[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]

Re: [T3] Fuel Pump Specs


On 14 Feb 2005 at 13:14, James Montebello wrote:

> Pumps don't deliver "pressure", they deliver "flow". 
> A  restriction in the line after the pump (like the
> fuel pressure regulator) is what makes "pressure". 
> The pump merely has to be able to pump fuel against
> that pressure to operate.  Increasing the flow w/o
> touching the FPR will increase line pressure. 
> Twisting the adjustment bolt on the FPR will alter
> line pressure w/o altering pump flow.  So, the two are
> related, but can be adjusted independently, so you
> can't really get pump flow from the pressure w/o
> knowing the restrictions.

Mostly true, but the FPR will actually regulate to a fixed pressure over quite 
a range of flow, so, in our systems, increasing the flow won't actually 
increase the pressure.

> SOME pumps are internally regulated to a certain outlet pressure, but I
> don't believe this is true of the Bosch rotary pump.  

Our pumps have an overpressure relief valve that bypasses the flow back to the 
tank if the pressure rises above some fairly high value (which I don't actually 
know.) It's not an active mechanism in normal operation.

-- 
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]