Decat vs Sports Cat

[JamJay]

Hi again all.

I can't find the info I need on the search thingy.

I was wondering if any can point out to me the benefits and drawbacks of decats & sports cats on LCR's? I am essentially new to turbo tuning and still learning.

I am after a turbo back exhaust system but I am not sure whether to go decat or sports cat. I know that if I choose decat, i'll have to get the EML light mapped out which bothers me a little as I want to know if something is wrong elsewhere. On the other hand, I don't want to install a 200-cell sports cat and find out that it makes the system very quiet, i'd like a little bit of grunt, a bit more than OEM anyway but nothing Japanese and garish. Is the decat system alot louder than OEM & indeed a system running a sports cat?

In terms of performance, which will help the car more. Will one option free up a few more horses & torques more than another? I am aware that reducing back pressure does help but if you reduce it too much, you'll end up underperforming.

I am assuming, from some higher powered NA cars I know, that using a decat will make lots of pops, bangs and flames? This surely will be more frequent and louder on a turbo car (mine with remap)? Will a sports cat prevent this or reduce it? I am not adverse to back firing and flames by the way, my mind is open.

 

[lordgibbness]

Will you be using this on public roads? If so a catalytic convertor is a legal requirement (i.e. It'd have to be there during your MoT).

 

[JamJay]

I would never dream of using a decat on a public road

I know of several people on here that might though and bolting the catalyst back on at MOT time doesn't seem to be such an issue for them...

 

[lordgibbness]

Heh, well I'd take the easier option of a free-flow cat, myself

 

[JamJay]

I am swaying more that way myself but the racer in me wants a bit of noise too. I have no experience with sports cats at all, nor have I ever heard one so I can't compare the the two option in my head, from any angle.

 

[Ronin225]

If you want lots of pops and bangs and spitting flames have a look at anti lag systems (ALS) its sometimes referred to as a bang bang system.
But you wont need one as its not a race car and not running a really big turbo either.
But a decat will need to be replaced every year for its MOT, lot of hassle if ramps not readily accessible

 

[paul-murphys]

i have a decat do so it. you will love it can here is popping sounds luch. an for the cat. it hardly does anything cars polution is nothing, one of the worse causes for polution is methane from cows

 

[L280R]

Paul is it really loud? I bought mine lcr with a decat, it has a miltek system on it, with a jbs manifold but as it stands its resonated. I've orded a non resonated section for it. Is this going tobe really loud or just nice? Worrying a bit now...

 

[jwfcms]

go for the sports cat!! i have done bother and removed the decat striaght away. was way too noisey, car ran crap with it in. didnt know what it was doing with the fueling because of the lambda sensor. didnt run good at all, was alot slower. Have said this too many times now when people have asked.
1. too noisey, 2, made a noticeable difference, was slower. 3, didnt fuel correct which is probably the reason it made it slower.

Go for a sports cat. with the cat back and downpipe it is still alot louder than standard and less restrictive. it isnt asloud as the decat which is too loud and chavy sounding i think. even the standard cats arnt really restrictive untill over 300 bhp.

 

[JamJay]

Thanks for the replies so far. I will be going for a non-res sytem, I forgot to mention that initially.

So jwfcms, do you think it will be quite loud and popping with DP, Sports Cat & non-res cat back? For noise purposes and the image that goes with it, sports cat looks like a good option.

 

[L280R]

its just the price of the bluddy miltek cats! Anyone know of any going cheap? miracle if one was i know

 

[jwfcms]

I got a brand new cat back blueflame for £ 250, boxed from forum.

Then i got the downpipe and decat for £ 150 from forum again.

I put it all on, wasnt happy with decat, I fetched a SPORTS CAT from HOFFMANN Sports catalysers in lichfield, west midlands. They do post aswell. It was a 2.5" outlets and a 200 cell/CPSI.

I fabricated the sports cat into the decat, it was only about 15 cm in length so i cut that out of the decat pipe and got the sports cat welded in.

cheaper option, cost me £ 95 quid more but was alot less than the miltek sports cat. Which isnt as good as what ive done i dont think..

Miltek dont do a downpipe, so even with the sports cat it hasnt got a uprated downpipe. The sports cat from miltek bolts onto the original downpipe so the gases still have to split into two pipes where it then enters the cats.

The blueflame system is straight and free flowing with a 3" diameter bore and using the decat to put the sports cat in place does the same job as any other sports cat system. Just get a good quality sports cat.

Its not too loud and it doesnt pop and bang. dont know if thats what your after but mine doesnt.. maybe others do but that indicates unburnt fuel id imagine which isnt good. Its loud enough and sounds good with downpipe and sports cat. It is ALOT louder with a decat thou. bit too loud would annoy you on the motorway after a while. with the sports cat you can still drive around quietly but when you put your foot down it opens up and sounds louder, it is alot louder than the standard system but not overloud. hard too explain unless you hear it obviously, sounds nice rather than raspy and like a cheap universal cherry bomb 5" slash cut jap style exhaust.