Re: 4KQ's

[James Marriott <marriott@lesbois.com>]

Haudi,

Bruce Bell wrote:
> 
> The later (85-87) 4kqs also had more sound deadening. In mid '85 there were
> some changes to the rear diff. UR gave way to the AEC. I suspect this is
> when final drive ratio went from 4.11 to 3.89 although it is generally
> accepted that only the 84's had the 4.11 ratio.

I've heard/read quite a bit about this alleged FD change. Without
meaning even the ***SLIGHTEST*** insult to anyone, I think the 3.89 is
all hooey. Chris Semple ("Mr. 4kq" to you, sir) recently posted about
counting up the teeth in a late B2 016, and came up with 4.11. The
Bentley shows 37:9 in the exploded view (pg 39.38), references 0937 for
the front diff (pg 39.43), and again references 0937 for the rear diff
(pg 39.77). No differentiation is made--either in the drawings or the
text--for '84 and '85-87 'boxes. I couldn't find a single reference to
3.89 gears.

Also, assuming my tach is correct, measured-mile readings with my car
('87 4kq) give a fifth-gear ratio of 0.8 (seems popular with the other
Audi 'boxes) with 4.11 FD. If it's a 3.89, fifth is 0.845. These
measurements were done over a five-mile stretch set up as a speedo/odo
test section. This particular measurement is based on a 73"
circumference. I haven't measured the rolling radius at 75 MPH. For the
FD to be 3.89, the rolling radius would have to be 0.6 inches less than
the circumference/pi. I do not think it's that much; maybe more like 0.2
inches.

Does anyone have data to contradict or support any of this? I, for one,
would like to know for sure what's in there.

Thanks and HTH,
James