MFI Pump Dyno build- My newest project
 

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.
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MFI Dyno
 

keep the pictures coming. I am impressed.

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

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.

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. http://forums.pelicanparts.com/uploa...1235953419.jpg

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

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. http://forums.pelicanparts.com/uploa...1235968411.jpg

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

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...

One squirt for every two rpm?

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

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

Kevin

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

...wicked cool!

Very impressive.

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!!!!!

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.

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

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.

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

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. :)

Scott, I have a full copy of the BOSCH PED 6 KL.. maintenance and test flow. Covers all 10 pumps from 69 to 73 but not the 2.8 or 3.0RSR. That I would love to have a copy of. Picture of one of the test flow pages for a 2.4T below:

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Finished the pulley adapter today and mounted the electric motor to the test stand. Bolted the test stand to the work bench. I will finish the wiring of the motor to variable speed control unit tonight. http://forums.pelicanparts.com/uploa...1236038806.jpg
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What is your plan for motor speed control? Variac?

How will you count revolutions for a test?

How will you monitor RPM? Would be cool to use a factory tach modified to take a hall sensor.

This project is OUTSTANDING, thank you for having the courage to tackle it.

When you are finished I'll share my plans for a Bosch distributor machine

John, The speed control is a frequency inverter also a phase-converter to operate a three-phase motor from a single-phase supply. The one I'm using is from "AC Technology Corporation" It's programmable with lots of features like; Independent Accel / decal ramp time; 8 programmable preset speeds; DC injection braking; Speed potentiometer control; Acceleration Boost; ect,ect.
RPM will be counted with a Shimpo Panel Mount Tachometer with an accuracy of 0.01% at all rpm's. Has a 5 digit LED display and reads from 1 rpm to 10,000 rpm. It uses a Photo-Reflective Sensor at 3 to 5 inch. away from the motor shaft. Reflective tape on the shaft.
Counting the revolutions will be with a stopwatch for now. One revolution of the pump operates each injector and of course the same timing, 1,6,2,4,3,5 of the engine. A test at 1000 RPM will take 60 seconds. Tests made above 1000 rpm can be run for 2 min. and then mathematically worked out for different rpm runs. Tests at slow RPM's like 400 work out to 150 seconds, 600 RPM would be 99.6 seconds. I think I'm figuring this out right, but I'm not 100% sure. Looks like it will take 4 hours or more to complete a full test on a good pump.

Installed the electric motor to the test stand and put on the pulley adapter. I will wire up the variable speed control unit tomorrow and test run for vibrations etc. http://forums.pelicanparts.com/uploa...1236047840.jpg
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Got the electric motor running today along with the RPM counter and throttle arm adapter for the angle of degree reading. Hooked up a MFI fuel pump and filter console, set pressure at 1 Bar, filled the boat gas tank with Stoddard Solvent, added the injectors and started pumping. Did a test at 450 RPM then ran it up to 4000 RPM with no problems.

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That is awesome... Congratulations.

Mark:

Would there be any benefit to mount the MFI pump body to some type of vibration isolating blocks on the stand?
Great project!

Regards,
jp

Great work Mark - glad to hear you could hit top speed without any problems- did you stay with the 1/2 hp motor? How was the overall rigidity of the setup ?

John

Mark, you are my hero. This rocks.

I love this kind of "take control" approach!! Bravo! This is what makes the Porsche DIY community so amazing!

Let me know if you need another test subject....'73 2.4S MFI pump currently running on 2.7RS motor....you know, just for more data points! SmileWavy

JA

Let me answer some of your questions: JP; Several people have been concerned about the stability of the pump mount, including myself. I used 3/4 inch OD solid round Aluminum stock for the pump mounts on all four corners. Made sure the 2 rear mounts were welded not only at the bottom, but also up the side of the drain bowl. Those two will carry most of the load. Running it today @ 4000 RPM showed just about zero vibration. Very smooth at all speeds.
John; As far as overall rigidity of the pump test stand, it is made up with 3/16 Aluminum and bolted to the table. I can work on the pump, like remove the outer pulley hub and also remove the inside collar nut that secures the space cam & counter weight with no problem. Solid as a rock. Oh, buy the way, It's a 1/3 HP motor. Happy to see it turn the pump so well.
JA; One of my reasons to do all this was so I could change the space cams like on a 72 T pump with a RS space cam and then dial it in to spec. I have 7 MFI pumps from year 69 to 73 I can't wait to check specs on.
And after a few pump tests and fine tuning under my belt, I'll be ready to take on someones pump.

Fantastic work Mark (and the custom glassware looks great too)

I'm sure you'll be needing a bunch of NLA tools (or substitutes) to help set up your pumps...

Here's a few I've built (for taking a micrometer head) - 17mm is the retracted "zero point" on the Mitutoyo spindles that I have.

http://forums.pelicanparts.com/uploa...1236141105.jpg

And for the rack displacement....(thread on right image is M14x1.5 for the MB/RSR threaded rack bush)

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I've also found that a cheap cast iron 2" G clamp with a few mods (cut, braze and bush) makes a great dial guage stand (for the baro cell, thermostat) - I'll post a pic if you're interested.

John

This just got even better.

John, This is great! This was the missing piece of the puzzle I hadn't had time to figure out. Yes pictures of the tools would be perfect. Thank you so much John.

Sorry to hijack - I'll run a seperate thread for some of the MFI tools I've made (drawings, how to's and explanations for each) and post a link here.

Mark - Are you using a commercial tool to remove the round nut that retains the flyweight assy from the cam?

John

I took a socket and ground it down until I had the two tangs needed to remove the nut and access the space cam. Worked great many times!

It would be interesting to develop some type of model or program so custom space cams could be CNC'd to fit a given builder's needs. Would not be complicated for the right person. Basically just a physical map of throttle position by rpm.

I used to run a black felt pen over the space map and go out and run the car at the place I need more fuel. Then take the pump apart. The space cam left tracks where the black was. Then I would bet my hand grinder and file out.

;)

:)

Not a hijack John. All good stuff and good information.
I made some tools for removing the flyweight assembly. The tool on the left is a puller made from an old VW transmission hocky stick. Drilled out a hole and taped it for a long fine thread bolt, works great. The tool on the right is for holding the MFI pulley while I use the modified scoket, below, to remove the collar nut.

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Great tools Mark - thanks for sharing

911st - like your idea of using the felt tip pen to record points of contact

Thx ;)