After taking delivery of the red
four door `89 iX, we had to endure
about two weeks of Denver's
typically dry November before the
next freezing rain and snowfall. We
had attached our "BMW4X4" vanity
plates, installed studded Vredesteins
on factory steel wheels and anxiously
awaited a chance to try the all-weather
Bimmer in the elements.
The opportunity came on a snowy
evening, but frankly the testing was
disappointing because it was so
uneventful and undramatic. But then
as we pulled into our driveway, a
Jeep slid through a nearby
intersection and bounced off the
curb. Perhaps the streets were slicker
than we had thought!
We decided to make a comparison
between the iX and our old faithful '71
Volvo 142E. With skinny studded snows,
limited power, and a 50/50 weight
distribution, there are few rear drive
cars which can match a Volvo's
traction on slippery roads. In the
heavily falling snow, we prepared for
a shoot-out on the streets of our
neighborhood. Starting in the lead in
the iX, Gordon blasted up the hill,
exercised the ABS at the stop sign,
continued up the hill and parked it in
the garage. As he climbed out of the
iX and closed the garage door, Bev
in the Volvo was nowhere in sight.
After she finally arrived, Gordon
took the Volvo to the hill and learned
why it took her so long to return. It
was extremely slick. From that night
on, we have been believers! The
325 iX truly is awesome in the snow.
Now with 38K miles on it, the `89
"BMW4X4" has served as Bev's
daily driver on her 50 mile commute
and has been perfect for occasional
winter trips to the mountains with
the dogs. Gordon, who has been
coaxing a heavily modified `74 Fiat
Xl/9 through 17 winters (and until
recently drove a tricked out 6-series
which rarely saw rain or snow)
became more and more envious of
the iX for its performance in poor
weather. Perhaps he should buy a
clean `88 iX 2-door with Recaros.
But Gordon really appreciates crisp
handling. He has been racing Bill
Schaefer's ITA tii and Gregg
Ten Eyck's ITC/GT-4 Datsun and
drove to a 3rd place finish with Co
VanHerwaarden in an M3 in the '91
SCCA Escort World Challenge Series race at
Sears Point. Could this BMW fanatic
be happy driving an understeering,
moderately powered, taller-than-your-average
Bimmer regularly on
Denver's normally dry streets? He
decided "yes" -- if some
improvements could be made.
After looking at five or six `88s, we
decided to buy the clean white one
with 58K miles we found at the
BMW dealer in Colorado Springs. A
week after we took delivery, Gordon
took it to the Rocky Mountain
Chapter's 1992 Icekhana on the lake
at Georgetown. We had installed the
white "4X4BMW" plates and
studded 185/65 R 14 T Hakkapeliitta
10's mounted on factory steel wheels.
Yes, we got some grief over the full
moon covers (you saw it here first),
but at least we had no trouble with
snow packing into the basket weave
of the factory alloys. Gordon, Bruce
Hazard and Bill Schaefer took 1st,
2nd and 3rd fastest times of day in Gordon's iX
and everyone who drove this iX agreed
that it was more than capable of
"burning some ice."
But now it was time to modify
Gordon's `88 iX for the 90% of the
time it would be driven in the dry
and to reduce the unsightly excessive
clearance in the front wheel opening.
As we had often done on our low
budget IT race cars, Gordon cut the
front springs. One and a half coils
were removed as shown in the
accompanying diagram to lower the
front of the iX one and a quarter
inches. This modification was done
with the struts still installed on the
car and using two sets of spring
compressors. It was a little tricky but
really not too difficult given some
experience with strut repair and a
good air die grinder/cutter. (Koni's were
installed about a year later.) After the
mods were completed, a front wheel
alignment check showed that toe
needed to be adjusted. Cutting the
springs resulted in increased camber
which was just slightly out of spec
on the right side. Overall camber
was within spec and the extra
camber would be perfect for driver
schools and spirited cornering.
But the real solution to the inherent understeer on Gordon's iX
was to replace the stock
wimpy rear 14.5 mm swaybar with a
19 mm Suspension Techniques bar
adjusted in the stiff position. (NOTE: If you upgrade the rear bar, you will need to strengthen all the mounting brackets for the bar on both the body and the trailing arms -- see iXchange Newsletter #4 for more info.) The
stock front 17 mm swaybar was
retained but the rubber mounts were
replaced with generic polyurethane
bushings from J.C. Whitney. (These
had to be carved somewhat to fit into
the stock brackets.) The iX looked
great and felt great on the street.
