Josh Able: puny fuel injectors

[pbureau@attbi.com (ATS - Patrick Bureau)]

Yanno, talk is cheap, Dyno Chart speaks by themselves .. (GRIN)
No I am not doubting what anyone is saying here...
Just wanted to throw 2 cents in the argument...
it's a canadian thing... don't worry about it. :)

==========================================
ATS - Patrick Bureau
1985 8v **Planning 3A/JH  Upgrade**
1988 16v ** FOR SALE : 1000.00$ **
Web Site : http://longcoeur.com/scirocco


=>-----Original Message-----
=>From: scirocco-l-admin@scirocco.org
=>[mailto:scirocco-l-admin@scirocco.org]On Behalf Of Josh Able
=>Sent: Tuesday, June 11, 2002 11:22 AM
=>To: Scott F. Williams
=>Cc: scirocco-l@scirocco.org
=>Subject: Re: Josh Able: puny fuel injectors
=>
=>
=>
=>31 pound = 310cc
=>running at about 75% duty cycle
=>
=>trust me Scott, other shops that sell full kits use these and
=>produce 350ish
=>hp.
=>
=>
=>These are larger than stock.
=>
=>
=>
=>Josh Able
=>
=>----- Original Message -----
=>From: "Scott F. Williams" <sfwilliams@comcast.net>
=>To: "Josh Able" <mkii@nycap.rr.com>
=>Cc: "Scirocco List" <scirocco-l@scirocco.org>
=>Sent: Monday, June 10, 2002 11:48 PM
=>Subject: RE: Josh Able: puny fuel injectors
=>
=>
=>> > nope, even 20v turbos pushing closer to 375hp use 310 many times,
=>anything
=>> > they tend to run to rich.
=>>
=>> My man, this is 100% *impossible*. Way more gasoline is needed to make
=>that
=>> kind of power. This isn't even an engine capability discussion. We're
=>> talking about the amount of chemical energy stored in a given volume of
=>> gasoline. There's only but so much in there! Like I said
=>before, there are
=>> three ways to flow more fuel:
=>>
=>> a) increase the fuel pressure
=>> In order to make 297hp at the wheels, you'd have to run a fuel
=>pressure of
=>> 185psi. This is about 4x the stock amount. Not only would this burst the
=>> fuel lines, it would blow the fuel pressure regulator to bits,
=>destroy the
=>> injectors immediately, and would completely overwhelm the engine
=>management
=>> system.
=>>
=>> b) leave the injectors on longer
=>> The injectors can only flow their maximum rated amount of fuel. In your
=>> stated case that is 310cc/minute at full duty cycle. However, the ECU
=>pulses
=>> them on/off at anything less than full load. That is how you get a
=>variable
=>> amount of fuel delivery. Figure at idle they might be running at 5% duty
=>> cycle. Running them at maximum flow (non-pulsed)is 100% duty cycle.
=>However,
=>> the maximum safe duty cycle is 80%. Pushing the injectors beyond this
=>point
=>> for a prolonged period of time will destroy them.
=>>
=>> To make the point clear, in order to deliver enough fuel at a
=>*dangerous*
=>> 100% duty cycle (at 50.75psi fuel pressure) you'd need to run 480cc
=>> injectors! Those 310cc pee shooters would be overwhelmed at
=>just 210hp! In
=>> fact, with that math considered, it sounds like the 310cc are
=>the engine's
=>> *stock* injectors.
=>>
=>> c) install bigger injectors
=>> If you're following me so far, you'll understand why what
=>you're claiming
=>> isn't feasible in the slightest.
=>>
=>> > hm..31 pound injectors do = 310cc right?
=>>
=>> Er... *no*. The conversion is actually 10.5:1. That is, 1lb/hour =
=>> 10.5cc/min. So, if you've really got .31 pound injectors, then
=>the metric
=>> flow rating is really 3.25cc. Now *that* really is far fetched! :^)
=>>
=>> Seriously, man. You need to go back to your builder and demand accurate
=>> information. Little injectors like that are simply incapable of flowing
=>> enough gas to produce the horsepower that they've sold you on. I totally
=>> believe that your engine can make that level of power. However, the
=>> injectors aren't up to the task. You've either got erroneous
=>flow capacity
=>> information or you're making a lot less power then you think.
=>>
=>> I'm not busting your balls, of course. These are the inflexible laws of
=>> physics and thermodynamics that we're playing with here!
=>>
=>> P.S. If you're injectors are grossly undersized, you will blow the thing
=>to
=>> smithereens in short order. You *must* do the research to ensure that
=>you've
=>> got a safe combination. Do it in the name of science, paranoia, or
=>whatever.
=>> Just do it and do it right away.
=>> --
=>> Scott F. Williams
=>> NJ Scirocco nut
=>> '99 Subaru Impreza 2.5 RS
=>> Mazda 323 GTX turbo "assaulted" vehicle
=>> Golf GTI 16v "rollycar"
=>> ClubVAC: "Roads found. Drivers wanted."
=>>
=>>
=>>
=>> _______________________________________________
=>> Scirocco-l mailing list
=>> Scirocco-l@scirocco.org
=>> http://neubayern.net/mailman/listinfo/scirocco-l
=>>
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