Calibrating FP1

[Mousehouse1]

If I had the FP1 set on mode 1A when I was using the 3.068 orifice which is suppose to be 1C would that make my cfm readings low? I am picking at straws to figure this thing out. I am lost.

I also haven't had the time since I received the FP1 box to sit down for a few hours and get everything working.

What is a good way to check for leakage?

John is there anything in the box I could have messed up by having the hoses on wrong?

[Mousehouse1]

I found out I was in mode 1A trying to flow or calibrate the two bigger orifice holes. Everything seems to be working the way it is suppose to now. I will know more when I can play with the bench later in the week.

On the big 3.068 orifice hole it takes 4-5 motors to reach 28" of pressure and then calibrate the FP1 down to the 118.3 calibration plate. Can't wait to flow test my cylinder heads.

Thanks everyone for all of your help.

[larrycavan]

[Mousehouse1]

Larry I have been reading over the information that came with the FP1. I am starting to understand it a little better. When I set up the orifice sizes I thought that changed which orifice the FP1 was reading. I was wrong. So for the past week I have been on the 1.270 trying to calibrate the other 2 orifice sizes.

Thanks again for all of your help.

[larrycavan]

Martin,

There you go. First set all your diameters, then go ahead and fiddle with the Cd and the calibration plate. Let me know when you're ready and I'll email you a tweaked version of the Excel sheet for the FP1.

Larry

[Mousehouse1]

Larry email away.

[Mouse]

Glad you got it working Martin.

Just for those who may be reading along, the FP1 comes calibrated as a dual manometer. When you connect it to your bench, you need to calibrate your bench, not the FP1. The FP1 gives you the ability to fine tune your bench calibration for multiple orifices. Of course, a Pitot tube flow element requires only one calibration value.

Larry, I have been looking at end caps at the hardware store trying to locate really flat ones. Working on it.

[Mousehouse1]

I ran into another problem today. I was able to get all of the orifices calibrated except the 1.270 one. With all 8 motors on I couldn't get the bench to 28" of pressure. I only had to use 5-6 motors for the 2.330" & 3.068" ones. I think the pressure peaked at 27.6". Any ideas why? I need to try the other two holes around the 1.270 one to see if it is just that one that is giving me problems. Since I only have to use 5-6 motors on the bigger ones I should be able to use less motors with the small orifice. Shouldn't I?

[Mouse]

Are all your motors the same rating?

[Mousehouse1]

Yes. They are all the same.

I used 5-6 motors for both the 2.330 & 3.068 orifice holes to get 28" of pressure. I had to almost shut the intake valve to get the pressure down to 28".

Here are the cd numbers for the 1.270 @ 10" of pressure (1.06), 2.330 @ 28" (.375) & 3.068 @ 28" (.413). All of them read 118.3cfm. Is this correct? Shouldn't the cd numbers be higher?

I need to try the holes on each side of the 1.270 and see if they need all 8 motors. I just find it strange that the other day I had to use all 8 motors with this same orifice hole but got around 30" of pressure. Today it was only 27.5".

I will mess with the bench more tomorrow. I am just glad I got two of them done.

[gofaster]

Maybe something cracked or came loose internally, creating an internal leak. I had a similar situation crop up where I was starting to chase depression during a test on my SF-110. It turned out that a loose electrical connection inside the bench (made up of U-connectors bolted together through an inner bulkhead) was getting hot and burning a hole in an inner wall. It almost got ugly!
That brings up another question for the members of the forum. What kind of bulkhead connections are you using? I was planning to use the same ones as I found on my SF-110. When I went to the local electric supply house, they couldn't recommend anything else when I asked them to suggest a better solution. If I don't do anything else different, I think I'll at least use a locknut of some kind on the U connectors.

[Mousehouse1]

I started to do the exhaust side. I used 1.270 & 1.780 orifice holes. The cd #'s are .73 & .492

If I use a bigger orifice hole like 2.330 or 2.5 I can't get more than 60-65 cfm out of the bench when testing the exhaust side. Would this mean there is a leak somewhere?

What is the easiest/best way to check for leakage on my bench?

[Mousehouse1]

I wasn't getting the calibration plate sealed against the bench. Everything is working fine now & everything is calibrated.

Thanks guys for all of your help.

[larrycavan]

[Mousehouse1]

Larry since I found my leak problem the cd's aren't as bad and all of them are in the .40-.70 range. I will see how close my machine is to Chad's when I fix the valve issues.