T5 Gearbox and 7" diff help please
Discussion
KAR 120C said:
Can anyone help with which models there were fitted too please. Is there any difference between T5 gearboxes or 7" diffs fitted to early and later cars?
Any help or directions to sites that may help will be appreciated.
Michael
Might help if you gave more info. ie, what car ? what age ? What are you using these for ?Any help or directions to sites that may help will be appreciated.
Michael
KAR 120C said:
Thank you stevieturbo!
I am sourcing parts for my Caterham 7 build. I need a gearbox and diff. I think CC used XR4i parts but I am not 100% sure. There isn't a lot of room under a 7 and I need to be sure I can fit the parts in the space available.
Thanks,
Michael
XR4i did not use a T5.I am sourcing parts for my Caterham 7 build. I need a gearbox and diff. I think CC used XR4i parts but I am not 100% sure. There isn't a lot of room under a 7 and I need to be sure I can fit the parts in the space available.
Thanks,
Michael
Im not sure what size diff it used, but it was teh crappy old one with push in shafts and drum brakes..
More importantly, what engine does the box need to bolt to ?
And what rear end combo is the chassis built for ?
Basically any 4cyl n/a or 4x4 Sierra/granada used a 7" rear diff. Thats a wide range of cars, with a variety of diff ratios too. Some with LSD, many without.
So again, what exactly are you looking for ?
stevieturbo said:
XR4i did not use a T5.
Im not sure what size diff it used, but it was teh crappy old one with push in shafts and drum brakes..
More importantly, what engine does the box need to bolt to ?
And what rear end combo is the chassis built for ?
Basically any 4cyl n/a or 4x4 Sierra/granada used a 7" rear diff. Thats a wide range of cars, with a variety of diff ratios too. Some with LSD, many without.
So again, what exactly are you looking for ?
I was looking to replicate what caterham originally fitted which after speaking with them appears to be the 7" diff with push in driveshafts but they had their own de dion tube arrangement with disc brakes and coil over shock suspension. Why do you say the 7" diff with push in shafts is 'crappy'? Caterham tell me they used 3.62:1 diffs for their 6 speed box and 3.92:1 for the 5 speed.Im not sure what size diff it used, but it was teh crappy old one with push in shafts and drum brakes..
More importantly, what engine does the box need to bolt to ?
And what rear end combo is the chassis built for ?
Basically any 4cyl n/a or 4x4 Sierra/granada used a 7" rear diff. Thats a wide range of cars, with a variety of diff ratios too. Some with LSD, many without.
So again, what exactly are you looking for ?
The 5 peed Caterham used was the XR4i Type 9. Presumably the ratio's are best suited to the VX red top for this box. They still sell this box I believe. They claim they have not had any problems with it, certainly up to 200bhp. So I would be happy to use that box if I can source a good one.
I would be happy to alter the specs once I have done enough homework, picked enough brains and found good engineering companies that could help me with the mods neccesary to fit other components. I don't want to reinvent the wheel so I am happy to go with what others generally accept as 'improvements' on OEM supplied specs.
I am just looking to build a really nice fast road Caterham 7 as they come 'out of the box' or with mods which actually improve it. I have 2.0l Red Top VX engine that I wish to use. I will be happy with around 200bhp so not really looking for an out and out racing car! But it will be quick, fun and most importantly, reliable. That is my aim.
Thank you for your help with this.
Michael
punch in 'sierra diff' on ebay motors to get an idea of whats around and ratio types,prices etc.there are a few sites with some good archive of what diffs were in what sierras/granadas.all sierras except 2 wheel drive cosworth were 7" AFAIK.i think the push in shaft type have smaller cv joints compared to the 100mm lobro bolt on ones.
here's one for a start.
http://www.carbuilders.info/pages/Sierra_Diffs
what do i know,according to this there is a 6.5" diff also
but this may refer to the front one on 4WD cars.
http://www.carbuilders.info/pages/Sierra_Diffs
what do i know,according to this there is a 6.5" diff also

but this may refer to the front one on 4WD cars.
Edited by garagewidow on Thursday 3rd February 00:16
I don't think there's space in a Caterham tunnel to fit a T5, as AFAIK they all run type 9s. Although it will depend upon what engine you're fitting. The most common Caterham engine is the Rover K series, and bellhousings are £250 or so new, and maybe half that on Ebay if you can find one. Red top bellhousings are available too, and I are about the same price.
The Caterham diff, as you say, is usually the 7" with push in drive shafts. You could easily fit the bolt on type, as it's only the shafts that change, and that's easy to do. This is what is all looks like in the flesh, although this is minus the de-dion ears that mount the hubs and brakes. They basically extend the plates on the de-dion tube forwards.

The Caterham diff, as you say, is usually the 7" with push in drive shafts. You could easily fit the bolt on type, as it's only the shafts that change, and that's easy to do. This is what is all looks like in the flesh, although this is minus the de-dion ears that mount the hubs and brakes. They basically extend the plates on the de-dion tube forwards.

I say crap basically as they had smaller joints and shafts as mentioned, and drum brakes.
Probably easier to source a more modern bolt in shaft 7" anyway. Buy one from a 4x4 car and it'll be an LSD.
As far as engines. Might be cheaper and easier to source a Ford Zetec and bolt an MT75 to it.
No messing about with buying different bellhousings etc, and it's still a very good engine as far as I know.
Probably easier to source a more modern bolt in shaft 7" anyway. Buy one from a 4x4 car and it'll be an LSD.
As far as engines. Might be cheaper and easier to source a Ford Zetec and bolt an MT75 to it.
No messing about with buying different bellhousings etc, and it's still a very good engine as far as I know.
stevieturbo said:
As far as engines. Might be cheaper and easier to source a Ford Zetec and bolt an MT75 to it.
No messing about with buying different bellhousings etc, and it's still a very good engine as far as I know.
A zetec is going to be cheaper, but heavier and probably less power as standard. There is the 160 VVC K series which is pretty good, albeit not so cheap. Also, I'm not sure an MT75 will fit, they're a fair bit bigger but a lot stronger than a type 9. It'll depend upon who's chassis he's using.No messing about with buying different bellhousings etc, and it's still a very good engine as far as I know.
I have written off the idea of a T5 in a Caterham now and will stick with what Caterham use, the Type 9. I understand BGH offer uprades and will focus on going down that route. As for Diffs I guess the best thing would be to buy a Sierra with a 7" 3.92:1 'flanged' diff and T9 box. I will have everything I need then! Does anyone know what model Sierra I need for this? I think one of the estates covers it but would welcome your inputs, as usual.
Many thanks to all for the contributions so far. I have learned a lot.
Michael
Many thanks to all for the contributions so far. I have learned a lot.
Michael
KAR 120C said:
I have written off the idea of a T5 in a Caterham now and will stick with what Caterham use, the Type 9. I understand BGH offer uprades and will focus on going down that route. As for Diffs I guess the best thing would be to buy a Sierra with a 7" 3.92:1 'flanged' diff and T9 box. I will have everything I need then! Does anyone know what model Sierra I need for this? I think one of the estates covers it but would welcome your inputs, as usual.
Many thanks to all for the contributions so far. I have learned a lot.
Michael
No idea on ratio, but any Sierra with rear disc brakes will have bolt in shafts.Many thanks to all for the contributions so far. I have learned a lot.
Michael
No reason why a Granada diff cant be used either, same would apply re-discs.
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