GONZO01

iTrader: (6)

Just looking for the general consensus on this (worth it or no). I currently have a prodrive back box with a scorpion centre pipe and prodrive downpipe and I'm going to have the car mapped soon and I was wondering is it worth taking out the prodrive down pipe and replace it with a decat downpipe or no? I want to remove all the possible restrictions if it's worth it and release as much power and drivability as possible for when it gets mapped, I have sourced the other mods needed (fuel pump, 3 port etc) from a kind fellow member on here (you know who you are lol) and yes I have a friendly mot person before you ask.

big daz2

If you have a friendly mot station then yes do it mate, anything that ristricks breathing is going to slow you down so if you make the breathing in and out as straight and clear as possible it will make a diffrance with a new map

redwards

iTrader: (6)

Keep the prodrive sports cat. Your mot man may be friendly, but I can guarantee the vosa man at a road side check won't be.

The Trooper 1815

iTrader: (31)

This.

dave_t

iTrader: (1)

Keep the sports cat. Just not worth the grief for a few BHP (it is only a few), unless you are specifically trying to get loud pops/bangs or antilag etc.

That being said, i'm looking for a sports cat ;-)

dazsti72

Sports cat is better for a everyday driver.Decat makes your car stink of fumes,,

drive

iTrader: (1)

Yeah do it, then sell me your down pipe cheap, ha ha
I'm thinking of doing the same thing, but not sure to be honest !!
Trying to weigh up the pro's and con's as I have a 3" straight through system at the moment....

GONZO01

iTrader: (6)

I just can't decided what to do, remove my prodrive sports cat and replace it with a decat down pipe I will keep the sports cat but just wanted opinions on if it's worth changing over power/performance wise then get a remap or keeping it as it is.

Cannon Fodder

iTrader: (100)

Gonzo, as I've said to you when we spoke before it's really not worth it for the sake of a couple of bhp that you might gain over your Prodrive sports cat.

You've already got the best sports cat on the market for a 2.5'' exhaust system, I'd leave it where it is and ignore the Scoobynet 'experts' advising you to fit a decat downpipe.

GONZO01

iTrader: (6)

I'm leaning towards keeping the cat in place to be honest Ty I just wanted a general opinion on what people have done to theirs and if the cat would be to restrictive come when I get it remapped. I have sourced a 3 port and one of the lads from the meet is sorting out the fuel pump we spoke about also then it's remap time.

big daz2

Evening Tyrone I'm interested to know how many cars you have had de cat'd? and how many had sports cats? My expert advise is based on cars I have owned that have been de cat'd and the most performance was gained with straight through exhausts, it doesn't make me an expert but it does let me offer an honest opinion without being rude about anyone. Can I ask why you feel your advise is worth more than others that have advised de cat?

wasbo

iTrader: (1)

My decat added 31bhp if that's any help

Cannon Fodder

iTrader: (100)

Brian, was the car remapped with the existing factory exhaust in place and then remapped later when the decat was fitted?

What I'm getting at is that a remap on the standard exhaust will give gains, do you have any before and after dyno plots for comparison?

wasbo

iTrader: (1)

The first map was single cat in downpipe straight through exhaust to genome backbox, second was full decat do have print outs somewhere but figures went from 321bhp/330torque upto 351/380

53

iTrader: (41)

I've done both and while a decat will give you more, it doesn't add enough to make it worthwhile over the Prodrive offering IMHO

Cannon Fodder

iTrader: (100)

Evening Daz, I have run with a decat on my Spec C but that was when the power was increased to 500bhp (albeit briefly) but there is no direct comparison as the turbo, injectors, fuel system etc were all altered prior to the mapping session.

I didn't even see your post Daz so no offence was intended to you or anyone else, the biggest increases will be seen in standard cat vs sports cat and not sports cat vs decat.

Also going to an exhaust system which is too large or free flowing for the possible power output may also rob you off power rather than increase it, there is no point going for a 3" system until the power output reaches 370bhp or more.

And the main point is that having a sports cat makes the car road legal, fitting a decat downpipe and removing all the cats does in fact make it illegal and if the car does have a VOSA roadside check they are perfectly entitled to issue a prohibition order against the car and take it off the road.

Cannon Fodder

iTrader: (100)

Brian, was the single cat the factory OE item?

If you believe the figures the Prodrive sports cat when used as part of the PPP in a UK STi helps can an increase of around 29bhp if I remember the figures correctly.

The figures go from 276bhp to 305bhp on the PPP generic map, if remapped by a specialist using the same exhaust then the gains can go from 276bhp to around 330bhp.

big daz2

Ty when did we get all socially responsible? How many times in the last year have you been stopped by vosa? All petrol heads have run de cat for many years and I don't see the problem. I know what your saying that the power gain isn't worth the hassle but there is a gain and sometimes every bhp counts. I took hum bridge to your comment regarding ignoring "experts" when mine was the only post.

Cannon Fodder

iTrader: (100)

Believe me VOSA roadside checks are going to become more prevalent as time increases as they are training up more enforcement officers to carry them out, and these will be may well be done in conjunction with the local constabulary traffic divisions.

I honestly didn't see your post, I was referring to a lot of the urban legends which do tend to taken as fact on Scoobynet and then passed on.

The Stitcher

iTrader: (12)

You say in the original post you want to remove all possible restrictions to release more power so de cat it is then as you answered your own question really

You have a nice mot guy so no worries there and a de cat pipe is cheap as chips so I would say go for it but keep the sports cat for if you ever sell up to give to new owner just in case they ain't got a nice mot guy lol

big daz2

For when the vosa man stops you lol

Cannon Fodder

iTrader: (100)

https://www.transportoffice.gov.uk/c...CONT032945.pdf

And the above legislation has been existence for quite some time, it's hardly new but as I have said if they find your vehicle emissions to be absurdly high they can take your vehicle away from you, or you might be obliged to get it recovered away to await repairs.

big daz2

I know what your saying ty and suppose it's weather the person who owns the car wants to take the risk I know the route I would take

drive

iTrader: (1)

Hi daz, from one non expert to another, would you recommend a remap....

big daz2

I would and I don't know one subaru owner that wouldn't recommend a re map the other bits are down to choice I'm afraid

Black-Hawk

iTrader: (4)

I is an expert and i say gonzo ring every last bhp out of the ****** and smile