Josh Able: puny fuel injectors

[sfwilliams@comcast.net (Scott F. Williams)]

> 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."