# Drag Racing Tech - Dyno Sheet, when to shift?

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bastien
05-13-2006, 04:00 PM
Could you guys tell me when I should shift according to my dyno sheet?

Thanks a lot

http://img444.imageshack.us/img444/7081/dynosheetlarge2ys.jpg

around 5.2k-5.5k, am I correct? I have a shift light so I don't have to worry about the tach lag.

black_z
05-13-2006, 04:40 PM
You want to shift higher than that. I would go 5900-6000.

iOWNaWRX
05-13-2006, 04:59 PM
Why would he shift at 6 if full torque was at 4.5 and tapered off badly after that

silkey
05-13-2006, 05:11 PM
as i understand it,when you shift into the next gear you want the rpm where the torque and horsepower cross.

silkey
05-13-2006, 05:15 PM
in other words,after you shift into the next gear you want the crossing to be the start(lowest drop) and go on from there.

BlueSix
05-13-2006, 06:15 PM
as i understand it,when you shift into the next gear you want the rpm where the torque and horsepower cross.
Horsepower and torque always cross at 5252 rpm. That point has nothing to do with determining your shift point.

BlueSix
05-13-2006, 06:16 PM
Why would he shift at 6 if full torque was at 4.5 and tapered off badly after that
Because you want to shift a few hundred RPM after your horsepower peak. He peaks at 5500. He needs to shift at 6000.

NHRAMAN
05-13-2006, 06:17 PM
Horsepower and torque always cross at 5252 rpm. That point has nothing to do with determining your shift point.
:judge: Thank you.... :engarde:

bastien
05-13-2006, 07:03 PM
thanks for the replies

CamTom12
05-13-2006, 09:42 PM
Think of it in terms of gear reduction and torque multiplication.

Even though you'd be making less engine torque at the top of 2nd at 6000, you'll still be making more wheel torque than you would in 3rd at any point in the powerband. The bottom-line is to shift at your red-line on a graph that looks like that.

bastien
05-13-2006, 09:53 PM
thanks a lot

mike c.
05-14-2006, 07:24 PM
the car is a m6? if so you are supposed to shift about 200 rpm's past your peak hp. this keeps you in the sweet spot of your power band. going 500rpm's past it will not help your times. get a shift light,summit has one for \$50.00. it has a dial on the back so you can set any rpm you want,no pills for this light. this will help you find where the car need to be shifted. i have one mounted on my steering colum in front of my factory tach,it's small and not really in the way. good luck to ya.

Ryan02SS
05-14-2006, 08:20 PM
Anywhere from 5800-6000rpms if it was mine. I would take it to the track and see if it makes much difference assuming your 60's and shifting times are similar.

silkey
05-15-2006, 06:39 AM
let me see if i can clarify my statements,i believe after you shift you would like the rpms to drop no lower than the cross over point.as far as the max rpm shift,that is yet to be determined,gear ratio,trans ratio and what the engine can turn safely.but what you have is what youre stuck with but i believe if you try to get near that goal you would see youre best times.if you dont want to go through all that trouble then just get the next gear shift to start in about the middle of the peak torque band.

SlickVert
05-15-2006, 07:36 AM
For the best ET 6,200 to 6,300rpm
Bob

BlueSix
05-15-2006, 10:10 AM
let me see if i can clarify my statements,i believe after you shift you would like the rpms to drop no lower than the cross over point.

:eyes:

bastien
05-15-2006, 10:33 AM
the car is a m6? if so you are supposed to shift about 200 rpm's past your peak hp. this keeps you in the sweet spot of your power band. going 500rpm's past it will not help your times. get a shift light,summit has one for \$50.00. it has a dial on the back so you can set any rpm you want,no pills for this light. this will help you find where the car need to be shifted. i have one mounted on my steering colum in front of my factory tach,it's small and not really in the way. good luck to ya.

silkey
05-15-2006, 10:42 AM
hey blue six,all i can say is it works for me.by the way,what times do you run?

BlueSix
05-15-2006, 11:01 AM
mid 13's in a stock GTO. Shifting at 6000.

You're telling people that you want the rpm's to fall to the cross-over point after their shift. That's not correct. The hp/tq cross-over has nothing to do with where you shift or where your rpm's fall after a shift. hp and tq will always cross at the same RPM, on every engine combo.

bastien
05-15-2006, 11:18 AM
I guess i'll keep shifting at 6000 rpms. Thanks guys

silkey
05-15-2006, 02:43 PM
not bad bluesix,im at 10.3 shifting at 6200.rpm falling back to 5000.

CamTom12
05-15-2006, 10:28 PM
I guess i'll keep shifting at 6000 rpms. Thanks guys

(based on your graph...) If that's your redline, that's going to net you the best times :)

Matt D
05-16-2006, 08:37 AM
not bad bluesix,im at 10.3 shifting at 6200.rpm falling back to 5000.

10.3 huh shifting at 6200? What mods, raceweight, etc?

Pro Stock John
05-16-2006, 08:53 AM
Depends on how the HP trails off, but I would shift at peak hp or up to 500 rpms past peak hp.

If you make like 400rwhp at 6000, and then make 350rwhp at 6300, you would need to find the best rpm to shift at. Shift points are a balance between where your power curve falls off and where you drop back on a shift.

bastien
05-16-2006, 11:48 AM
thanks, I'll just keep it at 6k for now