Injectors... M20B25

[BLACKCHARM88]

How many pounds do stock injectors push in a 1988 325is...? The reason is because I am looking to upgrade, not vastly but a subtle power boost. I have heard Bosch Gen III's out of 2.5L Ford Contours and some Mustangs work. I am planning on a chip and cold air by the end of the year, thank-you.

[FLG]

Only upgrade worth while would be m50 4 Pintle injectors.

Wouldn't bother with a "cold air" intake as mostly it's sucking hot engine bay air, only box I would consider is Castro motorsports intake.

Also hit up sssquid for a chip. Mepeh for injectors



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[digger]

upgrading injectors alone will do nothing unless yours are not flowing what they are meant to because they are clogged, dirty etc in which case you could get them refurbished and any non new set will need the same treatment in anycase.

don't do it for "subtle power boost" reasons because that is not how it works.

[FLG]

M50 4 Pintle work well because the injector design is newer, also once the ecu relearns the injectors it would be the same as stock injectors, though probably better because chances are his stocks are dirty as hell. Either way the injector design is better and does a better job atomozing fuel.

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[BLACKCHARM88]

I'am prepared to do some fabrication to get an air box down and low. I have heard the M50 injectors are a little on the large side, also yes I do know other things are required to have larger injectors to work properly. Other things are going to be in the works as-well.

[nando]

the ECU doesn't learn the injectors. It does alter the closed loop long term trims to respond to the richer O2 readings, but it absolutely cannot tell that you changed the injectors.

BTW, there's a lot more to different injectors than just lb/hr. newer injectors tend to be faster than older injectors - the difference between M20 and M50 are pretty small, but take an injector from the last 5-10 years and it's much faster at opening/closing, which means it the slope of the injector curve is different and it will never run correctly in an old computer that's not retuned for it. also the slope of injector response depends on voltage input, which also probably doesn't match between newer and older injectors (injectors get much slower at lower voltages, older ones moreso).

[FLG]

the ECU doesn't learn the injectors. It does alter the closed loop long term trims to respond to the richer O2 readings, but it absolutely cannot tell that you changed the injectors.

BTW, there's a lot more to different injectors than just lb/hr. newer injectors tend to be faster than older injectors - the difference between M20 and M50 are pretty small, but take an injector from the last 5-10 years and it's much faster at opening/closing, which means it the slope of the injector curve is different and it will never run correctly in an old computer that's not retuned for it. also the slope of injector response depends on voltage input, which also probably doesn't match between newer and older injectors (injectors get much slower at lower voltages, older ones moreso).

Nando i didn't actually mean it knows you changed injectors, I meant it as it alters fuel table as it responds to the readings.

Also sssquid could easily supply a chip for the m50 injectors though I've ran them with a Turner chip and never had issues, can't say I noticed some vast hp improvement but the old injectors were dirty as hell.

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[digger]

M50 4 Pintle work well because the injector design is newer, also once the ecu relearns the injectors it would be the same as stock injectors, though probably better because chances are his stocks are dirty as hell. Either way the injector design is better and does a better job atomozing fuel.

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m50 units will also need to be refurbished chances are so you are out of pocket for the new injectors. id worry more about a proper tune than some minuscule differences in atomisation, money spent here is much more beneficial

[FLG]

m50 units will also need to be refurbished chances are so you are out of pocket for the new injectors. id worry more about a proper tune than some minuscule differences in atomisation, money spent here is much more beneficial

That's why i said to get them from mepeh on the forum. His refurb injectors are like 60$ or so. He redid my 50lb ones for me and many other members injectors. The cost of cleaning vs just buying injectors from him are worth the upgrade. And sssquid chips are reasonable and work very well.

Support the people that support the hobby.

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[BLACKCHARM88]

Yea mine could really use new injectors anyways, shes got 180k and she's sat for the last two years because I've been in other parts of the world. Thanks for the tips gentlemen.

[mpowerful]

Gen 3 > gen 2 (m50).

[BLACKCHARM88]

I'm not really caring about mpg's because it already gets 30mpg, I'm turning her into a track /DD set up. Plus she DOES NOT get driven in the winter (too low).

[cudamank]

I just changed to M50 rebuilt injectors from MEPEH this weekend. Car has 200K on her so im sure the originals were dirty at the minimum. Took her on a 400 mile roundtrip drive to the coast. MPG is up 3mpg, quicker response, smoother idle. Was well worth the $60.00. (Yes Im sure if I replaced them with 6 new M20 injectors it would have been the same. )