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MG MGF Technical - I got a rattle in my cat !!


Hi all

returned from the Luton meet on Sunday to find i have got a rattly cat !!

With the MOT due in 4 weeks i decided to bang it in for a MOT quick in case it was on the way out and i am pleased to say it sailed through ok ! but the rattle is annoying so i am thinking of whipping it off and putting a bypass in, will give me a whole year before splashing out 4 a new cat or could even put this one back on for next years MOT

I'm not sure if i am likely to get any performance gains as mine seemed to be putting out plenty on the last RR day 162hp.

Any one got any thoughts or advice about removing it etc !!

STU
Wokingham
S.C. Dickens

Hey STU,

162hp sounds pretty good! Try the CAT bypass tube. One thing is that the exhaust note will be louder, and it sounds like your car already has a sport exhaust, so.... decide what you want.. :-)

Good luck.
Hanah Kim

Are you sure that the rattle is comming from the cat? If so, the matrix is completely knackered. :o(

An MoT test pass does not, unfortunately, mean that the cat is okay - it is just possible for K-series engines in good condition to pass MoT emissions tests without a cat (the 1.1 and 1.4 units were all designed to run without cats before punative government regs meant they became mandatory irrespective of whether they were needed or not).

If you are swapping to a bypass tube anyway, then a quick inspection of the cat will tell you the answer anyway...
Rob Bell

Stu,

I replaced my CAT a couple of month ago, it's worth giving Victoria a ring for a good secondhand one, works out considerably less than buying a new one. Good idea about the by-pass pipe, you may want to do than anyway and swap the pipe when ever you get an MOT done.
tim woolcott

I've just replaced my cat this W-E !!

BTW, a big shout to Nick from Britishcarparts. Thanks to him, I paid much less than I expected... See http://www.britishcarparts.co.uk/Offers.html
And also to Mike Satur : thanks to his "cat saver nuts", I spent much less time than I expected ! Even with some cleaning of my stainless exhaust, it took me less than 1 hour.

I knew that something was going wrong inside my old and loud cat, but not that it was completely empty ! The bad news is that the broken cells are now inside my SP supersports exhaust, and there's no way to get them out of it, except with some cutting and re-welding of the silencer box.
Now, does that block something ???
I have the impression it doesn't, although only a R-R session before/after would tell the truth if there are only a few bhp taken...
I need some advice, cos' welding stainless steel isn't a DIY job for me...

Fabrice

Fabrice

>>Now, does that block something ???<<

Nope, happily Fabrice, the busted Matrix will just rattle about in the space in the centre of the silencer box (see the bottom of http://www.mgf.ultimatemg.com/e_introduction.htm)
Rob Bell

that's what I also thought...
thanks Rob, you even got a picture of the inside of my exhaust !! ;o)
Fabrice

Right

A visit to B&G today and I have a cat bypass tube to install !! Oh and how did that splitter appear in the passenger seat !
Something else to fit !!

Trouble is visiting Mike's or B&G leaves you open to temptation !! The dark side force was strong and i was weak!! ho hum..

Rob be interesting to see if removing the cat will make any difference to the figures on the rolling road day next month..I havent changed anything else since the last day and in theory with a little less restriction i 'should' get a little more power...we shall see.. i just hope it doesnt make it to noisy !!

cheers all

STU
Wokingham
S.C. Dickens

You're welcome Fabrice! LOL

Stu - yes, that should be interesting to see whether you see the same result as we did when we swapped the cat for a bypass on the standard VVC - ie not a lot (http://www.mgf.ultimatemg.com/catalysts.htm)

:o)
Rob Bell

Rob

well as long a its not too noisy and i dont feel any obvious power loss i'll keep it on until the rr day

didnt know you had done the tests on your web page...bugger.. still worst comes to worst its only 40 quid gone...

On another note, i cant believe how many f's i saw today with the top up!! Are they mad !!!

Cheers mate

STU

S.C. Dickens

I can't understand the hood-up MGF drivers either... nice weather, soft top car... go figure...

Regarding the bypass - well, it'll be interesting to see whether you see the same results; Andy's car wasn't putting out quite the same amount of power, so perhaps you'll have more scope to see a benefit... :o)
Rob Bell

well i fitted the Cat by-pass today... my existing cat had broken inside ! still passed the mot though !! but rattles like mad...

No real feeling of power loss or gain for that matter but god its loud!!!!

but it does sound fantastic when using the engine for braking, it really chuckles and burbles....

Will keep it on till the weekend to see if i get used to it but first impressions are its a bit too in ya face...

So it looks like a new cats in order...bugger !! so whose do i go for?

Any suggestions

STU
S.C. Dickens

Second hand standard cat from the MGF Centre (Tim can probably tell you how much this costs).

Janspeed do a sports cat (same, I suspect, as the one sold by PTP). Not got any details on this.

I presume that the above are what Techspeed are able to supply?

To be perfectly honest, not an area I've researched much - I have to keep the standard cat in accordance with the sprint regs ;o)
Rob Bell

See my previous post...
£109 for a new cat from British Car Parts http://www.britishcarparts.co.uk/Offers.html

It's an "universal" one with welded flanges.
It fits perfectly.
It comes with the 2 gaskets, and if you ask, Nick will put for you 6 new bolts at no cost. (You'll need them as tou cannot re-use the original one that are soldered to the flanges of the cat)
Fabrice

You should have heard Trevor taylor exhaust without CAT! All Skyline GTRs / Impreza WRXs / Sti / Evos... they were afraid of my car, and kept good distance from my car..

it sounds awesome, but WAY too loud... but I sometimes want to go back......

STU - as expected, found it too loud huh?
Hanah Kim

Rob, on your page you talk about CO2 emmisions testing, don't you mean CO emmisions?
Will Munns

Yup, that's an error, thanks Will :o)
Rob Bell

Hi all

today i bought a new cat !! it was just too loud,,,sounded fantastic though..

I bought a cat from the britishcarparts,com crowd, £128 including VAT! which is actually a smaller cat than the one i removed..quite a bit smaller and my old cat had a sensor going into it sensing cat overheat with a light on the dash? evidently these were only fitted to the jap cars and mine being an import etc..

I have unplugged the sensor but now the cat overheat light stays on,, i assume if it gets no input the light defaults to on!

Does anyone know if i can just link out the connector,, i guess its only a normally closed contact being held open by the switch in the sensor ???

The new cat produces a slighty different sound to the original. a little louder but dare i say it the car feels a little more responsive....

it will be interesting to seem if this new cat effects my figures on the next RR day in May...

Kingsley ! If you want a cat-bypass tube thats had only 1 days use there's one going cheap!

Cheers all

Stu

Wokingham


S.C. Dickens

This thread was discussed between 14/04/2003 and 17/04/2003

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