Close Ratio G-box & Diff

[SeiW500]

bobd said:

John Read at Poulton will rebuild your existing diff or do an exchange for the ratio you want. Everyone uses him.
Close ratio box needs a minimum of 3:73 diff imho.
For me the best combo is standard box with 3:73 diff

Have you got contact details for him?

How is 1st gear with a 3.73 diff?

[glow worm]

http://www.readmanracing.co.uk/

I put a 3:73 with std. box in my Tuscan convertible (done by John fitted by X-Works), I'm much happier with it. Mainly did it to get rid of the diff shunt, shorter prop shaft and 4 flange diff... Dana Spicer/BTR changed the diff which went in later models, that's what caused the shunt so be careful you don't introduce a problem.

[alex_gray255]

Targarama said:

Mattt said:

Do you run a garage? Why would people hold you to figures?

Doing things via email almost defeats the point of a forum.

Agreed. If someone asks me how much something costs I'll tell them, no skin off my nose. The only time I'd go 'private' is when it comes to naming and shaming.

Each to our own I suppose.

And no, I don't run a garage. I just like to drive cars, not maintain them.

[SeiW500]

glow worm said:

http://www.readmanracing.co.uk/

I put a 3:73 with std. box in my Tuscan convertible (done by John fitted by X-Works), I'm much happier with it. Mainly did it to get rid of the diff shunt, shorter prop shaft and 4 flange diff... Dana Spicer/BTR changed the diff which went in later models, that's what caused the shunt so be careful you don't introduce a problem.

OK, so you went from 3.46 to 3.73...?

But what was the diff change are you saying there are 2 types of BTR diff? I know there are BTR & Hyratrak, i think there are also 2 types of Hydratrak, but are you saying there are 2 types of BTR as well?
I have a 55 Plate Tamora with 3.46 BTR Diff and don't have any issues with diff shunt!
Just want to improve the acceleration a bit but don't want to mess up the gear ratios in the meantime!
If i could get away with just changing the Crown wheel & Pinion in teh existing diff then that would be great!

Edited by SeiW500 on Thursday 2nd June 14:54

[SAGRIFF]

SeiW500 said:

glow worm said:

http://www.readmanracing.co.uk/

I put a 3:73 with std. box in my Tuscan convertible (done by John fitted by X-Works), I'm much happier with it. Mainly did it to get rid of the diff shunt, shorter prop shaft and 4 flange diff... Dana Spicer/BTR changed the diff which went in later models, that's what caused the shunt so be careful you don't introduce a problem.

OK, so you went from 3.46 to 3.73...?

But what was the diff change are you saying there are 2 types of BTR diff? I know there are BTR & Hyratrak, i think there are also 2 types of Hydratrak, but are you saying there are 2 types of BTR as well?
I have a 55 Plate Tamora with 3.46 BTR Diff and don't have any issues with diff shunt!
Just want to improve the acceleration a bit but don't want to mess up the gear ratios in the meantime!
If i could get away with just changing the Crown wheel & Pinion in teh existing diff then that would be great!

Edited by SeiW500 on Thursday 2nd June 14:54

Just upgrade to a 4.5 Supersport Speed Six engine and go for the 3.46diff and CRbox and then take it to Spa

[SeiW500]

Wish i could afford one!

[Geoff Ashcroft]

SeiW500 said:

If i could get away with just changing the Crown wheel & Pinion in teh existing diff then that would be great!

Edited by SeiW500 on Thursday 2nd June 14:54

Andy,
I had enquired about a crown wheel and pinion swap in my 3.46 Hydratrak, but was told its a major and not worth the hassle as its cheaper and easier to swap diff. It would be a great winter upgrade, if at all possible.

[Targarama]

Geoff Ashcroft said:

Andy,
I had enquired about a crown wheel and pinion swap in my 3.46 Hydratrak, but was told its a major and not worth the hassle as its cheaper and easier to swap diff. It would be a great winter upgrade, if at all possible.

That is all I had done by Topcats, CW&P plus something else needed for the 3.91 ratio which was not needed for 3.73. Obviously the diff has to come out anyway - good excuse to get that impossible to reach top diff bush replaced.

[glow worm]

SeiW500 said:

OK, so you went from 3.46 to 3.73...?

But what was the diff change are you saying there are 2 types of BTR diff? I know there are BTR & Hyratrak, i think there are also 2 types of Hydratrak, but are you saying there are 2 types of BTR as well?
I have a 55 Plate Tamora with 3.46 BTR Diff and don't have any issues with diff shunt!
Just want to improve the acceleration a bit but don't want to mess up the gear ratios in the meantime!
If i could get away with just changing the Crown wheel & Pinion in teh existing diff then that would be great!

Edited by SeiW500 on Thursday 2nd June 14:54

Dana Spicer bought out BTR ...yes there are two hydratrak diffs with different flange plates and sizes 8" amd 8.25" IIRC .. speak to John ..he is the expert.
http://www.spiceraxle.com.au/products.htm

Spicer said there was no problem with the new diff because it was used on the Holden Monaro in Aussieland..but TVR always had problems with the new diff.

Edited by glow worm on Thursday 2nd June 20:47

[SeiW500]

Geoff Ashcroft said:

Andy,
I had enquired about a crown wheel and pinion swap in my 3.46 Hydratrak, but was told its a major and not worth the hassle as its cheaper and easier to swap diff. It would be a great winter upgrade, if at all possible.

Geoff, speak to Racing Green, they go some good deals on Hydratrak diffs at the moment!

[Incognegro]

Have to bring this topic back to life as Car is currently having work done at Powers this 3.73diff I hear lots about what would that do for me on the standard gear box/ratios is changing diff the same as changing final drive?

The update Im having done is effectively making a Cerbera 4.0ss up to RR or S-spec in power so Im wanting to be able to not have to shift out of 1st so quickly but not have to shift down to often to get pull.

Thoughts advice welcome... please keep it relevant.

Many Thanks gang

[RedSpike66]

FWIW.. yes, the number (3.46, 3.93, 3.91) is the final drive ratio..... and the CR box and 3.73 diff give you 60mph in 1st and 100mph in 2nd !!!! Assuming you go to the red-line in a SP6.... Makes the 0-60 time fast as zero changes and the 0-100 time fast as only one change.

[Incognegro]

RedSpike66 said:

FWIW.. yes, the number (3.46, 3.93, 3.91) is the final drive ratio..... and the CR box and 3.73 diff give you 60mph in 1st and 100mph in 2nd !!!! Assuming you go to the red-line in a SP6.... Makes the 0-60 time fast as zero changes and the 0-100 time fast as only one change.

Thanks mate great info. I'm thinking of keeping my box wide and not CR so when I'm around town not constantly dipping the clutch. How would the standard box with a 3.73 go and how does it pull. Never been in a standard sag or Tuscan (both LS with 6 gears).

Cheers

[shep1001]

How do you know if you have a CR box. I know I have a 3:73 diff ratio as it is on the tag attached to the diff. It goes like a stabbed rat off the lights in first, mid 50's before it hits 7.2k revs but that is not very scientific! is it stamped up anywhere?

[anonymous-user]

Think the Gearbox man has a spreadsheet on his site that you could input gear ratios, wheel and tyre sizes, and final drives that will give speed in gears. Ratios are on the site too.


Or they were...