Date: Mon, 18 Mar 2002 13:10:16 -0500
Reply-To: Vanagon man <vgonman@MSN.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Vanagon man <vgonman@MSN.COM>
Subject: Re: I need help with selecting a transaxle ratio, rim and tire
Content-Type: text/plain; charset="iso-8859-1"
>> My goal is to be able to use 3rd up to about 55MPH and on a level road
> maintain lower RPM at 70MPH in 4th to both improve gas mileage and reduce
> stress on the engine.
This is difficult to improve upon, because, these vans are under-powered
from the get-go. You currently should be able to go about 50-55 before
putting it into 4th with your current tranny for acceleration
needs.......That is propbably well into the 4600 rpm + range, though. If
you put a taller 3rd gear so that you can go faster in 3rd before you need
to shift to 4th, you will suffer when you are shifting from 2nd to 3rd with
low bottom end. now, If you put a taller 4th gear in your tranny, you will
have a hard time getting it up to your desired cruising speed, for when you
go from stock 3rd into a tall 4th gear, the rpms are going to drop, and the
motor is going to be working hard to get them back. You may save a few
hundred rpm at 70 mph, but Any engine life increases will be at best a wash
for the motor had to work harder to get you there.
Much different case in a bug.........The car is lighter and thus peoiple put
taller gears in all the time and can accelerate without a hitch. We have
big brick-like vans with small engines. Different animal.
>
> I am considering aproaching this issue by either changine by tire/rim size
> and/or by changing the transaxle ratio.
Stay stock...could be your problem now...Maybe Po deviated from stock set
up.
>
> I recently learned that the transaxle gear ratio in my 83 Westy 1.9 water
> cooler 2WD is 4.89 to 1. At 70mph it feels like the engine is turning
> better than 4,000 RPM. The mileage is about 17-20 freeway. When I
attempt
> any hill at 60MPH or better the vehicle quickly drops to 40-45MPH
> and it seems that I need to move into 3rd and stay at about 50mph or under
> to keep the engine together.
I think you have motor Problems if you are dropping this fast..........have
you had the exhaust gas analyzed? Does it need a tune-up? All of our vans
slow down some up a steep hill.........you seem to be slowing more than the
norm.
>
> I am hoping to improve the engineering by changing the transaxle ratio
from
> 4.89 to 4.33 as tallest ring and pinion set that seems to be avail. I am
> also seeking to replace the 4ply 205 70R14's with a optimal rim and tire
> combination. At this point I am not sure weather to stay with the same
> profile tire and just upgade the tire to maybe a 6ply 65 series 215R14 or
> attempt to increase the diameter of the tire about an inch by using either
a
> 6ply 70series 215R14 or 70 seriese 215R15.
reinforced is always better and helps to eliminate sway.
>
> At this point, I am planning on doing the transaxle rebuild first (with
new
> CV's Flywheel, cluch etc..)in about 3 weeks and then the rims and tires
> next.
If the tranny ain't broke, don't fix it. Owning one of these, plaenty of
things will break that you need to repair. These tranny's are pretty solid
if not abused, so if you are staying in gear, etc., Find you r power gains
in tuning the motor with a fine tooth comb. They only can do so much.
>
Adam P
vw enthusiast extraordinaire.
