mechanical injection flow testing

kiwicar · Post by **kiwicar** » Thu Aug 29, 2013 1:42 pm

OK all this talk about EFI flow testing has me thinking again.
One of the things that ia always recomended with Mechanical Fuel Injection is to get you system "flow tested" this involves stripping your system off the car, parceling it up and sending it off to one of about 6 people in the states, along with about $600 for the testing, then guess what you need a whole stack of repair kits. . . net result before you know it you are out of pocket about £800 and Mr tax man is laughing his socks off for all the Vat he has got to charge you on the postage!
So what is the alternative, as with EFI, a big bucket, some fuel analogue and in this case a method of driving the fuel pump at a known speed. . .so first question anyone know of a good motor that I can use to drive a mechanical injection fuel pump with? At a guess it needs to be about 1/4 to 1/2 horse power, be able to be driven at speeds from about 500 revs to 4000 revs in 250 rev increments and be stabe at those speeds for about 30 seconds at a time (I will need a big bucket my pump is rated at 4 GPM generally they give about 3.6GPM, I think my spare does about 5 GPM

Anyway comments on my assumptions would be gladly received and a recomended motor type/ supplier/ part number would be very welcome.
Best regards
Mike

mgbv8 · Post by **mgbv8** » Thu Aug 29, 2013 6:56 pm

If you want a motor drive Mike then talk to me. I can sort out whatever you need at trade prices ??

kiwicar · Post by **kiwicar** » Thu Aug 29, 2013 8:14 pm

right your on, I just need to work out what I want!

Best regards
Mike

unstable load · Post by **unstable load** » Sat Aug 31, 2013 5:50 am

Back when I was an apprentice if one of the Mercedes' with the Bosch K Jetronic injection came in with problems all we would do was remove the injectors and flush them with a hand pump and an inert fluid. We never had to remove any other components for flushing etc.

The rig was effectively a wall mounted pump off a hydraulic jack with a reservoir and a line to connect to the injector.
It was also quite dramatic how the flow pattern changed as the injector was cycled to full flow rate and all the crud came free and got flushed out. Some would dribble and drop in the beginning and took a few good pumps to get them up and running with an even pattern and good atomisation.
The difference to the car was rather dramatic at times, too.

r2d2hp · Post by **r2d2hp** » Sat Aug 31, 2013 7:59 am

Hi Mike

You could adapt an old treadmill and that will have a variable speed control built in.

Plenty on ebay for not a lot of money

just a thought

stevieturbo · Post by **stevieturbo** » Sat Aug 31, 2013 10:25 am

Surely there are places in the UK that can test them properly ?

kiwicar · Post by **kiwicar** » Sun Sep 01, 2013 5:30 pm

Hi Reg
That sounds an interesting idea I shall investigate, it is the speed regulation bit that will be interesting, I may be able to do course control with toothed belts and pullys.
Hi Stevie
I have not as yet found any one who stocks Hilborn, Kinsler, Rons or Enderle stuff on this side of the Atlantic let alone flow tests it. In the US the people I know of that do test it are the manufacturers plus Harvey race engines, good vibrations, Alky diggers and Fuel injection enterpises (Spud Miller). Of this lot it seems Spud at FIE and Mike at alky diggers are the cheepest and thought of as the best, still it would cost me a good chunk of cash that I could spend building a rig to get him to do my set up.
Hi Mr Load, this is constant flow MFI not pulsed like the bosch system, I follow what you sre saying about spray pattern, it would be interesting to see the spray pattern at 120PSI on this set up, but I am a bit bussy at that end of the track

best regards
Mike

stevieturbo · Post by **stevieturbo** » Sun Sep 01, 2013 6:19 pm

So it's not like an old K-jetronic type setup ? Even the injectors ?

Would anywhere that tests those be able to adapt something ?

kiwicar · Post by **kiwicar** » Sun Sep 01, 2013 8:34 pm

Hi Stevie
no it is nothing like as sophisticated as K-jetronic there is no method of measuring air mass going into the engine, it works on the having the pump operating pretty well linearly over it's entire rev range pumping the same volume of fuel per revolultion you then if you know the amount of air going into the engine you can use jets in the inlet manifold and a single jet (called a pill) bleeding fuel back into the tank to feed the calculated correct AFR to the engine. You then check it by plug reading

The jets in the manifold port are basically a calibrated hole, well 8 of them all matched, and a spray deflector that shapes the spray pattern.
Fairley obviously it all relys on knowing pretty well the volumetric efficiency of the engine and the exact volume displaced by the pump over it's rev range. You also need to know how the fuel pressure of the whole system rises with revs for the rev range. This is so you can bleed more fuel back to the tank at higher revs by using poppet valves triggered by fuel pressure with further calibrated jets/pills.
There is quite a good explanation here with pictures! http://www.hotrod.com/techarticles/engi ... ewall.html
Best regards
Mike