ah so you can use lower flow injectors on a return system than you can on returnless?

 

Dear EVERYONE,

GM and other car manufacturer's use returnless fuel systems for ONLY TWO reasons:

1) Lower production Cost
2) Lower Emissions

THERE ARE NO OTHER BENEFITS TO A RETURNLESS SYSTEM.

WE should ALL USE RETURN-STYLE systems.

 

yes...and return systems can prevent cylinder rich/lean issues since pressure is kept stable across the rail...assuming u enter at one end and leave/reg pressure at the other

all evos including the current evo x use return systems...imo return systems are where its at

 

hmmm a return system will be added to the mod list

 

After sufficient testing and full completion of the product. Few months maybe?

 

Put it this way - In a returnless system you actually have more fuel pressure at high VAC (idle and decel) and lower fuel pressure at WOT. That is the exact opposit of what we actually want. With small injectors, this only plays a part at the upper end of the fueling where they run out of room causing high duty cycles. People get bigger injectors to get more fueling up top, but those bigger injuectors lose the ability to run linear at really low PWs, causing low PW errors. By going to return style, you have the same effective fuel pressure everywhere, because your regulator lowers pressure during VAC and raises it as you give it more throttle. That allows you to run higher PWs at idle and decel and eliminates the low PW errors. It also allows you to run lower PWs at accelleration, giving more room up top. Other advantages as far as tuning - Your IFR table is flat, one number across the board. Also, your offset table changes only by volts, not volts and VAC. Also, witt, I have tons of respect for you as a tuner, but IMO tuning your VE and MAF to make up for fueling issues is not the best way to dial in injectors. It's just semantics, but I believe that you tune fuel for injectors and MAF and VE for air.

 

There is no other way once you pass the 550cc mark. Not a matter of semantics, its a matter of consistently achieving desired afr.

You have to realize why the IFR table is written to understand why the slack can be taken up in MAF. Its made to be a quick change method of fuel injector swapping by using the table as a common devisor. You're taking commanded fuel from one side of the equation and moving it to the other.

I'm more concerned with load on the PCM circuitry for the high impedance driver than the tune itself. Fuel tune is nothing more than pulse width. Once you start getting up into high flow injector ranges, parts become larger and power demand needed to operate them is increased. This is why you don't see high impedance fuel injectors much large than 700-800cc.

 

The return-less fuel system is a problem as well from what I learned, but the intake manifold is yet another. Perhaps Mr. Hahn should give us a better intake mani? :P

I know some company is supposed to be working on one for us taht is supposed to be killer.

 

Actually SJShafer, I take that back about having to take up IFR slack in the MAF. djt81185 and area47 informed me that adjusting the voltage flow rate modifier does work. I've been meaning to retune using this table but haven't been able to keep my cable long enough to get around to it. The goat guys keep bumming it off me.

 

Scythe_Snake..., the problem with that is he really has no interest in the supercharged side of our cars. The twincharged method was of interest for a while, but when that became too problematic, then they scrapped that altogether. But you are right; we do need someone to develop a better intake manifold for our cars.

 

wrastle dem bitches up!

you can run up to 127 lbhr injectors in hpt.

not recommended by any means.

 

You mean you don't have a ballast box yet?
Slacker.

 

i have no desire to have a dsm or honda part on my car

mainly dsm part.

 

Atleast Hondas and DSMs have been known to go fast...

 

but you spend as much money on mods on a DSM as you do replacing broken pieces

 

Mod it when u break it..aka mod what u break

 

until the timing belt snaps and fubars what you just modded

 

true enough.

i got away from dsm's and anything related to them, i plan on keeping it that way

 

Wow this has nothing to do with Harrops thread I from what I can tell, but the injector resistor box does indeed work great. I used one from a CRX for my Integra. It allowed me to use the nice 560cc EVO injectors as they are much cheaper for the whopping $75 I paid for them than the expensive RC injectors! I now look at modding from a different perspective after owning my Integra. More expensive and sofisticated is not always the best way to get the same desired results.

 

I love how you mention we're so off topic and then proceed to steer us off course...

Classic!

I'm just eff'n w/ ya 2K5...

 

+1 Didn't even notice that

 

Not much else to talk about until Harrop releases some more news. /shrug why not jack the thread. Doing my part to keep it alive.

 

I need to get my hands on the 875's man, someone pm me the link. I'm hitting btwn 144-156% IDC now on the 60's lol. need more fuel.... car is hungry

 

Racetronix's website.

I bet they have damn near the same min. pulse width as our crap 650/660s being a disc setup. RC engineering has 750s as well.

 

gonna check that out. Also probably going to go with a return setup in a week or 2 jut need to order the rest of my parts .