re: 318 questions

[Ron Katona <ron3b@xxxxxxxx>]

Don Cicchetti wrote:
> Has anyone here changed the exhaust and intake around on a 4-cylinder 318i
> or ti?

Yes, many have. The big question is what year is your car? The Pre
OBD-II (1991-1995) M42 can gain a few HP from these mods. Don't expect
more than about 5 hp on a good day. The usual K&N cone setup (with heat
shield or ducting) and a Supersprint or Triflo cat-back system works
fine.

OBD-II M44 cars won't get much of anything from the exhaust side. In
fact, they usually lose some very precious torque on the dyno sheets
I've seen from friend's cars. The Supersprint sounds great! Just don't
fool yourself about power gains.

The stock intake on the '97+ cars sucks. You can get a few HP there just
from a K&N drop-in, some dryer tubing, and a pair of tin snips. Simply
remove all the stock tubing over the radiator and route the intake to
the area behind the driver's side headlights like God intended. You can
also gut the baffles and sound deadening from inside the airbox.

> I have heard that the injectors on these motors are close to maxed out, and
> if you make things flow better, either intake, exhaust, or both, or even
> put a chip in, you can get to an overly-lean mixture condition pretty
> quickly at high-rpms.
> 
> Is this true?

I don't know the exact flow rates and HP capabilities of the injectors;
maybe Jim C. can comment. The RD Sport cam and chip package for the M42
(soon to have one for the M44) is advertised at 168 hp and uses the
stock injectors. I'd guess that's pretty close to maxed out or the
forced induction kits available for the car that advertise 180+ hp
wouldn't have to go to secondary FPRs to get enough fuel flow. I
wouldn't worry at all about running lean with a stock motor and just
intake/exhaust/chip mods though. You won't come close to 168 hp from
those mods.

> If so, is there an injector upgrade?

Yes. Unfortunately, you have to buy six of them and they only come
attached to E36 M3 motors. The good news is that it's a straight bolt
in! ;-)
- -- 
Ron Katona

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