Re: 4KQ's

["Bruce Bell" <bbell@bbell.com>]

James et all,  

I've always been suspicious about the statement that only '84s had the 4:11
FD. However, there are several things that have convinced me *my* '87 4kcsq
has the 3.89 FD.

First I have radar verification of 67 mph at 3000 rpm with stock tires (the
originals). That works out to a little over 22mph /1000 rpm. A car with the
.83 5th gear ('85 Audi documentation) and a 4.11 FD would be at around 20
mph/ 1000rpm.

Second, after being challenged by Glen Powell on this list several years
ago, I too sought out long flat stretches of highway with odo check
sections. I did the test in *all* 5 gears. My results were inconsistent
with my '87 having a 4.11 FD. Note the following ratios.

Audi '85 book     My Car
I   3.60                  3.60
II  2.13                  2.13
III 1.46                  1.46
IV 1.07                  1.07
V  0.83                  0.78
FD 4.11                3.89

When I began my tests through the odo sections I, trying to prove my case
to Glen, went on the assumption that I had 4.11 gears. I was convinced Audi
had just tossed in a higher fifth gear for economy. When the testing was
done though, only a 3.89 ratio would explain what I found in gears 1-4 and
5th was still different. Just not as different (tall) as I expected.

I believe the gears ratios in my car were also used on some of the later
Ur-q in '87 or '88 - Phil?

It is also interesting to note that my speedometer and odometer were off
when I purchased my car by an amount that would be corrected by using 205
60 15 tires!! 

Now, I purchased my car new in July of 88 and I always wondered if they
didn't just grab from the available parts bin as the '87 models were
winding down. I have the special edition with the q stitch upholstery.

Last data point - my son has an '84 4kq and the ratios are definitely
different in all gears which again points to the final drive.

Hope this helps.

Bruce
----------
> From: James Marriott <marriott@lesbois.com>
> To: Bruce Bell <bbell@bbell.com>
> Cc: rxlouie@uswest.com; Quattro List postings <quattro@coimbra.ans.net>
> Subject: Re: 4KQ's
> Date: Thursday, August 07, 1997 11:14 PM
> Bruce Bell wrote:

> > 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