I want a 6th gear!

[toadusmodus]

I've had my Cerb for over 6 years now, and the lack of a 6th gear is something that has always slightly bothered me.
With so much power and torque, surely a top gear with 30ish mph per 1000rpm would be possible, the 26ish of the standard 5th seems a bit low to me.

As the box is a fairly standard Borg Warner affair, does anyone know of any options for this? Guess you can't just add another gear, but maybe a replacement box, or stretching 5th a bit maybe?

Would be interested in any thoughts/experience on this.

[toadusmodus]

Bump.

Nobody have ANY ideas????

[victormeldrew]

I beleive it IS possible to fit six speeds into the T5 box, if that is what's in the Cerb. Or replace with a T56 box (www.skulte.com/T56.html).

Already a thread here

Edited by victormeldrew on Saturday 31st March 13:16

[toadusmodus]

Thanks matey, will poor over the info.

[BCA]

A better suggestion is to just change the diff to something that'll make it a little longer geared. The Cerb is hardly lacking in torque, so it wouldnt hurt it anywhere (on a normal box, the CR box may be a little silly) and it may allow for a reasonable bit of extra reach in third for those that wish to grace Santa pod without buzzing to 8k rpm!

[toadusmodus]

BCA said:

A better suggestion is to just change the diff to something that'll make it a little longer geared. The Cerb is hardly lacking in torque, so it wouldnt hurt it anywhere (on a normal box, the CR box may be a little silly) and it may allow for a reasonable bit of extra reach in third for those that wish to grace Santa pod without buzzing to 8k rpm!

A fine idea. So who would like to change my diff for me? Anyone??

[v8sag]

toadusmodus said:

BCA said:

A better suggestion is to just change the diff to something that'll make it a little longer geared. The Cerb is hardly lacking in torque, so it wouldnt hurt it anywhere (on a normal box, the CR box may be a little silly) and it may allow for a reasonable bit of extra reach in third for those that wish to grace Santa pod without buzzing to 8k rpm!

A fine idea. So who would like to change my diff for me? Anyone??

Is the crown and pinion you only need to change,its Holden guts so don't know what supply would be like in UK,price for these parts downunder would be around 100 to 150ukp.
What ratio are you running,if its 3.45 you can go to a 3.23,or if your at 3.23 go down to a 3.08.

[kevin63]

The guys who have built the Sagaris race cars have a 6 speed sequential gear box mated to the 4.5 AJP engine have a word with then, won't be cheap though but it is quick, strong and tested.

[BCA]

v8sag said:

toadusmodus said:

BCA said:

A better suggestion is to just change the diff to something that'll make it a little longer geared. The Cerb is hardly lacking in torque, so it wouldnt hurt it anywhere (on a normal box, the CR box may be a little silly) and it may allow for a reasonable bit of extra reach in third for those that wish to grace Santa pod without buzzing to 8k rpm!

A fine idea. So who would like to change my diff for me? Anyone??

Is the crown and pinion you only need to change,its Holden guts so don't know what supply would be like in UK,price for these parts downunder would be around 100 to 150ukp.
What ratio are you running,if its 3.45 you can go to a 3.23,or if your at 3.23 go down to a 3.08.

There is some discussion over on the Sagaris forums about this very thing. From what I can see, im assuming that Cerbs have never run 3.45s? I think there would be a fair bit to gain in terms of cruising ability and 1/4 mile running without sacrificing any real pace, such is the nature of the AJP's torque. Certainly cheaper than looking to a different box. Can anyoen shed any light into what diffs we currently run? I'd be suprised if it was anything other than the 3.9/3.73s?

[BCA]

Here is a link to the discussion over in the Sagaris forum:
www.pistonheads.co.uk/gassing/topic.asp?t=373003&f=7&h=0

They want to go the other way to the Cerbera crowd due to the S6's different torque delivery and shorten the gears for better acceleration...

[Julian64]

Wow you could all do swapsies?

[BCA]

Julian64 said:

Wow you could all do swapsies?

Err... not sure how many takers there would be for a noisy(bearing?) 70k mile old diff?

[toadusmodus]

I'm pretty sure a standard 4.2 (and 4.5 for that matter) Cerb runs a 3.45 diff. Have been messing about with this www.geocities.com/z_design_studio/
and trying different diff ratios. With a 3.08 diff, you get a theoretical top speed of 209 mph at 7000rpm in top!! And a 90mph cruise at 3000rpm, which is more what I was after.

So, does anyone know who manufactures the Cerb diff, and if anyone offers alternatives??

Edited by toadusmodus on Monday 2nd April 08:30

[v8sag]

toadusmodus said:

I'm pretty sure a standard 4.2 (and 4.5 for that matter) Cerb runs a 3.45 diff. Have been messing about with this www.geocities.com/z_design_studio/
and trying different diff ratios. With a 3.08 diff, you get a theoretical top speed of 209 mph at 7000rpm in top!! And a 90mph cruise at 3000rpm, which is more what I was after.

So, does anyone know who manufactures the Cerb diff, and if anyone offers alternatives??

Edited by toadusmodus on Monday 2nd April 08:30

TVR BTR casing is made specific for TVR,the guts is standard BTR(BTR bought out Borgwarner diff division ) as in the Aussie Holden Commodores and Monaro's.You need to check the casing and check the third and ,it will probably read 76(7.6" crown) or 78(7.8"crown).These are commomly known as m76 or m78,the new Commodore now run a m80.BTW TVR also run the same GKN cv joints and drive shafts as Holden.There is some debate that a 7.8" will even fit in a 76 casing but doen't quote me.
Go to www.streetcommodores.com.au go to the forums then diff section and have looksie,its a long read

Edited by v8sag on Monday 2nd April 10:40

[mars]

I'd like a 6th simply because I've come from a 6-speed car to the Cerb and the number of times I've reached for 6th, stopping only at the last moment before destroying reverse, I cannot count.

Other than that, I actually think the gearing of the 5-speed suits the car well.