Re: Am I going to hurt the car?

[James Marriott <marriott@micron.net>]

Scott asked for a private reply, but the ones I saw were quite public.

Since the example 5ktq has a manual trans, and the 100/A6 has an auto, I'd
say this is apples/oranges. If there aren't many hills involved, the
trailer isn't too large wind-wise, and the throttle is kept off the floor,
the auto is probably fine.

What kills autos during towing is the waste heat from the torque converter.
If, for example, the TC is 90% efficient (when unlocked, which would
typically be at light throttle loads), then 10% of the power goes into heat
in the TC. Normal cruise at 70 MPH uses maybe 20 Hp, of which 2 would be as
heat (2 Hp = 1500 watts). Climbing a steep hill at WOT would use 200 Hp, of
which 20 would come out at heat (15000 watts). As you realize, 15000 watts
is a WHOLE BUNCH of heat.

As long as the heat generated is kept within the capabilities of the
system, everything is peachy.

If you want to tow a heavy trailer up a steep hill, don't floor it. Spend a
few more minutes and save the tranny.

>Stay away from boat ramps, Scott (that was the issue prompting the last
>thread on using Audis to pull trailers), and you'll be OK.  Your gas
>mileage will suffer significantly, but nothing else should.  I've pulled
>1500-2000 pounds (trailer and load) several times over 350-600 miles  with
>my '87 5kcstq, with no apparent ill effects.  My last trip like that a
>month ago, I pulled a 1200-pound jointer on a trailer that weighs about 800
>pounds from Moline, IL, to northern Michigan nonstop (except once for gas
>and "forever" at the bridge construction around Chicago), averaging 70 mph
>and 15 mpg.  Trailerless and at least 5 mph faster, I'd get 30 mpg.
>
>Kneale Brownson 
>
>At 08:53 AM 10/4/99 -0500, scooter@pseconds.com wrote:
>>I know this must have come up before, but I couldn't locate it in the
>archives.
>>
>>I'm looking for opinions, am I going to hurt my '94 100s if I tow a 1500lbs 
>>trailer 
>>on a 1700 mile trip?  I'm looking at bringing a trailer from Florida to 
>>Minnesota 
>>and the dealer wouldn't even give me a vague answer as to if this could do 
>>damage or even tell me how much I can tow.
>>
>>Please send a private reply.
>>
>>Thanks,
>>Scott

cu, James
'87 4kq (alias "late-B2 90q")
'89 200q (K26, wood/8-gauge dash, torsen, aero handles, Procon10/no bag)
Boise, ID, USA     http://netnow.micron.net/~marriott