Ls4 Dyno Numbers? 
Ls4 Dyno Numbers?
Originally Posted by oxidizr
I have tested a Monte Carlo SS and a Pontiac Grand Prix GXP. Ill post em' up tomorrow.
https://ls1tech.com/forums/showpost....28&postcount=7
Unfortunatley, you cant see more than this. Being an automatic it will nto allow you to sustain low rpm at full throttle. It simply downshifts. "Smart" transmissions are no easy to get full powerband numbers without some kind of transmission controller.
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When you dyno, the car needs to be in a 1:1 gear. Hence 3rd gear in an OD auto. What he is trying to say is that it won't hold in 3rd, but downshifts. Most F-body's and Vette's, dont have this problem on the dyno since almost all shops can hook-up something to hold the transmission in gear thru the computer.
Even with tapshift, it still might downshift automatically. (Or did I miss something about that feature in the Pontiac's when I read about it?)
Even with tapshift, it still might downshift automatically. (Or did I miss something about that feature in the Pontiac's when I read about it?)
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TECH Enthusiast
Joined: Aug 2005
Posts: 701
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From: crossett, Arkansas
the car will not downshift using tapshift. i many a time hit the car and frogot to downshift and watched a car blow by me... untill i downshifted ofcourse 
i almost miss it alittle... oh wait nm i have a TA now i dont miss it
i almost miss it alittle... oh wait nm i have a TA now i dont miss it 
Teching In
Joined: May 2006
Posts: 33
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From: VA - formerly NY, MI, MN, FL
The GXP in our local GP club dyno'd 239.0-242.5whp and 316.0-324.3wtq (not correcting for TC flash). These runs went from 2800-6200rpm.
Oddly enough, if you calculate for 20% drivetrain loss on the WHP, you get 303.125hp.
LINK to GXP member profile on MCCGP
Fairly consistent, and impressive as well.
- Dave
Oddly enough, if you calculate for 20% drivetrain loss on the WHP, you get 303.125hp.
LINK to GXP member profile on MCCGP
Fairly consistent, and impressive as well.
- Dave
