325E stock fuel injector flow rates?

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#21
Thanks Bichmgn and Rukus for the great posts. I dont know about just trying the injectors, I have not attempted it yet but from what I read you have to pull the intake manifold off on the 325's to get at the injectors. Sounds like a job to just wait tell I rebuild the motor.

As for the flow rates. I wish the "E" had better injectors for sure. I wish they would flow more. I can increase the pressure a little. I really just need to spend about $3k on an engine and fuel system.... money sucks.

Again thanks guys. Later

Aaron
 
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#23
I was only getting annoyed because it seemed that bvichmgnet was trying to pull apart the fact that i said it isn't possible, when i corrected myself to say that i never emant impossible, i meant i should have said that it was most likely a VERY BAD idea.

The thing is, bihmgntm are you trying to trick the ECU to think its a different ohm injector, or are you trying ot trick the injector to think its a different ohm injector?

Becasue i look at it this way., he wants to take a 17 ohm injector, and bring it down to 4 ohms. (you can't change a 17 ohm injecotr into a 4 ohm injector, you cna only change the load on the ECU) so now wiring a resistor in parallel is pointless. because that 17 ohm injector is going to behave like a 17 ohm injector, no matter if there is a resistor in parallel. Do you understand waht i am trying to say? its just a different part of the circuit. Any load on a circuit if you want to dumb it down, is basically called shorting out your battery. Except, theres benefits to this shorting out. with a lightbulb, its light, with a motor, its motion... etc.
energy is not lost. So wheres the extra energy going if the load (more current) on the ECU is greater??? The difference is getting wasted as heat out of the resistor. Hurray.

Now when you wire your injectors with a resistor in parallel, YES you have successfully lowered the ohm load on your ECU, and NOT that injector. the injector still works like a 17 ohm injecotr its part on the LOAD of the ECU has not changed. and that can STILL be proved by V=IR. and you can still prove to me that because that if it has less current it won't affect the way to works, and i can still prove to you that wiring an resistor parallel to the injector is pointless, because liek you said, less current makes no difference. So WHY wire a resistor in parallel? Why make the current load on the ECU greater if current ot that injector doesn't matter?? Why make the ECU work hareder for NO reason at all??? the current draw from the injector was PREDEFINED from factory, when they said "i am going to deisng this injector to be a 17 ohm injector". Just like when Kicker designed my subwoofer for my car and said it was going to be a 4 ohm subwoofer.

Even if i took that subwoofer and hooked it in parallel with another 4 ohm subwoofer. that 4 ohm subwoofer is still a 4 ohm subwoofer.!!! Even if my amplifier is putting out 300 watts instead of 150 watts. But thats 300 watts at 2 ohms. what that mean? it means that if your split that load in half, you get 150 watts RMS at 4 ohms. it means that my 4 ohm subwoofer is still a 4 ohm subwoofer. it means my amplifier can now put out 150 watts to each subwoofer at the cost of 4 ohms each, at the cost of a 2 ohm load when wired in parallel. It means the load is split equally to each subwoofer accordingly. It means that 150 watts rms at 4 ohms is 150 watt rms at 4 ohms.

So i replace one subwoofer with a resistor, the one kicker subwoofer is still a 4 ohm subwoofer. no matter if i make that resistor 1000 ohms or 1 ohm. its still going to behave like the subwoofer it is.



I hope to God that you understand what i am talking about now.
 
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#24
Well, when you put it like that...

But that is very different from what you said in an earlier post.

Rukus said:
...its trying to have an injector that can properly operate with the signal or current that the ECU puts out
if the ecu only puts out 2 amperes of current which is sufficent for a 3 ohm injector, on a 10 ohm injector, current is going to be significantly reduced. Which would obviously affect injecotr reponse and rate of fuel flow.
no matter WHAT you do.

...
(emphasis mine)
In the earlier post you said the current being lower would affect the injector response and rate of fuel flow and that's the statement I didn't understand. That's the statement I argued with in my last two posts. Maybe not as clearly as I should have, it seems. Now you are saying the amount of current doesn't affect injector response and rate of fuel flow. Is that right or am I not understanding what you are saying?

I always maintained that the injector worked normally with the resistor in the circuit and there wouldn't be a problem with it. I later said the circuit also would work normally without the resistor.

The only question is what does the ECU do when it doesn't have the load it is expecting? Some circuits are designed to work correctly only with the load designed for it. When they aren't loaded as designed, the circuit behaves differently. That was the purpose of the resistor - to ensure that the ECU is working at its designed load while leaving the injector unaffected which I stated in my first long post.

bichmgnt said:
...If a 3.75 ohm resistor wired in parallel with the new 15 ohm injector, the resistance that the ECU sees is 3 ohms and the voltage the injector sees is 12 volts. Both are getting what they expect.
...
After a while I started to think I was giving BMW either too much or too little credit - I'm not sure which - for their ECU design. I figured they would just keep it simple and let the ECU work over a wide variety of loads. That was when I said to try the new injectors without changing anything. But at the same time I was still fighting the statement you made earlier about the current affecting the injector response and the fuel flow rate.

