When to shift for best 1/4 mile time???

[Glennster]

Here's the Dyno sheet, I have a 727 tarnny and a 3.91 gear. At what RPM should I shift to get my best 1/4 mile times?
I'm thinking 5,00 is the magic number, my buddy says 6,000. I think taking it to 6,000 waists time where the torque is gone. I appreciate any theories!

[72cudamaan]

Looks like 5250 to me. You have a little  more at 5000
and way overshot at 6000

[Chryco Psycho]

I agree with your friend
typically shifting near your peak HP & having the rpm drop down near your peak torque works best, yes you are past the torque curve but the HP is still rising  .
 I would do a shift loop at the track , change the shift point by 250 RPM , start at 5000 shift point & work up to 6000 , the car will tell you what works best

[72cudamaan]

I guess I was figuring that since peak torque was at 5000
and peak HP was at 5500, that 5250 was a happy place?

[Oldschool]

I guess I was figuring that since peak torque was at 5000
and peak HP was at 5500, that 5250 was a happy place?

That is a great assumption.  What Chryco is saying is what happens when you shift too early and the torque drops back out of peak torque range. You don't lose anything as long as the horsepower is still rising. I guess it all depends on how much the rpm drop on the shift.  I agree to run it through some shift cycles and see what the car likes....     

[Strawdawg]

I agree that testing is the only definitive means if one is after every last ounce of power/time

By definition, Torque equals HP at 5250, and if it does not, then you should be looking at what kinda correction was applied to the data.  Therefore torque has to drop after than while hp can continue to climb.  Looks to me like the best point will be close to 6000 rpm as Chryco suggested.  HP is just barely beginning to fall at that point-6250 might even be the point assuming the valve train is up to the task.

[Aracer]

6000 first to 2nd, 4200 rpm when you start second, then shift at 6200, or just before it misses, this is so when you start Direct you will be at 4500rpm, the sweet spot for the 727 trans. Then HP will determine the final rpm in the trap. 6000 my guess.