DIY flow tested my Nismo injectors. And now I smell like gas. Bad.

[neech]

So I took these out to sell them, and a guy asked me if they needed to be cleaned or not.. Since my #2 cylinder just went out, and I have not yet found the reason, I couldn't honestly sell them to him and tell him not to clean them. I didn't feel like spending $100 some dollars to get them tested and cleaned, so I decided to flow test them myself.

I turned on my fuel pump via AEM EMS, and connected the battery to my MR2 while it was running to get constant voltage. I used a hacked injector harness a la Gavster and connected it to 12v one at a time, for exactly 60 seconds, spraying into a bottle of which I marked where 740CC was with a sharpie. They all came out within 5% of each other, which I think is pretty decent. Here are some pics of the process.

These are Nismo 740 CC injectors BTW, that are up for sale


Injectors


3 1/8th cup ~ 740 CC


Filled the slimmest bottle I could find, and made a reference mark.


The Setup::
Peekaboo


Engine bay with injectors in place.


Set the fuel pump output in AEM to stay on


The system was connected to my running MR2 so that I could get constant voltage across the fuel pump.



Fuel pressure was a tad below 50 PSI for the whole duration of the tests.


Testing:


Results:






After, I referenced 755CC and 770CC on the bottle to get an idea about how much more was being sprayed. I wish I would have done it before, but from the pics you can tell that it isnt much higher than the 770cc mark.



Just thought I would share!!

Mike

Oh, and if anyone tries this based on my thread, make SURE you don't make ANY electrical connections anywhere near the injectors

[BiG MiKE86]

Nice! Hey are u runnin that fuel pump with ur stock tank/pump setup? Whats involved? SOrry to go off topic

[WangonwWarrior]

Very nice, +1 ummm pats on the back and invisible rep.

[neech]

haha thanks!

Originally Posted by BiG MiKE86

Nice! Hey are u runnin that fuel pump with ur stock tank/pump setup? Whats involved? SOrry to go off topic

Yeah its the stock tank but the stock pump isn't being used. The guy that had the car before me did it, but the bottom of the tank is tapped for a 90 degree -10 an fitting. I can take some pics of it if you are interested. However, it sits really low and it makes me nervous that it could be knocked off spilling my fuel everywhere.

[S14DB]

Does that stress the injector keeping them open for so long? I know pro test benches pulse the injector at like 50% Duty Cycle. When you tune a car you don't want over 85% DC of the injectors can start failing. But keeping them full open bad? N2O solenoids last a long time open, but fail when used with a progressive controller.

[neech]

The printouts I have seen from injector companies include flow rates at 100% DC and 80% DC IIRC, since 100% does not take into account lag time. Gavster (room mate) has one from Deatschwerks I'll check it when I get home. My understanding of the 80-85% DC rule while tuning is that it was more due to the fact that the intake valve is only open for a finite amount of time of the entire period (crank rotation) and that at 100% duty cycle you are spraying when the IV is closed and pooling fuel and getting shitty atomization.

Maybe peak and hold injectors are bad to keep open like that, but since these are saturated injectors, there was only about 1 amp of current flowing, times 12 volts, the injector is consuming 12 watts of power. As long as fuel is flowing through it keeping it cool, I don't see a problem.

I could be wrong though.. I don't know anything about solenoid design haha.

I guess it would have been easy enough to set 50% DC on the AEM though and run it for 2 minutes.. Oh well, next time

[BiG MiKE86]

Originally Posted by neech

haha thanks!



Yeah its the stock tank but the stock pump isn't being used. The guy that had the car before me did it, but the bottom of the tank is tapped for a 90 degree -10 an fitting. I can take some pics of it if you are interested. However, it sits really low and it makes me nervous that it could be knocked off spilling my fuel everywhere.

Yeah some pics would be cool whenever you get around too it thanks!

[burnsauto]

I heard awhile back that injectors can't even run at 100% DC, that they max out at 90% - even though you may think its 100% ... any fact behind this? (this is just something i heard...i wasnt, and still am not sure.)