924Board.org

[chardorcher]

Hi Guys , been a while since Iv been here. Happy New year to all first. Im setting up a carb kit for my 924. I am going to use the 924 factory fuel pump which has been installed recently due to a suspect bad one (which was mistakenly tested by the mechanic but anyway) on a webber set up , I know I need to attache a fuel pressure regulator in order not to damage the new carbs. Has anyone done this or have any advice which pressure I should be looking for. Also the vacuum pipe going to the distributor needs a connection to the new inlet manifold to function or can this be by passed. thanks in advance
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MANY CARS

[chardorcher]

I believe it is possible to leave the fuel system inplace, cut off power to stock pumps, and place a aftermarket electric pump in the engine bay. The stock pumps being passive and your new electric pump being 3-5psi or a regulated higher psi pump.(done this on other makes)
But Ibelieve it to be impossible to regulate a high pressure system like ours(CIS injection) down to acceptable carb psi.
High pressure will not hurt your floats, might knock them out of tune. Problem is at the needle and seat... High pressure pushs on past no matter where the float sits. will push fuel right up out your vents and flood the mother out.

Found this on the forum, may this work? I have a facet pump which used to work on a set of 40's webber set up
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MANY CARS

[Rasta Monsta]

Sell the fuel pump and replace it with proper low pressure unit.

Find a Bosch specialist to recurve your distributor and you won't need vacuum.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[MikeJinCO]

Put a low pressure aftermarket pump, max of about 7psi down where the existing external pump is so that it is gravity fed with an inline prefilter. Put a fuel pressure regulator in the engine bay with gauge and set it to 2.5 psi MAX. Don't bother to run any vacuum advance, just plug the distributor. You will want to advance the distributor about 5 degrees. I set my race car to about 40 degrees at 3000 rpm, but then I wasn't worried about performance below 3000 rpm or idle.

The trick to getting them right is finding the local Weber expert, He will probably take an hour to get the balance and idle perfect, then put it on a chassis dyno and get the jetting right. It is not inexpensive, but i was in awe watching him tune it. That gets everything except the pump jet. if it coughs and stumbles when flooring it then its getting too much gas and a bigger bypass jet is needed.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[chardorcher]

Thanks guys, you just convinced me of going on with the idea of fitting a low pressure pump, which I will fit according to your advice. Now Iv got 2 high pressure pumps to sell.
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MANY CARS