Would you recommend fuel injectors for my BMW? 19# ?

[bissellh]

It is time to replace the fuel injectors in my 1992 BMW 525i E34 M50 2,5L non vanos? One has a tip broken in half. Many fins are broken off too. The only engine enhancements I have is a Dinan performance chip, a K&N replacement filter and a lower coolant temperature switch.

I currently have stock Bosch part # 0-280-150-415 fuel injectors that flow at 18.10# at 3.5 bars (50.75 PSI) fuel pressure.

I have heard about the low cost, better spray pattern, better gas mileage and perhaps improved performance of 19# Mustang fuel injectors with Bosch part # 0-280-150-943. I also like these because they do not have the fins that break off. These are rated at 18.25# at 3.0 bars (43.50 PSI) which is real close to the 18.10# in my stock injectors. The problem is that they would flow at 19.71# with the extra half bar of fuel pressure in my engine.

I am concerned that this is too rich for my engine. The difference in the flow rates is 1.46# and do not know if this is a lot or a little. I heard that the engine computer will adjust for the richer spray at idle. I do not know how the richer mix would affect acceleration. I am a novice and really do not know what I am doing.

One thought is to use in a 3 bar fuel pressure regulator with the 19# Mustang injectors. Another thought is to use Mustang injectors that flow at 16.75# at 3 bar because they would flow at 18.09# at 3.5 bar. That is also real close the the 18.10# in my stock injectors. I don't know if those kind of injectors even exist.

Any ideas or experiences , including sources to purchase from and web sites to reference, that could help me would be greatly appreciated.

NOTE: I pulled these figures from Stan Weiss' Electronic Fuel Injector (EFI) Flow Data Table at http://users.erols.com/srweiss/tableifc.htm#BOSCH and I did the flow conversion for varying fuel pressure at http://users.erols.com/srweiss/calcpchg.htm

[winfred]

the fins you speak of are just part of the replaceable heat shields, i am not sure how mustang sticks perform in a m50, id stick with the correct injectors as i think they have a specific spray pattern for the intake port, if you live in or near a big city theres probably a place that can rebuild and check your injectors for less or about the same as some mustang's off ebay, diesel repair shops usually do it or would know where

[ricksaia]

I put them in 635CSI and what an improvement. Smoother idle, great gas mileage and good pull from power. I do not know how they would work in a 2.5l motor. Good luck,
Rick

[winfred]

they work about perfect in a m30, a little big but they work in a m20, just not sure if they are ideal in a m50


I put them in 635CSI and what an improvement. Smoother idle, great gas mileage and good pull from power. I do not know how they would work in a 2.5l motor. Good luck,
Rick

[BillionPa]

Bosch 0280150415
6/Set $254.60
plus $90 refundable core chg.

http://www.fiveomotorsport.com/Injector_SetsBMW.asp

[bissellh]

the fins you speak of are just part of the replaceable heat shields, i am not sure how mustang sticks perform in a m50, id stick with the correct injectors as i think they have a specific spray pattern for the intake port, if you live in or near a big city theres probably a place that can rebuild and check your injectors for less or about the same as some mustang's off ebay, diesel repair shops usually do it or would know where

I know the fins are part of the replaceable tip. Do you have any resources you can direct me to regarding the spray pattern matching up with the intake port that you threw out there? I know I can rebuild my injectors or return them as a core for reconditioned. Do you have any specific recommendations, experiences or resources regarding using Ford Mustang injectors and perhaps a different fuel pressure regulator in an M50 engine?

[bissellh]

I put them in 635CSI and what an improvement. Smoother idle, great gas mileage and good pull from power. I do not know how they would work in a 2.5l motor. Good luck,
Rick

What is the Bosch part # for the original stock injectors in your engine and for the Ford Mustang injectors that you replaced them with? I want to compare the flow and fuel pressure ratings?

[bissellh]

they work about perfect in a m30, a little big but they work in a m20, just not sure if they are ideal in a m50

What is the Bosch part # for the original stock injectors in the M30 and M20 they work in so well and for the Ford Mustang injectors that you replaced them with? I want to compare the flow and fuel pressure ratings?

[bissellh]

Bosch 0280150415
6/Set $254.60
plus $90 refundable core chg.

http://www.fiveomotorsport.com/Injector_SetsBMW.asp

Thanks for the information. Do you have any specific recommendations, experiences or resources regarding using Ford Mustang injectors and perhaps a different fuel pressure regulator in an M50 engine?

