Right then. I bought the car from a bloke who has his own custom exhaust place, not then, when he had the car on the ramps i was gutted to see that he had only replaced the backboxes. He commented on how it needs a amount of back pressure to perform properly. But, i thought that as the car is the turbo model it wouldnt rely on back pressure? I want to get the exhaust upgraded but im unsure on what to do now

And what would be the best bore size? 2.1/5 or 3 inch??

 

Cheers,

Bradley

The N/A needs back pressure, but not so much on the TT, 2.5 inch is about as large abore as you want to go really.

If you do a search on exhaust size, there is lots of info and +'s & -'s.

 

HTH

Idealy zero back pressure is optimum for a Turbo,around 4" or even more especialy on high powerd cars around 700bhp or more,but the noise is going to be awfull,and your turbo has to be up for it as the seals will soon allow oil passed them,so 2.5" to 3" best suited.

 

Tony

So for example, on standard engine mods would a 3" bore suit? Or would it cause more of a headache than its worth?

3 inch will be fine , the turbo is enough of a restriction to provide backpressure

WooHoo! Cheers, thats all i needed to know!

If you still keep the cats on, that will retain a lot of back pressure...which is why, unless you've replaced the turbos recently, I'd not advise you remove them. Some people have no problems, but a large proportion see oil weep past the seals due to the decreased back pressure.

Is there an alternative to running the standard cats?? e.g sport cats etc?