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I don't know exactly what you are trying to say but I've done fuel flow tests as described many times and it was repeatable. The test as described will be MORE than adequate to show any problems. Tests like this aren't exact but you only need enough accuracy to show a potential problem.
I'm saying if its a close measurement or you want accurate repeatable results a hand held stopwatch isn’t the tool.
If a human could start and stop a stopwatch accurately repeatedly we would all have much more consistent reaction times.
 

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I'm saying if its a close measurement or you want accurate repeatable results a hand held stopwatch isn’t the tool.
If a human could start and stop a stopwatch accurately repeatedly we would all have much more consistent reaction times.
What's "close" and what's "accurate"? Sometimes .001 second isn't important when 1 second gives you reasonable results.

Comparing a test like this to racing reaction time is not a valid. Hundredths of a second are a big deal with reaction times, field flow tests only need to be accurate within a small percentage. I've run many valid field tests using the second hand of my watch which isn't as accurate as a stop watch.

Let's take a realistic look. If it's a 30+ second test than +/- 1 second accuracy will give you a 3.33% level of accuracy based on the time element.
 

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I'm not saying it didn't happen but the stopwatch is not going to be accurate.

Edit: Let me rephrase you will not be consistent or accurate with said stopwatch.
It's accurate enough. An old style sports stopwatch is not hard to be within a few 1/100th of a second to .1 sec. If you're more than 2/10th you have a problem with your reflexes.

Take the same -8 line and set the regulator at 5 psi, and then 8psi and you can measure the difference. It's noticeable.

Take the -8 line and then reduce it to -6 fitting at the end. You can measure the difference.

Take the same -8 line and put a -8 hose fitting on it that has a built in reduction because it's choked down and you can see the difference.

You can either run the stopwatch at 15 seconds, or 30 seconds. Or run to a pre-determined fill line and you can see the difference.

Try it sometime.
 

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I don't know exactly what you are trying to say but I've done fuel flow tests as described many times and it was repeatable. The test as described will be MORE than adequate to show any problems. Tests like this aren't exact but you only need enough accuracy to show a potential problem.
Obviously he has never done it.

Back to back the results are consistent.
 

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Discussion Starter #25
I've done the flow vs time test, too. I am not a fan of "close enough" but in trying to determine flow the length of a car, one second either way over 30 isn't going to make or break the system. At least not at 500 - 600 hp. Thanks everyone for your input... if I want to lose sleep at night, this won't be it! (y)
 

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Obviously he has never done it.

Back to back the results are consistent.
The tests could be consistent but not accurate. The flow is effected by start up time, fuel in line pump slow down and fuel momentum.

Can be good for comparison of 2 setups as long as very little of the overall design doesnt change.

The longer it runs the better the accuracy. Run each for minutes and you'll be pretty accurate, 1 second and it's a guess
 

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1982...

After having two oil filter adaptors blow off the block on my 351-C (using four 90's with 100 lbs. oil pressure cold) I asked my neighbor to come over and take a look.

He was a hydraulic engineer for Kearny & Trecker Machine Tools for 30 years.

He took one look and told me to ditch the forged 90's and use the "street el" style with the nice, curved tube. End of the issue. Raced that set-up on my dirt car for five years without any issue.

He said those forged fittings added so much back pressure that I was throwing the equivelant of 1000 lbs. of pressure on those joints.

BTW... one oil filter adaptor was a cheap, cast type. The other that failed I had custom built by NASCAR legend Banjo Matthew's shop. When I called Matthews to tell him his his threads blew out he told me I was on my own!

Just my experience...
 
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