LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

something wrong you tell me

Old Jan 29, 2009 | 08:20 PM
  #1  
Dnsean's Avatar
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something wrong you tell me

parts in sig, only got 270rwhp, 300rwtq??? something has got to be wrong... is it cause it was a jasper motor compression is down to 9.75? or is it something else, engine was rated at 340hp,380tq i believe from jasper with the cam, good flow air and exhaust. so i would have expected more rwhp so wht is the problem here?? kinda bummed out and feel like selling car now
Old Jan 29, 2009 | 08:52 PM
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Did you tune the pcm for that cam?
Old Jan 29, 2009 | 08:59 PM
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full dyno tune
Old Jan 29, 2009 | 09:00 PM
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Originally Posted by Dnsean
... only got 270rwhp, 300rwtq ... engine was rated at 340hp,380tq i believe ...
Sounds good to me... Assume a typical 20% drivetrain loss for an automatic.

340hp x .80(%) = 272hp


You're considering selling the car because once you dyno'd it the numbers weren't as high as you had hoped? lol

Last edited by MikeGyver; Jan 29, 2009 at 09:08 PM.
Old Jan 29, 2009 | 09:14 PM
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Different dynos give different numbers. What kind was it? The only important numbers are what it puts out at the track. If it should be faster and isn't figure it out before you dump it.
Old Jan 29, 2009 | 09:15 PM
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flp said 17% loss in auto, i would have expected more hp, esp with 1.6 rockers over 1.5 which was rated with orginally, cat and resinator too restrictive? or compression too low? how would i find out wht fwhp would be? is there a calculator?
Old Jan 29, 2009 | 09:23 PM
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Originally Posted by Dnsean
flp said 17% loss in auto, i would have expected more hp, esp with 1.6 rockers over 1.5 which was rated with orginally, cat and resinator too restrictive? or compression too low? how would i find out wht fwhp would be? is there a calculator?
ok 17%

340hp x .83 = 282rwhp

to go the other way, multiply by the inverse of .83

282rwhp x 1.2048 = 340 flywheel hp

Also whats your elevation? every 1000ft above sea level theres like 3% less air (oxygen)

One thing I've learned is that ratings dont really mean much... even dyno readings need to be corrected. Like MrMint69 said, what matters is what you run at the track.

Last edited by MikeGyver; Jan 29, 2009 at 09:30 PM.
Old Jan 29, 2009 | 10:47 PM
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chicago, well aurora, il so i dunno wht elevation is here lol
Old Jan 29, 2009 | 11:30 PM
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solid or hyd lifters, ....also cam over-lap can affect comp at crank speed

Last edited by Danny McAdams; Jan 29, 2009 at 11:38 PM.
Old Jan 30, 2009 | 07:30 AM
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the compression is a little on the low side. as has already bees said different dynos give different numbers. If it was a mustang dyno then it would be about right. What brand of stall is it? I think stalled autos are probably a little higher than 17% loss also. run it at the track and see what it does. MPH will tell you what kind of power your car is making.
Old Jan 30, 2009 | 09:32 AM
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What correction factor did they use for the dyno HP?

Why is the CR only 9.75:1? Is that what Jasper told you, or did you calculate it? What heads are you using? Unmolested stock, or rebuilt by Jasper? What is the combustion chamber cc? Was it a crate engine, long block or short block?

What mid-length headers? Describe the "custom exhaust".
Old Jan 30, 2009 | 10:15 AM
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all was jasper rebuild, grr, except springs, 1.6 full roller rockers, cam. they say its 9.7 compression, headers are pacesetter mid, not the best i know. w/ its ypipe and highflow cat, resinator, then straight 3" pipe all the way back tube y'd in back for dual as well
Old Jan 30, 2009 | 03:57 PM
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sae = 5 is this wht your talking about w/ correction? it was a dynojet as well
Old Jan 30, 2009 | 06:42 PM
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Probably not the answers you want to see but here is the skinny.
https://www.camaroz28.com/forums/sho...ghlight=jasper
Old Jan 30, 2009 | 09:24 PM
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im still waiting for a call back to see exact list of specs on car, maybe email for engine specs, in detail not wht is posted on website..

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