Cms 416
05-31-2011, 10:10 PM
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Cms 416 Hey every one just wanted to post my results for you guys because there is not a ton of info on 416
LS6 intake
LS3 Block 4.070 Bore 4.00 stroke
CMS Spec cam 243/247/ 623/623 112+2
West Coast Cylinder heads Edelbrock 245 heads in 72CC
Texas Speed ! 7/8 headers
Most of all Ryne@CMS Speed Dens tune
most of all Stock MAF and non ported LS6 intake
Final numbers 485 RWHP 465RWTRQ
LS6 intake
LS3 Block 4.070 Bore 4.00 stroke
CMS Spec cam 243/247/ 623/623 112+2
West Coast Cylinder heads Edelbrock 245 heads in 72CC
Texas Speed ! 7/8 headers
Most of all Ryne@CMS Speed Dens tune
most of all Stock MAF and non ported LS6 intake
Final numbers 485 RWHP 465RWTRQ
Last edited by racerfox; 06-01-2011 at 01:29 PM.
05-31-2011, 11:36 PM
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no i did not go for a sleeper look with the ls6 intake i just dont make enough from the corps so ill get it down the line the 425trq at 3500 makes my 315 seem like nothing i did not think about tire spin before the new motor lol
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06-14-2011, 12:18 PM
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this car really surprised me, i was thinking 460 max through the ls6 intake, but i was pleasantly surprised..... with a 102 combo this thing will fly....
to the people saying should have gone with a ls3 topend, this thread isnt about that, so leave it out...
06-15-2011, 10:45 AM
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sorry bro im just not sold on ls3 heads i wanted max trq so i built it the way i wanted i don't believe they carry the velocity that the 245 heads do down low to make massive low end
06-15-2011, 07:35 PM
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here is where i got some info for you
Thats a good point and I agree with you, especially comparing OEM cathedral heads to OEM square port heads.....that's not even a contest. Much larger valve, much larger runner and CSA with a raised intake port that gives the port a much better vantage point (angle of attack) into the back of the intake valve and ultimately the combustion chamber.
It does in fact take a really well designed cathedral port head with a smaller cross section (and a non raised runner) to compete with the latest offering from the general which in fact has the benefits I previously mentioned to help out the airflow curve in a substantial way.
However, if are wanting to compare a smaller high efficient port design to a larger less efficient design (in spite of how the peak intake numbers compare, although at this point they would be close) it's the delivery of the power curve thats more greatly effected....and especially if we are discussing lower RPM part throttle operation....this is NEVER reflected in the dyno curve at low RPM because that is WOT comparisons....its a feel thing you have to experience to understand and its for real. So when everyone points to the rect port heads dyno curve to compare low RPM data to a cathedral its a waste of time....yes its valid info but who in their right mind actually floors the accelerator pedal at 2800 or even 3400 RPM's....you most certainly downshift to a lower gear at that point.
Old school guys who have previously owned a BBC oval port performance motor versus a rectangular port engine and had the opportunity to experience both in the same vehicle will know exactly what I'm talking about....even if the peak power numbers were close, and the track performance was close, the drivability and low RPM torque at part throttle is night and day better with the smaller high velocity oval port heads. Hell the same car felt faster driving around town even if it wasn't....
The new LS3/L92 heads are a leap forward in a big way from the older OEM cathedral heads....no doubt about it, but IMO looking at them purely from a design stand point they are not terribly efficient and leave quite a bit of room for improvement....but thats all the good news honestly. As the aftermarket continues to invest time in building clean sheet design square port heads, the performance potential of these engines will go even higher.
Im confident I could take an L92 head and make it 20 cc's smaller and improve its flow at the same time....if that was the case what do you think the outcome would be come dyno and track day? The head would be alot more efficient and the power curve would certainly reflect that. Wanna make an L92/LS3 head better....spark up the welder and/or grab a can of your favorite epoxy....make it more efficient as well as adding CFM....don't just make a big head larger in search of added CFM, but unfortunately that's not very practical and to really accomplish this you need a clean sheet design casting to work with. Its the same argument we made 7 years ago when we launched the AFR 205.....everyone scoffed at it originally....a smaller port....what were they thinking?? But a port that head 5 cc's less finished volume than a stock LS6 head (the best OEM port at the time) and flowed almost 50 more CFM's. Alot more power in a package that felt like it wanted to explode down low if you were smart enough not to over cam the car.
I'm not sure why there is so much controversy lately with cathedral and rect port LS offerings....they both have their place in the world....they both have their upsides....and they both have their downsides. Picking the right head is just as important, if not more important than picking the right cam....it just depends on what your setting out to accomplish.
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
Hope this helped a few of you....
Thanks,
Tony
It does in fact take a really well designed cathedral port head with a smaller cross section (and a non raised runner) to compete with the latest offering from the general which in fact has the benefits I previously mentioned to help out the airflow curve in a substantial way.
However, if are wanting to compare a smaller high efficient port design to a larger less efficient design (in spite of how the peak intake numbers compare, although at this point they would be close) it's the delivery of the power curve thats more greatly effected....and especially if we are discussing lower RPM part throttle operation....this is NEVER reflected in the dyno curve at low RPM because that is WOT comparisons....its a feel thing you have to experience to understand and its for real. So when everyone points to the rect port heads dyno curve to compare low RPM data to a cathedral its a waste of time....yes its valid info but who in their right mind actually floors the accelerator pedal at 2800 or even 3400 RPM's....you most certainly downshift to a lower gear at that point.
Old school guys who have previously owned a BBC oval port performance motor versus a rectangular port engine and had the opportunity to experience both in the same vehicle will know exactly what I'm talking about....even if the peak power numbers were close, and the track performance was close, the drivability and low RPM torque at part throttle is night and day better with the smaller high velocity oval port heads. Hell the same car felt faster driving around town even if it wasn't....
The new LS3/L92 heads are a leap forward in a big way from the older OEM cathedral heads....no doubt about it, but IMO looking at them purely from a design stand point they are not terribly efficient and leave quite a bit of room for improvement....but thats all the good news honestly. As the aftermarket continues to invest time in building clean sheet design square port heads, the performance potential of these engines will go even higher.
Im confident I could take an L92 head and make it 20 cc's smaller and improve its flow at the same time....if that was the case what do you think the outcome would be come dyno and track day? The head would be alot more efficient and the power curve would certainly reflect that. Wanna make an L92/LS3 head better....spark up the welder and/or grab a can of your favorite epoxy....make it more efficient as well as adding CFM....don't just make a big head larger in search of added CFM, but unfortunately that's not very practical and to really accomplish this you need a clean sheet design casting to work with. Its the same argument we made 7 years ago when we launched the AFR 205.....everyone scoffed at it originally....a smaller port....what were they thinking?? But a port that head 5 cc's less finished volume than a stock LS6 head (the best OEM port at the time) and flowed almost 50 more CFM's. Alot more power in a package that felt like it wanted to explode down low if you were smart enough not to over cam the car.
I'm not sure why there is so much controversy lately with cathedral and rect port LS offerings....they both have their place in the world....they both have their upsides....and they both have their downsides. Picking the right head is just as important, if not more important than picking the right cam....it just depends on what your setting out to accomplish.
Sorry for the semi-lengthy rant but it seems no matter where I turn on the Internet the same BS keeps popping up everywhere with alot of the same players stirring the pot....hell it must be the topic of twenty threads in five different sections of just this particular site right now.
Hope this helped a few of you....
Thanks,
Tony