I'm interested in going for a decat. Now coming from having a focus with the 1 cat, I hear that my bugeye 02 wrx has 3 cat's? is that right.

I'm after a bit more oomph . I have a TSL firestorm backbox and want to know what bits I'd need. I'd prefer to be able to swop in/out the cat come service time so the dealers dont kick up a fuss. Is that possible?

Also what kinda price am i looking at for a decat?

 

I previously had a ST24 which i de catted myself.

Not sure if its the same to do as a scoob,but i suspect it is

Just get a coathanger and "gut" the cats.This way it will appear that they are still in place,but will give good performance and nicer sound too.

Im sure if im wrong that the others on this site with more knowledge than me will put you right.Id check b4 doing this,that its ok and DIY able

 

The Americans seem to be doing the "gutting the cats" thing-im not sure what performance gains they are getting,but i would suspect that it isnt as good as fitting proper decat pipes.
I for one, would certanly not gut the up pipe as there is the risk of leaving small fragments inside which could break off and smash the turbo.
The aftermarket downpipes also have a better flow compared to a gutted down pipe due to being "open neck" ect + would have a smoother route for the gasses to flow.
Also,if you wanted to change back to the original cats you would have to buy new ones.
All in all, i feel that it is a bit of a cheap scate way of doing it,but is a good idea as far as keeping it looking std , but i personally would get the proper pipes- makes a world of difference to the overall performance-more noticable than a non turbo car also

 

A couple of points-

1) a de-catted up / down pipe is probably of better flow design than the standard cat items.

2) to gut the up-pipe cat would entail as much work as to replace it with a decat.

3) you may fool the dealer on a visual inspection, but they ain't going to be fooled much further m8.

I would guess that the majority of the Imprezas in the UK are de-catted to one extent or another, so I wouldn't worry too much about it. just get it done

 

I'll go for the replacement decat pipes. But i'm still confused as to what parts to buy. I want my car to stay legal with emissions etc, so what cat should I leave in? If anyone can recommend decat pipes for my 02 wrx bugeye that'd be great!

 

If you want to stay legal with regards to emissions tests, you will need to fit a high-flow "sports" cat (you should then be able to remove all others). You can get downpipes or centre sections with sports cats. IIRC, Power Engineering do a sports cat centre sections. I don't recall who does the sports cat downpipe. Have a search around the Scooby Shop (http://shop.scoobynet.co.uk/).

If you don't mind about meeting emissions tests, then there are plenty of decat downpipes to choose from. For example; ScoobySport (i.e. Janspeed) and Hayward & Scott just for starters. Again, see the Scooby Shop.

 

you *should* still be legal if you keep the original downpipe. I would leave the up-pipe if you're worried about being legal, as its a pig of a job.

thus you will need a system from downpipe back.

 

As standard you'll have one in the uppipe, downpipe & centre.

The centre does very little either way - it barely restricts flow (unless you're looking at 350bhp+) but also is unlikely to help you get through an emissions test, unless it's in perfect working order & very hot!

The uppipe: removal of this should bring the spool-point down significantly & is well worthwhile if you ask me, but is an utter pain to do! Unless you're planning on moving to California, it will make no difference either way to an emissions test...

The replacement of the downpipe cat (with no cat ) allows significant improvement at the top end as it flows so much better. This is the main cat - the critical one for keeping emissions & passing tests. However... if you want performance & 'healthy' emissions, replacing this item with a 'sports cat' can make improvements almost as good as no cat, at least until the 350bhp+ mark is hit again

Lots of people make the things. I like the APS system as it's very well thought out & built well, but it's not the cheapest. I like subtle things too & it keeps the noise down .

That's the other thing to bear in mind - removal of cats will make the car much noisier. You've got good soundproofing in a bugeye, but it can be pretty noisy outside!

 

I`ve got a few questions about decating as well. I’ve got a WRSport RB5 and was wondering what the best options for myself are. I want to maintain the prodrive centre & rear stainless exhaust that I have fitted but I’m looking at maybe getting a de-cat`d downpipe fitted and was wondering the following:

1. Would this pass the emissions test on the MOT?
2. Will I need a re-map or will the prodrive ecu be able to handle the change?
3. Is it worth it for the gains I will get?
4. What DP do people recommend?

Cheers,

Chris