Re: Jim C chip

["John A. Virnig" <john@xxxxxxxxxxxxxxx>]

I don't have his chip (gotta wait to all the checks I'm writing for my
wedding clear) but I will in the not too distant future.  Lots of upsides,
very few negatives.

The negative is that you have to use 91 or higher octane gas.  BMW programs
conservatively for the 87 octane "Bob's Gas 'n' Go" that some people put in
their car.  Jim C. re-programs for 91+ octane fuel and uses more aggressive
timing, advance, etc. to create more horsepower and torque in the fat part
of the rev band.  There is also some misleading information out there - they
say you can increase you horsepower by 15 bhp.  You need to look at the
entire rev range and check for bhp increase at a given rpm.  In my case ('97
328is), there can be as much as 34 bhp difference between stock and Jim C.
at a certain rpm even though the it only bumps the max bhp by about 15.  See
what I'm saying here?  Peak hp isn't the whole story.

When you order the chip (through Turner or somebody reputable), make SURE
you tell them what other upgrades you've done to the car so the chip they
send you will use those parameters instead of the stock ones.  I've heard
that they will make custom chips for people in many cases.  Bonneville
Motorworks is the place that has all this info.  Call or email them for
specifics.

John Virnig
'97 328is

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