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L76 Intake manifold flow results

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Old Nov 3, 2006 | 01:11 AM
  #21  
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Richard, thanks for the info and effort
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Old Nov 3, 2006 | 08:53 AM
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Rick,
Intake flow in the high 320's with the manifold bolted on is really great. These heads have a lot of promise.......... Your right on about the intake bowl needing some attention. On the exhaust side 230's is much better than stock as well. These heads don't offer a lot of casting thickness so we'll have to port them and then slice up the castings to check for thin spots.

Richard
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Old Nov 3, 2006 | 09:13 AM
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Originally Posted by Richard@WCCH
Rick,
Intake flow in the high 320's with the manifold bolted on is really great. These heads have a lot of promise.......... Your right on about the intake bowl needing some attention. On the exhaust side 230's is much better than stock as well. These heads don't offer a lot of casting thickness so we'll have to port them and then slice up the castings to check for thin spots.

Richard
The numbers where done on a superflow 600 bench if this helps at all. So that way no one has to ask.

Yeah, the exhuast was done without a pipe, so there is more once you put the pipe on, but you are right about the porting meterial. That damn seat sits right in the way of the exhaust.

Rick
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Old Nov 3, 2006 | 06:32 PM
  #24  
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Originally Posted by Rick@Synergy
The numbers where done on a superflow 600 bench if this helps at all. So that way no one has to ask.

Yeah, the exhuast was done without a pipe, so there is more once you put the pipe on, but you are right about the porting meterial. That damn seat sits right in the way of the exhaust.

Rick
Always exhuast with a pipe at least 8 inches long with a curve replicating your headers. it helps the process. But hey a weak exhuast isn;t much to worry about and it can be fixe with a cam change.
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Old Nov 3, 2006 | 06:51 PM
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Originally Posted by CollinsAutomotive
Always exhuast with a pipe at least 8 inches long with a curve replicating your headers. it helps the process. But hey a weak exhuast isn;t much to worry about and it can be fixe with a cam change.

but no one knows what cam change you need.... or atleast they aint tellin?

so far the consensus says an extra 10 degrees of exhaust duration.... as far as lift i assume no one has said anything about intake:exhaust lift ratios.
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Old Nov 3, 2006 | 07:05 PM
  #26  
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Originally Posted by Forteen3GT
but no one knows what cam change you need.... or atleast they aint tellin?

so far the consensus says an extra 10 degrees of exhaust duration.... as far as lift i assume no one has said anything about intake:exhaust lift ratios.
Well, maybe this might help. We run about a 10-12 degree split on our LS7 setups due to the nature of the cylinder head setup. The same would go for the new L92 stuff I would think. Atleast thats what we are planning on playing with. I get away with over .600 on the lifts for the LS7 stuff, and I plan on the same for these heads too. But it comes down to what you can fit as well. Most stock motors might not like that big of lift, and if you have some relief in the pistons, then you should be good.

Rick
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Old Nov 4, 2006 | 11:53 PM
  #27  
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Originally Posted by Rick@Synergy
Well, maybe this might help. We run about a 10-12 degree split on our LS7 setups due to the nature of the cylinder head setup. The same would go for the new L92 stuff I would think. Atleast thats what we are planning on playing with. I get away with over .600 on the lifts for the LS7 stuff, and I plan on the same for these heads too. But it comes down to what you can fit as well. Most stock motors might not like that big of lift, and if you have some relief in the pistons, then you should be good.

Rick
actually its time to go back to cam school since the intakes behave so differently from the cathedral port heads. i have to rework a few grinds i like so i know that everyone else is going to have to start over. Also even though the flow bench says the exhuast port isn't great i don't always belive its ever that bad. Just look at small mopar stuff from 15 yrs ago guys were going fast with damn crappy headers and ports.If only Gm would have grabed the 15* valve angle sooner. Opps shouldn't have let that slip. :wink: rick will get that one.I think guys need to stop focusing on the heads/headers so much at least conecrning exhast and start looking down stream to the y pipes and x pipes and the exhuast system as a whole unit. the gas is superheated when the valve opens. As the tempature of air goes up so does it velocity, fluidity and its density goes down. I'd be willing to bet the exhuast port would have to be say 60% of the intake on a NA car before it got to far out of control. I think some the prostock engines are actually that bad or worse. Hence why GM left the port alone. All in All impromment over the previous designs whch GM has definately been on top of is a step in the right direction. I have been beating my head on the ls6 intake for a while would be nice to have something inbetween the ls7 and the ls1/ls6 designs.
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Old Nov 5, 2006 | 09:50 AM
  #28  
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Originally Posted by CollinsAutomotive
actually its time to go back to cam school since the intakes behave so differently from the cathedral port heads. i have to rework a few grinds i like so i know that everyone else is going to have to start over. Also even though the flow bench says the exhuast port isn't great i don't always belive its ever that bad. Just look at small mopar stuff from 15 yrs ago guys were going fast with damn crappy headers and ports.If only Gm would have grabed the 15* valve angle sooner. Opps shouldn't have let that slip. :wink: rick will get that one.I think guys need to stop focusing on the heads/headers so much at least conecrning exhast and start looking down stream to the y pipes and x pipes and the exhuast system as a whole unit. the gas is superheated when the valve opens. As the tempature of air goes up so does it velocity, fluidity and its density goes down. I'd be willing to bet the exhuast port would have to be say 60% of the intake on a NA car before it got to far out of control. I think some the prostock engines are actually that bad or worse. Hence why GM left the port alone. All in All impromment over the previous designs whch GM has definately been on top of is a step in the right direction. I have been beating my head on the ls6 intake for a while would be nice to have something inbetween the ls7 and the ls1/ls6 designs.

a few say 70%..... so we are in the ballpark with the L76/l92 combo.
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Old Mar 6, 2007 | 10:39 AM
  #29  
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Hey Richard, I'd like to see what your ported L92 head flows to the stock L76. Any test results you care to post?

Frank
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Old Mar 6, 2007 | 10:05 PM
  #30  
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Originally Posted by StingrayCrazy
Hey Richard, I'd like to see what your ported L92 head flows to the stock L76. Any test results you care to post?

Frank
I'll finish putting together some flow data by the beginning of next week. I'll be comparing a L76 and L92 intake to stock and ported heads.

Stay tuned.

Richard
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Old Mar 7, 2007 | 06:03 AM
  #31  
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Originally Posted by Richard@WCCH
I'll finish putting together some flow data by the beginning of next week. I'll be comparing a L76 and L92 intake to stock and ported heads.

Stay tuned.

Richard
Hey Richard,

Why don't you come up with a better street intake manifold for these heads and RULE THE WORLD!
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Old Mar 7, 2007 | 12:50 PM
  #32  
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Originally Posted by WKMCD
Hey Richard,

Why don't you come up with a better street intake manifold for these heads and RULE THE WORLD!
+1, i think the first person to come out with a resonably priced intake that would replace the L76 is going to make a lot of $$$.
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