Ported LS7 Flow numbers
TECH Addict
Joined: Jul 2002
Posts: 2,261
Likes: 0
Originally Posted by Greg Fell
I'm running a 246/257 112+2 cam motion grind.
i redynoed with the new cam
old cam
cam motion 246/257 112+2 .669/.652
new cam
comp xe-r 232/240 110+2 .630/.644
cranking compression went from ~185-190 to 210
Old cam vs New cam Dyno Graph
it gained ~ 12 peak hp and ~ 40 ft lbs of torque...didn't carry it quite as far but thats fine.
the car is still very low, in my opinion, based on what others have done. wondering if the heads are just too radical for the ls7 manifold.
old cam
cam motion 246/257 112+2 .669/.652
new cam
comp xe-r 232/240 110+2 .630/.644
cranking compression went from ~185-190 to 210
Old cam vs New cam Dyno Graph
it gained ~ 12 peak hp and ~ 40 ft lbs of torque...didn't carry it quite as far but thats fine.
the car is still very low, in my opinion, based on what others have done. wondering if the heads are just too radical for the ls7 manifold.
On The Tree
Joined: May 2005
Posts: 140
Likes: 0
What is your SCR and DCR w/ the new cam? If you could figure a way to get the cranking pressure up even higher (230-240/lb.) w/o closing your intake valve sooner than you are now, I think would show a good result. Glad to see the new cam took you in the right direction.
Originally Posted by Greg Fell
i redynoed with the new cam
old cam
cam motion 246/257 112+2 .669/.652
new cam
comp xe-r 232/240 110+2 .630/.644
cranking compression went from ~185-190 to 210
Old cam vs New cam Dyno Graph
it gained ~ 12 peak hp and ~ 40 ft lbs of torque...didn't carry it quite as far but thats fine.
the car is still very low, in my opinion, based on what others have done. wondering if the heads are just too radical for the ls7 manifold.
old cam
cam motion 246/257 112+2 .669/.652
new cam
comp xe-r 232/240 110+2 .630/.644
cranking compression went from ~185-190 to 210
Old cam vs New cam Dyno Graph
it gained ~ 12 peak hp and ~ 40 ft lbs of torque...didn't carry it quite as far but thats fine.
the car is still very low, in my opinion, based on what others have done. wondering if the heads are just too radical for the ls7 manifold.
Hello Greg.
Thanks for posting updates.
I am following your progress closely as I am also getting what I think are low dyno numbers for my similar set-up (LS7 top end on a 427 CI LS1 shortblock).
My first dyno session was 490rwhp/461rwtq SAE corrected.
Cam is a Comp Cam 229/237 .622/.636 113 LSA
What are you thoughts at this point to bring your power numbers up?
Thanks, Perry
Originally Posted by gtovan
What is your SCR and DCR w/ the new cam? If you could figure a way to get the cranking pressure up even higher (230-240/lb.) w/o closing your intake valve sooner than you are now, I think would show a good result. Glad to see the new cam took you in the right direction.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Originally Posted by Rollin Black
Hello Greg.
Thanks for posting updates.
I am following your progress closely as I am also getting what I think are low dyno numbers for my similar set-up (LS7 top end on a 427 CI LS1 shortblock).
My first dyno session was 490rwhp/461rwtq SAE corrected.
Cam is a Comp Cam 229/237 .622/.636 113 LSA
What are you thoughts at this point to bring your power numbers up?
Thanks, Perry
Thanks for posting updates.
I am following your progress closely as I am also getting what I think are low dyno numbers for my similar set-up (LS7 top end on a 427 CI LS1 shortblock).
My first dyno session was 490rwhp/461rwtq SAE corrected.
Cam is a Comp Cam 229/237 .622/.636 113 LSA
What are you thoughts at this point to bring your power numbers up?
Thanks, Perry
Was this a new motor, Perry? Or did you have this with an ls1/6 top end before?
Thanks for the update Greg. I see the cam made some nice improvements throughout the useable rpm range. I'm a little in the dark about the mph instead of engine rpm. Any idea what rpm the torque and hp is peaking at?
Greg, is it possible to elaborate on exactly what was done to the head ports? Were the valve seats retouched? The reason I ask is because the flow at .500" lift is let's say "optomistic" by a bunch. I'm not saying the peak flow isn't correct, but I've never seen more flow at .500" against what the stock LS7 head can deliver. Not to mention the .055" smaller test bore used. Something doesn't seem right here...........
Richard
Greg, is it possible to elaborate on exactly what was done to the head ports? Were the valve seats retouched? The reason I ask is because the flow at .500" lift is let's say "optomistic" by a bunch. I'm not saying the peak flow isn't correct, but I've never seen more flow at .500" against what the stock LS7 head can deliver. Not to mention the .055" smaller test bore used. Something doesn't seem right here...........
Richard
Originally Posted by Greg Fell
At this point, I'm not sure what I'm going to do.
Was this a new motor, Perry? Or did you have this with an ls1/6 top end before?