Gordon couldn't wait to get to the
track for some hot laps.
But what about the engine? A
Dinan chip seemed to be the answer.
Gordon had taken 0-60 times prior
to installing the chip, making
repeated runs in both directions on
the same section of highway. He
followed the same procedure with
the chip and found some significant
improvements. It was also time to
make some side-by-side comparisons
between the stock `89 "BMW4X4"
red four door and the modified `88
"4X4BMW" white two door, so he
also made similar multiple runs in
the stock `89. These runs were made
without abusing the drivetrain. And
for those of you expecting quicker
times, please note that they were
made at an elevation of about 5600
ft. where about 25% of horsepower
is lost to the thinner atmosphere.
The stock `89 was a little faster than
the stock `88, perhaps because of
fewer miles on the `89 or some
improvements by BMW in the `89
vs. `88 model. But the Dinan chip
made a very noticeable improvement
in the straight line performance of
the `88 iX. This showed up as a 1.4
second reduction of 0-60 times and a
feeling that the engine was very
strong pulling to the redline which
was increased to 7K rpm. (Such a
noticeable improvement may not be
possible on later models. Gordon
installed a Dinan chip in a `91 iX and
measured a smaller improvement of
0.7 seconds and no detectable
increase in the rev limit.)
But the real test would be on the
track where the effect of both the
chip and the suspension mods could
be measured. So on one of those
glorious Colorado sunny spring
days, Bev and Gordon left Denver
and convoyed 120 miles south on
1-25 to Pueblo Motorsport Park.
Cruising at 70-75 mph, mileage on
both cars was 26.8 mpg with no
detectable difference because of the
Dinan chip, except for the need for
premium unleaded. The Pueblo
track is a 2.2 mile road course at
4900 ft. which includes a full drag
strip on the front straight with
terminal speeds around 100 mph
before a 70 mph decreasing radius
sweeper at the end. The back section
of the track includes a good
combination of low speed turns and
elevation changes to test handling
and torque characteristics.
Gordon has probably taken 600 laps
around this track and the day we
were there, we had it completely to
ourselves. Unfortunately, the concrete
barriers separating the two drag race
lanes at the start line were in place.
This required entrance speed to the
front straight to be reduced from
about 65 mph to about 45 mph and
prevented a direct comparison with
ITB 2002 times which are in the
1:56 range. The `88 was run with
Pirelli 600s and the `89 with
Michelin MXV3s, both on the
factory alloys. Later testing of these
tires on the same car (the `88)
showed no significant difference in
lap times because of the tires.
The results of testing quantitatively
proved what is immediately apparent
from just driving the two cars. The
modified iX is significantly faster in
all regards and a real pleasure to
drive. And it handles like a BMW
should.
The test results summary:
* Average best three lap times on the stock `89: 2:08. On the modified `88: 2:01. (The difference of7 seconds is very significant, exceeding the difference between the fastest and slowest cars in a typical race class.)* Average Quarter mile results on the stock `89:18.6 sec. at 78 mph. On the modified `88: 17.5 sec. at 82mph. (This represents 8 car lengths, going away.)
* Average 0-60 times (5600 ft. elevation) on the stock `89: 10.76 sec. On the modified `88: 9.83 sec.
* On the track, the stock `89 exhibits significant understeer upon application of power exiting the turn. This requires the driver to try to "run over" the apex of a turn, get on the power early and rely on the plowing to move the car outward. It is not a comfortable handling characteristic for anyone who prefers the neutral characteristic of a typical BMW. The stock iX feels under-powered and has a pronounced flat spot when shifting from 2nd to 3rd.
*In addition to more power at the top end, the modified `88 has significantly more mid-range torque than the stock `89. It is still nearly impossible to break the rear end loose, but this "4X4BMW" can be driven through turns like a traditional BMW. Transient handling is much more crisp than the stock iX. Power can be applied much earlier in the turns without worrying about running out of track on the outside. Surprisingly, it also exhibits less oversteer when lifting in a turn, perhaps because the stiffer front springs decrease the effect of forward weight transfer.
In stock form, the 325iX is a very
capable vehicle. Especially if the
car is not driven in a manner in
which the few quirks of the all wheel
drive detract from driving
enjoyment. For driving schools and
other demanding encounters of daily
driving, the modifications described
have proven to be very gratifying.
With these relatively simple changes,
the 325iX is truly a Bimmer for all
seasons. Weather or not!