So I recently picked up a pre change 87 325i. It came with ie headers, 2.5 exhaust, and needing a top end rebuild. Since I have it apart I thought I would throw some money at it. Besides 4hole injectors is there any other mechanical upgrades I should invest in?
I have never heard of "4-hole injectors" being an upgrade for the M20 engine. Stock BMW injectors can handle an additional 20-25% power upgrade, and personally, I'd recommend sending your stock set off to RC Injection in California, for complete testing, ultrasonic cleaning, refurbishing, and re-testing. with precise printed results of before and after. Cost: $25 per injector - the best bargain in the automotive world.
Tweaks? Best one will be a good Schrick camshaft. Depending on mileage, a bottom-end refurbish might be in order. If you can't see good crosshatching, or it's gone on one side of the bores, maybe pistons and rings and overbore; otherwise, maybe just a quick hone and a new set of rings.
You can, of course, do a full on stroker, up to 3.2 liters, if you want serious power increases. See Ireland Engineering for these kits.
Whatever else you do, or don't do, make sure to replace the complete timing belt kit (with Continental!), and the water pump, thermostat, hoses, expansion tank and radiator.
Nice car - Best of Luck!
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
hey, thanks for responding again. you seem to know your motors. from what i have seen so far it seems like this car really has less than 40k on it. no wear and lots of neglect, so the bottom is almost new.
i am not into serious power. i have an full 2jz gte in storage, if i want power i can just swap it. i bought a 325i because it is a great "package" car. Good motor and handling and just fun. cams might be good. i will do some reading.
the "4 hole injectors" refers to bosh gen 3 injectors, like from a ford. matched sets go for about $45. not sure if it will boost power, but should make it run smother and give a slight boost to mpg without a major remap. check out the vid, it makes the difference obvious. Thanks for the suggestion for a cleaner though.
https://youtu.be/VfynoxL2RZI
i am still working on the top end. parts problems. tried a few different suppliers, i am on pelican parts now. they at least shipped on time and knew that i needed a 2 port water pump without me telling them.
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