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Injector flowbench test fluid

Injector flowbench test fluid

Injector flowbench test fluid

I'm in the process of building a fuel injector flow bench.My question is, what would a suitable test fluid be?

RE: Injector flowbench test fluid

I'm going to take a huge stab in the dark, knowing nothing about the above, but I would imagine alcohol would work well.  Shouldn't have any adverse effect on the injectors themselves, and will quickly dry out without leaving a residue once you're finished testing.  Deionized water would be a second choice, although it won't dry as fast... maybe a squirt of alcohol after using the water?


RE: Injector flowbench test fluid

From what I hear/read, a non-flammable fluid with similar physical properties as gasoline is used.I was assuming the question would be easily answered, I guess it must be a trade secret of some kind.Anyway, thanks for the reply

RE: Injector flowbench test fluid

Cheap and nonflamible would probably be the chief considrations.  How about DI water with soluable oil (cutting fluid).

RE: Injector flowbench test fluid

Bosch use heptane

RE: Injector flowbench test fluid

A 50/50 mix of DI water and Isopropal will work without the worry of explosion.  it will not dry as fast as pure iso - but better than Pure DI.  also will not cause the o-ring deterioration that pure iso will cause.

RE: Injector flowbench test fluid

I think the ideal fluid will vary depending on what you want to accomplish.  If you are just checking injector function or perhaps comparing one to another then the DI water suggestions are probably good.  If you wish to measure flow rate or check spray patterns then you probably need a fluid with properties similar to actual fluid in use.

Above comments are conjecture on my part and are NOT based on actual experience.

RE: Injector flowbench test fluid

Make certain you use Ethyl alochol.  It will then serve a dual purpose as you can also drink it if the testing is not going well.

RE: Injector flowbench test fluid

It is for flow testing, so yeah I need a fluid with properties similar to gasoline.

Viscor(as posted by NeilDS) seems to be the most appropriate.Anyone know how deionized water and alchohol(or cutting oil) compares physically to gasoline?

RE: Injector flowbench test fluid

Hi emetz564,

The Viscor is definitely your choice. It always depend on want you want to do. If you only test quickly an injector ( direct or indirect) that should not be any problems with water or alcohol. However, there is two problems. The first one is that water will tend to oxidise the parts, alcohol has not the same viscosity. Some damage my be occuring in long test usage to the injector. I also found out that the results are about 5 to 10% wrong.

The viscor ( or also called ISO fluids) have also the great advantage of not burning so easily and are not dangerous for your helth.

There is also companies in Europe that can test your injector to a great accuracy for really little money.

Have fun testing !

RE: Injector flowbench test fluid

All the fuel injection companies use 2 types of calibration fluids.  For regular production work the Rock Valley Viscor 16A and 16B are regularly used (there are other suppliers as well) for safety reasons.  However, the viscosity and density are not the best match to "gasoline" and thus flow ocorrection factors must be used if absolute accuracy is required.  For more accurate work, you need an explosion proof test rig and either n-Heptane or Indolene.  N-Heptane can be filtered and reused because it is a pure substance.  Indolene is your best match to "gasoline" but because it is a blend it can only be used for a single pass and then discarded.

Don't even think about using any kind of water or alchohol blend, you are likely to turn your injectors into scrap.

Lots of places can do injector flow testing, very few can do accurate, repeatable flow testing.  Stay away from anybody with an ASNU tester, they are a total piece of junk.  Russ Collins at RC Engineering can do good flow testing and injector matching.

SAE J 1862 will tell you all about injector flow measuirement.

RE: Injector flowbench test fluid

I use alcohol in my system, but it is designed for alcohol.

I think you mean do not use alcohol in a system designed only for petrol.

pat   pprimmer@acay.com.au
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RE: Injector flowbench test fluid

I'm also building an injector flow bench as well and just found this thread.  

dgallup said:
"Lots of places can do injector flow testing, very few can do accurate, repeatable flow testing.  Stay away from anybody with an ASNU tester, they are a total piece of junk."

Could someone elaborate on why?  I haven't ever seen one, I'd like to understand what the deficiencies are to avoid making the same mistakes.  Maybe I'm thinking too simplistic here, but I was envisioning on the mechanical side simply making a stand with a tank for the fluid and a pump, then running into a rail with an adjustable fuel pressure regulator (with a gauge).  Have the injectors spray into graduated cylinders or something like we used in a chemistry lab to measure the output.

On the electronics side, I'd run the injectors for a set length of time.  Fire all the injectors simultaneously, have a user adjustable pulse width, have the user set the "engine RPM" to simulate the firing frequency of a running engine.

What am I missing here? Wouldn't the ASNU device (or any injector tester) work similarly? Why would this not be accurate? This really doesn't seem very complex, which is why I'm perplexed by the cost of these testers and willing to build my own!

To clean the injectors, it appears that ASNU is simply using an ultrasonic jewelry cleaning machine that you can buy for $40.00 or so, filling it with some fluid and soaking the injectors in there.  Any idea on what cleaning fluid to use?  I was just thinking of filling the bowl with some carb/injector cleaning fluid you'd get from an auto parts store.  Or running the pressurized cleaners (such as 3M) through the rail as I cycled the injectors?

