UrS4boy

<center><img src="http://pictureposter.audiworld.com/61424/bosch_044curves.jpg"></center><p>Note how little the output drops with increasing back pressure. Might be overkill for most cars but you'll never worry about fuel delivery at full boost ever again.

UrSoccer_mobileĀ®

Still can't hear from inside with windows down and detonation is no longer there at WOT.

kday

So that's at least two cars with solved fuel-related detonation.

Another thing to note, the stock S car fuel pump is the same one as used in the naturally aspirated 2.8 liter 100/A6. Maybe it's not surprising then that a pump that is suitable for 160 - 227 HP doesn't have the headroom to do 300+ HP.

urS4guy

And decided to upgrade from my current dual 044 system to a larger pump. Given the age and mileage we also decided to pull out the old fuel lines and run new and larger lines.

Hap, wit dakine need foh da flow not from Evahboost, Maguire

UrS4boy

Pump needs to supply 86 psi to the fuel rail and the required flow. Can't do both (apparently).

nate @ 034MOTORSPORT

And we've got/seen B5 S4's putting down 650+ on a single 044.

nate @ 034MOTORSPORT

So what you're saying is that flow isn't a problem, but instead it's flow thats the culprit?

kday

That's how I read it.

urS4guy

My 2 pumps are run independently. The one in the tank acts as a boost pump and using the stock fuel lines feeds a reservoir up in front. The second is plumbed right after the reservoir using larger lines. The idea is that under full throttle applications, the extra fuel in the reservoir fills the void until after throttle lift. By using one higher flowing pump, we can eliminate some hardware. I'm also going to run larger lines all the way from the tank.

Hap, wit dakine need foh da fuelin not from Evahboost, Maguire

UrS4boy

low pressures. When they are asked to supply high flow and high pressures, some times that is not possible (with that pump). I think that for some UrS cars, for whatever reason, the OE fuel pump, even a new one, cannot supply the fuel flow requested by the ECU (injector duty cycle) at higher boost levels (Pump has hit the limits of its inherent compromise). The result is leaned out A/F ratio and pinging. The ECU hears the pinging (via the piezoelectric knock sensors) and dials back the timing (and boost) but then tries again and again.

There are two solutions:

1) replace the fuel line between the fuel pump and the fuel rail with larger diameter (with no pinches) to cut down the pressure losses due to friction, and/or

2. Upsize the fuel pump to a 005 or 044 Bosch Motorsport (like you sell) to over come the pressure losses in the fuel delivery system and supply both the required fuel pressure and flow to the fuel rail.

Personally, I suspect Audi kinked my fuel line somewhere during the early KY recall and I should either do 1 or 2 above or both.