ive attached one end to wastegate and other end to n75 valve and when i put my foot down it seems to cut out at about just over 0-5 bar any help would be apreciated cheers

 

Take the MBC out and just let the N75 do it's job.

 

Check a couple things. First, check to see if the MBC is facing the right direction. Second, Check to see if you are in limp mode. You shouldn't be running only a MBC. You need to have a chip or the diode mod. What do you have? What year is your car?

 

its a 97 model 1.8t no other mods apart from remus exhaust. whats the diode mod?

 

The diode mod uses a 4.3v zener diode to trick your MAP sensor and let you run more than 9psi as controlled by a MBC. It's also irrelevant because the 97 isn't DBW and doesn't have a MAP sensor. The reason Bryan recommended you remove the MBC and just let the N75 do its job is that cranking the boost up with a MBC is a good way to fry your turbo REAL quick.

 

i think a chip is the next step then

 

When used in conjunction with a chip, a MBC *used responsibly* can be ok. If you slap one on and crank it up to 25psi you're going to spend most of your time in limp mode and fry your turbo

 

Yep...so get a chip and leave the mbc alone....youll be doin just fine with a chip. Oh yeah, make sure you get a new diverter valve and a boost gauge!