[Bill R.]

Evidently you edited the post about threw out there, regarding the injection angles and ports. Meanwhile i was converting that info to something i could post. Here it is. I'm not certain if you still want it since you changed it.





Thanks for the information. Do you have any specific recommendations, experiences or resources regarding using Ford Mustang injectors and perhaps a different fuel pressure regulator in an M50 engine?

[bissellh]

Evidently you edited the post about threw out there, regarding the injection angles and ports. Meanwhile i was converting that info to something i could post. Here it is. I'm not certain if you still want it since you changed it.

Hi Bill -

I want use Ford Mustang fuel injectors instead of stock ones in my M50 engine because of reported mileage and HP gains using them in M30 engines and becuase they are more readily available and less expensive. I am not knowledgable about engines and do not know all the factors to consider in making a determination to use these in my engine or not. That is why I started the thread. I want to know if I can use them in my engine AND I want to know why.

One factor to consider is flow rate because you do not want your engine running or rich or too lean. According to Stan Weiss' web site table the Ford Mustang injectors with Bosch part # 0-280-150-943 flow at 18.25# @ 3 bars. The flow rate would be 19.71# @ 3.5 bars that my engine has.

I do not know if my engine could handle that increase in fuel flow with just a performance chip, a K&N replacement filter and a low coolant temperature switch. My guess is not because richer fuel flow is for engines with major mods like bigger bores and pistons. Do you know if my engine could handle the richer fuel flow?

If not, I could potentially use a 3.0 bar instead of 3.5 bar fuel pressure regulator in conjunction with the Ford Mustang fuel injectors. Like I said, I do not know much about engines and I do not know if adjusting the fuel pressure in my engine a half bar lower would affect performance. Do you know if I can do this without affecting my engine performance?

Perhaps there are other factors to consider?!?!?!? Can you think of any factors that I am not aware of that would prevent me from using the Ford Mustang injectors?

I have heard the intake port in the M50 is so much different from the M30 that it is not practical. Can you confirm or deny this?

Thanks for the additional information. I am a novice and do not have much experience with engines. I am not sure if the table you provided is helpful to me because I do not understand it.

I am new to this forum. I wrote on it for the first time today. I did not edit any posts; I only started this thread and replied to reponses by adding posts to the thread. Perhaps we are talking about the same thing?!?!?!

- Henry

[Robin-535im]

One factor to consider is flow rate because you do not want your engine running or rich or too lean. According to Stan Weiss' web site table the Ford Mustang injectors with Bosch part # 0-280-150-943 flow at 18.25# @ 3 bars. The flow rate would be 19.71# @ 3.5 bars that my engine has.

- Henry
Henry - the engine controller will tune the pulse time to get the mixture to the right ratio, so as long as you get close with the rating it will run at the correct mixture.

As to the spray pattern or angle I have no clue whatsoever...

HTH

[bissellh]

Henry - the engine controller will tune the pulse time to get the mixture to the right ratio, so as long as you get close with the rating it will run at the correct mixture.

As to the spray pattern or angle I have no clue whatsoever...

HTH

Hi Robin -

My stock injectors flow at 18.10# at 3.5 bars. The Ford Mustang injectors would flow at 19.71# at 3.5 bars. Do you think that is close enough for my ECU to adjust too? Will only adjust at idle or will it adjust throughout the RPM range under varying acceleration and load?

As for the spray pattern and spray angle, Bill sent me a reply entitled "Evidently you edited the post..." that has a table showing the spray angle on my stock injectors to be 20 degrees instead of the 30 degrees on the other BMW engines and presumably the Ford Mustang injectors too. I do not know if this a show stopper for me in using the Ford Mustang Injectors. I am waiting for Bill to get back to me.

- Henry

[Jon K]

Really wouldn't upgrade the fuel injectors in an M50 - its a much more modern fuel injection system than M20/M30 and I am not sure how it would respond. If you had a chip to utilize the fuel correctly then sure, but basically you're just going to richen your mixture across the board. The only engines you run richer are forced induction engines. Engines with work, like bigger bore pistons or stroked rods are still NA engines and you still want to hig 13.0:1 AFR for peak power.

My M50 has 42# injectors but also has more air than yours is seeing.

