Rear Differential Gear Change.

[spartanwarrior]

Question before i send my 3.46 lsd differential to MK-Motorsport in Germany to change the gears to 3.15 i need to know if it's worth it, i have the TS2 and yesterday i just ordered the cams and 8.5psi pulley:excited: but this gear change will cost me 1.850.00 euro will it be worth it? i mean what will the real difference be other than gaining like 12 miles per hour to my top end? won't the 3.46 i have be quicker than installing the 3.15?

[Custom3]

you would be downgrading instead of upgrading

[spartanwarrior]

you would be downgrading instead of upgradingSo what you mean is i am better off with the 3.46 i have? because Ess has said that having a lnger gear ratio would be better with the Twin Screw, that is whats confusing me.

[Custom3]

your car is automatic or manual?

[spartanwarrior]

your car is automatic or manual?5sp Manual.

[SeanC]

Ess is right, you don't want to have a 3.46LSD and a S/C together.. You want power, but you probably don't want that much power in the lower end of the RPM spectrum. 3.15 sounds good IMO.

[Custom3]

youll be changing gears quicker with the 3.46 since your pushing more power then stock...with the 3.15 will take a bit longer to switch gears...its really up to you...for the price tag to change it into a 3.15 your better off staying with the 3.46 and use that money for some other upgrades.

[Custom3]

exactly...youll have alot of torque with a super charger and a 3.46 diff...so youll must likely be spinning your tires alot...this is were your 3.15 diff will help you out...i would just buy wider tires.


Ess is right, you don't want to have a 3.46LSD and a S/C together.. You want power, but you probably don't want that much power in the lower end of the RPM spectrum. 3.15 sounds good IMO.

[HighBoostin330]

exactly...youll have alot of torque with a super charger and a 3.46 diff...so youll must likely be spinning your tires alot...this is were your 3.15 diff will help you out...i would just buy wider tires.

I only spin tires in first gear when I put my foot down. My 3.46 seems to be fine. Feels like the 3.46 is where it counts in the higher gears when the car traveling at a faster speed. But it is true that you shift gears much more often.

[spartanwarrior]

I only spin tires in first gear when I put my foot down. My 3.46 seems to be fine. Feels like the 3.46 is where it counts in the higher gears when the car traveling at a faster speed. But it is true that you shift gears much more often.But i still say that with the 3.46 i will be faster in the quarter mile, i believe that in the quarter mile right at the finish line i shift into 4th.

[Activ3]

But i still say that with the 3.46 i will be faster in the quarter mile, i believe that in the quarter mile right at the finish line i shift into 4th.
With a 3.46 on a boosted car you should be well in to 4th gear by the end of the 1/4 mile. The 3.46 puts the end of 3rd gear @ about 90mph or so, and you should be trapping 100+ boosted.

[spartanwarrior]

With a 3.46 on a boosted car you should be well in to 4th gear by the end of the 1/4 mile. The 3.46 puts the end of 3rd gear @ about 90mph or so, and you should be trapping 100+ boosted.Yes my mistake i am in 4th gear, but still even with 3.15 i will be in 4th gear at the end of the quarter, also how about this my tire size is 255 30 18 how about if i go 255 40 18 that would probably be better.

[aaronu]

Just run the car with 3.46 and see how you like it. You can always send it in later.

[2K5 325i]

I have an open 3.15 I can sell to you for far less than 1,850.00 Euros.

Granted you lose LSD dual wheel spin which is probably what you're after... but I just thought I'd throw the offer out there.

:hi:,
-Chris

[beanfree]

One school of thought believes that you are better off with a higher diff. no matter what the power (within reason) because the wheel spinning more gets more grip to the ground.

I don't think it is worth the change anyway. I have to change into 4th at the end of the quarter mile with my 3.07 LSD and I do lose the top end acceleration with a lower diff. too.

[pei330ci]

Advice from a racer:

You want to gear the car to cross the finish at peak HP, what ever RPM that is, in the highest gear reasonable.

From experience; under 120 MPH you want to be in 4th, over 120 MPH you want to be using 5th.

The name of the game in racing is to use as much torque multiplication as possible. Managing tire spin in 1rst and 2nd gear by lowering torque multiplication is BS, you should be doing that with the throttle. Data log some runs, and you'll find that you spend more time in 3rd and 4th gear than 1rst and 2nd. Which gears do you want to have the most "help" with?