Boosted2k2

iTrader: (3)

I have to make my final desicion on my fuel system setup by Monday. Here's the deal.

Original Setup:
4 Stock Injectors
2 GReddy 550cc Extra Injectors in a custom mini-rail
GReddy E-manage
Inline Fuel pump for the additional injection

For $300 more: (Return conversion)
4 440cc injectors replacing stock
Throw out the in-tank pump and regulator
Inline Fuel Pump
Custom Fuel Rail
Fuel Pressure regulator
Return line
GReddy E-manage

What I'm wondering is, at what point am I going to benefit from a returnless system. I've done A LOT of research on converting. Here's what has to happen. The in-line fuel pump on a return system is not controlled by the ECU. It is always a constant pressure system, unlike our returnless variable pressure setup. So if it has voltage with the ignition... the pressure is there. Contrary to popular opinion... I'm pretty sure the factory ECU doesn't know whether our cars are returnless or return. What the ECU does control is the injector pulsing. I'm pretty sure voltage to the pump is controlled internally between the in-tank FPR and the fuel pump itself. Contrary to popular opinion... I'm pretty sure the factory ECU doesn't know whether our cars are returnless or return. What the ECU does control is the injector pulsing. However, the E-manage overrides all injector singals, so that is taken care of. There is no real cost in running the return line because we don't have to drop the fuel tank to do so. The Cybernation kit was able to go returnless with one thing aside from the regular conventional EFI systems, that was a black box made by Cybernation. It's the same thing JR makes for some cars, but all it does is clamp voltage (The E-manage does this too).

So... what I'm looking for is some opinions. The shop said it will work, and they have the RSX to prove it (example of a return conversion). On the other hand, I'm not in any mood to shell out cash to R&D one of the first return systems for the 01+ Civic. If I was positive it would definately work, I'm all for it, it's only a little more money, and I don't really have to worry about running lean, stalling, etc.

1. Who thinks this setup sounds good/plausible?
2. Who can find drawbacks in the setup?
3. Is it worth an additional $300 over a 2 add. injector setup?

zinkyroo

iTrader: (2)

Id go with the additional injectors.

wenlyone

So the pump controls the pressure? I see. This is good info. I guess putting the right constant voltage to the pump will make it staic. Then you can use 440's and control it with some type of injector control.

just to let you know. www.import-parts.com has a summer sale on the rc saturated 440 cc's. Call and ask about the summer sale price. Very good deal.

If you are looking to push the turbo, Larger injectors will be the best way to go. Eventhough extra injectors are a better alternative than fpr/fmu setup, at high boost applications, even fuel distribution to each cylinders will be of concern. You will never know where the mist of fuel can travel to, since it is injected before the throttle body.

*edit*Even with returnless fuel system, isn't the fuel pressure static?*edit*

Boosted2k2

iTrader: (3)

This quote from you is exactly one of the main reasons why I don't like the extra injector idea. I wouldn't necessarily say that it's a better alternative, as much as it is just a cheap alternative. A return system is more expensive, but IMO is the right way to do it.

Also, you are right about both being static. I kinda reversed it there by accident. Both pump the same, but the returnless alters the fuel pressure before the rail (so no extra fuel makes it to the injectors), and the return system alters the pressure after the rail (so all the fuel you need and more at least makes it to the fuel rail, all excess goes to the tank).

My main concern though is just that I don't want to do more than I have to do. I don't want to pay for them to do something, find out it's ****, and go back to plan A again. At least I know extra injectors work in place of a return system up to a certain point.

I'll choose something Monday. I'll post up all the details, and results hopefully by the end of the week.

wenlyone

In which case, then you don't need to make the returnless to return system for larger injector setup.

All you need would be larger injectors and injector controllers. I don't think that will be too expansive. the sale at import-parts is 285 for 4 saturated rc 440 cc. and I think vafc can control 440's (not sure if you can add a boost option). But in any case, it still isn't that expansive.

with the larger injectors and stock fuel pressure, use a fuel injector controller to trim the fuel at vac, and increase duty cycle with boost. There are many ways to do this. GM 3 bar map sensor can be added to trigger the boost maps.

If what you described about how returnless works is correct, there isn't a difference on the large injectors setup.

zinkyroo

iTrader: (2)

Wenly I believe that price is only if you purchase a drag turbo kit...Correct me if I'm wrong.

Maverick

yeah, i would go with bigger injectors rather than adding the 2

rickinthescv

Some stuff about our cars.

1. The fuel pump is controlled by a relay. Off or on. The relay is turned on by the ECU, mostly for safety reasons. I.e. no motor revs, cuts off the fuel.

2. The pressure regulator is in the tank. So no excess goes to the fuel rail. The advantage of having the regulator at the rail is that one, more fuel is available than needed. This is a good thing. Two, the constant movement of fuel cools down the fuel, also a good thing.

To get more fuel into the cylinders, you either increase the pressure to the injectors or change to bigger injectors and change the ECU programming, add a piggy back, or change ECU.

Best way is this. Change the injectors over to 440's. Tune the car. Hondata has proven that a stock Civic could run on 720's if tuned properly, and was run well. Idle like stock, have power, no fuel starvation. Change the fuel rail, pump, fuel regulator, add a return line. Now you are guaranteeing that you have more fuel available than needed. Remember, too much fuel in the rail, just goes back to the tank. Too little fuel in the rail, you be going to the bank.

Sure it costs more. The best way usually does.

wenlyone

No. That price is summer special for honda-tech people. it is good till the end of aug.

wenlyone

So the pump is on and off... I guess without a return line, things are going to be messy... Why did Honda do this? Can anyone tell me why?

C2i0v0i1C

iTrader: (2)

building a return is not as hard as u think, look at my picture of it, u cant tell much on how to do it from that, but its a picture. tuning is the hard part.

wenlyone

running fuel lines are not hard, but very messy. anything to do with fuel system is kind of messy for me. my skin doesn't like gas much neither. always crack after touching fuel.

rickinthescv

Honda eliminated the return line to make things simpler for them. The 6th gen Civic ran fine, as did all the previous models. All you really save is one extra fuel line.
And it does reduce fuel circulation which produces fumes in the tank, but this does it at a reduction of the cooling effect.

IF you were building a million cars and a return less line eliminated just a bit more emissions, then for a major manufacturer, that would be a good thing. So it does do some good, clean air and all.

Just realize that a stock system is designed to deliver 80 percent of the total requirements of the motor. No more, just a bit for headroom and that is it. That is why adding forced induction will tax the fuel delivery past its designed output.

Boosted2k2

iTrader: (3)

I'm leaning toward the decision of a return system. I'll let you all know tomorrow exactly what's being done, and what I'm using.

Boosted2k2

iTrader: (3)

Return system is underway

zinkyroo

iTrader: (2)

Nice

Boosted2k2

iTrader: (3)

Anybody know if the AEM fuel rail is out yet. It's easier and cheaper to mod it, than getting a custom made one. And I don't really want to mess with the stock one (just incase anything happens.)