de-cat

[bigcol1988]

just wondering if anyone has put a de-cat pipe on a 1.9 dci any problems if you have done and does it make exhaust note louder deeper ect

[downsyndromedhorse]

Ooh, good question, i wanted to know this too but no-one knows.
Can't remember who raised a good idea, to replace the cat with a standard one, but with the insides scraped out.
I cant imagine it making a massive different on sound, you might just a get a few smelly gasses from the exhaust.

If you do it, let us all know because i'm keeping an eye out for a spare to try it out.

[Anthony]

Yup, best way is to get a replacement cat and then smash the insides out. As far as I know nobody makes a decat pipe specificly for the dci engines.

If you do smash the insides out the mess has to be disposed of correctly at a scrap yard, local tip or the likes.

It will probably sound a bit louder after the decat but nothing intrusive. The cat is a massive restriction on flow and noise.

[R55VYS]

You not thought about MOT time?

the FAIL more than anything, i would imagine if you keep your backbox on it will be a tad louder, possibly loads louder, but the emissions will be a straight up fail.

Ive removed my backbox from my 1.9dci, with 225 tail pipes out the back and its really not to much louder, its loud enough though, i had hoped it would be louder, but im so glad its not, doesnt really kick in till over 2k rpm.

An option if your mearly meaning for noise, lack of back pressure could also be a factor if you remove the cat.

[bigcol1988]

the mot is not an issue i would just change it back over, i was more worried about the electrical side would anything decide to fail, and ive replaced the back box and mine also only makes a nois above 2k would just like it a little louder/deeper, as for back preasure i was told that running a turbo less back preasure is better to allow the turbo to speen easyier and free'er, i will get underneath and have a look see what i can come up with does anyone know if the lamba sensor or anything is mounted into the cat section?

[Anthony]

No need to worry about the MOT. So long as everything is working correctly it will sail through even with a decat.

No need to worry about 'loss of backpressure' either.

Not sure about sensors messing up, but even if they do it wouldn't be too difficult to correct.

[bigcol1988]

maybe not difficult but exspensive mines blown 4 fuel rail preasure sensors at £175 each plus turbo, and air flow meter lol

[Anthony]

Damn that's bad luck matey. What I meant though is that the pipe could probably be adapted so the sensor reads correct. Do we even know whether there is an O2 sensor after the Cat?

[bigcol1988]

nope an its to dark to go look now but ive come up with a way to have a cat and no cat at the flick of a switch lol

https://www.google.co.uk/imgres?imgurl=h ... s%3Disch:1

this ones for a ferreri i think but you can get universal ones much cheaper this was just a good clear pic

[Anthony]

Wow. Would have to be about 5% of what that costs for it to be worth it.

[bigcol1988]

i was thinking more along the lines of making one, rather handy with a mig welder and dads a master mechanic lol

[downsyndromedhorse]

I did read somewhere about there being a 02 sensor after the cat, but if you join them together with a resistor then the light won't come on the dash and there won't be a fault code either. Not sure what the amperage is to work out the size of the resistor, but i doubt it would need to be huge.

The emissions wouldn't be a problem at mot because they measure it all different of diesels than petrols. Plus its an efficient engine so the chances of them going over the limit are pretty low anyway.

[downsyndromedhorse]

Just been to a few garages regarding this..
They said on the diesels, the cost of having a decat pipe up would be more worth it than using a different cat. The cat would cost to much from a scrappy because they know how much they're worth. They said they can knock up a pipe in no time. The cats can be weighed in and get about £60-70, so would pay for itself. The only problem would be resale, but that depends on the buyer.

They also said, both of them, that the dci's cats are very restrictive, so you will be able to notice the difference and free up some hp.

[Anthony]

They said they can knock one up for around £70! Sounds good that. They might change their minds when they see how difficult they are to access.

[downsyndromedhorse]

Thats true. They hadn't done a megane 1.9 before.
But i'll get a proper quote and see what comes up. I'd still prefer to use an empty cat, but its just finding one thats the problem.

I shall still keep my eye out for either. If they will do it for £70 then i'll just do that, because thats a fair price .