Testing injector flowrate

rs2000 · Post by **rs2000** » Mon Mar 13, 2006 5:00 pm

I'd like to test the flowrate of some injectors. What i thought was i'd attach one up to a manifold/fuel rail, hold it at 100% duty cycle and see how much fuel comes out in a minute.

3 questions i have about this method;

1 What is the correct way to hold an injector open using a 12v battery? Surely i need something to stop the current damaging it, a resistor in series or something.

2 Will a regulator with no vacuum applied give me the correct fuel pressure (correct being approx 43psi)? I believe it should.

3 Is this a correct method, and will my results be comparable to other lists of flowrates?

Thanks

andrew

woh · Post by **woh** » Mon Mar 13, 2006 5:08 pm

RS2000

If your injector is low impedance then you will need a resistor in series with it, otherwise 12V will be just fine.

But the more serious problem is safety. The injector puts out a spray and fumes that are very explosive in the open. A spark from the injector connection might set it off. You must confine the spray output, and assure that there are no sparks near the fumes. Don't just touch the connections to make a connection. It will surely spark.

I suggest you send the injector to:
http://www.witchhunter.com/
They will flow test it for you or test and clean it for you. Well worth it for what they charge.

rs2000 · Post by **rs2000** » Mon Mar 13, 2006 5:41 pm

I did think about the fumes, you're right it wouldn't be the safest thing. I'm planning to spray into a sealed container

PSIG · Post by **PSIG** » Mon Mar 13, 2006 6:37 pm

Bruce and Al did a piece about this along with designs for the cool cycling electronics here: http://www.bgsoflex.com/FI_tester_doc.pdf

Considering the fact that you can test at lower pressures and calculate for higher pressures, I have used the plastic garden sprayer in the shed like B&G suggest as well as an old TBI pump that put out 22psig consistently and calculated from there. It really is easier to rig them one at a time with a bit of fuel line and a burette than monkey around with a fuel rail.

I also was just interested in full flow-rate testing; although this only tells part of the condition of an injector. Wiring an injector connector to a 9v battery connector is also an option for limited 100% flow testing with the garden sprayer; but be sure to add a resistor for low imp injectors as well.

FWIW,
David

PS: Oh - forgot... You can also calculate for using a less incendiary liquid. Gasoline is not necessary for accurate testing.

woh · Post by **woh** » Mon Mar 13, 2006 6:39 pm

Andrew

I did not realize you are in Australia. Sending the injectors to the US does not make sense. I've done it with a sealed container, and using an external power supply that has current limiting.

Just be very careful and plan the test carefully.

rs2000 · Post by **rs2000** » Mon Mar 13, 2006 9:33 pm

Thanks guys. I hadn't thought about testing at a lower pressure, might be the way to go. I might also use a less combustable test fluid.

The Jector rate looks like a cool toy.. might be a project for the future