Fast16gawd

i'm looking into fuel options for a B16a, with a Rev hard stage 2 kit. I refuse to use a FMU, I don't think high fuel pressure is the answer. What I'm looking to do is run about 12 psi on the stock internals with this setup :

RevHard Stage 2 turbo kit
a 255 HighFlow fuel pump
Aeromotive Fuel Pressure Regulator
660 injectors ( maybe 550s depending on what others have)
stock fuel rail
also possible putting a 3/8 line from the fuel pump to the fuel rail.

Coming from a Mitsubishi, I want to know why this type of setup is not used as often, the people I see tend to use real small injectors, or when they have big injectors tend to go to hondata, or some other type of Programable ECU. What is the reason for this.

SpeedMonkeyRacing

i don't think your stock ecu will like 660's (or 550's)

Jeff-

Fast16gawd

but what is the reasoning behind this ? If I'm using the a AFC to control my fuel injectors, I don't see why that would be a problem ?

sgT

Mitsus use 450cc to start. +200cc is controllable with an AFC and a MAF.
However, we are talking about almost 400cc more than a stock honda ecu
is wanting to look at. Combine that with a speed density system and the fact
that the ecu can only compensate about 20-25% and the car will run very
poorly. Even with an AFC, 450cc seems to be the largest and even then
drivablility is not that great. Its best to just use a low rate FMU and slightly
larger injectors like 310 or 370 along with a low base pressure.

Fast16gawd

Right now the car has a set of 450s, and driveablity is still good. We have been able to put at 15 psi 12.6 @ 115 MPH. The only thing is we are still using the FMU, which we would like to get rid of, plus a second fuel pump. So basically it sounds like I'm entering uncharted waters here.

dbman96

What you have to realize is that the ECU can only make certain adjustments to the injector pulsewidth - if it's calibrated for 270s, a relatively coarse adjustment in injector duration is OK, but when your injectors can flow more than twice that much fuel, that same pulsewidth variation makes a much bigger difference in fuel delivery. The ECU ends up chasing its tail trying to get the right mixture in closed-loop, and the ECU is only capable of about a +/- 40% adjustment to catch up to the O2 sensor. If you're seriously running 12-15 PSI on a B16 you need a standalone engine management solution if you want to do it in a way that is safe for the engine and smooth as a daily driver.

hybrid901

With the 440-450's what kinda base fuel pressure are u running and what fmu disk are you running? How much did you have to lean out at idle to get it to idle properly? Also where can I get recalbration disks at?

Thanks

VaporTrail

the unmodified ECU cannot read/compensate for boost. It will cause a CEL if the MAP sensor sees boost. Check into a http://www.hondata.com system, which modify's the ECU so that you can totally customize it - a cheap standalone, if you will, without all the headaches.

chri5

I am running 32 psi at idle and -35% on the VAFC with 440cc injectors. Im hitting 48 psi and +5% on the VAFC at ~.45bar. Once I get my exhaust put on I plan on running a 4:1 rise rate and trim some fuel out with the VAFC whilst in boost.

I am using a second MAP sensor instead of the TPS input to the VAFC.

dbman96

How's the dual-MAP input on the VAFC working for you? I haven't checked up on this for awhile but it's still running really nice for me, and so much smoother than the TPS input. Only problem I find is as long as the VAFC is trimming -% out of the MAP input to the ECU, it won't trip into open-loop unless you're at WOT. So part-throttle detonation is kind of an issue. I'm looking at the old JRSC TPS mod to try to fix this but I need a boost-sensitive switch to put that together.

chri5

I've noticed this as well. I always try to stay out of boost when at part throttle, and only boost when I am going full throttle. Its a habit i picked up from the part throttel tip in detonation JRSC days of my youth Hopefully I wont have to worry about it come march when I should have one form of standalone or another.

edit- Other than that it works perfectly. Plenty of fuel in boost, and drivability is cool.


[Modified by Strng1dah, 1:34 PM 1/1/2002]