RE: <E30>How do I get big hp gains?

["Derek van Veen" <derek@xxxxxxxxxxxxxx>]

Mark wrote:

> I have an 87 325is.  I understand all of the bolt on performance
> improvements I can make to the car.  But I am interested in bigger hp
> gains on top of that.  What can I do to the engine itself?  Can I bore
> and/or stroke it?  If so, How far can I go with that and what are the
> recommended replacement parts?  Can an e30 engine be taken to
> say around
> 240-250 hp without the expense of adding things like performance
> aftermarket throttle bodies, intake manifolds, etc?
>
> Can someone direct me to a comprehensive web site that describes hp
> gains vs. cost for the e30?

There are all sorts of things you can do.  Korman (http://www.korman.com)
sells cams, turbo systems, exhausts, complete 2.7L 'i' motors, etc. for the
E30.  The 2.7L Turbo 'i' motor is good for about 240hp and 260lb/ft of
torque.  Metric Mechanic (http://www.metricmechanic.com) builds a really
nice 2.9L motor for the 325i that is (very) conservatively rated for about
200hp / 210lb/ft of torque without any other goodies (aggressive cams, JimC
chips, larger throttle bodies, custom exhausts, etc.).  However, you are
looking at about $5000 for the Metric Mechanic motor and god-only-knows how
much for the Korman 2.7L Turbo.  You can only do so much to the motor before
adding aftermarket throttle bodies, intake manifolds, etc.  You need either
displacement (there is no substitute for cubic inches), forced induction
*OR* a really high rev limit (remember, HP = (Torque x RPM)/5252 and
therefore the faster you spin the motor, the more HP you can
achieve--although at the expense of drivability).

Good luck!

- -Derek
 '90 325is

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