New 1990 325i - BMW Forum

Free Delinquency · 06-19-2005, 04:52 AM

I just bought this from a friend for 1500
160000 miles
1990 bmw 325i
It has an H&R suspension kit, exhaust, 3" clearance, Performance chip and 190hp.
I just sold my 2001 corolla s and i have $7000 left.

My friend recommended that I get the engine bored to a 3.3 liter and get a supercharger. I was also considering getting new headers, cams, coney yellow shocks, and raising the car up half an inch. I might also want to get an M3 transmission off ebay, because when i drop from 4th to 3rd i have to double clutch and match my rpm to the speed of the car. I think the transmission is starting to go bad.

I don't really know all that much about cars, so if you guys could give me some suggestions it would be greatly apprecaited.

nukeduster · 06-19-2005, 02:30 PM

you cant bore the m20b25 to 3.3L.

the max you can overbore the engine is .5mm recommended by bmw at least.. biggest conversion kit ive ever seen is 3.0L stroker kit which uses a modified s50 crank and custom pistons. Ive heard of people getting to 3.1L using m40 or m42 pistons but its just heresay and no one has yet to do it.

you arent going to be able to stroker and supercharge your engine for 7k unless you do all the labor yourself. its probably going to be one, or the other.

considering it has performance mods it was probably driven hard.. might as well go stroker since that way you at least know you basically have a new motor in the vehicle.

egk2 · 06-19-2005, 07:57 PM

Might want to take care of all the maintenance stuff first especially the timing belt,
then plan out the performance mods.

Free Delinquency · 06-22-2005, 12:56 PM

Ill have a shop look at it to see if the engine can be bored to a 3L. Do they even make superchargers for the e30?

Any idea of how much it will cost to bore the engine out?

Thanks for the help!

MrM3 · 06-22-2005, 06:36 PM

Welcome to the forums,

like nukeduster said, it isnt recommended that you overbore more than .5mm (which would result in about a .5L increase, i think), but 3.0L is achieveable with a modified s50 crank from ireland engineering. i think you should do more research to decide if you even want to stick with the m20

egk2 · 06-22-2005, 06:38 PM

Korman, Metric Mechanic and Ireland Engineering offer 2.8, 2.9, 3.0 stroker setups for the e30.
The m20 motor responds better to a turbo setup although SEAMBMW has an eaton supercharger project car in the works.