friend just got an 86 325e, need help

[Aricjm15]

One of my friends just bought a 1986 325e, its a 5speed
I admit I know almost nothing about this car, he has asked me to help him modify it, make it alitte faster.

Where should I start and where can I find parts? Looking at it, it has a very small exhaust, I figure somthing about 2.5 inches all the way back would make for a nice gain, the throttle body is tiny, is there a larger one that would fit, or does sombody make one?

Help me out!

[MrM3]

Welcome Aricjm15.

the best thing you can do for that car would be a Conforti chip from Turner Motorsports (www.turnermotorsports.com). exhaust wise, try to find a complete exhaust, from the manifold to the cat, out of a stock e30 87-91 325i/is/ic, then look for a decent stainless steel cat-back system; either custom or a cheap bolt on using the stock 325i diameter dual pipes.

no matter what you decide to do, you should always keep in mind that the 325e was bmw's economy car, and the engine's head design was heavily restricted in favor of fuel economy. therefore, nothing short of a stroker rebuild or engine swap will make the car fast.

[Aricjm15]

thats what I was kindof afraid of when he showed me this thing

so most of the parts are interchangeable between the 325i and the e?
what years did they start changing bolt patterns on manifolds and such?
how big of a pain would a head swap be if they are that different between the I and the E?
what about a shorter shifter, when he let me drive it I fealt like I was rowing a boat

what about boring out the stock throttle body? would that help out much/any/shouldn't waist my time?

I am very thankfull for any help you can provide me with

[MrM3]

the 325e (2.7l) and 325i (2.5l) both use M20 engines. the e's were made from 84-88, and the i's were made from 87-91. you can put the 'i' head on the 'e' block, but your compression will go to crap; therefore, you will need custom pistons (unless you can find pistons out of a 88 325). and since you would need custom pistons you might aswell get them 1mm oversize and take the bore out to 85mm (stock is 84mm on both engines). this will result in a 2.8L high revving (~6800rpm), torque-y M20. to do the 'e' to 'i' conversion you will need almost everything from the 'i' engine including things like the intake manifold and the full exhaust. the 2.8L 'i' engine will be huge improvement from the 2.7l 'e' engine, but the cost of building a 2.8l M20 will be close or more than the cost of doing a M50 engine swap (2.5l I-6 from 92-95 E36's) which has 189hp stock and a 24v DOHC head.

there's more info on this if you do a search. the M50 is obviously the best for the most power, but the 'e' to 'i' swap can be done pretty cheaply if you find the 88 325 (Super eta) pistons and know what your doing.