Attn: Duy/High HP KA-T/SR/ 240sx/drivetrain ppl.

[nightracer]

I talked to Ivan at SP/PK the other day and he was talking about having to go to a taller final drive to get some more mph out of his car.. Anyone had experience with a different final drive or tranny? Any info would be welcomed. :thumb:

[baldurann]

Hehe, ask any domestic guy that knows stuff about cars and they'll tell you all kinds of tranny / drivetrain info for cars. ;)

To start, you should find the stock gearing for the rear and the tranny for your car to see where you stand now, and then find transmissions that easily swap to an SR, and look at your choices there. You can always have custom rear-end gearing made, but that'd be a pita money-wise... so also, you should research and see what kind of rears you can buy for your car.

Oh, and hurry and find the info, I am curious to know it aswell! :thumb:

[NismoFreakS14]

I talked to Ivan at SP/PK the other day and he was talking about having to go to a taller final drive to get some more mph out of his car.. Anyone had experience with a different final drive or tranny? Any info would be welcomed. :thumb:

The stock ratio is a 4.083.

Duy won't be much help because he is running an auto, so his rear end ratio is gonna be alot different. In fact, Duy I heard you were hitting the limiter before the end of the track. The Q45 has a 3.54 rear end ratio and is a 200mm ring gear. If you need lower the S15 has a 3.36 (give or take) because of it's 6-speed drivetrain.

Any high powered 240 will be getting into 5th gear, so at that point for maximum acceleration you want a quicker ratio. Going up in ratio is kinda hard, compared to going down mainly because of the availability of cheap higher ratio'd 200mm ring and pinion sets is nil here in the US, to my knowledge.

I think an excellent ratio to shoot for is the 4.36 ratio'd J's / Q's early model Silvia's. Look for a non-turbo CA.

Another place to start looking is at trucks, particularly 4WD trucks. Their rear ends might be R200 units, and typically they have higher ratios. The front differentials are certain to be R180's or R160's.

[nightracer]

I had the stock KA tranny and V160 together and they're similar in size. So I've been thinking about using a V160 since it'll take the power I'll be making with my turbo/fuel set up. I was thinking of using an S15 3.36 or 3.692 but I wasn't sure if it'd fit. Will it?

Yes I'll be getting into 5th gear but I suspect I'll hit the rev limiter before the end of the track. It wouldn't make since to go with a shorter final drive ratio. I've had two different final drive ratios in the Porsche and from experience I can tell you that the shorter gears only helpped me in auto cross but killed my top end. Also killed my gas milage, I'd like to go a bit taller. And the the taller the ratio or gear, the smaller the number. :)


Thank you for the responses thus far though. :)

[nightracer]

Hehe, ask any domestic guy that knows stuff about cars and they'll tell you all kinds of tranny / drivetrain info for cars. ;)

To start, you should find the stock gearing for the rear and the tranny for your car to see where you stand now, and then find transmissions that easily swap to an SR, and look at your choices there. You can always have custom rear-end gearing made, but that'd be a pita money-wise... so also, you should research and see what kind of rears you can buy for your car.

Oh, and hurry and find the info, I am curious to know it aswell! :thumb:
Who'd custom fab a rear end? At what price range would this be? I just swapped two diffferent transaxels on my 944 from a shorter ratio to a taller ratio so I'm not to sure on pricing of a on-off rear-end.

[baldurann]

I've had two different final drive ratios in the Porsche and from experience I can tell you that the shorter gears only helpped me in auto cross but killed my top end. Also killed my gas milage, I'd like to go a bit taller. And the the taller the ratio or gear, the smaller the number. :)


Exactly why I'm going to keep my stock 3.42's in my car... :) :thumb:

[baldurann]

Who'd custom fab a rear end? At what price range would this be? I just swapped two diffferent transaxels on my 944 from a shorter ratio to a taller ratio so I'm not to sure on pricing of a on-off rear-end.
I honestly have no idea. I am sure it wouldn't be hard if you looked around though, check like a phone book for custom driveline fabrication or something of that sort. :)

[SecretAgent]

Another place to start looking is at trucks, particularly 4WD trucks. Their rear ends might be R200 units, and typically they have higher ratios. The front differentials are certain to be R180's or R160's.

the hardbody 4x4 has an R200 front diff. the rear diff is the same as the TT 300zx.

[NismoFreakS14]

the hardbody 4x4 has an R200 front diff. the rear diff is the same as the TT 300zx.

Which is an R230.

[NismoFreakS14]

I had the stock KA tranny and V160 together and they're similar in size. So I've been thinking about using a V160 since it'll take the power I'll be making with my turbo/fuel set up. I was thinking of using an S15 3.36 or 3.692 but I wasn't sure if it'd fit. Will it?

Yes I'll be getting into 5th gear but I suspect I'll hit the rev limiter before the end of the track. It wouldn't make since to go with a shorter final drive ratio. I've had two different final drive ratios in the Porsche and from experience I can tell you that the shorter gears only helpped me in auto cross but killed my top end. Also killed my gas milage, I'd like to go a bit taller. And the the taller the ratio or gear, the smaller the number. :)


Thank you for the responses thus far though. :)

If you are concerned with your gearbox, and you have V160 money.

Then why don't you upgrade the differential to a R230.

[Dorian]

moving...