Fortuna

Hi!
I need to buy a new petrol pump for 993tt. Which is better to buy from a non genuine? What characteristics (performance) should be at the petrol pump: pressure? liters / hour?
Thanks, Sergey

Basal Skull

Most people use the Bosch motorsport 044 pump as an upgrade. I found it difficult figuring out the l/h of the pumps as it depends at what pressures (3.8 bar or 5 bar) but often listed at one and not the other. I have a spread sheet somewhere. In the end I didn't think the stock vs 044 was much different at same pressures. I have the stock pump and 044 pump in my car installed in series. I recall one rennlister using the SX performance pumps for his very high output engine. I have 200l/h at 5 bar written down as a 'want' for myself but don't recall where I got the number from.

OverBoosted28

So which one is the back up, or the primary pump?

Fortuna

but in fact on 993tt only one pump?

Fortuna

Thanks!
200 l/h at 5 bar it's a great pump! You can follow any responses to remember his number and brand?

Basal Skull

The stock 993 turbo only has one pump. Many people use two pumps for higher output engines and for insurance. If you search 'fuel pump' on this board there will be a number of threads. The rennlister using the twin SX performance pump was 'Sonny1' but he was banned a while back. There was a thread by 'Spartan' that had some good info.
The 930 had twin pumps in series - the cis fuel system needed higher pressures apparently.
I have the stock pump in the stock location and the 044 pump where the fuel filter used to be. I deleted my hydraulics so the hydraulic reservoir is removed and the fuel filter is in that location - so in series...

Fortuna

is an interesting solution, thank you! Two pumps you work together at the same time?

Basal Skull

Yup working at the same time. There's some controversy re: series or parallel orientation of pumps. Series better for maintaining pressures and parallel better for flow/volume but in reality both pressure and flow are important, our cars have fuel pressure regulators, and either orientation in the end is probably better than just one.

OverBoosted28

So do you just feed the second pump from the outlet that went into filter, outlet on second pump goes through filter, then into fuel rail?

Basal Skull

yup that's the way we've set up mine. Was easier than trying to fit two pumps in the stock location, and how the 930's were set up in series with one closer to the tank and one in the engine bay afaik.
Seems to work pretty well with good AFR's on the dyno with the andial ecu/5 bar fpr.

OverBoosted28

So is the benefit that you get another pulse of "pumped" pressure, close to the engine? Does it help reduce load on primary pump (possibly lengthening service life) and the second one? Are they both doing about half the required work? Or is mainly just a back up?

Fortuna

http://www.bosch-motorsport.de/media...6426379pdf.pdf

Basal Skull

The Bosch pumps are I believe turbine pumps so no pulses like the mechanical diaphragm or rotating vane type pumps. If you read the Bosch 044 pump literature, it is an inline pump with an option to be used as an inline pump between the stock (in tank) pump and the fuel rail.
Some of the listers with higher output motors (and one pump) have shared some data logs with me that show some drop in fuel pressure and AFR under load so I wanted insurance, and decided to add a second fuel pump.
Not sure about extending service life but that would be nice!

Description for a reseller's web site.
"This is the popular Bosch Motorsports "044" fuel pump, as used by Japanese European & Australian tuner shops, JGTC cars, Touring cars, almost all WRC cars, and many more. Quite possibly, the most popular aftermarket fuel pump. Capable of providing 300 LPH free flow and 200 LPH at 5 bar (or 72.5 psi) for up to 685 BHP. In comparison, the Walbro GSS341 255 "high pressure" fuel pump can support 390 BHP (Note: Values calculated at 12V, 3 bar (43.5 psi) base fuel pressure, 2 bar (29 psi) boost pressure, 1:1 fuel pressure regulator ratio)

These are inline fuel pumps, we recommend they be installed between the factory (or another aftermarket) in-tank fuel pump, and the fuel rail. These may be installed in the fuel tank, but some custom fabrication will usually be required. In addition, feeding these inline pumps with another pump (in series), will boost the output of the Bosch 044 fuel pump even higher."

OverBoosted28

"Great", just what I needed, another project. :-)

DiegoR

I had a 044 Bosch pump in my ex e30 turbo and that was a noisy pump, nothign that bottered me because the car was modded anyways. Plenty of flow....