NoPistons -Mazda Rx7 & Rx8 Rotary Forum

NoPistons -Mazda Rx7 & Rx8 Rotary Forum (https://www.nopistons.com/)
-   2nd Generation Specific (https://www.nopistons.com/2nd-generation-specific-17/)
-   -   Injector impedance (https://www.nopistons.com/2nd-generation-specific-17/injector-impedance-1473/)

Powerpack 04-20-2002 03:03 AM

Does anyone know what impedance the injectors of NA '86 should have? I know they actually have about 2 ohms on mine. But according to the factory manual they should have between 12 and 16 ohms. In Haynes manual, it's 1.5 to 3 ohms. I figured that the factory manual is most likely to go with NA '88 specs, right? :dontgetit:

1Revvin7 04-20-2002 07:28 AM

86-88 low impedance

89-92 high impedance

Powerpack 04-20-2002 09:22 AM

So there's an error in the factory manual, page 4A-70 (fuel and emission control system). I hope that's the only thing wrong. :dontgetit:

13BAce 04-20-2002 10:04 AM


Originally Posted by Powerpack' date='April 20 2002,10:22
So there's an error in the factory manual, page 4A-70 (fuel and emission control system). I hope that's the only thing wrong. :dontgetit:

There should be a resistor pack near the airflow meter. When the resistor is wired in the impedance is in the factory range.

13BAce 04-20-2002 10:05 AM


Originally Posted by 1Revvin7' date='April 20 2002,08:28
86-88 low impedance

89-92 high impedance

86-early 87=low impedance injectors+resistor pack

late 87-91=high impedance

Powerpack 04-20-2002 10:25 AM

Thanks Ace, that's what I was figuring out since they don't say anything about those resistors in the factory manual. And it really is the 1988 manual.

13BAce 04-20-2002 11:16 AM


Originally Posted by Powerpack' date='April 20 2002,11:25
Thanks Ace, that's what I was figuring out since they don't say anything about those resistors in the factory manual. And it really is the 1988 manual.

No problem.

Infini IV 04-20-2002 12:56 PM

So can I put 13Brew secondary injectors into my 1990 T2?

Powerpack 04-20-2002 02:57 PM

You probably could do that but you should add the resistor pack in order to keep the total impedance to about 14 ohms. I think high impedance injectors might have a faster response since the injector system draw the same amount of current. With low impedance injectors (injector + resistor) , it is activated with about 2 volts only (11 volts in the resistor). So the energy going to the injector is about 7 times less.



All this is just a theorical explanation from an electrician (myseft). That could explain why they've change for high impedance injectors. At 7000 rpm, the injection cycle is less than 10ms (2 times shorter than a piston engine at same rpm). So it could be interesting to see the difference in performance or fuel economy. ???



I might add that I don't know anything about your 13Brew injectors, they may need more current to activate them so maybe you won't use the same resistor. You need the resistor to limit the current to nominal current needed by the injector. You need the specs of your injectors and the nominal ECU output current capability.

13BAce 04-20-2002 06:08 PM


Originally Posted by Infini IV' date='April 20 2002,13:56
So can I put 13Brew secondary injectors into my 1990 T2?

They won't bolt right in because they're side feed injectors. FC fuel rails are for top feed injectors. If you got them with an FD secondary rail and modified it to fit then you could do it.


All times are GMT -5. The time now is 09:23 AM.


© 2024 MH Sub I, LLC dba Internet Brands