Turbo help

[POWERHOUSE]

Yes ass frank said it should rise. With an fmu it will be a 1:6 ratio. So if the base pressure is 43, at 8psi it should be 90psi. If it's a 1:1, at 43psi at 8psi, it will be about 51psi.

AS Frank, NOT ass Frank! Not funny Rob!

[Boosted Cycle Perf]

Oh crap, sorry man! Didn't mean too.

[ColdBusa]

Pandaspeed, I just sent you a response to your PM. Check to see if your fuel lines are resting on the motor itself when the tank is lowered. You mention that it keeps fuel pressure when first fired up and under boost, but when it is warm it drops to 20psi. This could be the problem as your fuel is vaporizing in the lines. This has been seen before and corrected with some kits routing on the market. Check that out as well. Let us know what you find.

Also, get yourself a WEGO III or something simple to do some data logging, as it will assist you in multiple ways with a tuner setup.

[Pandaspeed]

Ok sorry it took so long I have some pics of the set up. What is the circle thing above the plenum?

[Boosted Cycle Perf]

Looks like a velocity kit.


That circle thing is the FMU.

The first obvious thing I see is the fuel pump isn't insulated. I recall you saying after the bike runs awhile it sounds like it's running out of fuel. Well that could be due to vapor lock. Insulate the fuel pump, lines and filter at are on the back side of the engine there. Then report back to us.

[Pandaspeed]

Ahh yes. Didn't think to do the pump and filter too. I just did the fuel lines and it didn't do anything. I'll insulate the rest and get back

[OZBooster]

Yep looks like a velocity stg 1

that filter in the hose from tank to pump will cause it to pinch the hose more often than not
sometimes your better off moving the whole pump and filter assembly, or at least adding a loop of hose so the tank can open and close without trying to fold the hose

[Pandaspeed]

Haven't gotten a chance to do more work on it yet due to work is busy as ****. But what does the fmu do? And what is the other line that goes from the fmu back to the gas tank?

[Boosted Cycle Perf]

FMU stands for fuel management unit. It's basically a fuel pressure regulator. While a regular fpr is a 1:1 ratio, and fmu is a 1:6 ratio. The reason behind it is because you have stock injectors, and the only way to get them to flow enough fuel is to raise the fuel pressure very high. Also gen 1 hayabusas fuel algorithm in the ecu is not boost referenced either.

The line going from the fmu is your return line to the fuel tank. If you follow the other one it should go to the fuel rail.

[Pandaspeed]

Ya it does.
Why would u need a return line to the tank? Shouldn't it go to the injectors and get burned?

[OZBooster]

Pump can make way more flow and pressure than the bike uses, regulator (FMU ) gives the fuel rail the pressure and volume it needs and puts the rest back in the tank
think about the difference in fuel use at idle compared to wide open throttle

[Pandaspeed]

Ok. But why would you need a return line to the tank? And if u look there is like a gold nipple fitting on the side of the fmu. What is that for?

[Boosted Cycle Perf]

Ok. But why would you need a return line to the tank? And if u look there is like a gold nipple fitting on the side of the fmu. What is that for?

Oz just explained it perfectly. Fuel systems have been ran like that for years, yours isn't an exception.

That gold fitting controls what your fuel pressure increases to while under boost, which should be about 90psi. The Allen screw in the middle is what adjust your base fuel pressure (at idle) which should be 43psi.

[OZBooster]

"That gold fitting controls what your fuel pressure increases to while under boost, which should be about 90psi. The Allen screw in the middle is what adjust your base fuel pressure (at idle) which should be 43psi."
This stuff is tuner adjustable , i would not recommend you change any of the fmu settings

If you just ran a hose from pump to fuel rail,with no regulator or return the pump would stall out at about 120 psi , have a very short life and you would run very rich if at all

its not like your barbeque regulator

[Pandaspeed]

Ok. Makes sense. Insulating the pump ect today. Do I need to insulate the return line to the tank also?

[Boosted Cycle Perf]

No you don't need to.