A "HOW TO QUAD CARBY" THREAD PLEASE!

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Re: A "HOW TO QUAD CARBY" THREAD PLEASE!

Postby Superscan811 » Sat Nov 12, 2011 6:27 pm

geezer101 wrote:is it possible to drop fuel pressure from an electric pump by lowering the input voltage to it?
A much better idea is to use a PWM circuit along with a pressure sensor.

If you are handy with a soldering iron Jaycar have a cheap 10A 12VDC Motor Speed Controller Kit KC5225 or you can buy a pre-built 9 - 28VDC 10A PWM Motor Speed Controller.

There would be a little bit of work required to adapt a pressure sensor output to allow it to what you need, but not much.

The reason for the pressure sensor is to be able to vary the fuel flow, depending on how the car is being driven. A constant low voltage may cause the pump to stall once it's up to pressure, this would destroy it in no time.

This would only work with the standard gear head style pumps (normal EFI style pumps),
NOT the "Solid State Electric Fuel Pumps", ie the ones that go "clack, clack, clack" most of the time..


Cheers.
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Re: A "HOW TO QUAD CARBY" THREAD PLEASE!

Postby Superscan811 » Tue Apr 03, 2012 10:05 pm

Superscan811 wrote:
geezer101 wrote:If the inlet runners were cast short enough, wouldn't it be possible to use longer silicone joiner hoses to adapt to virtually any carby set up?

Again, good in theory but silicon is flexible and if you pull 15-20lbs of vacuum, when you take your foot off the accelerator, a large long silicon tube will collapse in on itself.

Just to confirm what I posted before, here's a Youtube vid of a relatively short silicon runner. See how it's almost totally collapsed in on itself when the throttle is closed.

Cheers.
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Re: A "HOW TO QUAD CARBY" THREAD PLEASE!

Postby geezer101 » Wed Apr 04, 2012 9:13 am

Yeesh, I can see that causing all sorts of running issues. Looking at that I can also see the life of the hose will be dramatically reduced by the continuous 'bellowing' from on and off throttle driving. It's a shame, the VW in the vid sounded nice. The guy who owns it probably isn't getting the full potential out of it :(
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