PC111 & Standard Injectors ?

[paxo]

Is there a problem with using PC3 and standard injectors ? My bike has a bigger turbo and uses 1100 tb's, setup is racemode with adjustable boost and AFPR and currently has a resistor in the usual racemode circuit. Im going to get the bike setup on a dyno shortly.....question is i assume using a PC3 will make it easier for the dyno bloke....BUT will there be a problem as im still using standard (750) injectors ?

Cheers Paxo

[frankie.c]

Dont know if you can use standard injectors but in case not i bought bosch 310CC @ 3 BAR, 16.6 OHMS HIGH IMPEDANCE which are suitable only when pc is fitted.

[Lorcan]

The PC is not designed to be used with 750 turbo standard injectors. Standard injectors are low impedance - 2.6ohms - the injectors fitted to modern bikes are all high impedance - 12-16 ohms - and this is the range the PC is designed to operate in.

It *might* work with the low impedance injectors, but it's not proven and you *might* fry the PC or the injectors trying it. I don't know of anyone that has tried it. We know it works with high impedance, so that would be my recommendation. There is a guy on here who works for Dynojet, so hopefully he'll read this and might be able to help.

[M6NTL]

The PC is not designed to be used with 750 turbo standard injectors. Standard injectors are low impedance - 2.6ohms - the injectors fitted to modern bikes are all high impedance - 12-16 ohms - and this is the range the PC is designed to operate in.

It *might* work with the low impedance injectors, but it's not proven and you *might* fry the PC or the injectors trying it. I don't know of anyone that has tried it. We know it works with high impedance, so that would be my recommendation. There is a guy on here who works for Dynojet, so hopefully he'll read this and might be able to help.

If you were to put a 12Ω resistor in series with the injector, it would make it approx 14.6Ω - I know impedance and resistance are not the same, but since this is a DC system, they can be read as such...

[Lorcan]

I'm not sure it's that simple. Most low impedance injectors are driven by peak and hold circuits, whereas most high impedance are saturated circuits. Driving a low impedance injector on a PC (saturated) circuit might result in more "dead time" and the injector failing to open properly as the boost goes up, due to being designed for a peak and hold circuit that jerks the injector open with a high current.

Ultimately, that might not be good...

[M6NTL]

I'm not sure it's that simple. Most low impedance injectors are driven by peak and hold circuits, whereas most high impedance are saturated circuits. Driving a low impedance injector on a PC (saturated) circuit might result in more "dead time" and the injector failing to open properly as the boost goes up, due to being designed for a peak and hold circuit that jerks the injector open with a high current.

Ultimately, that might not be good...

I shoulda known it wouldn't be so simple!!!

[Betterthanfabio]

I'm not sure it's that simple. Most low impedance injectors are driven by peak and hold circuits, whereas most high impedance are saturated circuits. Driving a low impedance injector on a PC (saturated) circuit might result in more "dead time" and the injector failing to open properly as the boost goes up, due to being designed for a peak and hold circuit that jerks the injector open with a high current.

Ultimately, that might not be good...

I shoulda known it wouldn't be so simple!!!

I didn't understand any of that. Please Don't explain it!

[Lorcan]

Are you sitting comfortably? Right, then I'll begin

Once upon a time, there was an old fuel injector, made in the 1980s. Its insides were heavy, and it was slow to open. So a big bad ECU was developed to JERK that fucker open with a high current, like 4 amps, then hold it open with, say, 1 amp. This was called a "peak and hold" circuit.

Many years later, way after Fabio was born, lighter, faster, cheaper injectors were made that could be opened and held open by a small current, say 1.5 amps. The circuits for these were cheap and easy to make, and were called "saturated" circuits. This is what we all use today in modern bikes, and what the PC uses.

The PC doesn't really care what signal it receives, it's only going to use it to time when the injector opens and closes anyway, but it will give out a low-amp saturated circuit, because it's only a baby device. This might, or might not, be enough to jerk open the nasty old, stock, injectors. But it might also make them slow to open. The amount of time spent opening and closing is called "dead" time, because the injector can't flow the correct amount of fuel while it's doing this. If the injector doesn't flow enough fuel the engine could run weak, and you may not be able to compensate enough by using magic, or by altering the numbers in the PC map. This could make bad things happen to the engine.

Use modern injectors like the grand old wizards though, and you can be fairly sure everyone will live happily ever after

I know you said DON'T explain it, but tough shit

[tack1000]

I love a good story, got any more.

[paxo]

Thanks for all the info folks......I better start saving my pennies up for new injectors. any recommendation on size, spec and best place to get a set from when I've scraped up enough dosh ?
Cheers Paxo

[Diverteh]

Is this a Grimm fairytale

[Lorcan]

Search "RC injectors"

[Betterthanfabio]

Are you sitting comfortably? Right, then I'll begin

Once upon a time, there was an old fuel injector, made in the 1980s. Its insides were heavy, and it was slow to open. So a big bad ECU was developed to JERK that fucker open with a high current, like 4 amps, then hold it open with, say, 1 amp. This was called a "peak and hold" circuit.

Many years later, way after Fabio was born, lighter, faster, cheaper injectors were made that could be opened and held open by a small current, say 1.5 amps. The circuits for these were cheap and easy to make, and were called "saturated" circuits. This is what we all use today in modern bikes, and what the PC uses.

The PC doesn't really care what signal it receives, it's only going to use it to time when the injector opens and closes anyway, but it will give out a low-amp saturated circuit, because it's only a baby device. This might, or might not, be enough to jerk open the nasty old, stock, injectors. But it might also make them slow to open. The amount of time spent opening and closing is called "dead" time, because the injector can't flow the correct amount of fuel while it's doing this. If the injector doesn't flow enough fuel the engine could run weak, and you may not be able to compensate enough by using magic, or by altering the numbers in the PC map. This could make bad things happen to the engine.

Use modern injectors like the grand old wizards though, and you can be fairly sure everyone will live happily ever after

I know you said DON'T explain it, but tough shit

Very good explanation you sarcastic bastard!

[ThePadd]

I learns sumfink new evry day!

[Würstchens-Turbo 810]

....and the one and only different (old inj to new inj ) is the impedance ???

i use Bosch 0280150341 of a Saab turbo (350cc) , they are 12,7 Ohm / 4 jets

they are ok ?