willsy369

Hi all, Im going to be getting a remap real soon on the above car. Im looking at replaceing the centre section silencer to a straight pipe, normal procedure. However, I want to remove at least 2 of the 3 cats and was thinking of removing the up pipe cat before the turbo, keeping the main downpipe cat then removing the cat pipe. has anyone done this? I cant really afford to get a sport downpipe, hence leaving it in the system completely. I have not known of any probs this may cause and hope this would still pass an MOT, i dont want to be illegal. Also should I uprate my fuel pump too? Any Sugestions or better solutions welcome! Thanks in advance

Willsy

AndyMoody

iTrader: (2)

You can remove the 2nd cat and change the centre pipe and still pass MOT so I'm told. Not sure the car has 3 cats, someone will now tell me it does. I think the centre pipe is a resonator and not a cat.

TonyBurns

iTrader: (3)

1 cat in the up pipe, 1 cat in the down pipe and 1 cat in the center section.
Up pipe and center section are the best ones to remove if you want to pass the MOT

Tony

willsy369

Cheers, pretty much as i thought above. So that if thats the best way, Just need to buy the parts now!

Willsy

willsy369

I was led to believe the WRX has 3 cats and the STI has 2 cats. And the centre is a resonator, i just called it a silencer for some reason!

But ive just been told that only the bug eye had the 3rd cat and the blobeye has just the 2

so as i have the blobeye i must have just 2?

Willsy

Tuts

Blob eye STI has 2 cats(downpipe and centre). WRX has 3(up, down and centre).

richs2891

Tuts is correct 2 cats STI 3 cats WRX (bug eye, blobeye and Hawkeye)!
Why not remove the cat from the two part centre section for now, If you want extra noise ditch the second part of the two part centre section, which is simply a resonator.
IMHO seems a waste to pay for a remap and leave the standard restrictive downpipe in. Why not try and get a sport cat from either STI PPP package or a sport cat from either here, other Subaru forums or ebay (- Thats what I did on my MY05 WRX !) - then get a remap.
I got the extra fuel pump for safety.

Richard

S1mon. J

Not got any on mine.... Sod it, don't need an MOT for another 2 years yet

BedHog

I had two cats on my 02 WRX Import, removed the downpipe cat and it passed the MOT last year, but failed this year!

It was very close apparently, but still a fail.....

So have the downpipe cat back on atm and hating it lol

NXG

None, except a 100 cell CAT in the downpipe. Got one from H&S and it's MOT friendly. The resonator is personal choice. I don't have one and it's noticeable, but not too OTT.

Edited to say - Not trackday friendly without a 'bung'!

willsy369

Well from what ive got from you guys it looks like im best to get a sport cat downpipe, to be mot friendly. Then im gonna replace the cat pipe(one that joins from the centre section) and if i have one the up pipe cat too (pre turbo). but if i cant afford the sport cat downpipe then im going to stick with my norm downpipe but still do the rest!

How does that seam for now!

Oh and maybe a remap and up rated fuel pump?

cheers again guys

Willsy

white

Do you find MPG is a lot worse or not. I know MPG would decrease as power increases but just wondering out of curiosity

S1mon. J

Bought the car like it, so don't know fuel before, car is also mapped and has VF35 turbo runs just over 300BHP
So fuel economy is not good

Smiles per gallon are very good though

AndyMoody

iTrader: (2)

I e-mailed Hayward & Scott about WRX03. They suggested replacing the cat pipe and centre section which are both £90.00 + VAT. I already have a PPP backbox which I want to keep. I don't want lots of droning noise inside the car on the motorway. H&S reckoned about 10bhp increase, no ECU probs or MOT probs if you keep front cat in place.

Anyone got similar setup can comment on the cabin noise?

Andy.

willsy369

Did that then leave 2 cats still? one in the up pipe before the turbo and the downpipe cat? As you removed the cat pipe cat and the centre resonator.

Willsy

AndyMoody

iTrader: (2)

I ain't done anything yet except the PPP backbox which I've had a couple of years.

Here is what Ian @ H&S sent me.
Thank you for your enquiry.

The best thing to do, to keep it MOT friendly and the Ecu as standard, would
be to replace the 2nd cat pipe at £90 and the centre at £90, this will link
onto your PPP back box.

The will give a slightly deeper note without being to overbearing and will
give approximately 10Bhp gain.

All prices are exclusive of fitting/delivery and VAT.

Regards

Ian Reeve
Manager

I just want someone with this setup to confirm noise inside the car before I decide exactly what to do.

If you look at Scoobyworld site it shows you system setup.

willsy369

I will be doing that set up once i have bought the parts, but i also want to loose the up pipe cat then go for a sports cat down pipe and re map at a later date.

If I get the job done in the next week or so I can let you know as wont be doing the other stage for a while yet!

Willsy

Steve vRS

Bear in mind the advice in this thread when de-catting.

http://bbs.scoobynet.co.uk/showthread.php?t=496449

Steve

McWRX

Andy,

I have done this and with a Scoobysport back box (similar noise to PPP back box) and can confirm there is no cabin drone on the motor way.

In fact its very quiet unless you have the window down. This is on a MY51 Bug. Removing the centre resonator and middle cat did make it louder, but definately the car sounds like it should now without being intrusive inside the car.

Go for it.

jonjo

None of them

willsy369

So your saying to remove none of the cats? yet you have on the side '10 sec 1/4's are a must'

Not sure how you make them then!!

Willsy