So now we understand each other (I hope). For me it was about creating a circuit that mimicked the original design so that all components were operating at their designed specifications. For you it was about why put a resistor in the circuit when it doesn't really do anything.

If it's something else, feel free to correct me.

Steve
 
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#25
i think you got me. Sorry man, my original poast, i was sort of drunk/ overtired.

Why put a resistor in if the injector is going to behave the same? maybe the ECU needs to be tricked to see the ohm load in order to function properly. But you cannot trick a 17 ohm injector into thinking its a 3 ohm injector.

so (just throwing out figures) installing a 17 ohm injector with a flow of 200cc/min flow rate, wiht less current flow, might be alot more benefical than a 3 ohm injector with a 150 cc/min flow rate and more current flow. But is the injector response going to be there? i dunno how that works. and maybe the ECU needs the proper load to work properly who knows? so thats why you suggested throw in a resistor. but i thought that was silly to put the extra load on the ECU if it needn't be there.

best bet is still to spend the rextra money and do it right.

I see what you mean... it just didn't seem like that you understood that a 17ohm injector is a 17 ohm injector no matter what you put into parallel with it.
 
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#26
Rukus said:
i think you got me. Sorry man, my original poast, i was sort of drunk/ overtired.

Why put a resistor in if the injector is going to behave the same? maybe the ECU needs to be tricked to see the ohm load in order to function properly. But you cannot trick a 17 ohm injector into thinking its a 3 ohm injector.

so (just throwing out figures) installing a 17 ohm injector with a flow of 200cc/min flow rate, wiht less current flow, might be alot more benefical than a 3 ohm injector with a 150 cc/min flow rate and more current flow. But is the injector response going to be there? i dunno how that works. and maybe the ECU needs the proper load to work properly who knows? so thats why you suggested throw in a resistor. but i thought that was silly to put the extra load on the ECU if it needn't be there.

best bet is still to spend the rextra money and do it right.

I see what you mean... it just didn't seem like that you understood that a 17ohm injector is a 17 ohm injector no matter what you put into parallel with it.
Thank god. You're a drunk a**hole. I thought you were just a regular a**hole.

[rofl]

j'k

Rukus said:
so (just throwing out figures) installing a 17 ohm injector with a flow of 200cc/min flow rate, wiht less current flow, might be alot more benefical than a 3 ohm injector with a 150 cc/min flow rate and more current flow. But is the injector response going to be there?
Beneficial is a strong word. Having less current isn't necessarily better since the ECU is designed to work with 3 ohm injectors. I'd say there would be no real benefit over a three ohm 200 cc/min injector.

What exactly do you mean by injector response? The injector opens and closes when 12 volts is applied. I'm sure it's just as fast as a 3 ohm injector. They probably all are the same regardless of resistance.

Steve
 
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#27
i meant is... having an injector with more flow would be alot more benficial. I also figured that if the ECU is deisgned for a 3ohm injector and you run a 17 ohm injector, the added resistance might affect how the ECU tells the injectr to open and close.

But on the other hand.... more resistance in my opinion wouldn 't hurt the ECU. I think the ECU would agree jsuyt fine with the extra resistance. less resistance would be what i would worry about.
 
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#28
Hey.

So you two both think it wont hurt to atleast try the higher OHM injectors? I think I will get a air/fuel mixture guage before I try this and then watch the mixture to see if the ECU will work correctly with the different resistance injectors. I can get a new set of 19lb per hour injectors for around $170. From what I read the stock injectors flow at around 14lb's. I do not know what they flow in the metric CC rating... I am not the best at the metric system.

Thanks guys for the tons of good info. Later

Aaron
 
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#30
Myself, I think it wouldn't hurt to try it. If your plan is to replace the ECU and you have the injectors you want to use, see if it works. If it doesn't, replace the ECU. I don't think you can hurt the injectors. But I think it would work. You'll need an adjustable fuel pressure regulator to lower the pressure at first so the engine can handle the extra capacity but after running it for a while you should be able to boost it back up.

Dave Adams has a good article on this on his website. Search through the white section.

http://www.davelength.net/

I think you would be better off doing this with an i engine instead of an e because you can get a lot more performance out of it but you do what want to do.

Steve
 
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#31
Oh I want an "I" engine. That is plan eventually, put a nicely modified "I" engine into it. But I am going to start with the fuel system first.

www.sdsefi.com Has a really nice and inexpensive fuel system that should plug into most or all of the bosch parts on the car.

I have that Dave Adams website bookedmarked. I also plan to get that Bosch F.I. and engine management book and really get to know the bosch injection systems. You ever seen how close a ford fuel injection looks like a bosch one?

Later
 
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#32
I say thats the way to go, upgrade your injectors as needed, and upgrade your EMS to something better.

don't doa piggy back system if you are serious tho. If you aren't too too serious, a piggyback system can work for you.
 
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#33
One point the SDS website brings up is thaey need to know if you have the low or high resistance injectors so they can send the right harness. I think the injector plugs may be different. You may need to wire in all new plugs if you're thinking af starting with the injector swap.

Steve
 


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