L92/L76 Intake Manifold Flow Comparison
Originally Posted by Richard@WCCH
One things for sure, the L92 heads are badly in need of a high performance oriented intake.
Richard
Richard
You said the L92 intake limits high lift airflow, yet the L92 intake shows and increase in intake flow from .600-.650 lift in both comparisons (Port 2 and Port 5). In fact the stock combo (Port 2) outflows the CNC head (Port 5) in the entire flow range except between .450-.600. Port 6 shows nice gains above .450 lift, but at .650 the stock head outflows the CNC head (slightly).
I think this proves GM did a great job matching the L92 heads to both the L76 and L92 intake for a nice, flat curve. I can't help wonder if you switched stock valves to the CNC head and flowed them. Then backcut a stock valve and flow it. I would think you would pick up some low lift airflow.
Thanks for the great information, it sheds a lot of light on the subject.
Originally Posted by Richard@WCCH
I have a couple of customers who are going to use a carb style manifold. I'm not sure how their results will correlate to the late model cars as one is going to be a big turbo setup and the other will be a swap into an early year car. As of now I don't have a carb style intake but when one does show up I'll add the test to the results here.
BTW, I picked up my LS2 block last night in Austin.
Originally Posted by DrkPhx
I can't help wonder if you switched stock valves to the CNC head and flowed them. Then backcut a stock valve and flow it. I would think you would pick up some low lift airflow.
Originally Posted by Outlaw1
Hey don't forget about the customer that's planning to use a big turbo setup AND swap it into an early car. You should have said something, I would have sent my intake along with the heads. If I can make it over to the shop this weekend I'll grab the intake and send it to you Monday/Tuesday. The carb intake won't be any restriction at all. You can literally look at the intake valves when the carb isn't sitting on it.
Richard
Formerly 2001c3driver-7/31/10
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Thank you for taking the time to put that article together. Sounds good, for a truck manifold; 0- 4 or 4,500rpm. How much better is it than the LM7? would it be worth the trouble..................
Thanks
Thanks
Originally Posted by 2001c3driver
Thank you for taking the time to put that article together. Sounds good, for a truck manifold; 0- 4 or 4,500rpm. How much better is it than the LM7? would it be worth the trouble..................
Thanks
Thanks
Richard
On The Tree
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From: Indianapolis, IN
I'm not sure if the market will ever support an aftermarket intake for the L92 heads. I'm debating weather to pitch the L92 heads & L76 intake and go with the TEA 235 heads and FAST 90 intake. Maybe I'm being impatient.
Originally Posted by cybernco
I'm not sure if the market will ever support an aftermarket intake for the L92 heads. I'm debating weather to pitch the L92 heads & L76 intake and go with the TEA 235 heads and FAST 90 intake. Maybe I'm being impatient.
Personally.... I think if you went with a carb style and bad *** heads, you will pick up power down low over the L76 anyway... vs the 90/90 setup and the L76 intake setup. Just make sure you have good heads to help pick up more power on your block down low.
Richard.... is it possible to see what would happen if you increase the flow on the heads and put the L76 back on.... what percent does it gain up top or lose? Basically comparing the numbers from stock, stg 1, then stg 2 .... etc etc?
Lift____.100”_.150”__.200”_.250”_.300”_.350”_.400” _.450”_.500”_.550”_.600”_.650”
Port 1_ 76.3_113.1_155.7_191.1_225.5_252.5_276.3_296.1_312 .0_322.4_311.9_310.3
Port 4_ 73.9_110.7_146.7_188.2_220.6_252.7_278.9_298.8_322 .3_337.3_352.2_361.5
why did you fail to gain flow from the CNC work down low.... one would figure you should be at 300cfm with .400 lift???
Port 1_ 76.3_113.1_155.7_191.1_225.5_252.5_276.3_296.1_312 .0_322.4_311.9_310.3
Port 4_ 73.9_110.7_146.7_188.2_220.6_252.7_278.9_298.8_322 .3_337.3_352.2_361.5
why did you fail to gain flow from the CNC work down low.... one would figure you should be at 300cfm with .400 lift???
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On The Tree
Joined: Jun 2003
Posts: 143
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I was out of the game for a while and now I come back and there are LS2, LS7, L92, L76.
I have 3 questions:
1.) Will L92 intake fit on a 2000 LS1?
2.) If it does. What kind of difference will it make?
3.) What all is needed to make this swap.
I searched but couldnt find any definate answers on this.
Thank you
I have 3 questions:
1.) Will L92 intake fit on a 2000 LS1?
2.) If it does. What kind of difference will it make?
