what the hell made the LS7 BB tick???
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From: Hayward Wi
what the hell made the LS7 BB tick???
ok for my curiosity i have some cam specs for the LS3, LS5, LS6, L88 and ZL1/LS7 cam and have been playing around with them on an dyno progem to see the power gains and stuff with my friend just for some educated guesses.
i have been getting close to the rated HP from the LS5, LS6 and L88 for the most part.
but the LS7 cam um is not doing what i wold exspect it to do it droop the power down to 356 HP at 6000 RPM compared to the LS6s cams 418 at 6000 RPM.
i am keeping every thing constant except the cams why the big droop of power.
i have been getting close to the rated HP from the LS5, LS6 and L88 for the most part.
but the LS7 cam um is not doing what i wold exspect it to do it droop the power down to 356 HP at 6000 RPM compared to the LS6s cams 418 at 6000 RPM.
i am keeping every thing constant except the cams why the big droop of power.
Drifting
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From: Springfield Illinois
Your information is incorrect.. The LS7 used an even hotter cam than the L88. Most think the L88 and the ZL1 cam are the same. Truth is they aren't even close. The ZL1 cam is much hotter than the L88 and that is the cam that was found in the LS7's. HP is probably a little over 600 HP at over 7000 RPMs.
I have the cam specs if you want them..
edit: I reread your post.. What is the power output above 7000 rpms? Also, you have to remember that there are alot of factors that the your dyno calc cant take into consideration.. It all has to do with the heads and how well the flow. For most of the engines that you've dynoed the use close chamber heads. The LS7 should be open chamber which helps out alot at the higher rpm..
I have the cam specs if you want them..
edit: I reread your post.. What is the power output above 7000 rpms? Also, you have to remember that there are alot of factors that the your dyno calc cant take into consideration.. It all has to do with the heads and how well the flow. For most of the engines that you've dynoed the use close chamber heads. The LS7 should be open chamber which helps out alot at the higher rpm..
Last edited by FRSTR90; Aug 24, 2009 at 02:14 AM.
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From: Taylor Michigan
It also dropped a 1/4 point in compression with the open chamber heads so where is the higher compression? .
L88, .12.5
LS7, .12 1/4
Ever hear one? The real thing....
http://s238.photobucket.com/albums/f...t=68RedLS7.flv
L88, .12.5
LS7, .12 1/4
Ever hear one? The real thing....
http://s238.photobucket.com/albums/f...t=68RedLS7.flv
Drifting
Joined: Apr 2007
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From: Springfield Illinois
Wally since we are talkin about compression... I was curious as to what compression the second design L88's ran. If I am not mistaken, the second design L88 ran open chamber heads and the ZL1 580/620 cam.. Also, just to refresh my memory where the valves 2.19/1.88's or 2.19/1.84's
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From: Wichita KS
cc
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From: Hayward Wi
i also have been running 9.5:1 CR on my tests. also i have an high flow head close the 300s intake.
i never knew about the different type heads
oh i made an mistake on how i worded it wrong i said i have an L88 and ZL1/LS7 cam i ment i had an L88, and ZL1/LS7 cam. sorry for the confusion
i never knew about the different type heads
oh i made an mistake on how i worded it wrong i said i have an L88 and ZL1/LS7 cam i ment i had an L88, and ZL1/LS7 cam. sorry for the confusion
Last edited by PuddleJumper; Aug 25, 2009 at 12:47 PM.
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From: Millington Illinois
St. Jude Donor '08-'09
Dyno Sims are "crap in, crap out". You need to feed actual correct info in to get good results. I was wondering why the power numbers were so low. Try inputing actual compression ratios. These cams will have minimal DCR with 9.5 to 1 compression. The bigger cam will have a power drop @ 9.5 to 1 compression. The LS7 "ticked" from the combination of HP parts, compression, cam duration, carburation all being well matched for it's intended use.....Racing!
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Race Director
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From: CORVETTE 77 385 C.I. TEXAS
LS-7 engine on dyno w/ 2 1/4 headers 489 HP @ 6000
You could try LS-7 w/ Comp Cams 305H 9.2:1 CR Blueprinted 2 1/4 headers.
I have the nos. same dyno.
i also have been running 9.5:1 CR on my tests.
I have the nos. same dyno.
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
To get more realistic numbers out of DD2000 you have to input a custom head flow with all the CFM at at .100 lift incriments. you have to use true static compression not the pulled out the GM *** numbers. you have to input from the cam card the true .050 duration and valve lift numbers.
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From: Hayward Wi
To get more realistic numbers out of DD2000 you have to input a custom head flow with all the CFM at at .100 lift incriments. you have to use true static compression not the pulled out the GM *** numbers. you have to input from the cam card the true .050 duration and valve lift numbers.
i dont have the specs for the LS7 heads ie how they flowed.
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From: CORVETTE 77 385 C.I. TEXAS
LS-7 Cam I 262 E 272 @ .050 Lift I .578 E .617
COMP 305H if you want to try it: 253 253 @ .050 .575 .575 9.2 C/R
Typically actual CR is less than specs. as GKull alludes to.
This LS-7 was 12.2 C/R measured.
COMP 305H if you want to try it: 253 253 @ .050 .575 .575 9.2 C/R
Typically actual CR is less than specs. as GKull alludes to.
This LS-7 was 12.2 C/R measured.
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From: Millington Illinois
St. Jude Donor '08-'09
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
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From: Nice Lake Ontario
My bud had a real LS-7 in a 69 vette back in the day.
Hooker header-sidepipes with little restriction-->read LOUD, & an 850 Holley, shifted at 7,200-7,400 with a M-20 & 4:10 gears on Racemaster Cheaters. The one & only time the car ever saw a drag strip it ran an 11:87 (wish I could remember the mph, sucks to get old) thru the sidepipes
I've seen dyno's indicating upper 500s for that combo.
Was hard on rear ends & fuel...in that order!
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
A true engine dyno test they are not going to be using mufflers. Whole point is to see how much HP the motor alone is making, not how much it is losing through mufflers and other accessories.
If it is a good shop they will have stepped race headers but I usually use large tube headers with no mufflers on my DD simulations.
If it is a good shop they will have stepped race headers but I usually use large tube headers with no mufflers on my DD simulations.
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Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
A true engine dyno test they are not going to be using mufflers. Whole point is to see how much HP the motor alone is making, not how much it is losing through mufflers and other accessories.
If it is a good shop they will have stepped race headers but I usually use large tube headers with no mufflers on my DD simulations.
If it is a good shop they will have stepped race headers but I usually use large tube headers with no mufflers on my DD simulations.