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EFI/N2O JUNKIE
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Discussion Starter · #1 ·
I built my own flow bench so I could check my stuff and help out others I race with. Now it's time to check the flow rates I observed to the published flow rates. Anyone familar with this type of stuff?

What's the easiest way to do it. Convert the lbs/hr rating to cc/min? I am using graduated cylinders which are marked in cc's. I am using mineral spirits as the liquid.

I'm not so concerned about an injector flowing exactly what it should, more concerned that they all flow the same. I have a set of 83 lb/hr injectors that were flowed on a real bench, they all showed the same. Well, two of them weren't and almost hurt my motor! Six of them are identical, one was a little lower, another a lot lower! I caught this with the spark plugs and pulled them out and put my old injectors back in there. No damage was done.

This is what led me to build my own bench. I am using a real fuel rail I built so I don't have to pull the screens to check the injectors. They are being flowed exactly as if they were on the motor.

These 83 lb/hr injectors fill the tubes VERY FAST!
 

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i had mine flowed at a napa store in wv after i blew a headgasket...$10 each...their setup sounds similar to yours. they all flowed the same amount into graduated cylinders.
 

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We run mechanical fuel injection and do the exact thing, volume over a give time.
For EFI it would be interesting to know if they all flow the same at wide open and when they are pulsed. Do you have the elcetronics to try that?
 

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EFI/N2O JUNKIE
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Discussion Starter · #4 ·
I did my own electronics so I can basically do anything I like.
I am currently flowing them for 5 seconds with a 5mS pulse width. I only have 100cc graduated cylinders and they fill half-way with the 83lb/hr injectors right now! The 30's are a joke. Amazing how little fuel they flow!

If I had a store around here that would flow them for $10 a piece that would have been cool, but we were paying about $200 per set to flow/clean/re-flow/ then put in new screens. That's why I did my own bench.
 

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EFI/N2O JUNKIE
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Discussion Starter · #6 ·
Yeah, that guy can certainly give me more info than I can use! My old ECM has no provisions for the dead time much less individual cylinder correction.

Does anyone have the ability to actually open an injector and check it inside? I have two that flow a lot less than the other six. They've been cleaned with carb cleaner, brake clean, left in an ultrasonic bath for an hour, no change. I guess I will buy two new ones unless there is a way to actually fix these two.........
 

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mfi turbos rule
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I built my own flow bench so I could check my stuff and help out others I race with. Now it's time to check the flow rates I observed to the published flow rates. Anyone familar with this type of stuff?

What's the easiest way to do it. Convert the lbs/hr rating to cc/min? I am using graduated cylinders which are marked in cc's. I am using mineral spirits as the liquid.

I'm not so concerned about an injector flowing exactly what it should, more concerned that they all flow the same. I have a set of 83 lb/hr injectors that were flowed on a real bench, they all showed the same. Well, two of them weren't and almost hurt my motor! Six of them are identical, one was a little lower, another a lot lower! I caught this with the spark plugs and pulled them out and put my old injectors back in there. No damage was done.

This is what led me to build my own bench. I am using a real fuel rail I built so I don't have to pull the screens to check the injectors. They are being flowed exactly as if they were on the motor.

These 83 lb/hr injectors fill the tubes VERY FAST!



the mineral spirits, is it the same or very close to SG to the fuel you are using???

if not
don't waste your time...

been there, done that.
the spefic gravity ( spelling) is VERY important....


ash
 

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EFI/N2O JUNKIE
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Discussion Starter · #8 ·
That I could not answer. I was told to use mineral spirits since it would be close and not pose a fire hazard like gasoline would. I could certainly use the same race fuel but I would do it outside, not going to take that chance!

I am not looking to try and measure some unknown injector. I am only looking for the difference between the same type. My spark plugs and wideband showed me there was a problem and the flow bench verified it.
 

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Mineral Sprits is 0.790 which will be close enough depending on what fuel your running. The biggest thing is making sure they all flow the same and a good pattern. More then likely you are watching a/f and/or egt so mixture can be adjusted across the board accordingly.
 

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Has anyone had any real success with trying to CLEAN an injector? Back in the day, we used to pull the screen out, turn it upside down, apply 12VDC to open the injector, and blow compressed air through the body. Worked OK, but not great.
 

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EFI/N2O JUNKIE
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Discussion Starter · #11 ·
I have only seen people that got something in the screen be able to clean an injector. They would use a 9 volt battery to open the injector and spray carb cleaner backwards through it. Never saw anyone have any luck cleaning an injector without an ultrasonic bath.
 
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