Was this a new motor, Perry? Or did you have this with an ls1/6 top end before?
The short block had about 1000 miles on it and previously had AFR 225 heads. Static compression ratio is 11.3:1
Perry
Originally Posted by GrannySShifting
did any of you guys fiure out where the power is?
hope you figure out whats going on with it.. those numbers seem very very low.
btw.. dont think the manifold is restricting... your graph continues to climb. if you were maxing your manifold the power would level off alot more and alot sooner.. something doesnt seem right?
I hope you guys figure out the issues you are having. I've been following along on some L92/LS7 head stroker buildups. So far I have seen all kinds of great flow numbers, but I have yet to see anyone posting and decent dyno/track numbers.
There are plenty of 402+ engines with ported ls1/6 heads or dart/afr heads putting down better numbers. Not bashing you guys combos at all here, just making a concerned observation because I researching a build on a 408/L92 combo myself. These results make me wonder if the huge intake port volumes on these new heads have killed their velocity and swirl.
Again, good luck getting the bugs worked out, and thanks for taking the chance and the hit to the checkbook on these new parts so hopefully the rest of us can learn from what you learn here.
There are plenty of 402+ engines with ported ls1/6 heads or dart/afr heads putting down better numbers. Not bashing you guys combos at all here, just making a concerned observation because I researching a build on a 408/L92 combo myself. These results make me wonder if the huge intake port volumes on these new heads have killed their velocity and swirl.
Again, good luck getting the bugs worked out, and thanks for taking the chance and the hit to the checkbook on these new parts so hopefully the rest of us can learn from what you learn here.
Originally Posted by Ratical
I hope you guys figure out the issues you are having. I've been following along on some L92/LS7 head stroker buildups. So far I have seen all kinds of great flow numbers, but I have yet to see anyone posting and decent dyno/track numbers.
There are plenty of 402+ engines with ported ls1/6 heads or dart/afr heads putting down better numbers. Not bashing you guys combos at all here, just making a concerned observation because I researching a build on a 408/L92 combo myself. These results make me wonder if the huge intake port volumes on these new heads have killed their velocity and swirl.
Again, good luck getting the bugs worked out, and thanks for taking the chance and the hit to the checkbook on these new parts so hopefully the rest of us can learn from what you learn here.
There are plenty of 402+ engines with ported ls1/6 heads or dart/afr heads putting down better numbers. Not bashing you guys combos at all here, just making a concerned observation because I researching a build on a 408/L92 combo myself. These results make me wonder if the huge intake port volumes on these new heads have killed their velocity and swirl.
Again, good luck getting the bugs worked out, and thanks for taking the chance and the hit to the checkbook on these new parts so hopefully the rest of us can learn from what you learn here.
I think we just don't know what camshaft VEs work best with these new heads yet.
I'd opt for an even bigger split, Greg.
Comp LSK 235/251 110+2. Doesn't raise the IVC much, but pushes the EVO out a bit more, which is where the LS7 needs help. Anything like that might work though, i.e., a 227/243 110+2 for more torque or 247/265 108+2 for more power. Give the heads time to flow with the added lift and agressive curtain area of the LSK lobe.
LSK with those big, heavy valves might cause problems, however. Would need a helluva spring and some strong rockers/thick pushrods/heavy duty lifters.
I'd opt for an even bigger split, Greg.
Comp LSK 235/251 110+2. Doesn't raise the IVC much, but pushes the EVO out a bit more, which is where the LS7 needs help. Anything like that might work though, i.e., a 227/243 110+2 for more torque or 247/265 108+2 for more power. Give the heads time to flow with the added lift and agressive curtain area of the LSK lobe.
LSK with those big, heavy valves might cause problems, however. Would need a helluva spring and some strong rockers/thick pushrods/heavy duty lifters.
Originally Posted by JakeFusion™
LSK with those big, heavy valves might cause problems, however. Would need a helluva spring and some strong rockers/thick pushrods/heavy duty lifters.
I just got my LS7 heads, the intake valves are 76 grams and the exhaust are 72 grams. Ain't nothing heavy about them.
TECH Apprentice
Joined: Oct 2004
Posts: 329
Likes: 0
So the exhaust is 72G.
Those exhausts are 1.60 or 1.625"?
Intake is made of titanium so you can get the 2.25" titanium at nearly same weight as a 1.6x" exhaust valve in steel. Steel on the exhaust is better for heat.
What was the size of the intake valve on a 5.7L LT5? 1.85"?
What was the size of intake valve on a 4.6L ford 1.47"?
Those exhausts are 1.60 or 1.625"?
Intake is made of titanium so you can get the 2.25" titanium at nearly same weight as a 1.6x" exhaust valve in steel. Steel on the exhaust is better for heat.
What was the size of the intake valve on a 5.7L LT5? 1.85"?
What was the size of intake valve on a 4.6L ford 1.47"?
Why is everyone so quick to throw LSK lobes on all cam lobes they can now? I dont think LSK lobes are ideal for every lobe intake and exhaust on every combo.... not by a long shot