[Vwdiesel] Tire and Rims on VW pick-up

[decker at toledotel.com]

Hi Caleb:
    I am presently driving a 1981 Dasher station wagon with a 1.6 N/A
diesel. I have fitted the car with a Quantum turbo diesel 5 speed tranny and
a 2 inch exhaust system. The tranny is a little lower ratio than an FF or FN
5 speed that would have been stock in a Rabbit pickup. It is a higher ratio
than the 4 speed the truck would have been stock with. I have found that
wheel diameter doesn't seem to make much difference in the mileage of my
Dasher. I have two sets of tires I'm running now. My winter tires are
165-75-14 and my regular tires are 175- 65- 14. Although they aren't the
same circumference I see little difference in mileage between the two. I
belive through my years of running 1.5 and 1.6 N/A diesels that it is
over-coming wind resistance that makes by far the most difference in
mileage. Speed kills good mileage. If you are geared too low you have to
spin the engine too fast for best results and if you are geared to high you
have to put your foot to far into the pump and that doesn't make good
mileage either. With my Dasher if I drive at 60 under normal freeway
conditions I get 50 mpg. If I drive at 70 I will get 47 or 48 mpg. With a
strong head wind or tailwind all mileage bets are off. Punching a really bad
head wind I will probably have to go 60 in 4th gear and get about 42 mpg.
With a really big booming tail wind I have a couple of times gone a couple
of hundred miles and got well over 60 mpg.
    In a Rabbit pickup I figure about 5 mpg less than in the Dasher Station
wagon. I belive it must have to do with better aerodynamics on the Dasher
since a Dasher  weighs 4 or 500 lbs. more. The only time I was ever able to
hit 50 mpg on a Rabbit pickup was with a pickup I used to have that had a
1.6 turbo engine with a straight pipe and cruise control. It was on a two
hundred mile out and back trip at night on an almost empty almost flat
freeway at 60 mile per hour with the cruise control set. My temperament
doesn't usualy let me drive at 60 for very long.
    Now that diesel has gotten back to the same or less than gas I will have
to get an engine in my diesel rabbit pickup. I have a 1.6 diesel block that
I am going to bore .5mm over and put a set of 1.5 pistons, crank and rods in
it. I then plan to turbo it and install an intercooler. I have a set of
Raceware head studs, a BAE turbo exhaust manifold with a Ray-Jay turbo. I
will use a gas intake manifold if it will fit and I think it will. I will
finish it off with a 2.5 inch straight pipe. I will run a big
thermostatically controlled oil cooler and of course a pyrometer which is I
belive essential to keep a small non-computerized turbo diesel alive
Brian Decker

----- Original Message ----- 
From: "Caleb Van Dyke" <awaytothesea at yahoo.com>
To: <vwdiesel at vwfans.com>
Sent: Sunday, March 22, 2009 11:22 AM
Subject: [Vwdiesel] Tire and Rims on VW pick-up







I am running a 14", 165/R14 tire (mounted on Audi Rims) on my diesel VW
pick-up right not. I am thinking about using my older 13" steelies while I
re-do the 14" rims. The stock tire evidently was a 160/80/13 or a 170/75/13.
I am thinking about going with the 170 series tire, but was wondering if I
should even upsize maybe to a 185/70 or 75 13 incher. Will going with the
170 or 185 13's give me any better fuel economy seeing that's whay VW
recommends?

Any help would be appreciated.


Caleb Van Dyke




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