Tuning To decat or to not decat?

[Dayjw]

As you may or may not know I work for a custom exhaust place, so putting a cat back on for MOT is no issue. Therefore what are the pros and cons for having a decat?

I have a mk1 55sx, already have a cat-back system with no centre box.

Cheers

 

[m20b25]

Pros: the car will go like the clappers, no low down lag

Cons: the engine may not like the absence of backpressure...

 

[ChrisUK]

Not to mention you'll loose low end torque due to lack of back pressure. Be sure to get it re-map'd if you do remove the cat.

Edit: Just saw its a 55sx, really no point at all! both removing cat and getting a remap .

 

[Dayjw]

Not to mention you'll loose low end torque due to lack of back pressure. Be sure to get it re-map'd if you do remove the cat.

Edit: Just saw its a 55sx, really no point at all! both removing cat and getting a remap .

How would the Mckritch chip hold up then? Or would it make no difference?

 

[bredsticz]

Get a sports cat, still power gain without the MOT worry

 

[Dayjw]

Get a sports cat, still power gain without the MOT worry

They're not the cheapest of items though however a decat would be pennies...

 

[bredsticz]

They're not the cheapest of items though however a decat would be pennies...

Yeah, that's the only downside to that!

 

[Dayjw]

Any noise difference? I've heard they're raspier and sometimes it pops?

 

[ChrisUK]

I don't mean to put a dampener on things but it will sound crap on a 55sx thing of a high revving petrol lawn mower .

And a Sports cat would cost more than a 55sx is worth nowadays!

Stick to what you got until you can afford something that has real gains with modification . A Mckritch chip would be a good idea though.

 

[Dayjw]

I don't mean to put a dampener on things but it will sound crap on a 55sx thing of a high revving petrol lawn mower .

And a Sports cat would cost more than a 55sx is worth nowadays!

Stick to what you got until you can afford something that has real gains with modification . A Mckritch chip would be a good idea though.

My 55 sounds quite nice as it is, I just like to mess around with putting new things on haha. Plus it probably wouldn't cost me much to make a decat so I might just try it until i've saved enough for a Punto GT.

So is the Mckritch worth it then? I wouldn't expect miracles from a 55 but can you feel the difference? I hope it gets rid of that flat spot in fourth, man I hate that...

 

[MikeSalt]

Do bear in mind that it is not just the MOT, there are random emissions tests. The VOSA vans that carry out these tests are rarer than even the elusive TV licencing detector vans though.

 

[DaveMcT]

VOSA tend to be more fussed with HGVs and farmer's diesels just in case they are running red diesel fuel. As long as the car isnt obviously smelly or smoky (or you are very unlucky) they wont be bothered.

But on the 55 its really not worth the effort. As Mike says save up for something worth working on. The GTs are (were) nice but reasonable ones are like rocking horse poo and even fewer are any good.

 

[MikeSalt]

With regard to the Sports Cat, on an 8v engine, the exhaust gases take a tectonic amount of time to get hot enough to be effective. Chances are that an MOT tester may never get it hot enough to pass an emissions test. You need an extra 8 valves to keep a Sports Cat simmering nicely.

The only modification I did to my 55 was Fiat-fit alloys and good tyres. Completely transforms the handling and will get you from A-B quicker than any decat will. Buy a second-hand set, and keep away from the kerbs and pot-holes and they will be worth nearly as much when the time comes to sell them on. Always keep the original steel wheels since you will make more selling the car in stock configuration, and your modifications seperately.

 

[Dayjw]

I already had 15" fox alloys when I bought it and I've just put a set of lowering springs on so it handles really well. Better than any corsa/clio/106 anyway.

Like I said I already have a cat-back system on it I just thought I could add to it.

 

[Dayjw]

Here is a video of my exhaust
[nomedia="http://www.youtube.com/watch?v=VF9mlQ2Vq6g"]YouTube - Blue Flame Cat-back exhaust Fiat Punto[/nomedia]

 

[Fiatpuntomk2b]

Here is a video of my exhaust
YouTube - Blue Flame Cat-back exhaust Fiat Punto

thats lovely nice and raspy
is it decatted ?

 

[BTG]

has any 1 got a picture of the cat on a mk2 punto as i want 2 take mine off not sure on how 2 do it

 

[MikeSalt]

has any 1 got a picture of the cat on a mk2 punto as i want 2 take mine off not sure on how 2 do it

Good luck with that, it's part of the manifold itself

 

[BTG]

ha forget that then

 

[Dayjw]

Nope it still has a cat Just no centre box. That was when it was warm too, is alot raspier when it's cold