Will a down pipe affect the flow of wastegate? As I have the one that isn't open mouth, its got one pipe that runs from wastegate, straight into downpipe again. If they makes sense, think its the old Magnex one.

 

BTTT

 

Anyone?

 

Some think that this pipe can be fowled a bit and an open mouth design is better

 

An open neck decat d/p is supposed to be the better option of the 2 but how much the one you have actually restricts flow I don't know.

 

I have seen the down pipes you are on about and should present no problems as all the gases are exiting and no back pressure to stop the wastegate port from opening. The bellmouth ones are more desireable as they have a wider surface area to allow more of the gases to be forced down a single entry, ie : normal dp diameter - 2.5 inches, bellmouth - 5.3 inches.

 

Ok thanks for replies, might stick with what i have then.
I am thinking about nur spec r, cat back. But am finding out that they are three inch which connects to downpipe at 2.5. Will this effect anything going from 2.5 to 3 inch from down pipe?

 

Mrchips, I have a 2-port d/p with the 2nd port dedicated to the w/g too. Plus my whole system is 3" but with a 2.5" d/p-to-centre flange, like yours.

I mentioned this to API David and he didn't say it will be a restriction for my next round of mods - going for around 350-370bhp. If it were going to be a problem, I'm sure he would have flagged it up.

Hope this helps.