I would shift at 7000 then 7300 trap at 7500 for best et.

 

and leave at 4200 chip.

 

Not trying to sound like an ass...you have to shift it where it works best. I'm shifting mine 400 over peak HP and going thru the traps about 800 over peak.

For whatever reason, it likes it there.

 

Not trying to sound like an ass...you have to shift it where it works best. I'm shifting mine 400 over peak HP and going thru the traps about 800 over peak.

For whatever reason, it likes it there.

This pretty much sums it up, depending on RPM drop on shift, Converter, type of power adder/adders, etc. etc. there will be a lot of variables.

With a particular setup past experience will tell you where to start but like anything on a drag car the setting that nets et is all that matters.

 

My max torque is at 3,000 rpm - but I shift it at 6500.

I let it eat until it stops pulling. Once I know that rpm - I try to shift before that the next time.
Experimenting to find that line is the best part!

 

Theoretical target shift points are easy. You graph the HP or torque curves of each gear, AND WHERE THEY CROSS is the target shift point.

This of course gets a bit more complicated, and "loosey" / "tighty" TC will certainly affect

A graph example shamelessly stolen from the www

 

I would leave at 4200 to 4400 rpm. To get your shift point. Don't get crazy but take it up in low gear just until you feel the motor go flat. And then shift it 500 rpm lower then that rpm. So if it's flat at 6500 shift at 6000 rpm. This shoud get you close.

 

On the dyno, hie HP peak was at 7150


JOE SHERMAN RACING

 

This really does you no good if you don't understand the interlink of the ratios. Look at the example chart above. Notice how far AFTER the peak of each gear, the next gear starts to come "up."

 

I shift mine at 6500.
Blue line is more boost and race gas.

 

I was taught to shift based off of max hp. This is typically ~500 rpms over peak hp. You want to lay the highest "Average" hp down during a run. Wallace racing has calculators that can show you the after rpm shift to give you an idea on where your optimum shift points are. You'll have to plug in the tranny ratios. But general rule of them is that the 1st gear change is the highest rpm, then the 2nd is lower, and 3rd is lower, and so on.

-Mark

 

X-2.

 

Thank you for the responses.

According to the chassis dyno (maybe a happy dyno) the max HP was 589 at 7150. The dyno run was done in 3rd gear only (TH 400) so it doesn't show any shifts.

Because this is a very torquey, 512 at the rear wheels, the engine builder said to shift very quickly after launch so I had it set at 6300 second shift at 6900 with an electric shifnoid and a Elite Biondo shift box, so it is fairly accurate. The car weighs 3300 with me in the car so I tried shifting between 3800 and 4400.

It is a 434 SBC so the thought is to shift around 7000-7200 1st to 2nd? Then around 6500 2nd to 3rd?

Thanks again,
Barry

 

Thank you for the responses.

According to the chassis dyno (maybe a happy dyno) the max HP was 589 at 7150. The dyno run was done in 3rd gear only (TH 400) so it doesn't show any shifts.

Because this is a very torquey, 512 at the rear wheels, the engine builder said to shift very quickly after launch so I had it set at 6300 second shift at 6900 with an electric shifnoid and a Elite Biondo shift box, so it is fairly accurate. The car weighs 3300 with me in the car so I tried shifting between 3800 and 4400.

It is a 434 SBC so the thought is to shift around 7000-7200 1st to 2nd? Then around 6500 2nd to 3rd?

Thanks again,
Barry

Most likely the other way around lower 1-2 higher 2-3

 

It peaked at 7150? I'd be shifting at 7,200 and going up from there.

Mine peaked at 6,500, I shift at 6,900-7,000....I don't know the physics of it, what I do know is that it goes FASTEST there. I did recently find out that getting it into 2nd a hair early picks up a few hundredths. So 6,800 shift to 2nd, and 7,000 shift to 3rd.