Adjustable fuel regulator

[Laurie]

I have a Malpassi adjustable fuel regulator but have no idea on the plumbing side of things for it.
Can anyone draw a diagram on what pipes go where ?
Cheers

[tubbyG]

On the top half, the barb with an arrow pointing towards the centre/adjustment screw is for your boost reference pipe - Ideally you would take this from your turbo compressor housing but anywhere pre-carb should be sufficient.

The lower half (below the membrane) has 3 conections, fuel in/fuel out and return. The barb pointing down is the return....................the other two are fairly obvious now looking at the arrows on the body..


Also when you get the o.e reg off the car, I recommend you take off one of the barbs off it then swap that with the fuel inlet connection on your carb. I think the malpassi needs 8mm(??) ID fuel hose, std is 6mm I think............. fitting the larger barb onto the carb makes it easier to connect up and make a better seal

[Laurie]

Cheers mate much appreciated

[tubbyG]

Cheers mate much appreciated


No worries...... Hope it helps :agree:

[francob80]

Unless you are going for big boost and planning to rev your car high Laurie I wouldn't bother with the malpassi. I wish I'd kept my OE FPR.

[tubbyG]

Unless you are going for big boost and planning to rev your car high Laurie I wouldn't bother with the malpassi. I wish I'd kept my OE FPR.


Are you still having the bogging-down between gears issue mark?

Yes I would agree .... there is no point in increasing fuel pressure unless you are emptying the bowl.

What fuel pump are you using?

[francob80]

I am yes, solution is flat shift currently but I'm going to buy a much better quality FPR.

I need engine mounts first.

[francob80]

Been considering this https://www.ebay.co.uk/ulk/itm/311200764847

[tubbyG]

:crap: what makes you think its the reg, can you see fuel pressure during the gear changes?

That looks like a nice bit of kit...........

[francob80]

Frustratingly its currently a process of elimination. I've tried 3 carbs, 2 fully rebuilt.

if I lower fuel pressure no bogging (less bogging, almost non existent) but then leans off at 6500rpm plus. Put pressure up, afrs are good but it bogs. As you close throttle its bogs as too much fuel, my gauge shows flat 10s (probably lower but my gauge doesn't go lower than 10)

Ive run out of ideas now, ive considered replacing fuel return or general fuel hoses coming from/to tank but clutching at straws.

I will definitely go EFI in winter.

[Matt Cole]

I imagine the increase fuel pressure is pushing fuel past the needle valve. You want 4 psi fuel pressure above boost ideally maybe a maximum of six.

Maybe go for 2mm needle valve and adjust fuel pressure to suit.

[Alex]

Ive never dabbled with adjustable FPR's but 5psi base pressure seems a popular setting.....

[francob80]

It's currently set at around 5.2/3 and carb bowl stays full, good AFRs at 7k in 4th, If I lower pressure any further it leans out.

I do have a 2mm needle valve but I've been told by a few people that using a 2mm needle valve and malpassi makes it worse.

[tubbyG]

Is the richness occurring as soon as you stomp back down on the acc pedal? if so, have you then fiddled with the acc pump arm on the carb to see what it does to afr's?

[Laurie]

Unless you are going for big boost and planning to rev your car high Laurie I wouldn't bother with the malpassi. I wish I'd kept my OE FPR.

My car does have a lot of power and hopefully after this is installed and the carb set up she should push out about 200-205 Bhp.

[Alex]

It's currently set at around 5.2/3 and carb bowl stays full, good AFRs at 7k in 4th, If I lower pressure any further it leans out.

I do have a 2mm needle valve but I've been told by a few people that using a 2mm needle valve and malpassi makes it worse.

I have heard that too. Have you tried replacing the needle valve with a standard one but keeping the base fuel pressure around 5psi?

[francob80]

Yeah it is currently running 1.7mm needle valve at 5.2psi base pressure, still bogs like f**k.

I'm going to try that funky FPR and if that fails go EFI in winter, trying to tune 32DIS carb for high boost/big power on C1J is a massive ball ache. :D