M30b34

Specific conversations and info for the BMW E28 M5 and M535i.
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Adioprisan
Posts: 3
Joined: Nov 18, 2023 12:29 AM
Location: Romania

M30b34

Post by Adioprisan »

Hi,guys,my engine is m30b34,1992 ,i have following mods:turbo,modified intake with 100 MM throttle,m50 nv ecu and wiring,trigger wheel is stock,cars start very hard,and when IT starts i have flames in intake ,ireggular idle,not rev,Something is wrong with the timing,anybody knows how many advance degree stock has this kind of motor,or somebody put a m50 ecu wiring,sensors swapp in m30 engine?at idle ,my diagnostics show 3,4 degree timing
turbodan
Posts: 9177
Joined: Jan 09, 2007 10:19 PM

Re: M30b34

Post by turbodan »

The trigger angle offset is completely different on the M50. The M20 and M30 are around 87 degrees BTDC, the M50 uses 324 degrees. I wonder if something has been done to address this.

At idle it should be happy with 15-20 degrees of advance.
Adioprisan
Posts: 3
Joined: Nov 18, 2023 12:29 AM
Location: Romania

Re: M30b34

Post by Adioprisan »

Thanks,and because of this diference,i must change the position of cranshaft sensor,to meet the specifications of m30 trigger angle?
Adioprisan
Posts: 3
Joined: Nov 18, 2023 12:29 AM
Location: Romania

Re: M30b34

Post by Adioprisan »

Or leave the sensor to original position And just find somebody to change the trigger angle offset in m50 ecu,If IT can be done?thanks
turbodan
Posts: 9177
Joined: Jan 09, 2007 10:19 PM

Re: M30b34

Post by turbodan »

I think the best solution would be to re-clock the harmonic balancer to locate the trigger point in the correct position for TDC on the M50. Problem is that the M30 uses an eight bolt pattern for the harmonic balancer, so you can only rotate by intervals of 45 degrees using the original bolt holes. You will end up either ahead or behind the desired trigger angle by 12 or 33 degrees. Option number two is much more involved but if you were to pull the crank hub off you could cut a new keyway and get the trigger angle anywhere you want.

Again, I don't know what has been done to this conversion in terms of software or tuning. If this trigger angle issue has been addressed then your problem lies elsewhere. If they attempted to address this in the manner I have described but ended up off by 12 or 33 degrees, that could still be your issue.

I'd say pull that crank pulley off, take a look and see what's going on there.

If you can find someone who can change the trigger angle setting in the M50 DME, that's a great fix as well. I don't know if anybody knows how to do that, but it might be possible.
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