johnoggy

Hi all, just a bit of advice needed please, im looking change my exhaust for a decat system , i have already got a deres center pipe but the thing is its 2.5 all the way through , do i just buy the down pipe and back box 2.5 or replace the full system for 3 inch, will there be much difference in power gain between the two? 2.5 to 3 inch , thanks guys

Vxr2010

unless you are running somewhere past 400 bhp then the 2.5 inch is fine , better with a sports cat rather than a de cat mot time but your choice 👍

jaygsi

iTrader: (46)

I swapped my standard system for a 100 cell sports cat and all 3" bore. Really increased the the power delivery. Can't say if it would be much better than a 2.5" system. And as said go for sports cat.

Vxr2010

i’ve got 2.5 inch on all of mine , i had a 3 inch did not notice a difference ,im running around 340 bhp , a centre section either cat or silencer delete helps the car to flow better , a good sports cat v a decat on haywards and scott’s site they state only a 2 bhp loss , on the plus no mot issues , i went japspeed 200 cell sports cat as they are not silly money , and it works fine , it’s passed its last 3 mots , as long as with any sports cat it is fully warmed before the test 👍

jaygsi

iTrader: (46)

Yea with my 100 cell ninja cat it passes, but needs to be the temperature of the sun

So think I'm going 200 cell. Be interesting to see the power difference. Saying that I'm looking to fit new turbo at same times so might never find out.

Nick_Cat

iTrader: (5)

I've got a TSL 100 cel 'Thunder Cat', (2.5") a nice bit of kit but it needs to be very hot to pass emissions. It's been on the car for 14 years and is paired with a straight-through centre section and a TSL Group N backbox.

johnoggy

Thanks guys for the help , i think i will go sports cat then 2.5 , and back box , VXR 2010 where did you get your japspeed from ?

Vxr2010

an ebay job , 230£ or so a few years ago 👍

jaygsi

iTrader: (46)

This one is for a classic

https://www.ebay.co.uk/itm/200CPI-JA...-127635-2958-0

But to be fair I think any cheap eBay is all the same.

https://www.ebay.co.uk/itm/200-CELL-...-127635-2958-0

johnoggy

i have found some on Ebay but they all seem to be 3inch ,

jaygsi

iTrader: (46)

Oh yea forgot you don't want 3", try Japspeed website. What year Impreza is it for?

johnoggy

sorry i should have said , its to fit onto a 2005 sti widetrack

jaygsi

iTrader: (46)

Can't see anything on Japspeed website oddly.