M50 injectors
Moderator: martauto
-
chopper
- E30 Zone Regular

- Posts: 478
- Joined: Sat Nov 28, 2009 11:00 pm
Hi just bought some m50 injectors as I'm told they have a better spray pattern, and ideal for an m20b25? Will I need to buy a mild/wild chip to use with these injectors or arEe just play and play?
-
Grrrmachine
- E30 Zone Wiki / Team Member

- Posts: 8043
- Joined: Sat Feb 09, 2008 11:00 pm
- Location: Warsaw, Poland
For a start, you need to ascertain which injectors you have. M50B20 injectors are different to M50B25 injectors; look for a part number.
Whatever you have, you will have to modify your ECU to take advantage of the increased fuelling; Speedtouch may sell special chips for this, but his standard Wild and Mild chips are designed for standard, not modified engines AFAIK. To properly benefit, you will need a remap.
Either way, these injectors are less than ideal. If you search, you'll see most people recommend having your original injectors repaired rather than fitting different ones.
http://www.e30zone.net/e30zonewiki/inde ... #Injectors
Whatever you have, you will have to modify your ECU to take advantage of the increased fuelling; Speedtouch may sell special chips for this, but his standard Wild and Mild chips are designed for standard, not modified engines AFAIK. To properly benefit, you will need a remap.
Either way, these injectors are less than ideal. If you search, you'll see most people recommend having your original injectors repaired rather than fitting different ones.
http://www.e30zone.net/e30zonewiki/inde ... #Injectors
'89 325i Touring | Touring Resto Thread | In-Dash Screen install
-
e301988325i
- E30 Zone Addict

- Posts: 3701
- Joined: Fri Feb 01, 2008 11:00 pm
- Location: Taunton, Somerset
If you fit them your engine will overfuel, you can just about get away with fitting them if you have a lambda fitted so the ECU can adjust the fuel maps, but don't expect it to start well or easily.
Fitting bigger injectors is usually done in time with a significant engine tuning package, i.e. work done to each part of the physical engine plus revised management.
It is posible to fit an M30 AFM and injectors to the M20 although again this is not worthwhile unless the rest of the engine has been played with.
Fitting bigger injectors is usually done in time with a significant engine tuning package, i.e. work done to each part of the physical engine plus revised management.
It is posible to fit an M30 AFM and injectors to the M20 although again this is not worthwhile unless the rest of the engine has been played with.
I said:
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
-
blue30
- E30 Zone Regular

- Posts: 354
- Joined: Wed Jan 09, 2008 11:00 pm
- Location: Stoke on Trent
I think the m50b20 injectors are 160cc/min vs 150 cc/min for the m20b25 injectors so ideally you'd want to lean out just a touch, I would imagine getting the CO set after changing them would get you close enough.
There is more to injectors than just flow rate but I say give it a go and see what it's like! You can always bang the old ones back in if it's shit.
There is more to injectors than just flow rate but I say give it a go and see what it's like! You can always bang the old ones back in if it's shit.
-
Grrrmachine
- E30 Zone Wiki / Team Member

- Posts: 8043
- Joined: Sat Feb 09, 2008 11:00 pm
- Location: Warsaw, Poland
and replace the ECU due to burning it out from using injectors with the wrong impedance...blue30 wrote:There is more to injectors than just flow rate but I say give it a go and see what it's like! You can always bang the old ones back in if it's shit.
'89 325i Touring | Touring Resto Thread | In-Dash Screen install
-
blue30
- E30 Zone Regular

- Posts: 354
- Joined: Wed Jan 09, 2008 11:00 pm
- Location: Stoke on Trent
Erm, they're both high impedence so unless the new injectors you install are on fire at the time they're not going to burn anything out.Grrrmachine wrote:and replace the ECU due to burning it out from using injectors with the wrong impedance...blue30 wrote:There is more to injectors than just flow rate but I say give it a go and see what it's like! You can always bang the old ones back in if it's shit.
-
chopper
- E30 Zone Regular

- Posts: 478
- Joined: Sat Nov 28, 2009 11:00 pm
Thanks for the help guys I'll try them first and see what it runs like, but don't wanna burn anything out. 
-
Ant
- Retired Team Member

- Posts: 10496
- Joined: Tue Dec 21, 2004 11:00 pm
- Location: PD+E dept :D
M50/52 injectors are designed to mist into the intake and split their flow between two intake runners.
M20 shoots a single shot onto the back of the inlet valve, cooling it in the process and getting vapourised ready for combustion as a bonus.
A clear case of horses for courses ??
M20 injectors are noisy because they are old and run almost flat out for the capacity of the engine hence ticky tick tick
Never "upgrade" to higher flow rates unless you can scale the fuelling to suit
As mentioned , a closed loop setup with the appropriate mapping could adjust for the higher flow, but given the resolution of the NB02 circa 5% at idle and pert throttle would be the max I'd suggest, no gains there.......
The above are the facts, now for the opinion....... Dont Waste your Time and £££££ dude

M20 shoots a single shot onto the back of the inlet valve, cooling it in the process and getting vapourised ready for combustion as a bonus.
A clear case of horses for courses ??
M20 injectors are noisy because they are old and run almost flat out for the capacity of the engine hence ticky tick tick
Never "upgrade" to higher flow rates unless you can scale the fuelling to suit
As mentioned , a closed loop setup with the appropriate mapping could adjust for the higher flow, but given the resolution of the NB02 circa 5% at idle and pert throttle would be the max I'd suggest, no gains there.......
The above are the facts, now for the opinion....... Dont Waste your Time and £££££ dude
Product Development and Endurance for Delphi.
Original performance chips, original works not unlicensed copies
Email FTW
Original performance chips, original works not unlicensed copies
-
chopper
- E30 Zone Regular

- Posts: 478
- Joined: Sat Nov 28, 2009 11:00 pm
Yea pretty pointless then, may just get my m20 ones refurbed by injector tune.. Has anyone had this done?? And is there another places that offer this service?
-
e301988325i
- E30 Zone Addict

- Posts: 3701
- Joined: Fri Feb 01, 2008 11:00 pm
- Location: Taunton, Somerset
Ant, that does make sense, I guess there must be a flow limit for a single hole injector as the M30 runs 4 hole injectors.Ant wrote:M20 shoots a single shot onto the back of the inlet valve, cooling it in the process and getting vapourised ready for combustion as a bonus.
Of interest for everyone I think.

I said:
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
-
Ant
- Retired Team Member

- Posts: 10496
- Joined: Tue Dec 21, 2004 11:00 pm
- Location: PD+E dept :D
M30 with Lucas runs a 3 or 4 hole pintle iirc
M30 with bosch have the single shot setup, most are Lucas though, random....
M30 with bosch have the single shot setup, most are Lucas though, random....
Product Development and Endurance for Delphi.
Original performance chips, original works not unlicensed copies
Email FTW
Original performance chips, original works not unlicensed copies
