Shift points on an automatic three speed

[bobby]

Originally Posted by Todd Geisler

Sometimes the automatic trans (manual VB in mine) will have a delay from when the shifter is moved till the trans actually makes the shift. You then have to shift earlier to have the shift wind up where you wanted. With my th400, there's about a 400 to 600 rpm delay in the 1-2 shift and maybe only a 100-200 rpm delay on the 2-3 shift.

Also, the rpm rate of accelleration is much quicker in 1st gear, so the shift comes pretty quick compared to down track when the engine isn't accellerating as quickly making the 2nd gear pull.

WOW, that's a lot of delay from one to two. Mine is only 200 in both gears.

[Todd Geisler]

Originally Posted by bobby

WOW, that's a lot of delay from one to two. Mine is only 200 in both gears.

Are you sure? I use a data logger to verify the actual shift rpm.

[gymracer01]

I have played around with this and also use a logger to verify what is happening. My Buick likes a little (200rpm) early shift 1-2 than 2-3. My low compression stock head engine, could not be shifter too early really 1-2. I actually picked up a .1 one day at Bowling Green trying to slow it down by shifting early. Just have to learn your car.
Jim Netherland
2007 NMCA Nostalgia Super Stock World Champion
B/NSS 67 GS 400

[bobby]

Originally Posted by Todd Geisler

Are you sure? I use a data logger to verify the actual shift rpm.

It's a footbrake car, no-electronics. during timetrials, I actually watch the tach, ( who's watching the track?)sure I understand that it may seem like it's only 200, maybe more like 400. Maybe I am shifting sooner than I think? Wish I could afford a data logger, but with diesel prices as they are, I would have to not race for a year to be able to buy one, LOL.

[gymracer01]

Bobby, an Autometer Ultimate II Tach with the driveshaft sensor will get you what you need.
JIm N.

[Chris1529]

200 RPM lower on the 1-2 shift for my low hp car.

[bobby]

Originally Posted by gymracer01

Bobby, an Autometer Ultimate II Tach with the driveshaft sensor will get you what you need.
JIm N.

thanks, I check it out. I want to update my tach anyway.