Hi,

I remember reading somewhere that changing the gear ratio on 996 can deliever similar acceleration as adding a supercharger. I'm willing to sacrifice some top speed (hell, when can you ever legally drive 175 mph, I'm cool to have it top at 140 mph), to gain acceleration.

So, where do you get the gear set? Should I change the gear set or just the final gear? How much is the cost?

 

I looked into this...

It can be a VERY solid mod, especially with the 6-speed...But there aren't really any off the shelf setups. You have to buy the individuals gears and break open the whole tranny(=$$$$)

If you can prove me wrong I would LOVE to hear it!

 

If we can somehow change the final gear (which is 1:3.44) to something shorter (like 1:3.90 or even 1:4.11), we can get a lot more acceleration without putting extra stress on the engine. This is a very effective method for gaining accleration in Japanese cars, such as S2000 and NSX. Someone had done it on this board before, I just can't find that post anymore.

 

You can always go to a shorter tire, remember, C=pi D.
a 25 in dia tire has a circ. 0f 78.54 in, a 23 in dia tire =72.26 in. A 0.92 ratio this will bring a final drive from 1:3.44 to 1:3.74. The only penalty you pay is the appearance of a shorter tire in the larger wheel well.
James Greer

 

Check out Powerhaus II: www.powerhausII.com. They do complete gear sets, ring gears, whatever you want.

 

2 inches would be a big gap I think, not sure that would look good at all....

 

In addition, you would seriously need to consider load ratings and availability of tires. I don't think there are many "near zero" profile tires to get you that low if you're running, say 18" wheels.

In addition to Powerhaus II (boy, what happened to their website?), you might also contact Paul Guard at Guard Transmission. He makes LSDs and I'm pretty sure gear sets http://www.guardtransmission.com/products.htm (website also needs some help).

 

don't forget to put in a limited slip differential while you are in there.

 

O yah! You guys are great! Very helpful and real fast. How much is a real-world cost to do the tranny upgrade?

 

Just think how fun a supercharger AND a new gearset could be . . .

 

Just a total guess, but maybe $5,000

 

search on Rennlist, has been covered there

 

I think with a supercharger, you don't want to have too short for the first 2 gears, cuz you will be wasting more time shifting. But yah, after 2nd gear, the car will be a scary animial lol!!!

 

Nice try on the wheels, but it won't work. A 17" wheel with the same width tire as an 18" 30 series rear, may only come in a 40 series, and it works out the 17" tire is 8mm taller than the 18". I run 245/35's front and 285/30's rear. I couldn't figure out a combo nearly as wide that would reduce the height. If you can let me know! Can't go any smaller than 16" with big brakes. Oh by the way, hoosier has to make the tire size. - Only need the rears!