Starting line ratio for manual transmission application

[bykr]

Originally Posted by Jim Caughlin

The shift light is on in my car about as fast as I dump the clutch, I'm in 2nd well before the 60' timer. Looking at the data logger, the engine never drops below 6,000 and is at 8400 within 1 second. That's with a 3.29 1st gear, 6.50 rearend and 28" tall tire. I would guess that your car would be about the same. The ratio is so low that I usually drive around the pits in 2nd gear, I can outwalk the car in 1st!

Yes, very similar, never gets below 6k and first is only used on the starting line.

[Glenn Briglio]

Originally Posted by tavbfl

Thank you all for your comments! The chart from Black Magic was exactly what I was looking for. To answer some of your questions, my 60 ft has been between 1.38 and 1.46, 330 ft between 4.10 and 4.15, and my first gear is 2.80. Finding gears for the Doug Nash is a challenge so this can be my callout to any racers that have them in a box on the shelf somewhere. I am looking to change to 5.57 gears as I am crossing at 6300 with the 5.14's and motor makes power to 7000. I am also dialing in a slipper clutch for the first time so it's a matter of optimizing my combo and then focusing on consistency.

You’ll need more rear gear to cross finish line at least 7500 rpm

[Robin Lawrence]

Lots of good information here. I just finished my stick shift Mustang and have made 2 runs before the track closed. Started out with a 3.32 first and a 5.43 rear gear.

I plan to test a few different first gear as well as rear gear ratio's this year.

[BRETV]

Originally Posted by Robin Lawrence

Lots of good information here. I just finished my stick shift Mustang and have made 2 runs before the track closed. Started out with a 3.32 first and a 5.43 rear gear.

I plan to test a few different first gear as well as rear gear ratio's this year.

What class Robin?




Bret Velde
2003 ??/SA

[Robin Lawrence]

Originally Posted by BRETV

What class Robin?




Bret Velde
2003 ??/SA

FS/H 2012 Cobra-Jet Mustang with the 325HP Coyote G Force GF5R trans

[Adger Smith]

Years ago when changing from a good performing auto to a stick we just used 20% more ratio as a starting point. It may be a little different today with the trick clutches. That got us in the ball park.

[Eddie Rezac]

Originally Posted by tavbfl

Thank you all for your comments! The chart from Black Magic was exactly what I was looking for. To answer some of your questions, my 60 ft has been between 1.38 and 1.46, 330 ft between 4.10 and 4.15, and my first gear is 2.80. Finding gears for the Doug Nash is a challenge so this can be my callout to any racers that have them in a box on the shelf somewhere. I am looking to change to 5.57 gears as I am crossing at 6300 with the 5.14's and motor makes power to 7000. I am also dialing in a slipper clutch for the first time so it's a matter of optimizing my combo and then focusing on consistency.

Check my ad in parts for sale section! Eddie Rezac