Another decat question
Probably been asked before but I only want remove one cat, what's best? Down pipe or centre cat? I already have a cat back on my blob wrx, any advice would be great
Been trying to find this out myself so welcome to the club mate!
See the thread a couple down..
Downpipe decat & keeping the centre cat will give you more power than decatting the centre & leaving the downpipe standard.
Both 'should' keep you MOT friendly (although the gloves are out on running just a centre cat).
The only thing i will say is decatting the downpipe will be notably more expensive (pipe & fittings costs are higher) and if you have an MOT problem you will have to pay lots of money to refit the catted downpipe.
I chose to decat the centre (cheap as chips) and remap. Should MOT become an issue its a two minute job to bolt the original centre cat back up.!!!!
Whichever you choose, include the cost of a remap as thats where the real power gains 'per pound' are (assuming its not already mapped).

See the thread a couple down..
Downpipe decat & keeping the centre cat will give you more power than decatting the centre & leaving the downpipe standard.
Both 'should' keep you MOT friendly (although the gloves are out on running just a centre cat).
The only thing i will say is decatting the downpipe will be notably more expensive (pipe & fittings costs are higher) and if you have an MOT problem you will have to pay lots of money to refit the catted downpipe.
I chose to decat the centre (cheap as chips) and remap. Should MOT become an issue its a two minute job to bolt the original centre cat back up.!!!!
Whichever you choose, include the cost of a remap as thats where the real power gains 'per pound' are (assuming its not already mapped).
Yes I'm not bothered by fitting and refitting as I'm a mechanic, do they generally run like crap without the remap tho? I'm not really bothered with power at the mo just want a bit more noise
It's a scooby world ninja, don't have the money to throw a blitz or a new backbox on it, do want more power but don't have the cash for a remap straight away and you get everyone on here saying it must be remapped if you decat it and I don't have much experience with impreza as this is my first one
cheap option would definately be to decat the centre (£40 or so).
then find some nice person on this site to flash a PPP map on for the price of a few beer tokens.
PPP map is a mild 'out of the box' solution but it should give you a cheap result.
Expect maybe 15/20 bhp for £50 (& it don't get any cheaper than that mate).
Noise will increase a bit as you've removed a box...
then find some nice person on this site to flash a PPP map on for the price of a few beer tokens.
PPP map is a mild 'out of the box' solution but it should give you a cheap result.
Expect maybe 15/20 bhp for £50 (& it don't get any cheaper than that mate).
Noise will increase a bit as you've removed a box...
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That sounds like good idea, is there anything else I would need to make the most of the PPP flash? I only want more sound because my mates blitz is droning me out and that extra bhp would surprise him aswell
The advice will depend on whether you are happy sticking at those figures.
Some good reading is at http://racedynamix.co.uk/remap/subar...ewage-2-0-wrx/
Costs for bits (assuming you can deal with fitting)
PPP sports downpipe (£120ish S/H)
Centre cat removal (£40ish for pipe S/H or trash the internals)
Full decat (£80 S/H) but will fail MOT
Fuel pump (£75)
Turbo (£250+ S/H)
Injectors (£100+ S/H)
Custom remap £350+
If you are looking at a full decat/turbo/injectors you will need a full remap
(If sticking with just scrapping the centre you can have a PPP flash but you won't get 250-260, more like 235-240 IMHO)
Also remember if you fully decat now and have a full remap, then later choose to move on to bigger turbo etc you will have to remap again.
Unless you have plenty of money think hard, hatch a plan, work towards it, stick to it......
Some good reading is at http://racedynamix.co.uk/remap/subar...ewage-2-0-wrx/
Costs for bits (assuming you can deal with fitting)
PPP sports downpipe (£120ish S/H)
Centre cat removal (£40ish for pipe S/H or trash the internals)
Full decat (£80 S/H) but will fail MOT
Fuel pump (£75)
Turbo (£250+ S/H)
Injectors (£100+ S/H)
Custom remap £350+
If you are looking at a full decat/turbo/injectors you will need a full remap
(If sticking with just scrapping the centre you can have a PPP flash but you won't get 250-260, more like 235-240 IMHO)
Also remember if you fully decat now and have a full remap, then later choose to move on to bigger turbo etc you will have to remap again.
Unless you have plenty of money think hard, hatch a plan, work towards it, stick to it......
Last edited by dave_t; Nov 7, 2013 at 09:22 PM.
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