# using an fmu with a returnless fuel system **URL:** \ **Category:** PittSpeed Off Topic\ **Created:** [July 10, 2004, 11:29am UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651 "2004-07-10T11:29:57Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![T70\_Tsi](https://avatars.discourse-cdn.com/v4/letter/t/898d66/32.png) [@T70\_Tsi](https://forums.speedlife.net/u/T70_Tsi)\ **Post date:** [July 10, 2004, 11:29am UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/1 "2004-07-10T11:29:57Z")
how the hell does that work? i have a feeling i’m gonnna have to run a return line ---
**Author:** ![imported\_weaves](https://avatars.discourse-cdn.com/v4/letter/i/bc8723/32.png) [@imported\_weaves](https://forums.speedlife.net/u/imported_weaves)\ **Post date:** [July 10, 2004, 2:04pm UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/2 "2004-07-10T14:04:12Z")
I thought DSM’s had return line fuel systems from the factory ??? ---
**Author:** ![T70\_Tsi](https://avatars.discourse-cdn.com/v4/letter/t/898d66/32.png) [@T70\_Tsi](https://forums.speedlife.net/u/T70_Tsi)\ **Post date:** [July 10, 2004, 2:21pm UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/3 "2004-07-10T14:21:06Z")
yeah they do, this isnt’ a dsm 😉 ---
**Author:** ![HighBoostBuick](https://avatars.discourse-cdn.com/v4/letter/h/a88e57/32.png) [@HighBoostBuick](https://forums.speedlife.net/u/HighBoostBuick)\ **Post date:** [July 10, 2004, 4:02pm UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/4 "2004-07-10T16:02:11Z")
> [@BlueMeanieTSi](#): > > how the hell does that work? > > i have a feeling i’m gonnna have to run a return line If your talking an electronic FMU such as the AFC then it’s fine. If you mean a mechanical FMU such as the Vortech or a rising rate FPR then I’m pretty sure you have to run a return line. Having a pressure reference(boost/nitrous) AFTER an inline fixed regulator won’t do squat. Most returnless systems use a mechanical regulator with a fixed diaphram, such as the SRT, that can’t be altered into a rising rate system. There are ways to increase them for static pressure, but it’s still fixed. Break out the tools…looks like your running some fuel lines! :blah: But what the fuck do i know, I drive a Buick :blah: ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex034/uploads/speedlife/original/2X/b/b7170c8eddc0b95ece6b88172b2f416a08489a45.png) [@system](https://forums.speedlife.net/u/system)\ **Post date:** [July 10, 2004, 9:32pm UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/5 "2004-07-10T21:32:24Z")
yes you have to run a return line ---
**Author:** ![T70\_Tsi](https://avatars.discourse-cdn.com/v4/letter/t/898d66/32.png) [@T70\_Tsi](https://forums.speedlife.net/u/T70_Tsi)\ **Post date:** [July 11, 2004, 9:15am UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/6 "2004-07-11T09:15:42Z")
i kinda figured as much after talking to some people…now i dunno whether to buy a fuel rail tapped for one (mucho $$) or tap the stock one for a reg. ---
**Author:** ![EclipseRST](https://avatars.discourse-cdn.com/v4/letter/e/49beb7/32.png) [@EclipseRST](https://forums.speedlife.net/u/EclipseRST)\ **Post date:** [July 11, 2004, 9:15pm UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/7 "2004-07-11T21:15:51Z")
The FMU should have a port for the return, at least the adjustable ones like the Cartech that came with my HRC kit and the Vortech SFMU do…not sure about the non-adjustable ones though… EDIT: Not sure how much it will help you, but here are the install instructions for the Vortech SFMU… [SFMU install instructions](http://www.vortechsuperchargers.com/pdf/manuals/superfmuim.pdf) ---
**Author:** ![93BlackTSi](https://avatars.discourse-cdn.com/v4/letter/9/ac8455/32.png) [@93BlackTSi](https://forums.speedlife.net/u/93BlackTSi)\ **Post date:** [July 24, 2004, 10:30am UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/8 "2004-07-24T10:30:13Z")
negative kurt…me and my friend run an FMU on his 7th gen civic and its a returnless system. its not totally efficient but it gets the job done w/out a problem. the only way that it works is because there is an additional fuel pump inline with the system however. if you want to know more gimme a ring or i can send u a pic of the setup. ---
**Author:** ![T70\_Tsi](https://avatars.discourse-cdn.com/v4/letter/t/898d66/32.png) [@T70\_Tsi](https://forums.speedlife.net/u/T70_Tsi)\ **Post date:** [July 24, 2004, 4:16pm UTC](https://forums.speedlife.net/t/using-an-fmu-with-a-returnless-fuel-system/167651/9 "2004-07-24T16:16:31Z")
i saw the additional fuel pump setup and i was trying to shy away from that and go with a walbro 255 in tank