BIGGER is BETTER!!! A FAQ on the Bosch 550cc injectors for R53

Well.... These last 3 posts were pretty informative to me in helping to lift the grey fog of understanding injector duty cycle.... Thanks....

Still sitting on the sidelines and absorbing....

CG
Wouldent it be hard to judge where duty cycle is maxed out due to running 380s vs the stock injectors the leeway would be slightly higher or will your software account for this.
and obviously we all still know that 112% is not possible its just then static at that point in the open position.

mike@
the software has nothing to do with this... this is what the Stock ECU spits out in form of a data log. 112% is very possible; i've seen as high as 130% duty cycle.

Duty cycle is a mathematic calculation, do some research...

cct1
Colin, from my limited understanding, I think I see where you're coming from--the injectors are maxed out at what they can spray at 100%, they have a definite limit at what they can put out, there is no such thing as a spinal tap injector that goes to 11, but duty cycle is something different--once the injector is maxed out, if you keep pushing the RPM's up, you get over 100% duty cycle. Extremely rudimentary, but I THINK the gist of this is right....

 

You'll like the 450s!!! Mine are running like a champ!!!

...and yes if the injector is running at 100%, how could it do more? All it is, is constantly open after that, does that increase it's capacity or ability to flow more....me thinks not.

 

I believe duty cycle has more to do with how long the injector is being used to get the correct amount of fuel.

 

Duty cycle is a calculation of injector pulse width vs rpm of the engine.

Injector Pulse Width is a set number. Let's say 20 milliseconds is the fastest it can pulse. If your engine is at an RPM where it takes 50 milliseconds to complete a cycle (that's two revolutions, because two revolutions = 1 engine cycle) then your injector is at 40% duty cycle because 20 milliseconds is 40% of 50 milliseconds. The injector's open time is 40% of the time it takes or the engine to complete 1 cycle. Once the rpm reaches a point where it takes 20 milliseconds to complete a cycle, you are at 100% duty cycle and the injector is staying open. If the engine spins any faster, the calculation passes 100% because the engine is taking 15 milliseconds to complete a cycle, but the injector pulse width is 20 milliseconds. The injector is still static open at 100%, but the calculation can surpass 100% because the engine is spinning faster than the injector can open and close.

Rudimentary explanation, but it's simply because it's calculation of injector open time vs rpm

 

Well I was kinda trying to say that.........yea that's right.

 

Exactly.

 

And as you start to exceed 100% duty cycle and with no other changes except an increase in RPM, the engine starts to run leaner.... Am I correct?

 

Lol, come out to the track and I'll show you!!

....and when the lean condition occurs what does the MINI ECU do?

 

:beer

Thumper

 

Well dang, that's not very helpful at all....lol

I'll tell ya my data at the track.

 

You didn't get that data when your car was tuned on 450cc? Can you explain to me what the Siemens ECU does when it see a lean condition in Open Loop?

 

Already been to the track and encountered no lean condition, other than my IC blowing a hole in itself there have been no problems. My injectors are the correct size for my mods and the tune is spot on...

Just thought you might share what the Mini ECU does when a lean condition occurs...

 

Alright, I think we've had enough of the back and forth?

 

Why are you here in this thread anyways? Really? But continue to do so, because you are helping business big time, and you don't even realize it. Carry on

 

Glad to be of assistance!!

 

Can't wait to congratulate you in person at the Dragon

 

Oh no you better not go to the Dragon minimark :incazzato::lol:

LB