Fuel pressure question.
Turbo Mini Forums

Running 7psi of boost i'm getting about 12psi of fuel pressure from the regulator to the carb, but if i hook the gauge up to the float bowl using the pipe the "float chamber venting valve" comes off i only see 8psi in the float bowl ? is this right ? or could it explain why my needle needs to be like a drawing pin to get enough fuel ?

Phil.

WWW.TURBO-MINI.COM

I don't really know, but thinking about it the fuel pressure before the float bowl needle valve is likely to be higher than pressure after the needle valve i.e. in the float bowl. Mainly because its flowing in to a larger volume.

However, having said that there is also the isse of what exactly are you measuring? I'm not sure if the "float chamber venting valve" will be a true representation of the float bowl pressure.

Still if it is right, it would go some way to explain your thin needle.

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Phil - your carb float chamber (not the same as fuel pressure as you realise) is not increasing in pressure with boost - or not enough....

I had the same prob with mine a few years ago - carb was fine before the winter build - by Feb when the engine went back in, it was like yours.
put a tee-piece into the pipe from plenum to regulator, and connect the tee to the 'float chamber vent valve' pipe in the side of the carb. This by-passes the internal circuit and does what you want.

Needle will need totally doing again.

Of ourse it could just be that you removed your plenum and fitted the wrong gasket between the plenum and carb - or fitted it the wrong way round - but whichever way, the external pipe does the job and has been in my mini for 3/4 years now!

Edited by turbodave16v on 12th Nov, 2004.

Cheers for that guys.
Will try your method later Dave.

Phil.

WWW.TURBO-MINI.COM

I said I didn't really know.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

that magic t-piece again,