Which Diff for RV8/Granada

[bluetoon]

Hi Guys,
Just checked my Diff and its a 3.91 ratio (2.0l Granada)
After some investigation it seems this diff is great for acceleration but useless for cruising as the engine would rev to high.
So i need to find a replacement 7.5" diff for my sumo RV8/LT77/Granada .

The main choice seems to be between a 3.36 or a 3.6 as these are from the sierra cosworth / Granada scorpio range.

3.91 = Engine will rev very high when cruising.
3.6 = Better, but engine will still rev high when cruising.
3.36 = Revs a little lower but acceleration is compromised.

Does this sound about right.
What diff should i get and do i need a LSD.
Thanks in advance
Jim

[paolo]

This thread may be of use...

Duck

[bluetoon]

Thanks Paolo
I have read a few threads on this subject and am still not sure which is the best choice diff for the commonly used RV8/LT77/ Granada setup.

Which Diff did you use.

Anyone else running a sumo with this setup care to comment on diff choice.
Ie What is the acceleration and cruising like for your diff.
Cheers
Jim

[bobdude]

In the middle of MK1 conversion from V6-V8 my diff is cortina but have done my homework and found out that some cortina's were fitted with an uprated diff that they also used in the transit vans so it will be strong enough.

However it could be a 3.7 or a 3.54 if it is the 3.54 it may well be ok, but if it is the 3.7 it ain't no good

I shall be taking the back plate off sometime this week to have a look.

[paolo]

I actually have no idea what ratio mine is at some point I'll get round to measuring it, but I'm still halfway through building so I don't know if it's good for cruising or accelerating or what!

[TINKA]

If your main choices are between a 3.36 or 3.6 then it is quite simple as both would be fine in that ratio. The choice you have to make is do you want the best poss acceleration ( theoretically ) or a diff with great acceleration but which would be a lot better for cruising. My only thought would be that as the Sumo is a light cat the true benefit of a 3.6 might be lost due to traction or lack of. Personally I think you would be best off with the 3.36. IMHO

[bluetoon]

Thanks Tinka
I am persuaded to go for the 3.36 diff aswell, however there seems to be more 3.6 about.

........hmm, now where will i find a 3.36:1 7.5" Diff preferably LSD.
No one ever said this was going to be easy.

lets start with ebay................
Jim

[Purple AK]

Originally Posted by bluetoon

Thanks Tinka
I am persuaded to go for the 3.36 diff aswell, however there seems to be more 3.6 about.

........hmm, now where will i find a 3.36:1 7.5" Diff preferably LSD.
No one ever said this was going to be easy.

lets start with ebay................
Jim

Try http://www.donorspares.co.uk/

[Happy Jim]

I ran my RV8/LT77 with a 3.31 diff, and I wouldn't want a shorter diff than that (eg 3.54) as the increased revs would get to be a drone at cruising speeds. If you really want acceleration above all else (ie your into 1/4 mile times) then go as high as you can, if not then think very hard about the speed you will spend most time at.

Rgds

Jim