high or low impedance injectors?

[wolfie]

hi all,im looking to use vems on my s13 and have been looking for injectors and found these
http://cgi.ebay.com/ebaymotors/Nissan-720cc-Direct-fit-Injectors-Top-Feed-CA18DET_W0QQcmdZViewItemQQcategoryZ33554QQitemZ120084242544QQtcZphoto
they sell them in high and low impedance and i think ive read that vems can use either (i might be wrong on that) so which ones do i need?

[rob@vems.co.uk]

You can use Low Impedence Injectors just fine with the standard S13 resistor pack.  I set them up to run on Kev's car this way.
Damo has gone for a set of 50W resistors in his custom loom, they cost about £1.50 each so either way its not a real problem.

High Impedence injectors won't need the resistor pack (and wont open with it) so if you're using the standard loom theres no advantage.

[damo_S13]

if your going for a custom loom i would use high (just to save fitting the resistors) and if you doing the plug and play opition i would use low to save removing the stock coil pack

damo

[BrendanC]

Is there any advantage to either in thier operation? If I understand it correctly, the low Z injectors seem to behave better when they are large, but you need to get a good idle on a modified engine. High Z had problems with this, but I read that the newest high Z injectors have reduced or eliminated this problem.

Low Z are cheaper for the same size, say 72lbs. So if its no bigger hassle to fit them and tune them, that would be better.

[rob@vems.co.uk]

With the combination of 50W resistors and a transient voltage suppresion diode in the flyback we've had really good results with LowZ injectors.  I've personally got 1000cc injectors running nicely on a 1.8 engine, and Emil in Sweden has had 1600cc injectors running on a 2litre
This is with good AFR (lambda 1.0) and Hydro Carbon readings, with an injection duration of 1.2ms

[dnb]

Rob - you're making my getting highZ 600cc/mins on a 5 litre v8 working well look too easy!

[multiplex]

Can you talk more about the transient diode?

I'm looking to run resistors for low ohm injectors. Right now i have high owm injectors and the flyback board.  Does flyback still apply? where does the diode go

thanks 

With the combination of 50W resistors and a transient voltage suppresion diode in the flyback we've had really good results with LowZ injectors.  I've personally got 1000cc injectors running nicely on a 1.8 engine, and Emil in Sweden has had 1600cc injectors running on a 2litre
This is with good AFR (lambda 1.0) and Hydro Carbon readings, with an injection duration of 1.2ms

[rob@vems.co.uk]

If you have the flyback board already then you needn't worry about the transient diode, but... for the effort of soldering it inline with the flyback wire (EC36pin23) its worth experimenting with it.

For lowZ injectors you only need the 50W resistors.

Rob