Power loss with MSD intake
Thread Starter
Teching In
Joined: May 2014
Posts: 13
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From: Colorado Springs
Power loss with MSD intake I'll try to make this as quick as I can, first I am in Colorado at 6,000ft elevation, previous setup before I changed to the msd intake was Edelbrock Victor Jr efi with a FAST 1375cfm throttle body embarrassing at the 8th at 8.3's fastest time. It didn't seem to run right with it and I wanted more power thinking I should definitely be in the 7's at least. Change to msd atomic intake and a Warr 102mm TB. At the same track best I can get it is 8.8. Very embarrassing now. Doing a remote tune, the reputable tuner said everything is dialed in and maybe the intake is too big for my evaluation? I have a TBSS intake and a ls6 on hand that I can try out. Any input will be appreciated
Quick run down of my setup.
73 Nova
Callies compstar 4340 forged crank, 6.125 forged rods, Wiesco 4.030 forged pistons
Comp cam 281LR duration 281/289, Lift .617/.624
317 heads
MSD atomic intake manifold
Warr 102mm throttle body
4l80e 3200 converter
4.11 gears
Holley DominatorECU
Quick run down of my setup.
73 Nova
Callies compstar 4340 forged crank, 6.125 forged rods, Wiesco 4.030 forged pistons
Comp cam 281LR duration 281/289, Lift .617/.624
317 heads
MSD atomic intake manifold
Warr 102mm throttle body
4l80e 3200 converter
4.11 gears
Holley DominatorECU
Stock stroke crank? what compression?
A 8.8 is almost 2 seconds slower than what that combo would run here in TN... I wouldn't think 5500 extra feet of elevation would make anywhere near that much difference.
What is your MPH and 60FT?
Also that combo would be just fine with a TBSS intake
A 8.8 is almost 2 seconds slower than what that combo would run here in TN... I wouldn't think 5500 extra feet of elevation would make anywhere near that much difference.
What is your MPH and 60FT?
Also that combo would be just fine with a TBSS intake
Thread Starter
Teching In
Joined: May 2014
Posts: 13
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From: Colorado Springs
Thanks for the reply. Everyone is telling me elevation issue. Stroker crank 408 Stroker compression is around 10-5 if I remember correctly from what the paperwork said. The car runs fine no issues at all I drive it frequently but the power is just not where I would expect it to be. And unfortunately the track that's 10 minutes from me doesn't give out slips. They only give us the time we ran
Last edited by Franco Sj; Jul 28, 2021 at 01:09 PM.
Well if you had something like a 2.4 60 ft I could see it being in the 8's lol But that would be ALOT of tire spin....
Maybe someone else will chime in on the elevation but a 408 with healthy cam will run 6's with traction in a 3000lb car. If anything at all is holding it back it would be the 317 heads with lowish compression, but not a whole lot. Im guessing you plan to add boost?
Maybe someone else will chime in on the elevation but a 408 with healthy cam will run 6's with traction in a 3000lb car. If anything at all is holding it back it would be the 317 heads with lowish compression, but not a whole lot. Im guessing you plan to add boost?
Thread Starter
Teching In
Joined: May 2014
Posts: 13
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From: Colorado Springs
I was planning on boost but directions change and I'm putting a 150 shot installing it next week. But NA we both agree that it's not where the car should be at even at this evaluation. Going from a turbo car to this, it's not putting a smile on my face at all. But I was also going to take the intake to see if anything will change with power
Thread Starter
Teching In
Joined: May 2014
Posts: 13
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From: Colorado Springs
Sorry no slips. The track that I got to doesn't give slips. The car runs great though. Nothing indicates a dead or misfiring cylinder. Nothing coming up on the holley dominator or on the datalogs
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TECH Regular
Joined: Dec 2020
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From: Ohio
8.8 in the 1/8 @ 3400 lbs is 246 HP according to wallace racing
Google says air pressure at 6000ft is 11.7 PSIA
(246/11.7)*14.7=309hp at sea level
Something isn't right.
Edit: MPH and actual weight, or any data would help
Google says air pressure at 6000ft is 11.7 PSIA
(246/11.7)*14.7=309hp at sea level
Something isn't right.
Edit: MPH and actual weight, or any data would help
Last edited by Woodylyf767; Jul 29, 2021 at 12:19 AM. Reason: Don't want to blow up feeds
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Thread Starter
Teching In
Joined: May 2014
Posts: 13
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From: Colorado Springs
Thank you for everyone's input. Unfortunately the track that I go to doesn't give out time slips. I talked to a few drag racers that race in this evaluation for years and they were telling me a 102mm throttle body might be too big for this altitude. Next week sometime top end should come off and inspected. 243 heads will be going on with the same msd intake with a 92mm tb this time along with a zex nitrous kit.it will be getting dyno tuned instead of a remote tune this time and see what happens
I would not Swap 243s from 317s. . I dont see any gain besides some compression.
Go ls3 heads. I have stock ls3 heads on my 408 with a fast 102 in my Corvette. It makes 525 wheel and traps 108 ish in the 1/8th on the street .
Go ls3 heads. I have stock ls3 heads on my 408 with a fast 102 in my Corvette. It makes 525 wheel and traps 108 ish in the 1/8th on the street .
Thank you for everyone's input. Unfortunately the track that I go to doesn't give out time slips. I talked to a few drag racers that race in this evaluation for years and they were telling me a 102mm throttle body might be too big for this altitude. Next week sometime top end should come off and inspected. 243 heads will be going on with the same msd intake with a 92mm tb this time along with a zex nitrous kit.it will be getting dyno tuned instead of a remote tune this time and see what happens
It's not the parts you mention. You have something else wrong with the car for sure or the track is giving you the wrong time. Next time you go, try to see what your trap speed is when crossing the line.
Thread Starter
Teching In
Joined: May 2014
Posts: 13
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From: Colorado Springs
Thanks for everyone's input. I have the car with a trusted reputable performance shop. I don't have time and my body been hurting too much. I'll keep you all posted on any findings. Thank you