Any advice/thoughts would be appreciated. Thanks.

RE: Injector flowbench test fluid

Stoddard solvent is what we have used.
I've heard stories of methanol being used with disasterous results. Personally I wouldn't put anything water based through my injectors.

Hope this helps,

RE: Injector flowbench test fluid

As SUPERKYLE said - Stoddard solvent is an auto industry standard.
As ANDYV8 (hello andy) Bosch use heptane.
In the lab is used to work in we used Exsol D40 and industrial white spirit when we ran out.

RE: Injector flowbench test fluid

Stoddard solvent;
and it'll clean your clothes...

RE: Injector flowbench test fluid

Most fuel shops use Viscor in their Diesel test benches, but for gasoline, most get theirs from ASNU (www.asnu.com)

RE: Injector flowbench test fluid

The things I don't like about ASNU:

1) Most shops have to remove filters to flow injectors on the ASNU (although there are extra fittings available to flow without removing filters I have never seen an ASNU that had them, including ours).
2) You should never remove the filters unless an injector is on death row and it is a last resort, in which case I would replace the injector anyway.
3) NO CAR MANUFACTURE (or injector manufacture) recommends cleaning fuel injectors!!!  ASNU or otherwise.
4) Very few injectors need cleaning and for those that do, it is usually ineffective.
5) Their cleaning is very dangerous & should never be done.  The flow path inside the injector is far from straight and there are lots on nooks & crannies for the EXTERNAL carbon to be lodged INSIDE the injector only to later stick the injector open and hydraulic the engine.
6) Their flow test pressure circuit does not meet the SAE spec.
7) Their electronic drive circuit does not match the vehicle circuits.
8) Their test fluid is ?????
9) A gravimetric system is much more accurate than a volumetric system for measuring flow.  Particularly a low tech graduated cylinder volumetric system.  If you follow good laboratory practice you can get decent results but in my experience that rarely happens.
10) Their website is full of s#!t.

RE: Injector flowbench test fluid

I agree with you, DGALLUP.  We use N-Heptane to flow the injectors, and Viscor 120B to lubricate the injectors.  Bosch ans Siemens use the same.

You are correct - you cannot accurately flow test an injector if the filter is not in place.  Our machine (New Age) allows the user to flow the injectors exactly as they operate while in the vehicle.  We can change the fuel pressure, the pulse width of the injector, and the simulated RPM.

That being said, we replace every filter when we recondition injectors.  We remove the filter prior to ultrasonically cleaning the injector.  We then back-flush the injector, while lifting the pintle off its seat.  This allows any internal debris to exit through the large orifice at the top of the injector. We install a new, OEM filter, then proceed with our testing.

RE: Injector flowbench test fluid

I use stoddard solvent in my ASNU flow bench and windscreen cleaner in the ultasonic bath.It's old and seldom used these days - I have never cured a faulty injector or had any sort of performance change from an injector service,it's just used for testing and and if we have an engine apart we put them through just to make sure they are working,always fit new filter baskets,they are never likely to be changed again.

RE: Injector flowbench test fluid

We have used Stoddard, Viscor, and DI water for testing. With the use of DI water, we had to use correlation to oil (Diesel)charts as well. DI water WILL rust parts, and fast! Some of our other systems also had a Nitrogen flow guage. All of these have been integrated into our EDM injector drilling systems.

Hope this helps some.

In a hundred years, it isn't going to matter anyway.

RE: Injector flowbench test fluid

uummm  GBREMAN..  how do you open the err.. pintle on an orifice disk injector?

RE: Injector flowbench test fluid

Electrons flowing in a wire create a magnetic field which open the injector.  Works for all types of ELECTRONIC injectors.

RE: Injector flowbench test fluid

turbocohen....  my post above was intended to explain the processes that we use to clean fuel injectors - in general.  There are many different types of injectors, with varying specifications.

To answer your question; whether the injector has a pintle, a disk, or an oscilating ball, like many first generation Multec injectors, when energized, these areas move, creating an opportunity for the solvent used in the back-flush device to enter through the pintle/disk/ball section of the injector and remove any debris that the ultrasonic waves broke free.  The debris and solvent exit through the top of the injector, where the filter basket was removed.

RE: Injector flowbench test fluid


I use to build flow bench for Delphi and perform test all day as department manager so I may be able to help.

The fluids mentioned earlier of the threads are fairly ok, there is a ISO fluid for Diesel that can also be used for petrol test as we proved a few years ago.

To obtain repeatibility and accuracy, the temperature, pressure and test condition have to be really closely controled. I proved a few years ago that every °C out can bring a 5% error( roughly, this is ofcourse not linear !).

This make the industrial test bench fairly expensive, you will be takling about 200.000 € for a good one with full PC control. I know a couple of companie that have invested in such machine to support there development and want to maximize the usage of there bench. I guess they will be happy to help you on that for a fair price.


Jerome Douay

Jerome Douay

RE: Injector flowbench test fluid

The lab I worked at used stoddard solvent in production and some lab work, other lab activity involved normal heptane.

I built a few gaseous flow benches using nitrogen for static and dynamic flow but there was very poor correlation between N2 and any liquid.  Opening and closing times were different and there were other issues.

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