Which cat should I keep?
I've discovered that the exhaust is blowing on my car, around the turbo. Having looked into what's involved to replace the uppipe and downpipe gasket, it's got me thinking that maybe I should take the opportunity to replace the downpipe with a decat version while I'm at it, as everyone seems to say that this is one of the best performance improvements for reducing turbo spool.
Currently, I'm just running the downpipe cat and have a silenced (non-cat) center section as I didn't want the motorway 'drone' associated with a straight through pipe. However, I do still have my original center cat pipe stored in the garage. As I can't be bothered with messing around come MOT time refitting cats, I definitely want to keep one of them. So basically I'm asking which one is best to have fitted? If I fit a decat downpipe but refit my middle cat, would I be better off than I am at the moment with a downpipe cat, but no middle cat? |
Cobra full decat ;)
Track friendly so not silly loud and not droney on the motorway. Still has a nice bark when you give it large though |
It's the up-pipe cat that will improve spool.
I'd go Prodrive sports cat down pipe if you can find one. |
Originally Posted by ditchmyster
(Post 11737230)
It's the up-pipe cat that will improve spool.
I'd go Prodrive sports cat down pipe if you can find one. |
Originally Posted by Tidgy
(Post 11737183)
Cobra full decat ;)
Track friendly so not silly loud and not droney on the motorway. Still has a nice bark when you give it large though I'm looking for an MOT/emissions test friendly solution. |
High Flow Sports Cats
OK, so taking this on to my next question - high flow (sports) cats. If I'm going buy a new cat, and just have one, would it better to have it positioned in the downpipe or the middle pipe? Or will it make no difference at all?
Looking at what's available within my budget, it looks like I've got the following options: Option 1: 3" to 2.5" Bellmouth decat downpipe. 2.5" centre section with 200 cell cat clamped/welded on. Option 2: 3" Bellmouth high flow cat downpipe (200 cell) 3" to 2.5" decat centre section. Option 3: 3" Bellmouth decat downpipe. 3" to 2.5" centre section with 200 cell cat clamped/welded on. I already have a 2.5" Mongoose (I think) back-box, which I plan to hang onto. Any advice? Would either of these setups perform significantly better that the others or are they all much of a muchness? |
What is your budget? The Afterburner Sports CAT is 2.5" bore, so you wouldn't need to replace your centre section.
|
Originally Posted by TECHNOPUG
(Post 11740553)
What is your budget? The Afterburner Sports CAT is 2.5" bore, so you wouldn't need to replace your centre section.
My (possibly incorrect!) thinking behind this is that by moving the cat away from the turbo, although the restriction of the cat will still be there, there will be a much larger volume for the exhaust gasses to fill up before hitting that restriction. I'm on holiday at the moment, enjoying a tropical thunderstorm in the Florida Keys as I write this and haven't fitted the downpipe yet, so if I'm making a big mistake with my plans and I'd be better off with something like the Afterburner sports cat, it's not too late to change my mind! |
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