Gear ratios with the MT82

[Twinscrewgt]

Does anyone know or have any info on the rpm drop between shifts for diff gear ratios with the getrag?

 

[fdjizm]

I can punch any combo in a program if you like...
Here is with 3.31's and a 7k rev limiter.
3.66
2.43
1.69
1.32
1.00
0.65

3.31's

7k rpm shifts
1-2: rpm in next gear 4648 drop: 2352
2-3: rpm in next gear 4868 drop: 2132
3-4: rpm in next gear 5467 drop: 1533
4-5: rpm in next gear 5303 drop: 1697
5-6: rpm in next gear 4550 drop: 2450

 

[Twinscrewgt]

How about 3.73 and 3.55 with a 7800 rev limiter?

 

[fdjizm]

7800 rpm shifts
1-2: rpm in next gear 5179 drop: 2621
2-3: rpm in next gear 5425 drop: 2375
3-4: rpm in next gear 6092 drop: 1708
4-5: rpm in next gear 5909 drop: 1891
5-6: rpm in next gear 5070 drop: 2730

Forgot rear gears don't affect the drop RPM at a given shift point.

 

[Wnt2gofst]

7800 rpm shifts
1-2: rpm in next gear 5179 drop: 2621
2-3: rpm in next gear 5425 drop: 2375
3-4: rpm in next gear 6092 drop: 1708
4-5: rpm in next gear 5909 drop: 1891
5-6: rpm in next gear 5070 drop: 2730

Forgot rear gears don't affect the drop RPM at a given shift point.

Very good info

 

[tjm73]

new ratio / old ratio = multiplier for percent of change.

Example: 2.43/3.66 = 0.66393

Multiply that by your shift point RPM and that's your rpm at the moment of the shift. Subtract that number from the shift rpm for the rpm difference.

Example: 0.66393 x 7000 = 4647.5 rpm after the shift. 7000 - 4648 = 2352 rpm drop.

Simple. Make Sense?

Regardless of axle ratio the percentage of drop will be the same since it is determined by the transmission ratios.

 

[Twinscrewgt]

Ok so if rear axle doesn't effect rom drop would there be a disadvantage from going from 4.30s to 3.73?

 

[tjm73]

Ok so if rear axle doesn't effect rom drop would there be a disadvantage from going from 4.30s to 3.73?

The only thing the axle ratio change would effect is the rate at which the rpm's rise/fall and the corresponding multiplication of torque. The rpm drop with each shift will remain the same.

They are separate things.

 

[Full_Tilt]

It doesnt effect the rpm range youre in, but it does effect the torque multiplication and the speed that you are at in those given gears.
Youre balancing the time you waste shifting with the acceleration benefit you get with shorter gears. Oh, and traction...

 

[Twinscrewgt]

So is traction better with. 4.30 or 3.73. My car is making around 700. I'm going to be upping the boost a little. I'm also tired of being at 3k rpm on the freeway but don't wanna lose the fun factor of the car. This isnt a drag car I do some auto x and road courses too.

 

[fdjizm]

3.73 will be more than enough with 700hp.

 

[johnnyv8]

So is traction better with. 4.30 or 3.73. My car is making around 700. I'm going to be upping the boost a little. I'm also tired of being at 3k rpm on the freeway but don't wanna lose the fun factor of the car. This isnt a drag car I do some auto x and road courses too.

I would imagine any gear would be fun with 700hp LOL. I have 4.10 with my tr 3650 (5speed) and My 4.10 gear are too deep. I need a taller gear for the turbo, prob go back to 3.55.

 

[TimMcc]

I feel 3.31's are perfect with my power level and I struggle for traction on the street. 3.73's with 700 would be even sillier.

Enjoy!!

 

[johnnyv8]

I feel 3.31's are perfect with my power level and I struggle for traction on the street. 3.73's with 700 would be even sillier.

Enjoy!!

How much PSI are you pushing with your whipple?

 

[TimMcc]

How much PSI are you pushing with your whipple?

9 is all.

 

[johnnyv8]

9 is all.

Jes, those new motors are animals. Anything done to the motor?

 

[Nastystang06]

Twinscrewgt your gears explain why on your youtube videos you spin so bad, I think with that power you would be faster with 3.31 or 3.55 you would be able to carry out a gear longer. Lol

 

[Twinscrewgt]

Lol there were a few reasons i didn't have traction that day lol. But ya I'm going to drop to a 3.73. That should put me crossing the traps in 4th around 7600 rpm.

 

[VTXFrank]

Lol there were a few reasons i didn't have traction that day lol. But ya I'm going to drop to a 3.73. That should put me crossing the traps in 4th around 7600 rpm.

Personally, I think you'd be happier with a 3.55 gear with your setup.

 

[Twinscrewgt]

If it was strictly a drag car I'd agree. But my car sees the drag strip 2x a yr. I really love the 4.30s around town. Just not on the freeway. I think 3.73 will be a happy medium