39mmø in-tank pump vs basket

[anditsoundslikebells]

At the beginning of the year when I started to amass parts for the wagon I bought:

AEM 400l High Flow 044 Metrische Ersatz Benzinpumpe 50-1009
AEM 30 AMP Relais und Kabel Kit 30-2061
AEM 340lph High Flow Benzinpumpe 50-1000
AEM 20 AMP Relais und Kabel Kit 30-2062

I figured I would replace the fueling as the engine, gearbox, suspension, brakes etc etc were coming out.

I spoke with ML Performance in the UK who confirmed the 034 Motorsport fuel pump adaptor fitted in in 2004 C5 RS6:
https://www.mlperformance.co.uk/collect ... ive-walbro

Now it's all apart, it turns out that isn't true.

I have a pump that fits in an aftermarket basket, but the basket doesn't fit.
The pump won't in the OEM basket.

Fitting new pumps sounded like a good idea and I know if read it being done in this forum. I never found the exact details of how to fit a 39mm pump into our cars. I could (should have) stayed stock but now I'm in for all the above it would be good to finish it.


Anyone had any experience with the 034 adaptor plate?

Does anyone know another solution?

Does anyone know if a standard C5 basket fits in an RS6? One like this:

[Shoppinit]

Classik did a lot of work on fuel pumps. Maybe he can offer assistance.

Why are you changing the OE setup?

[Classik]

Hi,

Actually you need a proper basket which will fit with the Motorsport adaptor. I need to doublecheck, but from my notes I bought an Airtex E8368M which was perfect for the job.

https://www.ebay.fr/p/14038042598

[Classik]

Of course you just want to keep the basket and throw away the cheap fuel pump. I guess there must be a cheaper way (Aliexpress?) to get just the basket.. Hopefully this will get you sorted (of course double check size with the seller before buying)

[mavada]

......
Why are you changing the OE setup?

[Classik]

FWIW, my final setup which proved very efficient (and silent) is:

- External fuel pump : AEM 400lph https://www.driftshop.fr/pompe-essence- ... etric.html
- Internal fuel pump : Quantum 450lph Fuel pump https://www.highflowfuel.com/i-35474936 ... 485-2.html

Bear in mind that for a 2-pumps in series setup as in our cars, the pumps must have the same flow rate with a 10-20% margin max (good reading here, particularly at the end of the page here: https://aeromotiveinc.com/tech-help/faq ... uel-pumps/).

As far as the internal fuel pump is concerned, my first setup based on a Walbro F274 (https://walbrofuelpumps.com/walbro-450l ... .html.html) didn't work well as the Walbro doesn't run properly when fed with 10v (the controller sends either 10v or full battery voltage depending on engine load).


The question wasn't addressed to me, but as to why I changed the setup, 2 reasons: first my use of E85 leading to additional fuel consumption (15-20%) compared to standard fuel. Second, and this could interest some of you, because those ageing pumps tend to slowly loose their capabilities. No later than last week, an Audi S6 C5 friend reported a dramatic change (for good) of the engine behavior after changing the fuel pump. Changing the fuel pressure regulator doesn't cost much and could also make a dramatic difference.

[anditsoundslikebells]

With the car in parts and me needing it for Christmas we went down a different route:

- External in-line pump: AEM 400lph (50-1009) - same as Classik
- In-tank pump: DW400 415lph https://www.deautosportshop.nl/dw400-in ... -pump.html

(The DW400 is a rebranded Bosch BR540 https://www.fuelperformance.co.uk/index ... h=bosch+br. We got the DW400 over the BR450 as it was in stock.

Both the DW400 & BR450 have a diameter of 46mms so 'should' fit into the original basket.

The flow rates are also more comparable in this set-up.

As Classik said the use of E85 in Holland will be coming and I simply wanted to replace the 140,000km original pump.

On the subject of fuel pressure regulator.... how do these wear? would you replace it as it is no longer accurately regulating the fuel pressure? or, is it a case of it working, or not working?

[Shoppinit]

I have seen a couple of FPR failures. There are different failure modes. The most nefarious is where it is just not giving the right pressure leading to mixture problems and excessive trim correction. Sometimes you can smell fuel when you are driving. They can cause hot start problems, too. It's a cheap part, but you could always test the fuel pressure if you have a doubt.

I don't know if increasing line pressure would accelerate FPR failure. Seems like it might.

[Classik]

The DW400 is from a trusted brand and has great specs as well, but can't comment on the form factor. In particular I hope the pump is not too high when the strainer is fitted as there isn't that much space to close the fuel tank trap.
Electrical power consumption is on the high side though, but the RS6 C5 has 2 power lines, each protected with a 20A fuse, to feed the pumps controller so you should be OK on that front. Let us know how it goes.