new diff fitted

[maccavvy]

Well finally after much hassle got the new diff fitted .
gone from stock 3.4 cv8 to 3.7 .
feels much perkier
did some in gear measurements before need to do some after .
so far so good. well happy.. not in a rush to do the job again though

[vxr2010]

I got the 3.9 done on mine a cv8 , well worth the money car is a lot better for it

[fred bloggs]

Did you go for new lsd or not ?

[maccavvy]

it was a 2nd hand diff. 45 k miles on it from a 5.7 vxr

couldn't find a 3,9 for sale . not easy to find at the mo

[lythaby]

I've got a little weap on my cv8 diff, and I can see blue sealant oozing, but no receipt for a diff.
Short of cracking the casing open I guess you can't tell if it's been changed?

Does anyone know what a std diff does mph vs revs based on gear?

[Janosh]

lythaby said:

I've got a little weap on my cv8 diff, and I can see blue sealant oozing, but no receipt for a diff.
Short of cracking the casing open I guess you can't tell if it's been changed?

Does anyone know what a std diff does mph vs revs based on gear?

In 6th gear, 70mph comes at:

3.4 - 1500 rpm
3.7 - 1750 rpm
3.9 - 2000 rpm

[monkfish1]

lythaby said:

I've got a little weap on my cv8 diff, and I can see blue sealant oozing, but no receipt for a diff.
Short of cracking the casing open I guess you can't tell if it's been changed?

Does anyone know what a std diff does mph vs revs based on gear?

Blue sealant is factory. Supposed to be like that.

[lythaby]

Oh, i expected a gasket/seal.

I'll check the revs and see.

Thanks all.

[Mud_]

Janosh said:

In 6th gear, 70mph comes at:

3.4 - 1500 rpm
3.7 - 1750 rpm
3.9 - 2000 rpm

Something like this, but I think they're a bit closer together - if the 3.46 is 1500, then 3.73 would be 1617, and 3.91 would be 1695. IIRC my 3.91 gives me just under 2000 rpm, so maybe they're all a hair higher.

[robbyd]

I think with the 3.9 and 18" rims, 1000 revs gives you about 37/38 mph rather than 35 (according to GPS anyway)

[maccavvy]

stock cv8 is 2000 rpm 85 mph on the speedo .. not that id ever do that speed.. something I heard

[Mud_]

maccavvy said:

stock cv8 is 2000 rpm 85 mph on the speedo .. not that id ever do that speed.. something I heard

So @70mph
3.46 - 1647rpm
3.73 - 1776rpm
3.91 - 1861rpm

[Well_Fans]

maccavvy said:

it was a 2nd hand diff. 45 k miles on it from a 5.7 vxr

couldn't find a 3,9 for sale . not easy to find at the mo

the 3.7 from the early VXR was the best all rounder in terms of ratios.

[maccavvy]

Glad I located one then ...;-)