Where to locate a fuel pressure regulator in the engine bay?

PostPost by: Flying Banana » Tue Oct 06, 2020 4:19 pm

I've just bought an S3 with a low pressure facet fuel pump fitted, but no fuel pressure regulator (FPR).

For non FI applications, most people fit fuel pressure regulators near to the carbs (weber floats don't like >2.75 psi generally and can flood). Where would an FPR sit in the engine bay? There doesn't appear to be much space under/around the carbs?
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PostPost by: ericbushby » Tue Oct 06, 2020 7:42 pm

I also have an S3.
I fitted a Filter King, bracketted off the top of the wheel arch, under the front carburettor, with its centre line a little forward of the centre line of the carb.
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PostPost by: Flying Banana » Tue Oct 06, 2020 7:49 pm

ericbushby wrote:I also have an S3.
I fitted a Filter King, bracketted off the top of the wheel arch, under the front carburettor, with its centre line a little forward of the centre line of the carb.
Eric in burnley
1967 S3SE DHC


Thanks Eric. I haven't had the carbs off yet, but given it looks like a difficult job for large hands to remove them, I wanted to check I wasn't going on a wild goose chase!
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PostPost by: Quart Meg Miles » Tue Oct 06, 2020 10:06 pm

Mine is loose and has been for over thirty years! It is a bit tight and needs care to stop the hose kinking. I set it to 1.5. This picture is from 2014 and it is rather cramped on its way to the rear Weber. A single hose to a T-piece on the front Weber would be a neater layout, as would different clamp types, but I'm too mean to buy the bits.

Regulator after engine pump 118-1581.JPG and
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PostPost by: alan.barker » Wed Oct 07, 2020 6:09 am

Change the Pump for a "Huco" Pump low pressure for Webers and no regulator needed.
Have a look at "Webcon".
Alan
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PostPost by: Flying Banana » Wed Oct 07, 2020 9:27 am

alan.barker wrote:Change the Pump for a "Huco" Pump low pressure for Webers and no regulator needed.
Have a look at "Webcon".
Alan


I'd rather ensure the pump is supplying fuel pressure (and volume) above that required at the carbs to ensure that I can regulate this down to the specified level (2.5 - 3 psi depending upon needle size).

Low pressure can sometimes leave the fuel bowls slightly low at high revs, which changes how the emulsion tubes function (from their intended spec), leading to a chasing of a problem with the carbs which is instead a problem with the fuel supply.

The Huco pressure pump referred to above (if I have the correct pump) per this link https://www.webcon.co.uk/shopexd.asp?id=16672 only appears to be rated at 0.3psi? I don't believe this to be sufficient to maintain float levels?
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PostPost by: alan.barker » Wed Oct 07, 2020 9:43 am

You are getting mixed up with Bar and PSI, it's .3 Bar= 4.3 PSI. 1 Bar = 14.7 PSI
It's not the pressure that will keep the Float Chambers full it's the flow rate.
There are 2 choices of "Huco" Pump so you can choose which suits your application. 133000 at 4.3 psi or 133010 at 2.1 psi. 125 Litres/Hour flow. For upto 160 BHP is your engine more than 160 BHP?
I am still running mechanical glass bowl on my 1972 Elan Sprint.
BUT i also have a 1976 TVR 3000M and also a 1978 TVR 3000S and BOTH are running "Huco" Pumps no problem.
Now these are Ford Essex V6 three litre engines are thirsty beasties and with the "Huco" Pump running very well indeed :D
Of course it's your personal choice and the most important is that you can drive your car and enjoy.
Good luck in resolving the problem
Alan
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PostPost by: vstibbard » Fri Oct 09, 2020 3:02 am

+1 on the Huco set up, quiet, and option have boot mounted or engine bay mounted pumps.

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