Do the injectors have the same impedance on both the 3.0 and 3.2 liter NSX motors?
Armando
Armando
Injectors
- Thread starter MiamieNeSeX
- Start date
I don't believe so.
the 3.0L is a peak and hold and the 3.2L is saturated.
the 3.0L is a peak and hold and the 3.2L is saturated.
Yellow Rose
Suspended
- Joined
- 22 November 2001
- Messages
- 2,256
the 3.0L is a peak and hold and the 3.2L is saturated.
Hi Andrie - could you please explain what "P-n-H" vs "sat" means?
Hi Andrie - could you please explain what "P-n-H" vs "sat" means?
When I was researching my ongoing CTSC acquisition, assembly and install, I ran accross this information:
91 – 94 NSX injectors also fit:
86-95 Legend
92-94 Vigor
97 CL
95-03 NSX injectors are only applicable to those year NSX’s.
2004 NSX injectors are also proprietary to their year (At & MT are different).
**
Even then the impedance values can be the same even with different injectors. At least that is what my college education thinks...
91 – 94 NSX injectors also fit:
86-95 Legend
92-94 Vigor
97 CL
95-03 NSX injectors are only applicable to those year NSX’s.
2004 NSX injectors are also proprietary to their year (At & MT are different).
**
Even then the impedance values can be the same even with different injectors. At least that is what my college education thinks...
My 1992 and 1997-2002 electrical manuals show an external series resistor for each injector. This implies that they are low resistance injectors.
A "saturated" driver will apply 12V directly to the injector with no current limit. This is the most common type of driver (ie. cheapest to make for the OEM). There are two ways that the current is limited external to the ECU:
1. A series resistor is added to each injector, and the injector internal DC resistance is low (ie. 1-3 ohms). This is used on the NSX and many other cars.
2. No series resistor is used, and the injector internal DC resistance is high (ie. 10-15 ohms). This saves the cost of the external resistor.
A "peak and hold" driver will apply 12V to the injector with a high current limit (around 4 amps). Once the current has reached 4 amps, the injector is fully open and the current is reduced to about 1 amp to keep it open. The advantages of this type of driver are high peak current to open the injector quickly, and low hold current so that the injector will close quickly when the driver is turned off. This is advantageous when using very large injectors and small pulse widths are required during idle.
"Peak and hold" drivers are typically used with low resistance injectors, although high resistance injectors CAN also be used. However, with the high resistance injectors, the peak current of 4 amps in never reached, so the benefits of faster turn on are not realized.
Here are the most common combinations:
1. Saturated driver with low resistance injector and external series resistor.
2. Saturated driver with high resistance injector.
3. Peak/hold driver with low resistance injector.
4. Peak/hold driver with high resiatance injector, although the benefits of faster turn-on are not realized.
The following combination will DAMAGE the ECU because of excessive DC current:
5. Saturated driver with low resistance injector and NO external resistor.
Andy, "peak and hold" and "saturated" actually refers to the circuitry inside the ECU driving the injectors, not the injectors themselves, although there is some relationship.
A "saturated" driver will apply 12V directly to the injector with no current limit. This is the most common type of driver (ie. cheapest to make for the OEM). There are two ways that the current is limited external to the ECU:
1. A series resistor is added to each injector, and the injector internal DC resistance is low (ie. 1-3 ohms). This is used on the NSX and many other cars.
2. No series resistor is used, and the injector internal DC resistance is high (ie. 10-15 ohms). This saves the cost of the external resistor.
A "peak and hold" driver will apply 12V to the injector with a high current limit (around 4 amps). Once the current has reached 4 amps, the injector is fully open and the current is reduced to about 1 amp to keep it open. The advantages of this type of driver are high peak current to open the injector quickly, and low hold current so that the injector will close quickly when the driver is turned off. This is advantageous when using very large injectors and small pulse widths are required during idle.
"Peak and hold" drivers are typically used with low resistance injectors, although high resistance injectors CAN also be used. However, with the high resistance injectors, the peak current of 4 amps in never reached, so the benefits of faster turn on are not realized.
Here are the most common combinations:
1. Saturated driver with low resistance injector and external series resistor.
2. Saturated driver with high resistance injector.
3. Peak/hold driver with low resistance injector.
4. Peak/hold driver with high resiatance injector, although the benefits of faster turn-on are not realized.
The following combination will DAMAGE the ECU because of excessive DC current:
5. Saturated driver with low resistance injector and NO external resistor.
Great Info Bryan,
Thanks,
LarryB
Thanks,
LarryB
Honda Injectors/ecu wiring are not true peak-and-hold as described above.
AFAIK the injector driver pulse is always flat on Honda ecus. The only difference is
low impendance injectors with resistors
high impedance with external resistor box
I'm saying this from experience of doing lots of honda setups with ecus that were 'saturated' with peak and hold type injectors and external resistor boxes and vice versa.
However from your combinations it seems that they are all valid setups, so maybe we are saying the same thing.
If you have some data to contradict I'd love to see it because we've been mixing and matching for a long time without problems. But yeah you're #5 option defintely is not a good combination.
AFAIK the injector driver pulse is always flat on Honda ecus. The only difference is
low impendance injectors with resistors
high impedance with external resistor box
I'm saying this from experience of doing lots of honda setups with ecus that were 'saturated' with peak and hold type injectors and external resistor boxes and vice versa.
However from your combinations it seems that they are all valid setups, so maybe we are saying the same thing.
If you have some data to contradict I'd love to see it because we've been mixing and matching for a long time without problems. But yeah you're #5 option defintely is not a good combination.
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