[Diy_efi] newbie questions (m)

[R P Davis]

I'm new to this board. I've been trolling for a few months now and
have learned a few things. But I still have questions. I am more of a
hobbyist trying to keep my car running and operating as inexpensively
as possible. My goal is to increase the fuel economy of my new to me
car.It is an 89 BMW 325iX w/215K miles inline 2.5 liter 6 cyl with
bosch motronic 1.3 (last 3# on ecu = 173). When I got it I could get
22mpg highway and I run premium fuel.

Is it someway possible to use a wide band O2 sensor in this
application? Will I need to have a new chip burned for the ecu? I
haven't searched the archives much but I did come across a 528e BMW
(2.8/2.7 liter inline 6 efficient engine, had it in my last 325e) that
someone had installed a wb02 into. I couldn't find anymore info other
than it was installed.

Any ideas? I can do basic soldering and wire maintenance. What will I
need to make this work? Also, would a MAF be useful as well? Anybody
have one that will work and is inexpensive? If not, I'll probably take
the AFM which is larger off the m30 BMW engine and swap the
electronics to make it work.
Right now I'm running a K&N panel filter, Amsoil 75w90 gear lube in
the front & rear, Amsoil ATF in the 5 speed transmission and in the
transfer case. Once I replace a leaky valve cover gasket and leaky
pressure relief on my oil cooler I'll convert the engine to Amsoil
10w30 motor oil and use a bypass filter to extend my drain to 25K
miles. I also installed an ignitions solution plasma booster (multiple
spark discharge device) and the car came with "high performance"
spiral wound ignition wires from Bavarian Autosport. Without
synthetics in the engine is getting 26mpg avg (80% highway, 20%
stop&go city).

Any recommendations on what I can do to get this car closer to 30 mpg
would be great. I plan on keeping the car for at least 100K miles
(3years or so with my driving habits). I've got 215/60-14 Cooper
Cobra's (only tire i could find in that size) tires on it right now
and my winter tire for Vermont is a 185/70-14" Nokian Hakka's. I know
tire size plays a big role in fuel efficiency so I try to keep them
with a small diameter.


Thanks,

~ryan