Gordons Pitot - Very experimental bench so far...

[slracer]

Hi Gordon, I never thought of myself as a "pitoter" before, but I guess I am. :O I went back to some of my calibration runs to try to answer your question: "How much do you other pitoters get from your motors?". With a 100CFM calibration plate and a 1.57 inch flow element (nominal 1.5 inch PVC), a single motor gets a max depression of about 6 inches H2O. This is about 44CFM when corrected to 28 inches H2O and at Sea Level on a Standard day. The second motor raises the depression to over 22 inches H2O which is about 84 CFM corrected. I am not able to get 28 inches with this calibration plate. I will be ordering a 50 CFM plate soon. I have run from 2 inches elevation to 7 inches on my variable manometer and the results are pretty consistent (except at 5 inches max inclined - have to figure that one out yet). When I block the entrance, I reach 44+ inches depression on the vertical before I reach 100% on the second motor. I do this to check for leaks and show no flow on the inclined so there are no leaks. I have attached a spread sheet (that has been seen before) with these results (but they don't indicate the single motor limit). The Actual flow values are shown on the spread sheet before correcting to SLS. Hope this helps! -- Doug

Hmmm! It seems that something is blocking the spreadsheet results. If you "Save As", it either disappears or you can close the chart causing the problem. Any computer (Excel) gurus out there?

[GordonE]

Thanks guys!
The bench is still up an running, sadly I havnt had time to build the pitot probe yet. I havnt got the outer tube yet. I guess my friend that should order it has forgotten about it.
I must fix that soon, I must lern to use it... Its stupid not to when I got a trancducer for it!

I have done some more porting now this weekend and I always use one of the plates to calibrate the machinery. It works great. I think I dont even have to think about the pressure and temperature when im doing it this way... I just alter a multiplicator to get it right!

Im now up from 181 to 226CFM, its almost 25% increase and over 20% over most of the curve! I have installed 2mm OS valves.
I have done a little test with backcut on the valve if someone is interested.

I am getting a little carried away, so I have baught a Mira valve seat cutter and a almost antique Van Norman valve grinder that needs some service and paint. I havnt gotten them yet but in a couple of weeks they are in my possession!

SLRacer: I have never tested below 28" so I am not that sharp at that. Do you mean that each motor could give around 44CFM @28"?

Regards Gordon

[GordonE]

Hers some pictures!

Me and my bench!


Inspirational Car craft magz from 1982! The owner of the magazines said that he had copied the articles at least
10 times, but noone had ever built a bench!That felt good! Eventhough i havnt used much of the design!


Heres some Volvo intakes that flow alot differently!


Here is some before and after flow data on a volvo 531 head.Standard intake valve is 44mm now it is 46mm.


Here is a 32 degree backcut on the valve. As you can see mid lift gained and high lift loss flow. Overall 1.8CFM increase!




Other head pics!

[bruce]

Thanks for sharing your pictures! Looks good another well done home built flowbench!

[GordonE]

Thanks Bruce!
Thank you for having this great site! Without it and its members I would never have come this far.
Sorry for not buying your flow computer, I got a little bit to eager and couldnt wait. Had your computer been ready
a couple of months ago I would defenetly have baught it!

[bruce]

[slracer]

GordonE, I missed the question in the earlier post! Sorry for the delay. My flow comments are based on whatever depression I could get, then converted to a "sea level, standard day" at 28" depression. The converted numbers for the results would say first motor about 44CFM (at 28) and second motor about 40CFM more. There has been much discussion on this forum about what happens at higher depressions so I would not be comfortable saying that each motor will draw 40-44CFM at 28 inches. I'm trying to make some changes in the bench right now and want to look at it in more detail when those are finished, but I don't think it is totally linear, i.e., 1 motor - 44CFM, therefore 8 motors - 352CFM. Just my opinion. I also am not interested in big engines so I have only 2 motors.

Doug

[GordonE]

[color=#000000]Hi!
It has been a long time since the last update.

Tests

I havnt used the bench much, my garage buddy has worked on a head that he s going to use on his Volvo 5cyl engine. This head was preaviously ported by a old man that is a little famous around here, but he is pushing 80years, so he is not so up to date(wich it turned out).

The head had bigger valves so my buddy has always been certain that this head was much better than a standard head(bigger is better). When we compared this head to a standard head it turned out that she standard head outflowed the modified one all the way up to 12mm, there after the modified one was a little bit better. His cams lifts 11mm.
It turned out that the valve seat had a too small inner diameter. I think that it was around 80% of the valve area.
Now he has worked a bit more on the areas and now it works much better!

Im happy that my buddy has lerned something

I also flowed a RallyCross head that had been on a 2.7L volvo four banger. It is told that it were built by a famous engine builder(K

[FPV_GTp]

GordonE again I must comment nice work , what electronic/flowmeter are you using on your bench ?

cheers

[GordonE]

Thanks!
I use my own diy made stuff. Its based on some motorola sensors and board, together with a DAQ and a lab program and a Excel sheet to savethe graphs on. I can easyly do a intake test in five minutes with 15 mesuring points.
Its a Pitot bench, 3" home made mesuring pipe with averaging pitot made out of a copper brake line.
The bench is very accurate between the tests. Very easy to calibrate!

/Gordon

[GordonE]

Today I tested exhaust/blowing for the first time. It turned out to be no problem at all.
I just flipped my pitot pipe 180 degrees around, and recalibrated with my plate.
Then I had to make a pipe to bolt on the exhaust. I tested the difference with and without when I had no valves installed on the exhaust side. Without pipe it flowed 240CFM and with almost 280!
So dont try to flow exhaust without one!

I also tested the flow of the ports without the valves installed. The exhaust side flowed more with the valves removed, and the intake was the other way around.


I am trying to get a friend to CNC mill my intake ports. I have made a model for him, but right now im waiting for him to make time for it! He also is going to mill the final shape on my new flywheel in the nearest week I hop. I will update when the head is milled and when im beginning with the final grinding!

Thanks Gordon

Intake and exhaust:
The flat lines are ports without valves installed.