3.) What all is needed to make this swap.
I searched but couldnt find any definate answers on this.
Thank you
Originally Posted by blackcat
I was out of the game for a while and now I come back and there are LS2, LS7, L92, L76.
I have 3 questions:
1.) Will L92 intake fit on a 2000 LS1?
2.) If it does. What kind of difference will it make?
3.) What all is needed to make this swap.
I searched but couldnt find any definate answers on this.
Thank you
I have 3 questions:
1.) Will L92 intake fit on a 2000 LS1?
2.) If it does. What kind of difference will it make?
3.) What all is needed to make this swap.
I searched but couldnt find any definate answers on this.
Thank you
I can send you the IFR numbers to use but you will need EFILive or HP Tuners to actually make the change.
Originally Posted by glenn gerzik
I have the new l92 heads and l76 intake on a 408 but the injectors are flooding my old ls1 tune can any one help ?
carb Please tell me you've flowed the carb intake!
I'm on stand-by to see if the car intake is supperior to the L76. GM High Tech Performance did an article from livernois motorsports, and the carb intake didn't make as much power as the L76 intake.
As soon as I hear the verdict, I'm going to purchase.
Thanks for the write up and comparision. That was one of the questions that I had asked b-4.
Moss
I'm on stand-by to see if the car intake is supperior to the L76. GM High Tech Performance did an article from livernois motorsports, and the carb intake didn't make as much power as the L76 intake.
As soon as I hear the verdict, I'm going to purchase.
Thanks for the write up and comparision. That was one of the questions that I had asked b-4.
Moss
13 Second Truck Club
Joined: Apr 2006
Posts: 691
Likes: 0
From: Cajun Country...Lafayette, LA
Originally Posted by Richard@WCCH
The L92 manifold design limits high lift airflow and I can't help but wonder if this was done by design. Speculation here: I don't think GM wanted to deal with drivetrain warranty issues in the truck line therefore they choked off the high peak intake flow. It allows the engine to make nice low and mid range torque and produce the 400+hp goal. Nice work GM. 
Richard
Richard
Richard,
Thanks a mill for all of your research. I have an 07' Sierra Denali with the 6.2L. Do you think a L76 intake manifold swap would payoff on such a heavy truck? I see where the top end flow gains are on the L76 vs L92. Do you think the L76 manifold runners would cause a loss low end tq? I need all the low end I can to get in order to get this big boat moving..In your opinion would it be worth the swap or should I wait and see what the new LS3 manifold will be like?
Thanks again...
Mark
Last edited by markislive78; Jul 18, 2007 at 03:58 PM.
Originally Posted by markislive78
Richard,
Thanks a mill for all of your research. I have an 07' Sierra Denali with the 6.2L. Do you think a L76 intake manifold swap would payoff on such a heavy truck? I see where the top end flow gains are on the L76 vs L92. Do you think the L76 manifold runners would cause a loss low end tq? I need all the low end I can to get in order to get this big boat moving..In your opinion would it be worth the swap or should I wait and see what the new LS3 manifold will be like?
Thanks again...
Mark
Thanks a mill for all of your research. I have an 07' Sierra Denali with the 6.2L. Do you think a L76 intake manifold swap would payoff on such a heavy truck? I see where the top end flow gains are on the L76 vs L92. Do you think the L76 manifold runners would cause a loss low end tq? I need all the low end I can to get in order to get this big boat moving..In your opinion would it be worth the swap or should I wait and see what the new LS3 manifold will be like?
Thanks again...
Mark
Good luck,
Richard
13 Second Truck Club
Joined: Apr 2006
Posts: 691
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From: Cajun Country...Lafayette, LA
Originally Posted by Richard@WCCH
The L76 runners are pretty long and should help maintain low end torque. Is it worth the hassle to make the swap? I can't say for sure. If your application calls for massive torque from just off idle, I would start with the L92 intake and evaluate from there. Truck's don't typically dwell in the upper rpm ranges in daily driven street form so it stands to reason that the L92 intake manifold may do exactly what you're looking for especially if your cam is stock or near stock.
Good luck,
Richard
Good luck,
Richard
U da man!
Based on this dyno from GM do you think the CAM profile is pretty aggresive in the upper end for a stock "truck"? If so maybe it could be worth a LS3 or L92 intake maifold swap just to see the diff at the track and my 60' times...
Last edited by markislive78; Jul 19, 2007 at 05:44 PM.
Curious - is that L92 intake manifold different than the LS2 truck manifold from the SSR or TBSS? I think it is (I'm pretty sure my SSR mani has the cathedral style ports), but I'm not 100% sure.
