RE: injectors

From: Bernd D. Ratsch (bernd@texas.net)
Date: Fri Aug 22 2003 - 06:52:51 EDT


If your LTFT is at -25, what's your STFT at? On the engine mods, I can
see why it's running rich as well. Cam, Heads, Intake,
Exhaust...uhhhh...did you forget something else in the equation?

On the specs, yes...the first two are from specifications (but change
the fuel pressure and you can figure it out). The 3rd one was done with
"real world" testing (still have the sheet as well after they were sent
back).

- Bernd

-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bob Mankin
Sent: Thursday, August 21, 2003 11:14 PM
To: dakota-truck@dakota-truck.net
Subject: RE: DML: injectors

Tony, don't forget to take the square root of that driven/test pressure.
That would put them at ~22.5# with a rail pressure of 50 psi.

Another data point: I currently run Design II Accel 24# injectors in my
R/T. Purposely changed the connectors out some months ago in
anticipation of eventually going to 36# FMS units. For those that don't
know, you can't get the newer Design III in larger sizes just yet, so it
was the only option. LTFT is right close to -25 with these 24 lb units.
You do the math. Does that suggest 19 or 21 lb injectors are a better
fit?

BTW, that's with a 215/218 @.050 .521 lift cam, heavily ported 2.02 R/T
heads, 52x55mm TB, M1 intake, full exhaust, etc. Still think an injector
upsize is an absolute necessity for heavy mods????? Caveat: the truck
doesn't get alot of WOT work in it's present condition.

I've never seen a definitive for where the 21# figure came from. A book
is nice, but eventually you have to put it down and get in the real
world. I've seen Bernd's posting and once I wade through the confusion I
see a spec for the injector flow rate and I see a spec for the fuel
pressure. Two different specs, not two parts of the same spec. An
injector is assumed to be rated at 43.5 psi or 3 bar(industry standard)
unless otherwise stated.

Real world testing was done yesterday with a brand new injector for an
'02 Ram 5.9L application. Take it for what it's worth.

All done.....now back to your regularly scheduled programming :-)

Bob



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