[pastry_chef]

Originally Posted by AdamIsAdam

I found that the torque in 1st at 5300 RPM is 704 and the torque in 2nd at 3950 RPM is 705, making that the ideal RPM to shift.

Where is 704 and 705 coming from?
What are the gear ratios?

What hits the rear wheels is the important thing.
If you provide your specifics I can show you both methods that end up with the same final result.

[AdamIsAdam]

Originally Posted by pastry_chef

Where is 704 and 705 coming from?
What are the gear ratios?

What hits the rear wheels is the important thing.
If you provide your specifics I can show you both methods that end up with the same final result.

Using the formula from EE's video and my own torque curve from when I first dyno'd the car on the chassis dyno 3 years ago, I got the following math:

2.2 (1st gear) x 320 lb.ft = 704lb.ft @ 5300 RPM
1.64 (2nd gear) x 430 lb.ft = 705 lb.ft @ 3950 RPM

and to get the RPM drop of 3950 it was:

2.2 5300
---- * ------ = 3950
1.64 x


At a 5300 shift point, the torque was the same before and after the shift.

[pastry_chef]

Originally Posted by AdamIsAdam

2.2 (1st gear) x 320 lb.ft = 704lb.ft @ 5300 RPM
1.64 (2nd gear) x 430 lb.ft = 705 lb.ft @ 3950 RPM

From that you have more horsepower at the lower RPM

320 lb.ft @ 5300 RPM = 322.9 horsepower

430 lb.ft @ 3950 RPM = 323.4 horsepower

Engine torque is dropping like crazy up top. Agree you would not shift higher.

[TedRamAirII]

Adam. What phone app do you use?

[AdamIsAdam]

Originally Posted by TedRamAirII

Adam. What phone app do you use?

Tapatalk. Why do you ask?

[TedRamAirII]

Originally Posted by AdamIsAdam

Tapatalk. Why do you ask?

I thought you had a phone app for measuring your car performance? Maybe I misread that.

[PontGuy]

Just curious Adam, what is your rear axle and suspension setup? Knowing this might help experts here (not me) to judge how much risk there is.

I proved the hard way, twice, that the stock suspension and rear in my 67 FB were not up to a hard launch at the track with the engine that I put in that car. And that was on DOT (Pro-track) tires. A long time ago now but I can still hear the big bangs on the "non-launches.".