diff ratio info.

[frogisland]

Mr Bump, be aware if you look for a crown wheel and pinion, they need to be a matched pair - they are usually numbered. I managed to find a 10 hole 3.91 in Germany, struggling to find a 3.45 and 3.64.

The pinion output to flange teeth come in both fine and course (latter shown); so make sure you have the appropriate output flange.

Not as straight forward as you might have thought.

CW & P also two varieties, one normal, one reduced drag to reduce parasitic loss. On the crown wheel the gear widths are 30mm (normal) or 25mm (low drag) with similar width reduction on the pinion.







Some questions:

Does anyone know if the medium case CW & P (188mm) fits onto the sideloader LSD?
Are the 10 fixing holes on the same PCD?

If a medium case LSD unit is used in the sideloader diff casing, do the original (e9) output flanges fit the LSD unit?

Does the medium case pinion fit into the sideloader case ok (assuming use of a medium case LSD unit)?

Might be as well for me to buy a complete medium case LSD unit to test (three units to have built for my project)

JP

 

[Bill 74 3.0 CS]

Mr. Bump, quick question. You mentioned that you are running a final drive of 3.07 on your car, and that it is a highway cruiser. My curiosity is what is the reading on your rpm on say, 120 kph? And what is it like in 1st and 2nd gear? Are you using the stock getrag gearbox, or do you have a 5 speed installed?

 

[WISE9UY]

I up graded my diff in my 72 cs last year to a pre 79 E24 side loading LSD diff along with the dogleg box out the same car.
The diff ratio is 3.07 and is a 10 bolt crown wheel and lsd unit. Its a great motorway cruiser with the 3.07, but I want to pep it up a bit.
So im after a 3.64 or round that type of ratio. The original ratio in my cs when it was auto was a 3.64 but its only an 8 bolt crown wheel and wont fit to the 10 lsd unit.
Does anyone know if a later E28, E34 ect crownwheel will fit into the e24 sideload casing or if therewas a 3.64 available in the E24 range of engines?

How did you find acceleration with the 3.07? I would expect that would make good use of the torque and could get to 62mph with just one gear-change.

Also as an fyi, there is good conversation on this topic currently in the parts for sale section:
http://www.e9coupe.com/forum/threads/wtb-limited-slip-diff.20246/page-2#post-175255

And formerly:
http://www.e9coupe.com/forum/thread...ar-for-different-gearboxes.23432/#post-172438

 

[WISE9UY]

Hello All,

So yesterday I finally got to drive an E9 with the 3.64 with 265OD gearbox. I have my answer and thank the input of the many that have responded to my questions on diff/gearbox combo. I am sold on the 3.64 with 265 OD box. The car had an M30B35 in it and with my turbo will be exactly the feel I will want. With the 3.07 mated to this set-up, you would only ever see 5th on the motorway, and while this is what I had in mind, the reality was that driving with the 3.64/OD setup, it was 50mph at 1500 rpm and that was perfect. I also liked that slight revving nature of the setup. Let the preparation of the driveline and transfer begin!

I think the 3.07 would be good with the Close-Ratio box and with the power, but I state the above as my preference. For a highway stormer, I think as the factory intended with the M90, this 3.07/CR setup would be the way to go. I will now also start the sale on these items and help fund my own path!

I will soon start a project thread as this will be quite a journey!

Here is a pic of the car: Fully Coupe King restore and every aspect perfect. This was one stunning car!

 

[Gary Knox]

Glad you got to drive and are happy with the 3.64, It does give excellent acceleration and better 'off the line' performance than the 3.07. The car looks absolutely great.

Gary

 

[HB Chris]

Glad you got to try one out, great selection. Just one thing, 3000 rpm will give you close to 75 with 265, no way 1500 rpm gives you 50mph though.

 

[Gary Knox]

I agree with Chris, as my speedo with the 265/6 OD transmission and the 3.64 differential was 20% fast vs GPS. Now, with only changing to the 3.07, it is dead accurate - well within <mph, at least to speeds up to 60 mph. Still don't have the front seats installed, so can't drive it much (or fast).