Fuel system for Yamaha R6

[JoeSchmoe]

Hello fellow FSAE'ers =) This is my first post here. I need some advice on fuel pump selection. I've been tasked with making an in-tank fuel system. I don't have a lot of experience with cars so I have no idea what to look for when selecting a fuel pump. I heard horridous things can happen if an incorrect fuel pump is used. The engine we have is yamaha R6 and I decided to get a car pump because the motorbike one is just too expensive. At the moment, I'm looking at walbro GSS250 190 lph pump. I don't know if that will work on the car. I picked it because I found some charts for it. Thanks for your help.

[JoeSchmoe]

Hello fellow FSAE'ers =) This is my first post here. I need some advice on fuel pump selection. I've been tasked with making an in-tank fuel system. I don't have a lot of experience with cars so I have no idea what to look for when selecting a fuel pump. I heard horridous things can happen if an incorrect fuel pump is used. The engine we have is yamaha R6 and I decided to get a car pump because the motorbike one is just too expensive. At the moment, I'm looking at walbro GSS250 190 lph pump. I don't know if that will work on the car. I picked it because I found some charts for it. Thanks for your help.

[Wesley]

What is it about these charts that make you want to run this pump?

[JoeSchmoe]

I think it is that I have the charts for this pump in case I need them. I couldn't find the charts for other pumps and they all seem to have very smiliar specs. To be perfectly honest, I don't even know how to read those charts. Is there a beginner handbook for people like me?

[P. Jayaraman]

Just a baseline guide:

http://www.injectorrx.com/fpump.html

The method near the bottom of the page is very basic but should get you most of the way there. They do make sure to point out one good thing though: make a note of the current draw that the pump requires. Your electronics guys will need to know this.

[JoeSchmoe]

Thanks a lot for the link. I'm reading now. The current draw is 5 amps I believe. I once saw a walbro table somewhere for current and fuel pressure. I don't know how to use it. Should I just read the corresponding fuel pressure for a particular current draw and see if it satisfies the fuel pressure requirement?

[Wesley]

Your required system pressure will depend on injectors - flow ratings are given at a specific pressure, and you should keep your system pressure relatively close to operating specs unless you know how they will react to changes. Without testing time, I recommend running stock pressure as long as you can tune pulsewidths enough to compensate for idle.

So if you know what pressure you have to run at, you need to figure out what pump will supply the necessary flow at that pressure (increasing pressure reduces flow rate.)

Necessary can be estimated based on "rule of thumb" BSFC and horsepower numbers or determined empirically if you have the time and means. Google will turn up several general "rule of thumb" calculators that will get you close enough to run.

As for amp draw... find one that is the lightest at the least amp draw at your required flow rate and pressure.

[Rex Chan]

The main spec for a fuel pump would be its max flow rate, at battery volts. We run fuel pumps at full voltage/current all the time, which means max flow rate. Excess fuel flow is diverted back into the tank via pressure regulator (we run a return-less fuel rail, so return happens in-tank). The electrical guys will want to know the max continuous current draw.

Some newer cars have variable voltage/flow pumps, to reduce energy use when high flow not needed, but if this is all new, I'd keep it simple.

As a result, the only graphs that we have for our pumps are flow vs. voltage, and current draw vs. voltage.

My advice for fuel systems is to use a plastic automotive fuel module. We are sponsored by Delphi, so run one of their OEM, in tank fuel module (they call it an MRA). It does limit you in tank size (must have flat bottom/top, be a certain height), but makes packaging a lot easier (no AN fittings/hose to run everywhere, esp if you want return-less), plus will be lighter (plastic is lighter than alum AN fittings). They apparently also have anti-surge built into the MRA, though I don't exactly how it works.

Lastly, if you spec a too small pump, you will lose control over Lambda on the dyno. If you are careful on the dyno, then you will notice this well before anything bad happens. I know this because we ran a pump that couldn't keep up, and at 8000RPM, changes in pulse widths had no/strange effects on lambda.

The most important thing when you get your pump is to flow test it, so you know exactly what it will deliver.

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Rex Chan:
We are sponsored by Delphi, so run one of their OEM, in tank fuel module (they call it an MRA). </div></BLOCKQUOTE>
Happen to know the part number, or what vehicle(s) it's from?

Thanks, Ian

[Rex Chan]

@murpia

From what I understand, the MRA is a standard size for many cars, and accepts many different pumps. The pump we run is called a T11, but due to poor documentation, I don't know exact model numbers (and seems like Delphi call several of their fuel pumps T11...). We currently have one good pump (6A and 25g/s flow @ 3.5 bar). The other pump we had (its getting replaced right now) only drew 1.5A, but only had 11g/s flow @ 3.5 bar. Both fit the MRA (Although the small pump needed an adapter).

From speaking to Delphi, they indicated that the 6A pump is from a small car, whereas the 1.5A pump is for scooters. I've seen a Ford Territory fuel pump, and it looked just like our MRA. I'm guessing that most OEMs run the same system, so maybe call up some spare parts suppliers to see what's common + cheap. I've seen some online for $300, which is a lot, but saves you on AN fittings + hose (to get to the pump) - just run one fuel line to your fuel rail, and that's it (pressure reg is inside the MRA).