[urq] More Weird UrQ Behavior - fuel starvation

[Ben Swann]

Cody has the pretty much correct reasoning here and basically what this pipe ends up
doing and rather simply without costing much.  The best kind of engineering is low cost
KISS!
 
Ben

  _____  

From: Cody Forbes [mailto:cody at 5000tq.com] 
Sent: Sunday, March 28, 2010 1:06 PM
To: Ingo Rautenberg
Cc: urq at audifans.com; Ben Swann; Quattro List; Grant Lenahan; afinn1 at gmail.com
Subject: Re: [urq] More Weird UrQ Behavior - fuel starvation


That's like saying you can solve traction problems by installing a smaller turbo ;-) 

In Bens case no. His car is making enough power that he needs the flow capacity of the
big pump. The solution is to increase the fuel flow to the pump.

My idea for a possibly cleaner solution was a quart or so capacity canister between the
pump and the tank with the fuel return emptying in to the little tank. You'd want the
return entering radially along the side so it swirls in to help separate any possible
air bubbles.


-Cody (mobile)

On Mar 28, 2010, at 12:32 PM, Ingo Rautenberg <ingo.rautenberg at gmail.com> wrote:



Could the solution be to (gasp) install a lower pressure pump instead, due to the
considerably lower EFI fuel pressure requirements, which should lead (theoretically) to
less cavitation as well?

Ingo



On Mar 28, 2010 12:18 PM, "Cody Forbes" < <mailto:cody at 5000tq.com> cody at 5000tq.com>
wrote:

When it comes to fuel pump output flow is inversely proportional to
pressure. When you decrease the pressure that the pump has to work
againt you increase the volume of fuel that the pump moves. Since the
engine is using basically the same amount of fuel you end up with more
volume being returned to the tank.

This is why the fuel pump that is stock on a 5000tq, designed to work
at almost 100psi, is the fuel pump of choice for racers and high
performance street cars everywhere. When used in EFI systems the flow
rate of this Bosch 040 (or 044 in out of tank version) pump is one of
the highest flow pumps on the market.

 <http://www.boschfuelpumps.com/> http://www.boschfuelpumps.com/ for specs.

-Cody (mobile)

On Mar 28, 2010, at 11:16 AM, Grant Lenahan < <mailto:glenahan at vfemail.net>
glenahan at vfemail.net>
wrote:



> OPK, so it sounds like ( for mysterious reasons) that the EFI 
> systems have a higher proportio...

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