maximum power the standard aan fuel pump can cope with?

[K7ERG]

what is the maximum power the standard fuel pump from the aan can deliver for?

[S2central.net]

I think there are graphs of this here or maybe on my site - can't remember... You *MUST* factor the voltage at the pump terminals for this - thats how the factory graph is... When you get the max flow rate for the max delivery pressure required (FPR plus max boost) then I can calculate max power.... From memory its something like 400-450bhp limiting the stock pump, but thats right at its limit I reckon.

[S2central.net]

For reference, a 280bhp S2 running at 1.5bar needs approx 1.8 liters per minute from the fuel pump.

[S2central.net]

And a 600bhp monster with 2bar max boost needs 4.3 liters per minute to feed it !

[UrS4boy]

I think there are graphs of this here or maybe on my site - can't remember... You *MUST* factor the voltage at the pump terminals for this - thats how the factory graph is... When you get the max flow rate for the max delivery pressure required (FPR plus max boost) then I can calculate max power.... From memory its something like 400-450bhp limiting the stock pump, but thats right at its limit I reckon.

Sorry to disagree but I am running RS2 hardware on my 93 S4 AAN with a MRC chipset (around 288 whp, 350 crank) and I think I am pretty well at the limit. And this is with a relayed fuel pump (as per the write-up below I did a few years ago). The problem is not just flow but pressure. The 091G can't supply enough pressure at WOT, e.g. 2 Bar Boost (29 psi boost) to supply enough fuel, hence pinging develops. I will be going for a 044 or 040 in a 60mm basket very soon.

Link to my C4 UrS-car fuel pump relay installation DIY

[EspenW]

It is also important to have some headroom, in case the ECU detects knock and tries to dump fuel to combat it.

Relaying the pump is a great idea. I relayed mine with 10ga wire straight from the battery. With 14.7v at the battery (diode on voltage regulator), I had 13.2v at the pump before the mod, 14.5v after it was relayed.
I found that I still need the 044 pump to support 380+whp on E85.

[UrS4boy]

Relaying the pump is a great idea. I relayed mine with 10ga wire straight from the battery. With 14.7v at the battery (diode on voltage regulator), I had 13.2v at the pump before the mod, 14.5v after it was relayed.
I found that I still need the 044 pump to support 380+whp on E85.

One thing that I wanted to do but didn't was to run the thicker gauge wires right to the fuel pump (instead of just to the top of the fuel gauge sender). I was afraid that the coating on the wires would be eaten by the gasoline. Has anybody found aftermarket wires that don't lose their coatings in a fuel tank? Telflon coated wire would probably work but the gauge issue makes it hard to find. Any ideas?

[S2central.net]

Sorry to disagree but I am running RS2 hardware on my 93 S4 AAN with a MRC chipset (around 288 whp, 350 crank) and I think I am pretty well at the limit. And this is with a relayed fuel pump (as per the write-up below I did a few years ago). The problem is not just flow but pressure. The 091G can't supply enough pressure at WOT, e.g. 2 Bar Boost (29 psi boost) to supply enough fuel, hence pinging develops. I will be going for a 044 or 040 in a 60mm basket very soon.

Link to my C4 UrS-car fuel pump relay installation DIY

You could be right - I don't have the graphs in front of me - and yes the greater the boost the harder the pump has to work to sustain high flow at high pressure.

I doubt the RS2 pump would like 2bar boost, for a maxed out monster torque mid range, but it might be perfectly happy at ~1.4 bar on the redline for 350bhp and maybe more.

Headroom is important too of course - thats what you get with the higher spec pumps.

[EspenW]

Bigger injectors means that the pump can deliver more flow and support more hp.
My setup, installed by former owner (Jonus setup with Turbonetics E50) was supposed to run stock RS2 injectors at 5 bar base pressure with 1.8bar max boost.
Fortunately, I installed a wideband, and found that AFR at high rpm was 15:1+
I had to set base pressure at 6 bar plus in order to get into the 12 AFR range.
Clearly, the ADU injectors (approx 37lb) could not deliver, not even close.
I installed Siemens 60 lb injectors and found that I could lower base fuel pressure to 2bar in order to run mid 11 AFR at WOT and high rpm. At this low pressure, the stock RS2 pump (at 14.5v) delivers enough petro with no problems. However, on E85, it can't deliver enough, so I have a 044 on the way.