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AncientOfMu
07-04-2007, 06:52 PM
I want a de-cat pipe, more for the additional noise than anything.....

should i go for the 2 1/2" to go better with a standard system with ralliart backbox or go for a 3" for when I eventually get a custom cat back exhaust???

With de-cat fitted will I be over the noise limits for combe??

Opinions gratefully recieved :).

Kieran
07-04-2007, 08:32 PM
You won't be over the limit with that Ralliart back box.

I have a decat you can have if you like, for a small contribution to the KieranCorp 2007 polish fund! It's the one I fitted at Nicks. I drove home with it and took the fecker off the next day - Didn't like the noise and was paranoid about an emissions check. Not that I've ever seen one, but anyway...

If you can hang on to Japfest I'll bring it down... That'll give me time to find it! /pan It's a 2.5" one.

Just one thing.... When I got the car from Nick it was Decatted and I didn't notice much noise difference with it on.... It was marginally louder and throatier, but not as much as you'd expect.

ANTHONY
07-04-2007, 08:54 PM
very interesting, i'v just had a cat back full s/s exhaust fitted and the noise is just right i belive . now if i was to decat it would it make a difference to perfromance and noise, as you know its a 2.0 (1 for Kieran to answer i feel.)

psbarham
07-04-2007, 08:56 PM
as kieran says it won't make it much louder , with my de-cat fitted mine howls like a 355 ferrari , but without it , it still howls just not so ferrari-esque sort of deeper, the cat seems to just take the note down an octave or 2 .

bernmc
07-04-2007, 09:56 PM
mmm... I've got a decat for mine (just had its MOT, so cat still fitted). Apparently makes it sound more aggressive and results in flames on the overrun...

I just don't like the idea of decats in principle.

Kieran
07-04-2007, 11:16 PM
The effect the cat has on noise depends on the rest of the system I guess. For example, with the standard VR-4 exhaust, with all it's bends and inline silencers, there's not much in it.

Put on a 3" Blitz system with only 1 silencer (the rear box) and decatting it turns a loud and growly exhaust INTO A REALLY LOUD AND GROWLY EXHAUST, HELLO? PARDON?! :inquisiti

Funkstar
07-04-2007, 11:57 PM
Just one thing.... When I got the car from Nick it was Decatted and I didn't notice much noise difference with it on.... It was marginally louder and throatier, but not as much as you'd expect.

Kinda agree with Kieran here. I've just taken mine off for the MOT (which it passed flawlessly I may add :evilgrin: ) and haven't noticed any difference in performance. But.... there is a slight increase in noise, especially at a cold idle. Say when I'm shutting the gates at work with the car ticking over, there was definately more of a burble at standstill, but nothing when I gave it some beans.

So, as a summary, good for the noise when cold, but jack at any other time.

stuey
08-04-2007, 02:32 AM
Kinda agree with Kieran here. I've just taken mine off for the MOT (which it passed flawlessly I may add :evilgrin: ) and haven't noticed any difference in performance. But.... there is a slight increase in noise, especially at a cold idle. Say when I'm shutting the gates at work with the car ticking over, there was definately more of a burble at standstill, but nothing when I gave it some beans.

So, as a summary, good for the noise when cold, but jack at any other time.

Standard exhaust on mine, when de-cat fitted noticed no real change in tone/volume at all !!...

bradc
08-04-2007, 05:33 AM
I've heard KiwiTT's car and it sounds the same as a normal car. It has a stock exhaust but has a decat pipe installed.

My exhaust on the other hand with custom downpipes and twin exits sounds great!

http://www.clubvr4.com/forum/attachment.php?attachmentid=15109

AncientOfMu
08-04-2007, 09:30 AM
Thanks for the replies.

So basically until I get some boost control and a cat back aftermarket exhaust a de-cat pipe really isnt worth it...

Would that be a fair assumption?.

Ill have to spend my money elsewhere :).

bradc
08-04-2007, 09:37 AM
they aren't that expensive anyway, go for it! Every little bit helps

stuey
08-04-2007, 01:50 PM
I got my one mainly cos i reckon on a 10 year old car the cat will be pretty shot i'd have thought (mine was rusty as hell and almost fell aprt on removal) and as mentioned, it's a little free power thru less restriction

Kieran
08-04-2007, 02:29 PM
Thanks for the replies.

So basically until I get some boost control and a cat back aftermarket exhaust a de-cat pipe really isnt worth it...

Would that be a fair assumption?.

Ill have to spend my money elsewhere :).

I would say that is a good summing up.:scholar: With a cat-back system the difference is mental. With the standard setup, they tend to be a little more 'free' at high RPM, but it won't blow your socks off.

ralliart-type-s
09-04-2007, 12:33 AM
I noticed a diff with de-cat fitted, better mpg but better pickup and now sounds like a jet plane at about 6k rpm.

djb160
12-04-2007, 12:48 PM
If you change anything whatsoever make sure it involves a replacement of the downpipes, those tiny wee squashed pieces of metal are ridiculous.

Beastlee
12-04-2007, 09:33 PM
I looked at the 3" de-cats on E-bay but they would be £60. I was concerned that the end that meets the downpipes as mine is only 3" cat back.
I'm thinking of new downpipes as mine have been crushed but I'm not sure how the cat would work for MOTs then. Can anyone clarify?