55 psi? 5.5 lbs of boost on a 10:1?
6.8 lbs of boost on a 8:1
9.2 lbs of boost on a 6:1
I'm familiar with a lot of turbo's. I don't really know any that put out 340 hp @ 9.2 lbs of boost.
Just because the base pressure is 55 lbs, doesn't indicate actual fuel pressure with the FMU. You do understand how an FMU works, right?
Forget Bench Racing....
* Brake specific should be .45 to .50 for naturally aspirated engines,
.55 TO .60 for supercharged engines,
and .60 to .65 for turbocharged engines.
That's from RC's site.
www.rceng.com
Plug that into the calculator.
Assuming it had a 10:1 FMU, at 6 lbs of boost, the fuel pressure started to increase at 10 lbs fuel pressure per lb of boost. So, let's say it was pushing 13-14 psi, on a rather good sized turbo, proper sizing would have been around what? an 8:1 FMU to achieve the needed 100 psi fuel pressure to feed it? Do you not understand, it can be done with an FMU, but 440cc/min won't supply enough fuel for 340 hp.
In fact, with 100% duty cycle, minimum calculation of .60 for a Turbocharger, and 55 psi of fuel pressure, you'd need 477cc/min to make that power level. That's assuming the motor design was able to harness every drop of fuel you put in. (Most run about 90% efficiency, some would argue much less.)
Excerpt from article found here:
http://www.hondatuningmagazine.com/f...ems/index.html
Fuel Pressure
The relationship between changing the fuel pressure and the amount of fuel delivered is the square root of the ratio of fuel pressure. If fuel pressure is doubled, then about 40 percent more fuel is delivered. To double the fuel delivery, four times the fuel pressure needs to be used. But that's only possible if the pump itself is capable of delivering fuel at that pressure.
How much does a Honda fuel pump actually flow? The results may surprise you. A stock '99 Civic Si (B16A) fuel pump flows enough fuel at 35 psi for 400 crank hp. A stock '97 Prelude fuel pump flows enough for 476 crank hp. It's interesting to note that as pressure is increased to 75 psi, such as with a rising rate fuel management unit (FMU), the pump can only flow enough for a little more than 200 hp.
If the rest of the fuel system is up to scratch, and even allowing a 20-percent safety margin, you should have no problem making 300 crank hp with 550cc injectors at the stock 40 psi fuel pressure with a Civic fuel pump. Honda ECUs will even idle injectors as large as 800 to 900cc, as long as they're calibrated correctly. On the other hand, if you boost your car, use a rising rate FMU set to rise to 75 psi or higher, and have more than 200 crank hp, then you're in trouble, as you'll probably experience significant leaning.
Too much pressure has other disadvantages. Fuel injectors require more current to open, meaning they run hotter and are less reliable as a result. In addition, they can take longer to open, and there's a greater tendency for the fuel to leak past the injector seals. If the fuel pressure is really high, there's a chance of rupturing the diaphragm of the fuel pressure regulator (usually rated to 100 psi), resulting in fuel simply dumping into the intake.
This is why manufacturers don't run high fuel pressures, and instead use larger injectors and tune the engine management system. Rising rate FMUs are inexpensive, but the cost of injectors and an electronic fuel management system is normally less than the cost of an engine rebuild. The Civic fuel pump even has an internal pressure relief valve set to 75 psi, which bleeds fuel internally back into the tank above this pressure if things go really haywire.
A good link to an injector and pressure sizing calculator can be found at RC Engineering's Web site,
www.rceng.com/technical.htm.
Real world, your method will work. Is it ideal, or the best way to go????
NO!