Returnless Fuel System conversion
 

Can someone lend some advice on this topic.
2001 up Beta 2.0's run the returnless fuel system, be it Elantra (which I have) or for 03 Tibs. Both run MAP I beleive.
This system limits us in F/I and Nawz apps. What benefits would there be to converting?
What would the best option be to do said conversion?

Currently we (EXD ppl) are thinking raiding the H parts bin for a return system. What model years use this and MAP intake, if any?

Also, if more info is needed, just ask. wink

[ May 05, 2003, 09:24 AM: Message edited by: vdubcoop ]

To be honest, this is sort of an unknown area.

Physically, you could convert to a Beta1 fuel rail, fuel pressure regulator, and fuel pump. You would also need the fuel return line from the engine back to the tank.

Assuming you did this, I have NO IDEA how the stock ECU would react. It is my understanding that the fuel pressure is NOT constant with returnless fuel systems. The Returnless fuel pump has a fuel pressure sender in it. It sends a pressure signal to the ECU which then varies the voltage to the pump to keep fuel pressure at the desired level. At idle, it lowers fuel pressure, at WOT, it raises fuel pressure. I don't know what the "stock" values are. So converting over to a normal "return" based fuel system with a "conventional" fuel pressure regulator might cause the car to run rich at idle and lean at WOT. The ECU might also go into "limp" mode and assume the fuel pump is not working right since the FP sender is no longer in the pump....

You could try to keep the stock pump, and convert over to a "return" based system by plumbing your own return line back into the tank...but I'm not sure HOW you would do this. I'm not crazy about welding a bung onto a former gasoline container....

It's all possible in theory, I just don't know HOW you would do it.

I would suggest you go with a Nitroux Express "wet" nitrous kit. Then fuel pressure is a very minor issue.

If you go forced induction, you would replace the stock ECU with a stand alone, then you could convert to a standard fuel pump with return line and not worry about ECU limp mode or CEL's.

[ May 05, 2003, 11:06 AM: Message edited by: Random ]

Sport Compact Car did a story on turbocharging the XS Engineering Toyota Matrix XRS about a year ago. The VVTL-i motor also had a returnless fuel system of which they found a way to convert it to a return system and make it work. I don't remember details but i do have that back issue and i'll re-read it and see what they did and post anything usefull. You SCC readers know what article i'm speaking of right? :D

Very good info, thanks guys. I would like to know more of the SCC article Dude.
Sorry Random, perhaps I should have been ALOT more specific in my details of the request. Guess I left ya hanging.

(my) Plans are to go turbo, unsure of engine mgt at this point. I had a line on a new E6K from a dealer. BUT, they are too far away from me to get it tuned by them and there is also nobody in my area that has ever tuned one of them (that I know of). Needless to say that doesn't give me much inspiration to go Haltech.
My second consideration is the Greddy e-manage. As many have stated, its never been proven to work or tried even (??). who knows?

My first priority is the spare engine (15K miles) which is getting torn down later this month and I now have the exhausting task of sourcing all the parts for the rebuild. However, my secondary concern is the limited fueling options and engine mgt.
Like you said, I will most likely go full replacement on the intank pump, filter, regulator a$$'y. Run a line back for the return, but welding and or plubming, albeit, an empty tank is SCARY!! lol
Hoping to get OE parts to use though.

*edited because I wrote A$$

[ May 05, 2003, 01:12 PM: Message edited by: vdubcoop ]

if you had a stand alone, why can't you just use the existing returnless fuel system, and program the standalone accordingly?

<div class='quotetop'>QUOTE</div><div class='quotemain'>sharkey9883:
if you had a stand alone, why can't you just use the existing returnless fuel system, and program the standalone accordingly?</div>I don't know of a standalone system currently on the market that will work with a returnless fuel system. They don't have the programming to control the fuel pump, and most don't have sensors for fuel pressure to make injector adjustments.

so i wonder how apexi did it dunno :confused:

<div class='quotetop'>QUOTE</div><div class='quotemain'>sharkey9883:
so i wonder how apexi did it dunno :confused: </div>That is assuming they did do it, and that their kit really works. We'll know if they ever put it on the market.

BTW...Some of the "newer" Stand alone ECU's might work with returnless fuel systems. I'm not 100% up on the capability of the Tec3, all of the higher end ecu's like Pectel and such. The E6K can't do it, and neither can the E-manage, or M-4.

what about the tons of people running nitrous and turbo on their MAP cars?

im going to run both of these in my car until it goes BOOM

This is the problem I have. still dont know what to do. cry