7" up! (long)

[Alan Stamper <stamper@iwaynet.net>]

First
	Thank you to all of the peolpe who posted on my questions about my 8"
wheels.  I've now run on them for over 30 runs and the answer is clear.
The seven inch wheels are faster!

Last weekend I finally got a hold of a tire pyrometer and was able to take
some temperatures.  On the 8's I found that I had a 6 degree spread across
the front tires, with the outsides warmest.  This is not to bad. The
temperature was mid 60's and it was sunny.  The tires were reading 95 to
101 F on the front, 87 to 93 on the rear.  Our course was around 38/39
seconds and wae had 54 cars in our heat so there was lots of time between
runs.  Front pressure was 23, rear was at 20.  

The alignment settings were
Right side -2.5 degrees camber  (max)
Left side -2.1 degrees camber (max)
Toe was set at 1/8" out

The car was pretty well balanced with a touch of oversteer while left foot
braking.  Under power it still had that slight push that I had before.

After 3 runs my best time was 39.613.  All three runs were pretty good and
second 2 were within 0.10 sec of each other.

After the third run we took our lunch break and I changed to the old
wheels.  I made no other changes to the car whatsoever.

Mt fourth run was a 39.293, my fifth & final run was 38.597.  There was
still a good half second I could have trimmed off too! (there always is!).
Tire temps on the front were within a four degree range  99 - 103F.  The
rears were also within four 91 - 95F.  Pressures were 33F/28R.   The cars
balance was great (rotated beutifully) and it had a slight oversteer with
the power on through the corners.

The 8" wheels had much better initial turn-in than the sevens, but the
sevens are much more progressive.  I also was able to get on the power
sooner out of the corners with the 7"s as compared to the 8"s.  The only
place I found that the 8"s had an advantage was the starting line.  I was
able to rev the thing to 4200 RPM on launch & get a good hook up!  The 7's
only take about 3700 before they spin excessivly.

I double checked the 8" wheels against my competitors and they are exactly
the same. He also has to use an 1/4" spacer to clear his brakes.  There are
3 other cars in our division that run this same setup, there is even one
guy who runs a set of 9" wheels (all GTI's).  I can run as fast or faster
than these guys on my sevens.  If it's not broke then don't fix it I guess.

 The car might work better with these things with a larger rear bar or a
stiffer rear spring.  The biggest detriment to the 8" wheels seems to be
the increased rolling resistance they have.  I'm not sure if this is from
the increased width of the wheel or the fact that they stick out so much
further and increase the track of the car, but the difference in
acceleration is noticible right from the line.

I might try this again if I can find a wheel with a different offset, but I
don't know how much this will help since I can only move the wheel in about
3/8" of an inch. It might be possible to reset the entire car to get these
wheels to work, but I'm not inclined to throw away 6 years of parts and
research thats made the car faster than the compitions on most days.

If anyone want's to try this experiment themselves then E-mail me with an
offer.  I paid $140 Ea for these wheels, and they only have 30 runs on
them.  I'm sure they'd look great on your car!

Alan  








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