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ive heard in may cases the idea of changing our fuel system to a return system
why does this matter
and what is the difference
and what can you expect from it

thanks man

 
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our fuel system IS already a returnless fuel system. basically its not good for a forced induction set up. the guy doing my turbo explained it a little to me but i forget the whole basis behind it. in a nutshell though a turbo will only work when our fuel system is modified in some way, and one way is to make it a return system. this is the system that was used on all the other gen civics until now, which is why every kid and his mom could get a turbo kit on their civics before 2001. you dont need to change your fuel system unless youre running a turbo (or maybe a supercharger for that matter, but im still just learning this stuff). my fuel system was just finished being converted to return style today. i can't give all the secrets, but it involves customizing our fuel rail, adding in a fuel pressure regulator, and running a return line back to the gas tank. hopefully ill be able to explain it better after the turbos on and i know everything. and hopefull grey can mechanically explain it better, but thats the short of it. heres some pics of what the return fuel system looks like.

Fuel system conversion

 
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o and to add this. i drove the car for about 5 minutes and it runs a whole lot smoother in my opinion. it felt a little more torquey too especially on the low end. everything just felt a little better for one reason or another.

 
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sounds good civicpunker. i would love to swing by SKR one day and check out your cars progress

 
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i dont mean to sound rude or anything
but i can you really tell a difference

i know you did it for your turbo, but just because you changed it are you inclinded to think that it did make a difference
or did it really make a difference

 
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also...how much does this fuel system morph cost?

 
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hmm. why would u keep things secret? i hate it when people know what to do and they go oh umm its a secret. or some people did a turbo setup and tehy say o it costs blah blah i wont tell. whats with that? wasnt this fourm created to help each other out on the 7th gen?

 
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i just feel that it runs smoother now. i mean its not like neck snapping faster or anything but i think in doing something with the fuel maybe it did something. or maybe it was the weather. either way its running perfect so far. and the conversion cost me around $1500 so i mean i wouldn't do it unless youre gonna be running a turbo.

speedracer-skr is going to actually PRODUCE a kit based off of my car to sell to the public with everything you need plus instructions. since the kit's not finished, i cant give out too much information. i will once its all done and yes i'll give the cost, people should know so that they know what theyre looking at. think of it this way...if you wrote a novel that would sell millions but would take a while to get published, and you leaked out the entire plot and someone else that knew a publisher better wrote the same book but had the rights to it, itd be quite a kick in the nuts wouldnt it?

 
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Well... It's easy to add on a turbo with a return fuel system since there are so many DIY's out there that tell you exactly what to do. Plus you can hook in a fuel management unit to the fuel pressure regulator to control how much fuel is sprayed by the fuel injectors. You can also control how much fuel to add by varying the pulse width of the fuel injectors. The ECU does that, but a piggyback unit could do that as well.

Our cars are set up with the fuel pressure regulator in the gas tank along with the fuel pump. The ECU is hooked up to that fuel pump and to the fuel injectors. It has these fuel maps for various rpm's and other variables (such as the amount of air injested by the engine). It controls how wide and for how long the fuel injectors open and how much fuel pressure they receive. It controls all of this to get a good atomization of fuel into the air from the fuel injectors.

Now, for a turbo you would have to get a fuel management unit that controls how much extra fuel to add when the turbo spools up (boost is present). The ideal situation would be to have an FMU (fuel management unit) that is capable of plugging in-line with the fuel pressure regulator and the fuel injectors. That way you could control everything nicely. A cheap way out would be to only vary the fuel pressure or the injector pulse width. The ideal setup could just re-program the ECU and have it sense boost. Unfortunately nothing like that is out yet for the 7th gen civic.

You could do something else too... Get a separate injector and an FMU to add in extra fuel. I think RiceBurner has this setup. Although like I mentioned, controlling the injector pulse width is a good thing too. Having the injector as close as possible to the intake ports is a good thing as well (as it is stock). I will try to have an FMU that is capable of modifying the signal to the injectors and to the fuel pressure regulator. That way I can control all of the variables. It's not ideal, but it's pretty close. I'll need to swap out the fuel pump for a larger one a little later on when I raise the boost past a certain level (unkown what yet). Larger injectors will be better after a certain boost level as well since the stock ones will not have enough of a flow rate to provide good atomization at higher fuel pressures.

 
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Grey, I got a little lost, so we can in fact run the returnless fuel system but we need the standalone and bigger injectors, but need the upgraded fuel pump, correct? thats the way I was going to go and I didn't see any problems with that as long as the you have standalone. there just isn't one out for your cars yet.

 
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Exactly. I know the injectors are puny in our cars and maybe the fuel pump is as well, but I don't know which ones we should replace first? Maybe the injectors? I have a feeling that the fuel pump in our cars may be the same one as in the RSX's. The injectors are standard, so there's no problem with sizing. I don't know what size we'de need? It depends on how much boost you plan to run in the end. The signals to the injectors are pretty standard, so there should be FMU's out there that are capable of reading the signals from the ECU to the injectors and modifying them. I'm not sure about the fuel pressure regulator in the gas tank, but I would assume that it's the same way with that thing. I haven't researched FMU's yet, but I will soon enough. I bet that it'll be possible to use one of the existing ones with our cars. It'll probably require some modification to the wires going into the injectors and the fuel pressure regulator, but nothing serious. Hopefully I can find an FMU that is capable of doing all of this (for a reasonable price).

 
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what is the pressure rating on the stock fuel rail? that might need to be replaced too.

 
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Hmm... Not sure. Wait, there's some stickers on it. I'll check it out and let you know later on today. I'm working on the throttle body, so it's not a problem.

 
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im pretty sure its about 47psi

 
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I couldn't find the pressure rating on the fuel rail. Sorry...

 
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On AEM's website, the EMS is supposed to be out already.

 
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all I want to know is what are you doing with the stock regulator...are you blocking it off but leaving it in the tank? or are you removing the regulator and leaving something in its place to take space up. I switched my neon to a return style. It alos has the returnless fuel system. If its similar I could do this easy as pie.

 
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I am interested in this myself. I have the my turbo kit ready to go, the only thing holding me up is the fuel system. I don't mind converting my system to a return style system, I just don't know what to do with the regulator in the tank. I have 450 cc DSM injectors and a Granatelli 155lph in-tank fuel pump, and the Apexi Safc Air/Fuel Controller. My Apexi AFC hasn't come in yet though. Can I control my fuel pressure with this in a return style fuel system using the stock regulator in the tank? :help: