Dump valve queries..
Turbo Mini Forums

im going to weld an outlet on the plenum for the dump valve to connect to,now the questions are

1. do i have to remove the spring off of the carb butterfly and replace with a solid butterfly for it to operate correctly? as i have been told it would work in a 'sluggish' manner

and

2. is there any other modifications i need to make to the plenum for the dump valve to operate correctly?

thanks alot

dan, No i left mine alone works fine,

weld a adapter on to the plenum and away you go,
i drilled and taped mine 1/2" BSP and fitted a short peice of threaded pipe in and coupled the dump valve with a short peice of hose there, but this was befor i fitted my intercooler, on doing so i placed the dump valve about 3" before the plenum.
the butterfly spring in the carb will be un afected
turbo dave coverd this a short time ago
do a search on carbs

Nice one,cheers ben. just thought id ask because my mates old turbo mini's dump valve used make a long hissing sound,like its just leaking air.

this is my first turbo engine,quickest engine to date ive had is the one thats just come out,mg 1275,vmax head.tis a quick little thing but decided to go turbo.

im hoping to get the engine in tonight,one other question.my rad is a 998 one,worked fine on my mg1275, will it be ok on me turbo (standard engine) ???? only one way to find out i guess!!

thanks

Think you will struggle with a std rad. See how you get on but keep a close eye on the gauge.

Also be a good idea to block off the standard spring and plunger on the front of the plenum, i just used a large nut/bolt/washers. My dumpvalve used to hiss under boost because the seals react with the fuel and swell up causing it to seize. Special seals are available but i took the dumpvalve apart and cut little segmants of the piston seal out until it could move freely, been fine ever since.

-MINI CLUBMAN 1380 TURBO-

Also make sure you have the correct TURBO gasket between plenum and carb with the extra holes. May sound obvious but many have made this mistake and get all sorts of running problems.

-MINI CLUBMAN 1380 TURBO-

I can think of only one turbo mini that I've worked on that the dump valve worked properly on with the standard throttle disc. Try it by all means, but first sign of sluggish dumping, get it changed out. I can only assume it's down to how strong/weak the butterfly poppet valve is, compared to how strong/weak the DV spring is...