131mirafiori forum

Hi guys any advice on changing my 131 racing from manual engine mounted fuel pump to an electric one. My engine is running twin downdraft carbs. All help and advice appreciated  ???

I too have twin carbs (45 DCOE sidedrought) so the mechanical pump was probably not going to be able to keep up the supply! I have a Facet "Fast Road Competition Silver Top" pump which is meant to be good for engines up to 170bhp. My engine is only 155bhp so doesn't need anything more. In fact I changed the pump just about a year go and you can read that thread at http://131mirafiori.com/smf/index.php?topic=736.0. Facet make several versions of this pump from "Standard" to "Fast Road" to "Full Race".

(http://www.131mirafiori.com/images/fuel_pump/1.JPG)

The pump is fitted in the boot near the fuel tank.

(http://www.131mirafiori.com/images/fuel_pump/3.JPG)

Ideally, you should also fit an inertia cut-off switch so the pump will stop pumping in the case of a sudden impact i.e. an accident. If the car is in an accident, you don't want the engine to be off and the pump to be still pumping fuel everywhere. I have the inertia switch mounted inside the rear quarter panel. You'll also need to get a blanking plate to cover the hole left behind by the old mechanical fuel pump. The plates should be readily available from Fiat as several twin-cam engined cars had electric fuel pumps but it's a simple enough plate to make.

I too have an electric fuel pump on one of my 131s to fill my twin 40 dellortos. Spookily it is in the same place as yours Theo. I don't yet however have the inertia switch or blanking plate, my old mechanical pump is still in place. I guess I will get round to it sometime!

A simple solution is a relay wired in to the oil pressure switch circuit, a simple timer to allow current to the pump when ignition is turned on overcomes starting issues. It can also save an engine if you lose oil pressure.

Yes a lot of cars use a relay energised by the oil pressure switch to power the pump. As Tas131 correctly said a timer is used to run the pump for a while when the ignition is turned on or a second relay can be used connected to the starter solenoid circuit so the pump runs while the engine is being cranked.

Are those hints of Orange in the boot Thotos?
I think weve been here before!  ::)

Yes definite hints of orange and yes we've been though this before  ;D My car was restored in 1995 by the previous owner using a donor shell from an orange Sport and as many new panels as he could get (doors, wings, bonnet, bootlid etc). So maybe I can join the "Orange Boys" even though my orange car is wearing a disguise  ;D ;D

Any one can join the orange boys, as long as you have an orange car ;D
and Theo as your car IS Orange! your a welcome member :D

aboout those fuel pumps...
i think i read somewhere (fiat 132 service book probably) that standard fuel pump delivers 86l/h at max rpm (6.000?). why do you all think it ain't enough fuel for twin carb setup? with single carb at least 80% of fuel goes straight back to fuel tank anyways...

You are probably right that the standard fuel pump in good condition can deliver enough fuel but the advantage of the Facet electronic pumps is that they deliver a steady supply of fuel while the mechanical pumps deliver 'bursts' of fuel.

My super fitted with bored out chokes on twin 40 idfs and high lift cams ,still used mechanical pump
 with  no problems
jay

Thank you all very much for the help very much appricated  :) :) :)