
Likes: 406
From: Florida
Just remember that more duration is what helps you make power on the top end as valve events speed up. Lift will not help in that regard. So I would go with Andy's cam of your two choices. However, I would agree that the TR 214/230 cam seems about perfect.
Many like the GT-11 cam, but IMO (and IMO only) running +.600 lift on a hyd high RPM valvetrain (which the LS is) is going to create reliability problems in the long term. At the very least, you'd be looking at spring replacements every 15K and accelerated seat and guide wear, as you are exceeding the geometry and stress the head was designed for. Again, this is IMO, not a fact.
Many like the GT-11 cam, but IMO (and IMO only) running +.600 lift on a hyd high RPM valvetrain (which the LS is) is going to create reliability problems in the long term. At the very least, you'd be looking at spring replacements every 15K and accelerated seat and guide wear, as you are exceeding the geometry and stress the head was designed for. Again, this is IMO, not a fact.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Just remember that more duration is what helps you make power on the top end as valve events speed up. Lift will not help in that regard. So I would go with Andy's cam of your two choices. However, I would agree that the TR 214/230 cam seems about perfect.
Many like the GT-11 cam, but IMO (and IMO only) running +.600 lift on a hyd high RPM valvetrain (which the LS is) is going to create reliability problems in the long term. At the very least, you'd be looking at spring replacements every 15K and accelerated seat and guide wear, as you are exceeding the geometry and stress the head was designed for. Again, this is IMO, not a fact.
Many like the GT-11 cam, but IMO (and IMO only) running +.600 lift on a hyd high RPM valvetrain (which the LS is) is going to create reliability problems in the long term. At the very least, you'd be looking at spring replacements every 15K and accelerated seat and guide wear, as you are exceeding the geometry and stress the head was designed for. Again, this is IMO, not a fact.
I was trying not to recommend any one particular cam, least of all the GT-11. I was only offering my opinion that a cam with a shorter duration than the GT-11 on a NA car would be a waste of money.
I would like to also correct myself. The GT-11 cam duration is 215 on the intake not 218 as I stated earlier. However, perhaps the cam is going into an engine with a blower, so a shorter duration cam would be fine.
Thread Starter
Safety Car
Joined: Aug 2004
Posts: 4,067
Likes: 62
From: Houston Texas
I totally agree the N/A cam is completely different in regards that you need it to "pull" air in as opposed to a F/I car forces it in so you don't have to worry about having a long duration cam. The trick is to keep the duration on the intake side as short as you can with a high lift so you won't lose your bottom end and tq. Thats why I like the TR cam because its perfect all around. Thanks for the input.
