cuci591

I'm thinking of swapping in a Viper t56 trans. I will faceplate the gears so it can handle high rpm shifts. The stock viper t56 trans is rated to hold almost 500ft/lb of torque from the factory. My question is what would be the mph per gear be as this would change everything up. My rear diff is a r200 (4.09 gear ratio) out of a 300zx (inlinepro kit)and the viper t56 trans is as follows.

1st Gear 2.66:1
2nd Gear 1.78:1
3rd Gear 1.30:1
4th Gear 1.00:1
5th Gear 0.74:1
6th Gear 0.50:1

I have tried to use some online converter scales and I guess i'm just to stupid to figure out how to use it. So if anyone could chime in that would be great.

Thanks in advance

spdracerut

Use the equations in here:
http://www.motoiq.com/magazine_artic...-datalogs.aspx

s2000Junky

Well without any math, just from basic understanding of the Viper power curve and therefore its gearing, it will prove to be geared much taller then you would prefer, I can almost guarantee that. Not just the 6 gear overdrive which is totally rediculous, but all the ratios are meant to be coupled with a very torquey low rpm range, which means tall gear ratio, opposite of the S2k. The easiest solution would be to swap out the rear end final drive ratio. Probably something in the high 4 or 5.xx range is my guess.

But the info you want to compare to is this link bellow for gear contrast. As you can see starting out in second gear on the s2k trans would be almost like 1st on a viper trans, as I suspected it would be. Thats going to be difficult to drive and kill your clutch quicker.

http://www.turnzero.com/technical_re...ear_calculator

Based on the spread contrast between the two trans I would say if your running a 4.09 now, 5.09 will be a close equivelent to s2k trans, at least to get the 1-5 gear spread. The 6th gear is still so overdriven that even with that final drive, you still have enough gear for 200mph abouts.

urBan_dK

Assuming a tire diameter of 25 inches, your final drive of 4.09, the Viper T56 transmission gear ratios, your speed at 9000 RPM in each gear will be:

62 mph
92
126
164
221
327

Your transmission choice is a poor one. You would need an extremely high final drive ratio to make this reasonable.

s2000Junky

That 6th gear overdrive is crazy to me. I don’t know what the thought was there with Dodge, other then possibly it had something to do with EPA gas mileage. The motor makes so much low rpm torque it could effectively pull that gear, sipping gas a about 1200 rpm at 60mph

The 1-5 gear spread looks pretty typical for v8+ super cars of today. Not good for a 4 cylinder though. As I mentioned, its missing a 1st gear, and 6th wouldn't likely be usable no matter what the final drive was.

passmans2kny

327 mph haha

urBan_dK

Bingo. It's fuel economy. Corvette does the same thing with their 6th gear. BTW, it would be cruising at 1650 RPM at 60 MPH assuming Viper tire diameter and final drive are similar to the S, which is probably not a great assumption.

s2000Junky

1650rpm The S would sound very unhappy trying to maintain freeway speed at that rpm. It just wouldn’t do it.

cuci591

This is all good info maybe ill just have to stick with getting a v160

s2000Junky

Yeah maybe, or run a high enough rear end ratio, and learn to live without a 6th overdrive gear possibly, since it sounds like it could be too over driven no matter what.