[s-cars] Addict Motorsport Fuel Pump

forgied at direct.ca forgied at direct.ca
Sun Jul 30 15:58:12 EDT 2006


Matt et al: This is my email 'conversation' with Jason at Addict regarding
the Walbro kit they offer:

****************

"Jason Petek" <addictmotorsport at hotmail.com>
To:	<forgied at ae.ca>
Date: 	7/3/06 11:14AM
Subject: 	RE: Audi UrS4 bits and bobs

Because the Walbro will flow more at lower pressure, we were able to lower
the base pressure to stay out of the extreme pressures at high boost.  That
being said, the Walbro HP pumps (high pressure) are still plenty capable at
90 psi.  It is currently supporting 29 psi boost and 42lb injectors on the
AMD S4.  Interestingly, before the swap the peak fuel pressure recorded on
the SPA was only 87psi with a base pressure of 66psi, after the swap the
base pressure was turned down to 60 psi and the max pressure recorded (with
the same max boost limit) was over 90 psi.  The reality is, this pump is a
significant upgrade over stock, and can FULLLY compete with all but the most
expensive bosch units.  I would say, unless your running at least a GT35R
with 28 psi of boost (AKA 600+hp) I wouldn't worry about the Walbro.


>From: "Dave Forgie" <forgied at ae.ca>
>To: "Jason Petek" <addictmotorsport at hotmail.com>
>Subject: RE: Audi UrS4 bits and bobs
>Date: Mon, 03 Jul 2006 11:28:29 -0600
>
>Jason: Thanks for the reply.  I and a few others here in Vancouver BC are
>likely interested in the bushings.  I will circulate your info to our local
>S-car list.
>
>On the fuel pump, my previous investigations of the Walbro indicated to me
>that at high boost pressures, e.g. 28 psi,  (86 psi at the fuel rail), the
>Walbro 255 fell off its pump curve and couldn't deliver the required fuel
>flow.  The obvious alternative was a Bosch Motorsport 044 pump installed in
>a two-piece 60 mm Audi V8 pump carrier.  That is a bit expensive.  The
>other alternative is a 005 Bosch pump.  Less money, same 60 mm size, but
>still able to keep up with the pressure and flow requirements.
>
>Am I wrong about the Walbro?
>
>Dave F.




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