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**Austrianvespaguy** · 05-19-2022, 04:27 PM

No, but you can make an educated guess and then verify that you're at least 'close' with experimentation. Being so small they probably are on the shorter-than-normal for dead time, so I'd hazard a guess at a starting point of 0.8ms rather than the standard 1.0ms @12v. To check, get your car warmed up and take a datalog holding the RPM at a slightly-elevated, consistent 2000 RPM, and see what your steady-state AFR is at this point. Then, just either double or halve the number of squirts/cycle and repeat the experiment. If your dead time is set lower than it really is, you'll get less fuel than anticipated, and AFR will go leaner with increasing squirts. If it's set too high, you'll get more fuel than calculated and go rich with more squirts.

**E30Bastard** · 05-20-2022, 07:19 AM

I appreciate that. I think I have tuned with a bad M50 injector, maybe more than one. Have had nothing but a bad experience with these “rebuilt and flow tested” M50s (this is my second set, swapped out the first set due to unknown leaking injector/injectors causing a really bad hard start).

Right now it only idles happily when set ridiculously more rich than the tune it originally ran well with. And my VE table looks insane lol. I am an amateur at this, so not sure what else would be the culprit.

So these new Bosch M20 replacement injectors pretty much cancel out the whole reason of upgrading to M50s in the first place, they have a four spray pattern for better atomization and they one up by going to modern design and removing the pintle.They also operate at the expected parameters due to getting 3 bar vs the required 3.5 for the M50s (I had to tell MS2 these were 152cc injectors to get it running ok).

**E30Bastard** · 05-20-2022, 07:23 AM

Should be noted that Bosch also makes updated versions of the M50 but they are sold out. Saw one set on ebay for 350 haha

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Bosch 0280156346 Injector Specs

Bosch 0280156346 Injector Specs

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