exhaust experts help/advice??!!

[anthonys2]

guys

ive just ordered a stainless steel exhaust with a 2.5 inch downpipe and single flow sports cat, i already have a miltek back box to middle these guys will go from from middle including cats to engine.

my first concern was going down to a single sports cat cause obviously it has a standard twin cats but he said it was no problem and actually helped the flow, my second concern was the 2.5 inch downpipe but he assured me that this is good for up to approx 300+ bhp but not much more is this correct? theres so much talk on the forum about 2.75 or 3 inch downpipe??!!

I have no real intention of increasing the bhp cause am more than happy with current power and output of the standard set up

The guys that are carrying out this job are A.A.S (advanced automotive systems ltd) specialists in custom made titanium and stainless steel exhaust sytems recommended to me by Autobahn in hexham who service my S2 anyone heard of them?? apparently one of the best in the country

cheers

Anthony

[Jamo]

2.5 downpipe starts hurting around 270 bhp yes you can push higher but your EGT's and backpressure are going to be high.

If you can afford it buy an RS2 downpipe it's 2.75" and has the dual output or go to Prospeed for a custom 2.75 or 3" one

Even if you have a 3" downpipe going to 2.5 centre section doing it now will save hassle and improve turbo pick up.

[Rusty]

Why spend so much money replacing a 2.5" down pipe... with another 2.5" down pipe? Waste of money there IMO. If you want to go sports cat then get the OE down pipe modified to 3" after the WG inlet and then get a flange to fit the cat and a 3" link pipe to the Milltek. I had this done on the first Prospeed system and it worked well. Or just get a full system off them

[anthonys2]

cheers il go and talk to them and go for a 2.75 inch downpipe to be honest i wasnt sure ive seen alot of talk on here about various sizes thanks again rusty and jamo