[bissellh]

Really wouldn't upgrade the fuel injectors in an M50 - its a much more modern fuel injection system than M20/M30 and I am not sure how it would respond. If you had a chip to utilize the fuel correctly then sure, but basically you're just going to richen your mixture across the board. The only engines you run richer are forced induction engines. Engines with work, like bigger bore pistons or stroked rods are still NA engines and you still want to hig 13.0:1 AFR for peak power.

My M50 has 42# injectors but also has more air than yours is seeing.

Hi Jon -

Thanks for your reply! Someone in an earlier reply said the ECU will adjust the fuel spray pulse width so that it would not run too richly. Do you agree with that? Another thought I had is to change the fuel pressure regulator to a 3.0 bar regulator so that the flow rate is the same as the stock injectors with the 3.5 bar regulator. Do you know if that would work for me if I am hell bent on using the Ford Mustang injectors? To me knowledge the ECU does not have knowlwdge of the fuel pressure and it woud not throw off the program?!?!? Another concern is that the stock injectors spray fuel at a 20 degree angle while most other BMW injectors and probably the Ford Mustang injectors spray fuel at a 30 degree angle. Do you know if this would affect performance and or engine longevity?

pulse to

[winfred]

if you absolutely gotta have em the best way would be to just install them and leave the 3.5 bar regulator alone, the computer will cope with the excess fuel by backing down the pulse width slightly, they may or may not improve the running/power of the car, most of the gain would be due to new vs old injectors. i had 19#ers in my 535 and have them in my 325 they work great in the 535 and ok in the 325, not sure how hot they would be in a m50 but you seem hell bent to have stang sticks and they shouldn't do any damage so have at it

[bissellh]

if you absolutely gotta have em the best way would be to just install them and leave the 3.5 bar regulator alone, the computer will cope with the excess fuel by backing down the pulse width slightly, they may or may not improve the running/power of the car, most of the gain would be due to new vs old injectors. i had 19#ers in my 535 and have them in my 325 they work great in the 535 and ok in the 325, not sure how hot they would be in a m50 but you seem hell bent to have stang sticks and they shouldn't do any damage so have at it

You recommend against putting in a 3 bar fuel pressure regulator. Is that because it would throw off the ECU and the performace of the engine? Or do you just figure it is extra work since the ECU will adjust for it anyway by reducing the fuel spray pulse width? To be honest I would rather not wait on my computer to readjust after each time I disconnect the battery to work on my car.

The other concern I have is the difference in the spray angle. It is 20 degrees in my stock injectors, but it is 30 degrees in most other BMW injectors and probably in the Ford Mustnag injectors. Does anyone know if it will make a difference or is it really trial and error?

[Jon K]

You recommend against putting in a 3 bar fuel pressure regulator. Is that because it would throw off the ECU and the performace of the engine? Or do you just figure it is extra work since the ECU will adjust for it anyway by reducing the fuel spray pulse width? To be honest I would rather not wait on my computer to readjust after each time I disconnect the battery to work on my car.

The other concern I have is the difference in the spray angle. It is 20 degrees in my stock injectors, but it is 30 degrees in most other BMW injectors and probably in the Ford Mustnag injectors. Does anyone know if it will make a difference or is it really trial and error?

17# vs 19# isnt that big of a difference. As far as spray pattern, I am running 440cc (42# hr) Ford SVT Cobra fuel injectors (Bosch part numbers) with no ill-effect. However, I am also controlling my fuel on a standalone computer. The 19# are not that much larger - I do not know what the threshold of pulse width control is for the motronic ECU so I dunno if the 19# can be pulled back to be proper, but it's worth a shot I suppose.

[Robin-535im]

if you absolutely gotta have em the best way would be to just install them and leave the 3.5 bar regulator alone, the computer will cope with the excess fuel by backing down the pulse width slightly...
Yeah - what he said... :)

The ECU will make the mixture right for all the RPM/Load points you hit, it stores a trim map to make the fuel pulse just right for emissions under idle and mid-throttle, and just right for power at wide-open-throttle. Definitely want more psi rather than less.

[Bill R.]

weren't just sitting around tossing dice to determine what angle to make the fuel injector pattern on the m50, same with choosing 3.5 bars over 3.0 for pressure. If you look at the angle that the injectors mount in the port as well as the port size and valve location, you may be able to determine why they chose 20 over 30. I'm guessing that the injector they use has a slightly smaller orifice and they are running it at slightly higher pressure to try to atomize the fuel even finer and the angle is kept narrow to avoid spraying mist on the port walls themselves since that does no good and hurts rather than helps the performance/economy/power/emissions of an engine. Next point the fuel injection will not compensate during wide open throttle, it goes to the predetermined map during wide open so if you have too big of injectors it will be too rich. This is to the best of my knowledge. Anybody want to correct me on this or show me data to indicate otherwise.?






