Running low impedance injectors on a OEM ECU?
Discussion
Hello moto,
Does any one have any solutions for running low impedance injectors on a factory ECU? Most factory ECUs use high impedance jobbies, as the circuity is far cheaper to produce. I need something to drive the 'peak and hold' type, without burning out either the injector itself of the inj. driver...
Any thoughts? The option of putting an inline resistor in place is a weak one as they'd have to run in saturated mode with the high impedance ECUs. This is not good because you are externally reducing the injector current all the time in order to save the drivers in the ECU. You would lose many of the benefits you were trying to get in the first place....
ta
Does any one have any solutions for running low impedance injectors on a factory ECU? Most factory ECUs use high impedance jobbies, as the circuity is far cheaper to produce. I need something to drive the 'peak and hold' type, without burning out either the injector itself of the inj. driver...
Any thoughts? The option of putting an inline resistor in place is a weak one as they'd have to run in saturated mode with the high impedance ECUs. This is not good because you are externally reducing the injector current all the time in order to save the drivers in the ECU. You would lose many of the benefits you were trying to get in the first place....
ta
Ben
low imp injectors are called 'peak and hold' as they require a similar current feed to a dimmer switch. They need a ramped up high initial current to pull back the pintle (or disc, depending upon type), then a slightly lower current to hold the inj open. All this is only for a few ms, or what everever the pulsewidth is, but it won't work with a relay, which just (typically) allows a larger current to flow accross an electronically activated low current 'gate' or switch (but you knew that anyway)...
bugger!
I may have to go to MoTEC or PECTEL, but the latter starts at about £5k!. MoTEC (direct from aus it is I think)!
low imp injectors are called 'peak and hold' as they require a similar current feed to a dimmer switch. They need a ramped up high initial current to pull back the pintle (or disc, depending upon type), then a slightly lower current to hold the inj open. All this is only for a few ms, or what everever the pulsewidth is, but it won't work with a relay, which just (typically) allows a larger current to flow accross an electronically activated low current 'gate' or switch (but you knew that anyway)...
bugger!
I may have to go to MoTEC or PECTEL, but the latter starts at about £5k!. MoTEC (direct from aus it is I think)!
£5k for an ECU, must be pretty bloody seriousFirst off...why do you need to do this ?
Secondly, Id be interested to hear about this. Does running low impedance injectors, via a convertor, reduce their performance in any way ?
I would like to use low imp on my car, as they are available in much larger sizes easily. But does using them in this way make them better, or worse than a similar high impedance injector wired directly off the ecu ?? or does the low imp inj perform as it should do ??
Im sure there are others, but here is one such convertor.
www.acceleronics.com/
Motec is def not £5k, and as far as I am aware, can drive any type of injector.
Pectel is bloody expensive though.
Im using DTA, and was reccomended byt them, not to use low imp + convertor, and instead to just run large high imp injectors, of which they could supply up to 850cc.
I was thinking of a bit larger than that, but they should do.....
>> Edited by stevieturbo on Wednesday 8th September 20:43
Secondly, Id be interested to hear about this. Does running low impedance injectors, via a convertor, reduce their performance in any way ?
I would like to use low imp on my car, as they are available in much larger sizes easily. But does using them in this way make them better, or worse than a similar high impedance injector wired directly off the ecu ?? or does the low imp inj perform as it should do ??
Im sure there are others, but here is one such convertor.
www.acceleronics.com/
Motec is def not £5k, and as far as I am aware, can drive any type of injector.
Pectel is bloody expensive though.
Im using DTA, and was reccomended byt them, not to use low imp + convertor, and instead to just run large high imp injectors, of which they could supply up to 850cc.
I was thinking of a bit larger than that, but they should do.....
>> Edited by stevieturbo on Wednesday 8th September 20:43
stevieturbo said:
First off...why do you need to do this ?
Secondly, Id be interested to hear about this. Does running low impedance injectors, via a convertor, reduce their performance in any way ?
I would like to use low imp on my car, as they are available in much larger sizes easily. But does using them in this way make them better, or worse than a similar high impedance injector wired directly off the ecu ?? or does the low imp inj perform as it should do ??
Im sure there are others, but here is one such convertor.
www.acceleronics.com/
Motec is def not £5k, and as far as I am aware, can drive any type of injector.
Pectel is bloody expensive though.
Im using DTA, and was reccomended byt them, not to use low imp + convertor, and instead to just run large high imp injectors, of which they could supply up to 850cc.
I was thinking of a bit larger than that, but they should do.....
>> Edited by stevieturbo on Wednesday 8th September 20:43
Stevie (wonder)
Fair comments. I am going down the low imp route, as I need a much higher flow rate than my current setup, but I can't find other injectors which fit straight into to the fuel rail without loads of grief. I too have had a look at the acceleronics converter, and need to make sure it converts the standard high impedance driver (on a 'pulse'), not only into a lower current 'pulse', but also a 'ramp' to open the injector in the first place.... Most of the rationale is on acceleronics website btw!
If I could find a straight swap for a high imp, high flow injector, I would go for it. By the way, I'm not after monsters like you, just moving from a bosch 751 to an 803 (around 190cc/min to 390cc/min) for a 911.
850cc/min is enough to flood my flat!
Why did DTA not recommend the 'stock ECU + converter' approach? (I know DTA is not a 'stock' ECU)
PS I wasn't referring to the MoTEC when I said £5k! You can get a non-enabled M600 for around £1k, or an enabled unit for around £1.6k (direct from australia) - don't buy in the UK, you'll get robbed! Pectel are serious bits of kit!
So, you just require a 400cc injector ? So why the need to go for the awkward low impedance type, when using a relatively small injector ??
I had previously been using Bosch Motorsport, '434 injectors, rated at around 440cc, or 42lb/hr, and they worked perfectly.
I know of several Subarus ( and other cars ) running 850cc high impedance injectors again, with no issues whatsoever, from idle to WOT.
Its apparently the larger sizes that do benefit from being low imp, as they offer better control, especially at low openings...
I never enquired more with DTA, as to why not. I simply asked in an email enquiry as to how I could run low imp injectros with the DTA, and they said they didnt reccomend it, but they could offer injectors up to 850cc that would work fine, so I guess for most applications, doing it is unnecessary.
I had previously been using Bosch Motorsport, '434 injectors, rated at around 440cc, or 42lb/hr, and they worked perfectly.
I know of several Subarus ( and other cars ) running 850cc high impedance injectors again, with no issues whatsoever, from idle to WOT.
Its apparently the larger sizes that do benefit from being low imp, as they offer better control, especially at low openings...
I never enquired more with DTA, as to why not. I simply asked in an email enquiry as to how I could run low imp injectros with the DTA, and they said they didnt reccomend it, but they could offer injectors up to 850cc that would work fine, so I guess for most applications, doing it is unnecessary.
Running low imp injectors with ballast resistor from standard ecu's gives a sort of half way house - faster opening than high imp injectors but not quite as fast as low imp with dedicated driver circuits - but much cheaper overall.
Honda used this for all its engines untill a few years ago then went for the cheaper still high imp route apart from thier highest performance engines.
(Don't know what they put into the F1 engines though)
Honda used this for all its engines untill a few years ago then went for the cheaper still high imp route apart from thier highest performance engines.
(Don't know what they put into the F1 engines though)
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