Ok I tee'd into the brake servo line right beside the inlet plenum and before the check valve in the line. At idle the boost gauge shows -20psi, when I rev the engine however it won't go into positive figures just goes as far as 0 as I lift off and the dump valve activates. What am I doing wrong?

 

nothing.

will only see positive while driving. if you are seeing positive at idle/ revs then u have anti lag.

at idle as long as gauge moves when revved it is working. take it out for a spin and you will see positive boost baby

 

You'll be lucky if you see a boost pressure without creating any load on the engine (driving the car)

And, im sorry to criticise but the brake servo line

Thats the one pipe i would steer well clear of, if that blows off or gets a leak while you are driving then you may end up running into the back of someone

 

Thats what i thought

 

servo line