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Can some1 explain to me the difference between a return fuel system, and the one's in our cars in lamen's terms... lol ... i'm not a crazy mechanic, so I need to understand this stuff better for my own sake.

Thanks alot guys.

 
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in lamens term, here we go

on a return system, its basically a continous circuit of fuel flowing from the tank --> pump --> fuel filter --> fuel managment unit --> fuel rail --> fuel pressure regulator and back to the tank.

on a returnLESS system, you basically eliminate sending the fuel back the to tank

 
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our computer and injectors supply only the amount that is need to the rail and engine, from that point it is all used. return system allows whatever fuel that someone is supplying ie. fuel pressure if u up it/or mess with ur fuel in any way, and anything that is not used goes back into the tank.

 
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so basicaly having a return fuel system is more of a safety benefit?

or is it needed to be able to supply the injectors with more fuel then normal? ie. turbo setup

 
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not necessarily a safety thing, obviously our cars work just fine without a return. and second question is correct i do believe.

 
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lol...woudl that save some gas in the long run? since our cars don't burn 100% efficiently, won't it be better to send the fuel back into the tank?

 
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Not just turbos, but if you up start putting a few boltons like exhaust, intake manifold, CAI, cams, anything internal on the motor like port and polish job or bigger valve, bigger pistons, longer stroke crank, etc. it allows you to up the pressure on the fuel to compensate for the lean condition of the air/fuel ratio, if there is one. A lot of cars you can just put it on there if the cars stock and get some power, but I think our cars fuel system does fine up until the point where the injectors just cant flow anymore fuel, then you would probably need bigger injectors, not higher pressure, although Im sure it helps on a turbo car.

I did this on my '01 Z28 after I read an article showing a gain of about 6 HP on a stock one except for exhaust. That is a bigger motor so it would probably translate to nothing to MAYBE 2 HP on our cars.

As for with a turbo, it can add more than that I'm sure, but there are other ways to control the fuel, but are much more expensive.
I would think it wouldnt matter if you put it on our cars untill you had a lean condition, but just my .02

Anyone car to elaborate? I would surely like to know.

 
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if im thinkin correctly i think a too lean condition is dangerous, my return is working fine, i guess i could say that it allows for better ease of adjustment quite possibly in the future, ie...more boost. putting a return system on relies alot on tuning too. u cant just take our stock car and slap soemthing like that on there and expect it to work, im not saying thats what ne one is saying, but. and no it most certainly dont save on gas, gas mileage is roughly the same, but of course one does get less with a return and turbo and all that, not to mention the cost of gas moves up the pricing chain though having to put 93+ in there all the time.

 
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but if more air is added to the engine, wouldnt the FMU? (thats the fuel monitoring computer i think) or whatever computer takes care of that, wouldn't it automaticaly sense the added oxygen and compesate by adding more fuel, thus balancing it out?

or no?

 
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so your saying a return allows for better ease of adjustment in the future?
or are your saying it relies on alot of tuning too?

u lost me

u have a returnLESS right?

 
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a

 
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confusion confusion...ima just save for a k20 swap..thnx for all the info...i can understand it better now...i dun think its worth it to convert at the moment.

 
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Most turbo kits come with a return fuel system and a FMU for it.

Dont be scared by all the technical stuff, its as easy as having the money to spend.

Buy the kit, install it, and then the FMU/ return system that comes with it.

Then all thats left to do it take it to a dyno and get it tuned properly, then make sure you always use the highest octane fuel at the pump(usually 91-93 where I'm at) and break it in.

Most people find the hardest thing to do is installing the oil return line(you have to drop your oil pan for that bad boy) and getting the tubing for the intercooler and turbo fitted and sealed just right.

I recommend taking the oil pan to a shop to have it welded up. Some kits have an option of a little doodad that keeps you from having to weld anything, but you can have problems with that if it isnt done right.

Pay the $25-$50 to get it welded and youll thank yourself.

Of course, theres always the added stuff people dont tell you about, like a turbo timer, boost/fuel psi gauges, etc.
Would be wise to add oil and fuel pressure safety shutoff switches, too.

Then, break it in for a few miles, and enjoy your stuff.

 
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no i do have a return feul system

 
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so if extra air is added to the engine, wouldn't the FMU automaticaly add extra gas? just like a gettin a CAI adds slighty more air, the engine light comes on, the FMU realises the engine needs additional fuel because its running slightly lean, adds more fuel, and the engine light goes off.

or is the FMU preset so that at every stage in the throttle opening, it adds a bit more gas? and that cannot be changed?