Bracket Talk
Share your driveshaft curves

This topic can be found at:
https://drr.infopop.cc/eve/forums/a/tpc/f/80760912/m/8347047696

August 12, 2021, 10:05 AM
CURTIS REED
Share your driveshaft curves
quote:
Originally posted by banjo:
quote:
Originally posted by CURTIS REED:
quote:
Originally posted by banjo:
Here are mine, Mine typically bump down.

Footbrake


Transbrake



Bill, am I reading right that you are shifting about 7500 and falling back to 7200ish?



No, shifts at 7000, falls back to 6200ish depending on the track.


Gotcha. I couldn't make out the line to rpm with everything displayed. thanks.



____________________________
2017 and 2018 Osage Casinos Tulsa Raceway Park No-Box Champion

2018 Div4 Goodguys Hammer award winner
August 12, 2021, 10:10 AM
Bob Payton
quote:
Originally posted by Mike Rietow:
This graph is interesting at the shift, in the car it probably feels like it shifts hard, but it looks like a mistimed shift on the driveshaft graph, like the band is slow to get off the drum.

Then when finally does, it spins the tire.

How much line pressure in gear, above 2000 rpm's?




No idea on line pressure. I will check the sensor tonight


--------------------
Bob Payton
S/P, T/D, S/C, TOP
309Z, 393, 3093, 8X93


www.apdracing.com
www.diamondracecars.com
www.callies.com
August 12, 2021, 10:17 AM
Mike Rietow
quote:
Originally posted by Bob Payton:
quote:
Originally posted by Mike Rietow:
This graph is interesting at the shift, in the car it probably feels like it shifts hard, but it looks like a mistimed shift on the driveshaft graph, like the band is slow to get off the drum.

Then when finally does, it spins the tire.

How much line pressure in gear, above 2000 rpm's?




No idea on line pressure. I will check the sensor tonight


If the line pressure is high, it can make the band slow to get off the drum.

6.0's @ 2600-2800lbs 215 psi line pressure would be as high as I'd wanna run it.

Up around 260 psi it could possibly cause the band to be slow. Not saying that's what's going on, but it's something to take into consideration if a failure arises.

If it bangs real hard going into high, riding it around warming it up in the pits, when you shift it, I'd probably look in to it a little.
August 13, 2021, 05:30 AM
adv ET 266
Record the fall back RPM. Once you have enough data and plot a scatter diagram and fit a curve, you can use it to verify relative power independent of traction. Excellent help when sorting out an odd time slip or making tune up changes.



2005 2000lb 4 link dragster
home brew 582 BBC Dart 355
1.058
2.98
4.629@149
6.094
7.310@185