gear shift and the dyno

Joe DeMarzo · 06-21-2011, 03:42 PM

How would you use the dyno sheets to help determine what to shift 1st to 2nd and then 2nd to 3rd in a small block stocker? We use the dyno sheets as a guide for the converter stall, is there a formula or guide for torque & HP in relation to shift points? Then it will be time to test that theory. How does everyone determine before testing what to shift at their cars at?

ron mattson · 06-21-2011, 04:26 PM

this is a very good question, i use peak tq to figure stall speed and peak hp for shifts
and then look at the playback to see where motor falls back to after each shift and
adjust accordingly. P.S. Joe you have p.m.

Joe DeMarzo · 06-21-2011, 04:55 PM

Ron, I have PMed you back.

Dinsdale · 06-21-2011, 11:06 PM

Dyno with shift simulator.. This is cool!

Owen S Quirion · 06-22-2011, 07:40 PM

Joe,

The way I do it is to determine the RPM drop going from 1-2. Then look at your Torque curve to find the peak and also see how flat the curve is around the peak. I take the net rpm difference and overlay that around the torque peak to try to take as much advantage of the flattest part of the torque curve when the engine is recovering from the shift. For the 2-3 I would run the car out closer to the HP peak using the same RPM Drop philosophy.

Mike Taylor 3601 · 06-23-2011, 10:48 AM

Superflow says about 10% above peak, on glide that work pretty good,but 3 spd. or stick is a little much for low gear, what I always have found is usually shift low as soon as can without bogging then second close to peak to about 10% above peak hp rpm.
Like everything else depends on lots of factors,closer ratios are together less you'll need
to stretch out that gear,most cases the sooner you can get in high gear the quicker it will be.
Mike Taylor 3601

Vic Santos · 06-23-2011, 05:47 PM

Joe, here is my theory. First maximize the HP put to the track in high gear by gearing the car to go through the eyes at approx. 10% above the dyno peak HP rpm. Next choose a convertor that flashes 150-250 rpm above the dyno peak torque rpm. The 1-2 shift is done at the track by testing. Shifting early (below the peak HP rpm) takes you back into torque multiplication in the convertor while in the high torque rpm's. You are trading HP for more torque at the wheels early in the run. This usually helps ET. The 2-3 shift should be such that the engine falls to approx. 10% below dyno peak HP rpm. The result is that high gear (the one you spend the most time in) goes from -10% to +10% of dyno peak HP rpm.
Testing is the hard part. You need good shift points and good data (air shifter and data logger) as well as good traction and a good valve train.
Good luck, Vic

Joe DeMarzo · 06-23-2011, 09:43 PM

Vic you have a pm.

Glenn Briglio · 10-05-2018, 07:59 AM

Quote:

Originally Posted by Dinsdale

Dyno with shift simulator.. This is cool!

Who makes this for engine dyno ?

Kevin Musial · 10-05-2018, 11:30 PM

Quote:

Originally Posted by Glenn Briglio

Who makes this for engine dyno ?

That looks to be a Depac dyno systems controller.
https://www.depac.com/loadcontrol.htm

06-21-2011, 03:42 PM	#1
Joe DeMarzo Senior Member Join Date: Oct 2002 Location: Mahopac, NY Posts: 666 Likes: 48 Liked 114 Times in 9 Posts	gear shift and the dyno How would you use the dyno sheets to help determine what to shift 1st to 2nd and then 2nd to 3rd in a small block stocker? We use the dyno sheets as a guide for the converter stall, is there a formula or guide for torque & HP in relation to shift points? Then it will be time to test that theory. How does everyone determine before testing what to shift at their cars at? __________________ Joe DeMarzo 1317 STK

06-21-2011, 04:26 PM	#2
ron mattson Member Join Date: Nov 2005 Location: cloquet mn Posts: 458 Likes: 15 Liked 54 Times in 26 Posts	Re: gear shift and the dyno this is a very good question, i use peak tq to figure stall speed and peak hp for shifts and then look at the playback to see where motor falls back to after each shift and adjust accordingly. P.S. Joe you have p.m. __________________ Ron Mattson 5015 STK

06-21-2011, 04:55 PM	#3
Joe DeMarzo Senior Member Join Date: Oct 2002 Location: Mahopac, NY Posts: 666 Likes: 48 Liked 114 Times in 9 Posts	Re: gear shift and the dyno Ron, I have PMed you back. __________________ Joe DeMarzo 1317 STK

06-21-2011, 11:06 PM	#4
Dinsdale Member Join Date: Oct 2004 Location: Canada Posts: 313 Likes: 0 Liked 6 Times in 2 Posts	Re: gear shift and the dyno Dyno with shift simulator.. This is cool! __________________ Dale Posnick

06-22-2011, 07:40 PM	#5
Owen S Quirion Junior Member Join Date: May 2005 Location: Captiol District of New York Posts: 71 Likes: 0 Liked 0 Times in 0 Posts	Re: gear shift and the dyno Joe, The way I do it is to determine the RPM drop going from 1-2. Then look at your Torque curve to find the peak and also see how flat the curve is around the peak. I take the net rpm difference and overlay that around the torque peak to try to take as much advantage of the flattest part of the torque curve when the engine is recovering from the shift. For the 2-3 I would run the car out closer to the HP peak using the same RPM Drop philosophy. __________________ BF/S 1985 Grand Am 3.0 V6

06-23-2011, 10:48 AM	#6
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,303 Likes: 198 Liked 116 Times in 48 Posts	Re: gear shift and the dyno Superflow says about 10% above peak, on glide that work pretty good,but 3 spd. or stick is a little much for low gear, what I always have found is usually shift low as soon as can without bogging then second close to peak to about 10% above peak hp rpm. Like everything else depends on lots of factors,closer ratios are together less you'll need to stretch out that gear,most cases the sooner you can get in high gear the quicker it will be. Mike Taylor 3601

06-23-2011, 05:47 PM	#7
Vic Santos Junior Member Join Date: Dec 2008 Posts: 26 Likes: 0 Liked 1 Time in 1 Post	Re: gear shift and the dyno Joe, here is my theory. First maximize the HP put to the track in high gear by gearing the car to go through the eyes at approx. 10% above the dyno peak HP rpm. Next choose a convertor that flashes 150-250 rpm above the dyno peak torque rpm. The 1-2 shift is done at the track by testing. Shifting early (below the peak HP rpm) takes you back into torque multiplication in the convertor while in the high torque rpm's. You are trading HP for more torque at the wheels early in the run. This usually helps ET. The 2-3 shift should be such that the engine falls to approx. 10% below dyno peak HP rpm. The result is that high gear (the one you spend the most time in) goes from -10% to +10% of dyno peak HP rpm. Testing is the hard part. You need good shift points and good data (air shifter and data logger) as well as good traction and a good valve train. Good luck, Vic

06-23-2011, 09:43 PM	#8
Joe DeMarzo Senior Member Join Date: Oct 2002 Location: Mahopac, NY Posts: 666 Likes: 48 Liked 114 Times in 9 Posts	Re: gear shift and the dyno Vic you have a pm. __________________ Joe DeMarzo 1317 STK