silverscoobydan

Hello All,

I am looking at upgrading the exhaust system on my WRX (MY05). I am aware that there there are 3 cats in the system (up pipe, down pipe and cat section).

I want the best possible power increases but also to pass MOT/emissions.

If I remove the up and down pipe cats the turbo will spool up quicker but will a sports cat in the cat section be enough to pass the MOT. Or is it better to have a sports cat in the down pipe as well and risk a little less power/spool up time???

What have you done? and what do you think? Any recomendations on brand/manufacturer?

Any help greatly appreciated.

34srm

your car dont need mot yet

Henrik

iTrader: (5)

I would just go with a downpipe sports cat... I don't know about you, but at least I can't be arsed with changing exhausts just for MOT

Edit: and also, allegedly it doesn't affect spool too much anyway (sports cat vs decat)

funkyspider

Prodrive sports cat downpipe (can be picked up second hand), or similar - Search for Mike Wood posts on the efficiency of their Prodrive downpipe vs full decat. A Decat up pipe and straight through centre, a decent back box and a K&N or Green panel filter. Oh, and a remap to ensure it's set up for the new kit.

Will void your warranty tho, so that has to be a factor.

silverscoobydan

Yep I know, but it will within a year and I cannot be bothered swapping parts just for the MOT.


Funky - Prodrive sports cat downpipe (can be picked up second hand), or similar - Search for Mike Wood posts on the efficiency of their Prodrive downpipe vs full decat. A Decat up pipe and straight through centre, a decent back box and a K&N or Green panel filter. Oh, and a remap to ensure it's set up for the new kit.

Will void your warranty tho, so that has to be a factor. - Funky

Thats great thanks. So one sports cat is enough to cope with MOT and emisions - wow!!!

I have spotted a few second hand Prodrive down pipes but was wondering whether it would fit an aftermarket centre section, Miltek or similar?

Want the free flow without too much noise (that's the age showing!!)

Henrik

iTrader: (5)

The centre section actually has two parts, I believe.
There's the front part, which is the last cat, and then there's the part behind it (but before the backbox) which is a resonated centre section (which is what looks a bit like a fourth cat).

The Prodrive down pipe should mate up to most after market centre decat sections, as long as the new decat pipe retains the original dimensions (e.g. I believe that the original exhaust is 2.5")

I'm planning on the following from the headers onwards:

* hayward and scott up-pipe
* turbo of some sort
* prodrive down pipe
* afterburner centre decat
* OEM or another resonated centre section
* OEM backbox

I'm hoping that the above will flow well enough and also be quiet enough not to annoy me (I've currently got a TSL Firestorm backbox and that's just obscenely loud inside the car, imo, so i'm going back to standard)

Arch

iTrader: (59)

The Prodrive Sports cat does not fit onto the TD04 turbo without modification (thanks to all who helped with the info especially Mike Wood and funkyspider).
I am going down this route also with an MY05 WRX. I have purchase a new style (heat blanket enclosed) sports cat and the prodrive decat centre section which looks exactly like the third cat but is a straight through pipe fitted inside the standard heat shields. I already have the prodrive back box. So just need to get the samco 3 piece intercooler hose kit a panel filter then a remap. Cost all in around £1000. My aim is to get a car with similar power figures to the WRX PPP but with a map specific to my car and for a considerable saving.

The Prodrive sports cat is designed to fit the STI turbo and has a seperator welded at the flange which mates with the turbo outlet, this splits the waste gate and exhaust gases. The seperator protrudes to far out from the flange to fit the TD04 so it has to be ground down to fit the WRX turbo.

These parts are readily available on most of the forums and ebay and can be had for excellent prices considering the quality of the items. Think of it as recycling, as people mod their cars to a higher standard these parts become available, so modding your scooby is actually eco-friendly Try that one on any tree huggers you know.

andythejock01wrx

Other alternatives to the Prodrive downpipe are the sports cat exhausts available through API and Scoobyworld (Ninja) for approx £300 (dp).

Andy

AFRIKANZ

Have a cracking exhaust for you, a cat back Blitz Nur Spec R, complete with bung!
The ultimate exhaust!

silverscoobydan

Thanks all for your replies.

Just to clarify: Any Prodrive downpipe will not fit my WRX without modification. But if modified it will fit aftermarket cat/centre section as long as it is 2.5''.

Arch

iTrader: (59)

As far as I am aware all the flanges etc should be the same but not 100% sure. I went for the prodrive items as they fit no problem and are readily available. The mod to the sports cat is simple enough but if you are unsure or unwilling to try it go for one of the other options suggested. There are a lot of quality parts being sold by people as they enhance their cars and sell on the items they no longer need. All the parts I have purchased after a quick clean look like they have just come out the wrapper.