Understanding differential ratios?

I have a j-spec TT6 diff in my car, I read that the UK TT6 diffs have a different ratio and will give me an extra 4mph in 3rd if i had a stock rev limit and wheels.

http://www.mkivsupra.net/vbb/showthread.php?29830-Gearboxes-Diffs-and-Speed-In-Gear

What would i have to change in my diff the get that ratio? or is it a case of getting a new diff

Cheers.

The ratio is determed by crownwheel size and pinjong size i think its the crownwheel you would need to change.

4:1 meens pinjong spins 4 Times for 1 revolution crownwheel.

Happy new year!

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I am here: http://maps.google.com/maps?ll=57.729290,11.786238

T.T. 6MT 3.266 A03B

U.K. 6MT 3.133 B03D

Numbers from memory, not sure re. U.K. VIN code?

Crown wheel and pinion JP, it wont just be 3rd that changes its every gear.

Crown wheel and pinion JP, it wont just be 3rd that changes its every gear.

I know mate, but 3rd is the gear im interested in, i want to be able to crack 130 in 3rd without going to high with the rpm limit.

I think the part number for the 3.133 ratio is 41201‑80058, according to ToyoDIY.com. From what I read, you can swap the internals in the B series diff casing?

Cheers mate, im going to look into it next week, get some prices, might work out to much money for just one event though, im trying to avoid having to do another gear change in the mlr 30-130

Cheers mate, im going to look into it next week, get some prices, might work out to much money for just one event though, im trying to avoid having to do another gear change in the mlr 30-130

Could you look at other options, like an increased rev limit just in third, for that event?

I could but i dont like to rev it to high if i dont have to, at 8200rpm it does 123 in 3rd, id guess id need to go to 8700-9000rpm

The cost of the Gear set is about the same as a UK diff from memory. Taller tire will do the same thing.

The cost of the Gear set is about the same as a UK diff from memory. Taller tire will do the same thing.

I cant find any 3.13 uk diff's for sale, the one amir had turned out to be j-spec.

No way i will get a bigger tyre on than 28", its mm tight everywhere.

I cant find any 3.13 uk diff's for sale, the one amir had turned out to be j-spec.

I just fitted one with the last 6 speed conversion, maybe the guy would part ex it with you !!!

Im up for a px, ive got a few big case TT6 diff's

Talking of tyres, 325/50/15 MT is a monster tyre, i had to cut about 10mm off he back of the side pod just to get it on, then with a 10mm spacer i only have about 2 or 3 mm clearance a the back, im going to change to a 15mm spacer, strange at how much bigger they are than a BFG 325/50/15, god knows how people get them on stock body cars, they must hammer the hell out of the inner well.

Try pm'ing him dude, its jim_jimmy1

You need a decent gearbox with alternative ratios for all internal gears and preferably a drop gear output to enable overall ratio changes, just like changing the diff. I can change the overall ratio in 20 minutes on mine. It's time you stopped messing about and started spending some money on this old clonker of yours You could go the other way on diff ratio and have better acceleration and use 4th properly to get to 130? Having effectively a 3 speed gearbox to hit V-Max for the run is not very good.