Dyno Testing re: Chevy Wheels on BMW hubs re: E36 fuel economy.

["jkerouac@xxxxxxxxxxxxx" <jkerouac@xxxxxxxxxxxxx>]

re: Chevy Wheels on BMW Hubs

Several years ago Tire Rack sold off Camaro 16x8 wheels with 45 mm offset.
They fit on my E36 rear excellently.
On the E36 front, the minor inner ridge of the hub hole circle was about
2mm in diameter too small.
So a rotary file bit in a strong hand held drill drill turned round and
round  for a few minutes milled that down for a perfect front fit too.
     I found that these 16x8 wheels with 245/45x16 ries looked quite nice
in the wheel well and had no clearance problems.
     Btw old GM 4 bolt wheels fit the 4 bolt BMW hubs nicely too.  For
instance Vega GT rims on a 2002.
     Volkswagen bolt patterns are the same as BMW, however they ten to have
more offset then BMW in general so you may need spacers and longer lug
bolts.

re: E36 Fuel Economy and Dyno Testing
Best in my 97 //M3 was 30.6 mpg, with cruise set on 79, on a regular drive
from San Jose to Sacramento.  This included never stepping on the gas for
the whole trip.  This was with fresh Bosch Platinum plugs and Redline in
the engine.  Fuel was Chevron premium, the California only blend.  Air
temperature was in the eighties with low humidity.
     Typical for this run is high 28/low 29mpg with Mobil 1 5w30 grade and
some stepping on the gas along the way.  If I go out there and street race
my way up the mileage drops at worst to about 25.
     On a trip to Las Vegas and back, overall for a thousand miles at
80+mph when possible the economy was about 28mpg with fresh plugs and fresh
Mobil 1 5w30 in a loaded down car.
     For tire pressures I use 37 rear/41 front.

Dyno testing:
     I tend to develop my own setups rather than buying out of the box what
others $ay you $hould uSe.
     My exhaust is Supersprint. Intake box is stock with the air horn and
fresh air snout replaced with a 4 in to 6 inch rubber flexible plumbing
coupler.  When in place this flexes into a nice bananna shaped arc pressed
behind the headlight.  There is a 3 inch diameter 90 degree arced rubber
plumbing coupler from the fog light bracket hole up to just below the
opening of the snout.  Air filter is K&N.
     My ECU mapping is the final and most recent factory burn that
accompanies the crankshaft position sensor recall.  This final mapping is
virtually identical in power output what the major tuners sell.
     I say this because remember that dynomometer does not lie.
     On the dyno this setup tests equivalently with another E36//M3 that
had a Dinan carbon fiber $nout, Dinan $tage 2 computer burn, and Dinan
Exhau$t.
My dyno run gave 218 hp@6200rpm and 213 pounds of torque@4100rpm at the
rear wheels while the Dinan gave 221hp and 211 pounds of torque at the same
power peaks.  There was also a Dinan that had a Euro hfm for more air.
That gave 225 hp@6500rpm producing less pounds of torque.
     Several other E36 //M3 all made less power.  They tended to have
immitations of Dinan's snout and buzzbomb loud lower quality untuned
exhausts.  Those power curves had fluctuations up and down the power band
with peak power not about 210, only slightly above the baseline figures of
205 hp for a stock E36 //M3.
Food, and Fuel, for thought.
Enjoy all,
'jk

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