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RE: Supercharged M3

>>From: "william m driegert" <bdurgert@domain.elided>
Date: Wed, 21 Aug 96 05:19:27 UT
Subject: Supercharged M3

I've had the Dinan supercharger kit installed on my 95 3.0 L M3 for
about 2 
mos. now , and it has performed exceptionally. 341 hp is more than
adequate, 
but the speed bug has already bitten. I want more power, and I've got a
number 
of ideas and quite a few questions. <snip>
<<

First of all, wow. What more can I say? Anytime you want to trade
drives, let me know: I'll swap you seat time in PeeKay for ditto in your
blown M3. I can't even carry Dinan catalogs out to the garage, or PeeKay
starts to tremble all over, he wants a supercharger so bad. As they say
in Chermany, give them a finger, they want the whole arm...

Aside from all that, I thought I'd better do the obligatory raining on
your picnic. You're getting close to learning what race teams learn all
the time, which is that everything has to work together. I'd guess at
341 hp you've significantly exceeded the capabilities of the stock
brakes, for example, and the drivetrain must be seriously stressed.
Probably they can handle it for a reasonable period of time: Dinan
strikes me as careful not to exceed component capabilities. Start adding
more hp, which you can certainly do, and what happens? Weak links now
will be clutch and transmission. Upgrade them (to M5 components? Euro 96
M3 stuff?) and you'll overwhelm the driveshaft and differential
eventually. And so on. Also you'll be capable of driving the car up to
supersonic speeds on some tracks (assuming you do that stuff). Will your
brakes, suspension pieces, and aerodynamics handle the kind of pressures
super high speeds will put on it? Probably, but as speeds go up these
things go up exponentially. Remember that the 993 Twin Turbo produces
400 hp and Porsche largely reengineered the car to support that much
oomph. 

Another factor is the guy under the helmet. Significant amounts of power
can get you in significant trouble Real Quick Like. 

Of course, if all you want to do is run the parking lot grand prix, then
you can safely squirt nitro into your supercharger and none of what I
said will matter. But if you're going to use all that power at the local
racetrack, be advised: Sooner or later something will break, unless you
move the whole package along. Be careful it's not your neck...

All that said, if you really want to improve performance, skip adding
horsepower. You've got a good platform to work from. Start removing
weight. The only reason a Formula Ford can get around Laguna Seca faster
than your M3 is weight. There's lots of weight available for removing on
your M3; aluminum doors are one place. Seats are another Very Heavy Item
(particular on a M3 Lux) that can go. Good wheels can be very light. You
can get carbon fiber or fiberglass fenders, hood, trunk. You can buy
lighter batteries than stock. Removal of AC, cruise control, radio,
carpeting, etc can make the car lighter but less streetable. You'll see
the biggest handling gains from removing weight at the ends or that is
unsprung. If you can drop a couple of hundred pounds off the car you'll
really notice it.

Cheers,

John Browne
BMW ACA Puget Sound Chapter
BMW CCA
95 ///M3 LTW (PeeKay)
95 ///M3 (gone, alas!)
91 iX (Spunky the Brave Little Car)
96 Suburban 2500 (needs a name...)