Transmission Ratios & MPH Per Gear

[10/10ths FOCUS]

Tried a search but can't seem to find.

Need info to gear a race car for a 1/2 mile circle track.

Top speed will be close to 100mph with corner speeds about 70mph. Max rpm about 7500+.

Must be able to stay in one gear. I will assume 3rd maybe 4th with the lower ratio.

My questions are does anyone have the gear ratios for the 5 speed & 6 speed trans including final drive? 3:75? Also any lower ratios 4:06?

Also the max mph per gear with both ratios? Please include your tire size & rpm limit

Thanks in advance

[Sponsor]

[Egz]

Stock MTX-75 with 3.82 gears and 205/50-15 tires:
7500 RPM: 1st=36.72 2nd=62.98 3rd=92.94 4th=130.84 5th=175.03

Stock MTX-75 with 4.06 gears and 205/50-15 tires:
7500 RPM: 1st=34.55 2nd=59.25 3rd=87.45 4th=123.11 5th=164.68

Stock MTX-75 with theoretical 4.55 gears and 205/50-15 tires: (not 100% sure these exist)
7500 RPM: 1st=30.83 2nd=52.87 3rd=78.03 4th=109.85 5th=146.94

[10/10ths FOCUS]

Thanks for the info that is a big help.

I wounder if there is any gear ratio lower then the 4:06 for the 5 speed?

Any other Ford or Mazda gears that will fit?

Your estimate of a 4:55 is real close for my 100mph top speed in 4th. Maybe more like a 4:86.

In the perfect world I would love to be in 4th at 1:1 to get max hp.

Any more input out there?

[austin]

these cars are geared higher than I thought