You recommend against putting in a 3 bar fuel pressure regulator. Is that because it would throw off the ECU and the performace of the engine? Or do you just figure it is extra work since the ECU will adjust for it anyway by reducing the fuel spray pulse width? To be honest I would rather not wait on my computer to readjust after each time I disconnect the battery to work on my car.

The other concern I have is the difference in the spray angle. It is 20 degrees in my stock injectors, but it is 30 degrees in most other BMW injectors and probably in the Ford Mustnag injectors. Does anyone know if it will make a difference or is it really trial and error?

[Robin-535im]

Next point the fuel injection will not compensate during wide open throttle, it goes to the predetermined map during wide open so if you have too big of injectors it will be too rich. This is to the best of my knowledge. Anybody want to correct me on this or show me data to indicate otherwise.?
Be interesting to have that documentation for sure Bill.

Mark D. mentioned a while back that the WOT map was the mid range map plus ~10% fuel... which is confirmed by the motronic documentation I've seen. Now is the trim map included in that? I always thought it was but it's possible these same non-dice-rolling engineers only designed max power for cars operating as spec'd from the factory, i.e., the WOT map never adjusted to the health of the car. Safe assumption if the expected deviations are small, but implementation-wise it's not any more effort to use the lambda trim map instead of the base map.

Conflicting messages in the images below: 1) "controls" the lambda to 0.9... but these are not WBO2 sensors so you probably can't close the loop about the 0.9 operating point. 2)"a particular operating point has no influence on determining other operating points" literally the trim map is not smoothed or interpolated, but does that mean the WOT map is not influenced by the mid-throttle map?

I bet Mark *could* answer with certainty, but would it be giving away a trade secret? :)

[ryan roopnarine]

Anybody want to correct me on this or show me data to indicate otherwise.?


hahahahaha, lolercoaster.

[Bill R.]

the m50 motronic 3x series.




Be interesting to have that documentation for sure Bill.

Mark D. mentioned a while back that the WOT map was the mid range map plus ~10% fuel... which is confirmed by the motronic documentation I've seen. Now is the trim map included in that? I always thought it was but it's possible these same non-dice-rolling engineers only designed max power for cars operating as spec'd from the factory, i.e., the WOT map never adjusted to the health of the car. Safe assumption if the expected deviations are small, but implementation-wise it's not any more effort to use the lambda trim map instead of the base map.

Conflicting messages in the images below: 1) "controls" the lambda to 0.9... but these are not WBO2 sensors so you probably can't close the loop about the 0.9 operating point. 2)"a particular operating point has no influence on determining other operating points" literally the trim map is not smoothed or interpolated, but does that mean the WOT map is not influenced by the mid-throttle map?

I bet Mark *could* answer with certainty, but would it be giving away a trade secret? :)

[bill g]

I have experimented with minor changes to AFM spring and wiper settings. I recall that Mark D. said in a previous post that WOT mixture is also trimmed. However I cannot find anything confirming (or denying) this in the Bosch Motronic Tech instruction or Probst book.
In an attempt to richen the WOT throttle mixture I set the AFM wiper arm back slightly (to lean) on the assumption that after some weeks of driving around the computer would adapt and trim the mixture correct and would apply a corresponding correction to WOT ie richen it. The O2 sensor output at WOT before this adjustment was in the range 0.85 to 0.90v, and after adjustment it is 0.81 to 0.83v. This suggests to me that there is no trim applied at WOT.

Bill G Melbourne Aust

[bissellh]

Thank you everyone for your responses. It seems to me that there is some contention about using Mustang injectors in my M50 engine. I decided to rebuild mine with new o-rings, spacers, pintle caps and filters and pour some BG 44K in my gas tank before my next oil change. My injectors look much happier now. I was not getting any ECU codes for the injectors anyway. I was getting a 1215 that turned out to be some vacuum leaks and a faulty AFM that I learned how to diagnose and correct by reading the archives. I also learned how to clear out the codes.

I know that does not sound like much to the more experienced guys in the forum. But, let me assure you it seems huge to me. After my mechanic looked at the engine light and read the code, he told me it was an electrical problem that could take anywhere from 2 to 10 hours of labor to diagnnose. Thanks again!!!