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MG MGF Technical - de-cat or not

i have replaced my rear box with a milltek stainless one and also a stainless downpipe just wondering if it is worth making a stainless cat replacement pipe as i have tig welding experience and can easily lay my hands on the materials but i know i will have to keep putting the kat back on the f for mot. also somebody at work said he has been stopped for a roadside emmissions test he said if it hadf failed it was a fine on the spot but at the moment only some county's are doing this any light on this would be appreciated thanks.
d l brown

The only thing it will make is more noise. If you have an MPi, you might make 1-2bhp. If you have a VVC you could lose 1-2bhp. I don't believe it's worth the grief TBQH.
crapuccino

A Miltek with a de-cat is very very loud! Especially as they get older. I would suggest that you try the Miltek with the cat first.
Steve Ratledge

Standard K-series engines are very clean - clean enough to pass some exhaust emissions tests without a catalyst - but it can be very boarderline. It may be worth the risk of the roadside test, but as the guys say - there isn't a huge power advantage in doing this, and Milltek exhausts are infamously LOUD when used without a catalyst...

That all said, if you are handy with a TIG welder, why not give it a go? You can always put the cat back on later if you want to :o)
Rob Bell

thanks for the feedback going to try anyway as it won't cost anything because making it myself.

also sinse fitting downpipe now getting what seems to be from the archives a common tizzing noise from front of downpipe i have seen on dieter's site that a bracket was avaliable to reduce this can anyone shed any light pls.
d l brown

de-cat complete and as you all said earmuffs at 50paces real headturner think i'll keep it on for a bit just to see not sure yet if it's a little bit too loud.
d l brown

What about a decat on a tuned engine (ported and fast cams timed correctly)

Would this help in any performance increase of any kind????

Chris Glen

A tuned engine is a different ball game. The standard cat is probably good for 180bhp before it really starts to become obstructive. Thereafter, replacing with a plain section of tube is going to yield sizeable dividends.
Rob Bell

I like the word sizeable!!

The next time you arrange a rolling road session prehaps we should see what difference it makes. My car already sounds loud with its new cams. Maybe the decat can defan the neighbours now!!
Chris Glen

A laudible aim that Chris - see if you can set off car alarms from 50metres! LOL

Okay, no problem. I suspect that we won't be looking at another RR session until next year?
Rob Bell

Hi All

After I fitted a custom zorst pipe to my '02 TF160 and replaced the cat with a resonator, I had the engine warning light come on.

Since then I have learnt that one can get a MIL Light eliminator which fools the ECU into thinking there is a catalytic converter still fitted on the car, in turn it does not show a "fault code" in the ECU or turn on the engine management system warning light located on the drivers instrument display panel.

I put the cat back on, which made the car slightly quieter (darn!) and gave the zorst note a more bassy and less crackly quality.

The MIL light eliminator costs around GBP20, and I just may opt for this as a future enhancement to get the more crackly note back.

As for power differences, I noticed no change with and without the cat.

James
James Reinhardt

But with a de-cat you do get those lovely pops and bangs. With the cat in place I only get them when the zorst is stone cold.
Steve Ratledge

One thing you might want to watch for is failing a noise test at a track day or any competitive event. I have the Miltek exhaust and only just pass the 98 db noise test at venues like Goodwood and Castle Coombe. If the decat pipe made the noise worse then I think Id fail.
marc h

>But with a de-cat you do get those lovely pops and bangs.

Nope, disagree.
It does lovely pops and bangs also when equiped with a TT MK2 back box and a metal catalyst (200 cells).
:))
Dieter

<< It does lovely pops and bangs also when equiped with a TT MK2 back box and a metal catalyst (200 cells). >>

Yes true. But take the cat off and POP and BANG and become a dog-worrier ;-))
Fiona

My TF160 exhaust is on it's way out now and I'm after a stainless replacement, did you guys fit the exhaust yourselves (is that a real word?) or go to a mechanic?
Which exhuast would you recommend and how much £££s??
Timmeh

I had the garage fit mine, think it was about £20 or somthing around that figure. Well worth it considering they had to cut some of the bolts off with an oxyacetylene torch -- yeah like, I was going to do that myself ;-)

They then charge me a tenner to put the decat pipe on and off and on and off as and when the MOT requires it, a lot easier now it has the fresh nuts & bolts.

Fiona
Fiona

fitted mine myself easy to fit if cat nuts are not to corroded one of mine required a large file and a little patience.
d l brown

This thread was discussed between 13/07/2006 and 27/07/2006

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