Where to Shift? Based on Dyno Graph
Where to Shift? Based on Dyno Graph What rpm and mph should I set the shift points in HP Tuners based on dyno graph?
LS1, Patriot LS6 Heads,224/224 .581 Cam,Fast 90/90,Headers,
Stock Automatic(3600 Stall),3.23 Rearend.
LS1, Patriot LS6 Heads,224/224 .581 Cam,Fast 90/90,Headers,
Stock Automatic(3600 Stall),3.23 Rearend.
Last edited by OLDSCHOOL85; Sep 11, 2011 at 10:51 AM.
If he waits to 6500, when the next gear is engaged, the torque where it reengages, will already be droppin off. Torque is what gives you speed/acceleration. HP is what keeps it there.
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I have the gm hotcam, a bit smaller then what he is running.
I went from a 12.30 down to a 12.09 just by raising my shift points from 5900rpms to 6300. Runs were back to back, less ten maybe 15 mins in between.
His shift extension will determine how far down in rpms he will drop as the next gear is engaged.
Shifting any sooner then 64-6500 rpms will mean that much less time in the powerband and will hurt his et.
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My car peaks at 6000rpm and has gotten faster with each raise in shift rpm from 6200 all the way to 6500rpm.
I won't spin higher due to 98 rod bolts.
I'd shift it right below the limiter.. 200 rpm maybe just so the car won't hit it. I went thru this experiment with my own car at a couple different levels of power over the years, you will get to a point that shifting higher won't get you any additional gains, but I never had the car perform worse by doing it.
Try whatever ya want but I'd be surprised if that doesn't net the fastest times.
Try whatever ya want but I'd be surprised if that doesn't net the fastest times.
Cars typically run the fastest numbers shifting just past the peak. Most guys start by shifting at peak then extending it 200 rpms at a time until they find the fastest E.T. On automatic cars, some people find that shifting at a little lower RPM on the 1-2 shift can work well, but this might not be true with your 4L60 transmissions because of the wide gear spread between 1st and 2nd.
The OP and my dyno #s are very similar. Mh car dynoed at 398whp/378wtq. My car consists of 227cc Patriot Heads w/ 59cc chambers, 224/230 Comp Cam 581/592, LS6 Intake, P&P TB, Yank 3600, & 3.42s gears.
I have gotten my best ETs shifting right above my peak hp. I peak around 6250, so I shift around 6400-6500. That's probably around where your car will like to be shifted too.
I have gotten my best ETs shifting right above my peak hp. I peak around 6250, so I shift around 6400-6500. That's probably around where your car will like to be shifted too.
HP is just a calculation of TQ and RPM.. and they're always going to cross at the same place..
Determining the best shift point I would look to try to keep the car in the highest HP as much as possible, and not let it drop any power in the power band then you have to.
Try to keep the engine in the best "average" power you can, wether that be before, or after peak HP.
(Hence why shifting higher usually only helps and doesn't hurt, unless the engine dramaticially falls off due to running out of air or another causing factor)
Determining the best shift point I would look to try to keep the car in the highest HP as much as possible, and not let it drop any power in the power band then you have to.
Try to keep the engine in the best "average" power you can, wether that be before, or after peak HP.
(Hence why shifting higher usually only helps and doesn't hurt, unless the engine dramaticially falls off due to running out of air or another causing factor)
