Supermono Project - students racing team needs flowbench

[Rik (the Netherlands)]

[color=#000000]Let me introduce myself and my problem.

I am Rik from the Netherlands and i am a student at an "automotive engineers college". This college has a racing team that races a Yamaha 686cc supermono bike. The members of this team are all students who can build up experience in this team. Of course (a motorcycle fanatic as me) i am part of this team.



Recently we have decided to try to optimise our cilinderhead by flowing it. And because we want to learn something from it we want to do it ourselves. Our budget wont allow us to buy a new bench so we have done some research and i have decided to build a bench (pitot type) for the team.

Building it wont be a problem, but the choise for the vacuum unit will be difficut as well as the calculations about CFM. Of course we stiffneck europeans have the metric system, which will be a little different (i have allready experienced that wile restauring my 1943 Harley WLA, recalculating all the tolerances from inches...).

I thought of using vacuum-cleanerengines but i cannot run 8 of them on a circuit. In the Netherlands we have 220 volts at 16 amp

[gaz]

Hei Rik. I'm really glad I'm not the only european here :). Seams Like we have a lot common. I also am a student and studing automotive engineering in Tallinn Technical University.
For the metric system and calculating cfm have a look at my little homepage .
Ive done alot of searching and i think I have made a working excel file for calculating flow. I'd really appreciated if you (or anybody) would give your opinion or suggestions about it. If anybody wants to communicate with me directly then in that file there is my email and msn address.
Thanks everybody.

[Rik (the Netherlands)]

[color=#000000]Yo Gaz,
i can tell you have put a great effort in there. The excel will be very handy.
But i have only one request: could you translate the scandinavian to english? that would be even greater

[gaz]

Now it's OK I think.
One question for older flow bench gurus: is the valve lift always 0.05; 0.10; 0.15 ... inces? I remember finding a formula for calculating the right steps for lift once but I can't find it any more. How do you take your measurements?

[bruce]

If you are working with various valve diameters and comparing flow numbers you can do a conversion based on lift/dia ratio so your lifts would give you the same approx curtain area to compare changes of flow. So you can compare flows of different valve diameters to each other in the same head.

This again all depends on the level of accuracy you want to attain in your numbers? There is no right or wrong way to flow anything, there are some things that work better though. If you acheive whatca are looking for then you did it the way you needed to do your testing. Don't be stuck in your thinking process . . . dare to think outside the box!

I personally utilize the great ideas I hear on this forum or read on the net to accomplish my own flow testing procedures, is it right or wrong I don't know but thats half the learning process. I work on mostly flathead engines so the "procedures" for OHV engines might not give me the same findings on the flathead style of engine.

One tool I added in the past few weeks was a swirl meter that sits in my cylinder and shows me rotation of flow and speed. I've found some interesting things just playing with it. I need to develop some procedures that give me numbers that mean something from test to test. So what I am getting at is you need to develop what works for you in your testing . . .

[84-1074663779]

Greetings from Australia.

Bruce is spot on, there is no right and wrong way to go about this. The main thing is to have a reliable, repeatable, stable system of measuring things so you can detect small changes.

America is about the only country in the world still officially using Imperial units, but as a lot of parts, literature, and software originate from America, so Imperial units are still widely used as an alternative system.

Even though we are supposed to be fully metric in Australia, inches of water, and pounds per square inch are in universal use and will probably never die out. Camshaft duration is still quoted at 0.05" lobe lift by all the cam manufacturers here.

[Rik (the Netherlands)]

HE hey.
Does anyone have looked at my question??? :angry:
About the vacuumengines.



:laugh:

[bruce]

There has been plenty of previous posts on the use of various blower motors to include some Excel charts that actually plot flow curves and shows you the differences.

What flow depression do you want to test at and how many CFM's of flow do you require? My current bench uses a leaf vac motor and shows very small changes on valves up to 1.380" dia. A shop vac allows higher flow depression. Alot is going to depend on what your requirements are going to be. My answer would be yes 2 motors will work well for the testing you need to do on a budget. Make your bench so you can add more later on if you feel you need to upgrade

[2seater]

I'm not sure what the end performance will be, (still in the process of building), but I purchased cheap GS Electric vacuum motors from Surplus Center, $17 each U.S. Maximum flow rate is 127 cfm each and maximum of 91" of H2O vacuum. They are single stage, Max. of 12 amps @ 120 volts (1440 watts). Probably not as good as the Ametek motors, which seem to be the standard here, but very reasonably priced. Even if you cannot pull the vacuum you desire, you can interpolate the results to whatever pressure drop you desire. E-bay may be a good source also.

[2seater]

I'm not sure what the end performance will be, (still in the process of building), but I purchased cheap GS Electric vacuum motors from Surplus Center, $17 each U.S. Maximum flow rate is 127 cfm each and maximum of 91" of H2O vacuum. They are single stage, Max. of 12 amps @ 120 volts (1440 watts). Probably not as good as the Ametek motors, which seem to be the standard here, but very reasonably priced. Even if you cannot pull the vacuum you desire, you can interpolate the results to whatever pressure drop you desire. E-bay may be a good source also.

[84-1074663779]

Rik, I suggest you try fitting a couple of vacuum motors to a simple wooden box and try some blower tests for yourself. As Bruce says, this topic has already been pretty well covered in previous threads.

I suggest you R&D a suitable blower "system" before you do anything else, then build your flowbench around your choice of blower. Everyone seems to have different ideas about how much air is required. You will soon discover that high flow and high test pressures require massive drive power, and astronomical drive current which may, or may not be practical in your situation.

Another problem is that vacuum cleaner motors usually give high open flow, and develop huge zero flow stalled pressures, but often are not very good at providing reasonable mid flow at reasonable mid pressures. Some are better than others, so some testing might be in order.