Problems with scaling P2s
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< me
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Pulse flow is the actual flow under engine conditions. The injector is not open all the time while the engine is running--right? The rapid opening and closing of the valve does influence the the max flow of the injector. A lot of so called companies, when they flow test an injector just locked the valve open when testing for max flow. To get the true flow rate the injector has to be pulsed as when the engine is running.
OD
OD
This throws some light onto the argument and comes close to explaining the results I got in the first post of the thread..... almost .
Can we assume that 380 stock yellows are "pulse flowed" to get the 380 figure ?
Last edited by Brettus; Mar 6, 2011 at 09:35 PM.
I don't know of ANY facility today that doesn't use a "pulse" system to rate injectors.
They use a preset duty cycle which they reveal as part of the testing.
No one just pops them open for a set period of time and measures the volume. It is bad for the injector core.
They use a preset duty cycle which they reveal as part of the testing.
No one just pops them open for a set period of time and measures the volume. It is bad for the injector core.
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/\ OK . But here is the thing ....
The shop that tested for me didn't pulse flow them (ok they must be useless - I agree)
But : they came up with 800ish ccs as a flow rate and guess what the well known shop that does the mod came up with ? ...... yep 800 . That is what everyone (except OD) has been reporting as the rate for the uncapped yellows .
See where I'm heading with that ?
The shop that tested for me didn't pulse flow them (ok they must be useless - I agree)
But : they came up with 800ish ccs as a flow rate and guess what the well known shop that does the mod came up with ? ...... yep 800 . That is what everyone (except OD) has been reporting as the rate for the uncapped yellows .
See where I'm heading with that ?
Go to www.injectordynamics.com for a good read on fuel injectors.....might help understand how they work.............
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Check out the link
http://kgparts.com/index.php?page=rx8modinject
http://kgparts.com/index.php?page=rx8modinject
Check out the link
http://kgparts.com/index.php?page=rx8modinject
http://kgparts.com/index.php?page=rx8modinject
I've been on Keith's page a million times.
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This for starters ....
420-900 is quite a bit different from 720-750 . Plus if you get a test sheet from them they come back generally at 800ish ccs
And this , which is at odds with what they say above
Q: How much will the injectors flow once modified?
A: This all depends on the rate at which they are tested. Common flow rates will be between 720-750cc for the Secondary and 600-620cc for the Primary
A: This all depends on the rate at which they are tested. Common flow rates will be between 720-750cc for the Secondary and 600-620cc for the Primary
And this , which is at odds with what they say above
These injectors have an excellent spray pattern and flow 47% MORE than the injectors in their stock form.
Last edited by Brettus; Mar 6, 2011 at 11:03 PM.
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OK - think i'm on top of this now ...
These uncapped yellows flow around 500ccs on stock fuel pressure/latency . Or put another way .for scaling purposes ... 30% more than the capped yellows.
Think the reason I got another figure for them when tuning NA was that in that operation they would only just be coming on and the % they come in at was throwing the results .
That's my story and i'm sticking to it
These uncapped yellows flow around 500ccs on stock fuel pressure/latency . Or put another way .for scaling purposes ... 30% more than the capped yellows.
Think the reason I got another figure for them when tuning NA was that in that operation they would only just be coming on and the % they come in at was throwing the results .
That's my story and i'm sticking to it
Last edited by Brettus; May 18, 2011 at 07:12 PM. Reason: Changed from 550 to 500
Brett ... this is not what uncapped P2's look like ... riiight? http://www.motoiq.com/magazine_artic...injectors.aspx
My favorite bit:
Stands in stark contrast to the typical answer I get from customers when I inquire about their injector sizing.
On the other hand, it is the tuners responsibility to know, not assume, that injectors, MAF/MAP sensors, fuel pressure, etc. are beyond question before starting a tuning process.
Brett ... this is not what uncapped P2's look like ... riiight? http://www.motoiq.com/magazine_artic...injectors.aspx
Wow. Good find!
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