MFI Pump Dyno build- My newest project

[356RS]

Inspired by Jeff Higgins sharing knowledge with his MFI pump on his 3.0, "MFI Open Heart Surgery" I decided to build an MFI Pump test stand/ Dyno.
Here are some photos of the first step. This stand will hold the pump and electric motor needed for testing at various RPM'S & throttle angle. The stand well have lots of area around it for working on the pump. A drain in the tub part for catching oil after the cover is removed for adjustments etc. I'm just now finishing a mount for an inclinometer that will fasten to the throttle arm of the pump. A 1/2 HP variable speed electric motor will be mounted under the test stand. An optic sensor will be used with an RPM display for RPM monitoring. Next step is to build another stand for the graduated cylinders, glass funnels, for seeing injector spray patterns and drain area for the Stoddard Test Solvent after tests are documented.

[Fritz Peyerl]

keep the pictures coming. I am impressed.

[jcge]

Mark - not sure that 1/2 hp will have the required power to get the pump to 4000rpm

Just a suggestion - try taking a "static" torque reading with a torque wrench slowly turning over a pump (with injectors and fuel connected) to get an idea of the torque required, then calculate the power required (I'd probably add 30%-50% capacity above that)

OEM Pump dyno's are rated much higher that 1/2 hp - think 10hp or 20hp (although they are designed for running huge diesel pumps)

I'd think 4-5hp would be required.

Great work - very interested in your progress

Regards
John

[356RS]

Thanks John. I'm putting on the fuel lines and injectors now. Will set up the electric fuel pump at 1 Bar and see what "static" torque reading I find and let you know.

[356RS]

Not much of any load at 1 bar with all injectors running and spinning by hand as fast as I can. Injectors were all delivering fuel even at that low hand speed. I'm sure at 4000 rpm there will be a load.
Making a hub for the electric motor so I can bolt on a MFI cam pulley. I will be able to us the stock MFI belt with the motor mounted under the pump test stand.
Worked on a cardboard mock-up of a stand that will hold the graduated test tubes and the funnels.

[jcge]

Mark - The torque to turn the pump does seem low, but it all adds up at speed....just 4 ft.lbs of torque equates to about 3 HP at 4000rpm (just for illustration - I've NOT measured the torque at 4 ft.lbs)

Maybe shaft size will help put you in the ballpark for motive power requirements....the MFI pump cam is 17mm diameter at the bearing journals....electric motors of about 3.2HP are typically 16mm (5/8")....

In terms of measuring pump output - the specs are usually defined in terms of cc/400 strokes @ speed & angle.

With your belt drive setup (I'm assuming no clutch), you will need to divert the injector output away from your measuring cylinders until the pump is up to speed, then redirect into the measuring cylinders for measurement for 400 strokes, and then bypass the measuring cylinders again on the wind down. Maybe need to link into the tach signal to facilitate the counting of the 400 strokes aand use some solenoids to divert the flow ???

Hope this is useful info - not trying to be critical !!!

Regards
John

[356RS]

Thanks John,
I am looking into the variable speed motor set up, and from what I read the motor can rev up to a programmed speed, like 4000 rpm, from dead stop to full speed in less that a second. But I under stand what you are saying.
I have a copy of the Bosch pump manual and it looks like the tests are run for 1000 strokes, but my German is very bad. Wish I could find a USA edition.
Any additional feedback would be appreciated. Again, Thanks John.

[jcge]

My error Mark - it is 1000 strokes

You may also need to damp down the mist from the injectors - steel wool might be good for this - not sure how it's achieved on a full sized dyno.

Mock up is looking good !!!

John

[RWebb]

Holy Moly -- I am either impressed or aghast.

Since you are investing so much effort already, how about re-engineering the pump out of titanium, aluminum, magnesium and berylium? It would be really light wt. then...

[911st]

One squirt for every two rpm?

4000rpm at the pump, 8000RPM at the crank?

[kwikt 911]

WOW, very impressive Mark!!!!! Can't wait for the results.

Kevin

[356RS]

Yes, that's right. Engine @ 8000 and pump will be @ 4000 rpm.

[arrivederci]

...wicked cool!

[Zeke]

Very impressive.

[Gary De]

Have you check Bernd Buschens photo galleries at pbase.com? There are some great photo's of an MFI dyno at Pacific Fuel Injection. Thought it might help.
Keep the pictures coming. Great Job!!!!!

[356RS]

Yes I did Gary, and the pictures were very informative. I noticed the funnels on top of the test tubes are more like a tall wine glass than a standard funnel. As a mater of fact I started looking for some tall funnels like that and after 3 days of looking came up ZERO. It seems the Lab Glassware companies make the normal funnel or a power funnel, but if you need a tall, 3 inch. or so, it falls into the Filter Funnel class. I found you can't get them without the filter. So I had some made by a Custom Glassware company @ $30 each and they are perfect. The tall funnel on top is needed so to see the spray pattern coming out of the injectors and of course to funnel the fuel down into the test tubes/graduated cylinders.

[jcge]

Mark - you may want to attach something a bit more structural to the bottom of the 4 pump mounting bosses - from the pics above they appear to be welded to the tray sheet metal. At full speed, vibration / fatigue would likely crack the bosses at the bottom welds, or perhaps flex the sheet sufficiently to throw the belt. Maybe drill and tap the bottom end of the bosses and and attach them to some angle welded to the frame.
Regards
John

[356RS]

Good point John. I will see what can be done to strengthen the 4 posts. Making the pulley adapter for the 5/8" motor shaft after work today. Should be able to mount the motor under the test stand tonight.

[Porsche_monkey]

Brace them with flat plate in an X pattern....or add an aluminum plate to each side.

[YTNUKLR]

Does anyone have copies of the MFI pump flow spec. books? I don't recall them being in CMA. I do have a correct spec. sheet Gus has done for an RSR 2.8 pump, if you need a copy.