Minimum Injector impedance and max Pk/Hold currents?

[KevlarUK]

Hi all,

Have the oppurtunity to use a McLaren electronics ( ) high pressure (12Bar) fuel injector but it has a DC coil resistance of 0.65 ohms, would this draw too much current for my MegaSquirt ECU? its a MS1 processor and V3 board.

It'll be running on a Husqvarna 577cc single cylinder, so just the one injector to worry about.

Also, it requires 4A/1A peak/hold currents, is MS capable of this? I have had a hunt around but couldnt find anything.. Can the peak/hold currents be adjusted in megatune?

Thanks in advance

Kev

PS - I know duplicating posts is often frowned upon in forums, i did just post about this in the general section but my last post in there didnt get a response and i thought this was more relevant in here... sorry

[KevlarUK]

Hi Lance, thanks for the response.

Yep, I have installed the PWM flyback damping circuit, so I'm going to go for it and use this Low impedance injector when it arrives.

Is there a way to work out how quickly the current rises through the injector? I've forgotten most of the electronics from my 1st year at uni I'll be able to hook the injector up to a scope to measure the time accurately once it gets here if not.

And just to confirm i understand you.. if I've got a 0.65Ω injector and want 1 amp, that would mean supplying 0.65 volts, which means at 14V I'd want to set the PWM to 4.5% ?

Thanks for your help

Kev

[KevlarUK]

Cheers Lance! - saves me rooting through all my lecture notes!

One other quick thing.. I've just noticed on the spec that this injector (I got an email yesterday explaining that it is second hand and from an old F1 engine!!) has a MLPT of just 0.9ms, so I'm guessing the rise time will be pretty quick. Please forgive my ignorance as I have not yet started tuning the engine, but will MS be able to go as low as 0.9ms? What is the shortest duration MS is capable if I'm using peak/hold?

thanks again - Kev