View Full Version : what downpipe to get the best out of Nurspec R exhaust

30th March 2003, 13:18

I have a Nurspec R exhaust which included the back box and centr section. It is 3" all the way through except where it joins to the original downpipe where it narrows to 2.5"

When I get round to changing the downpipe I'm thinking that the best set up would be a 3" to 3" with a custom made 3" end put on the blitz centre so its 3" all the way through from the turbo back.

It would be a lot easier & cheaper to just get a 3" to 2.5" downpipe & leave the 2.5" narrowing.

I'd like to know if:

The 3" to 2.5" narrowing is advantagous in any way? ie backpressure? To my layman thinking its just an obstruction to flow.

Or if 3" all the way through is the best set up and over the best gains

Any info much appericated



Adam M
30th March 2003, 15:42
A wise man once said on this forum (pasted) (some bloke from garrett) that on a turbo charged car you dont want any back pressure at all. Especially after the turbo as it reduces the pressure ratio across the exhaust wheel.

Danny Fisher
30th March 2003, 16:00
Adam, I am running a BPM twin dump D/P, with the HKS mid and Ti-Backbox using a TD04, I suffer from lag low down.

But if looking for power then a good 3 inch system is the way to go.