DeCat Pipe - Which One

[jon16v]

Are they any different - is there any solid proof that one performs better than the other, they are just a pipe???!!!??

Cant I just get the cheapest, people dont really look underneath my car much so it doesnt bother me, cheers guys and gals

 

[BUTRE]

You can get a supersprint cat-replace... not really my thing cause its to damn expensive for the job.

I got a pipe just like de cat. Once attached, never saw a reason why go for the supersprint one. Maybe the wallet.

You can experience a noise at certain rpm... I dont know if supersprints decat would quiet that sound. Its nothing of another world.

 

[lofty]

the magnex one looks like a cat and might even have some sort if silencer in it, i would say its the best depending on what you want from it

 

[BRUN]

it depends what you buy

there are 2 types.......cat replacement and de-cat pipes

a de-cat is simply a straight through pipe and there all the same, just go with the cheapest made out of the material you want

 

[Paul16V]

I got mine done by a place called Torque Technique. Makes custom exhausts. It was a stainless pipe that bolts where the cat was. It is spot on, been on for months now and no problems. Cost me £70 fitting and everything in.
Their numbers 01722 744747. Its slightly louder but now pops between gear changes when thrashing it sometimes. If you go there till him I sent you. Hell remember me if you tell him it was a blue Clio 16V.

 

[BUTRE]

it pops between gear changes? whats that? the blast exhaust noise?? cause mine is doing it now.
It "blasts" when I go up gear to 6000rpm. PAAAAA!!! opps hate that noise.

 

[Pysco]

The popping is caused by unburnt feul igniting in the exhuast, normally the cat stops the fuel reaching the end of the exhasut so you dont hear it, but with a de-cat pipe you do.

 

[BUTRE]

so... it can happen even in a 1.4lts? I only got the cat away.
couldnt it be ignition problems?

I hate that noise... since Im no racer. I dont like having ppl looking at me.

If its only because of the de-cat, how can I stop this without puting back the cat?

 

[Nick Read]

A straight through pipe will give you popping and possibly flames if you can get the over-run fuelling right or can cause a misfire while youre driving.

A Magnex one like Ive got is actually a whole silencer the same shape as the original cat (roughly) so its no louder than the original cat and looks the same. But it also (I assume) is baffled inside, so no flames and hardly any popping unfortunately!

 

[BUTRE]

hum...

I was thinking of getting a new exhaust system by changing manifold to a 4-2-1 one, get rid off the first box, keep it de-cat, and only use a back box.
Since it will problably make this "blasts" even lounder, can I use a bigger backbox? like a valver one... I dont think that it fits... I dont know.

 

[BenR]

The popping/crackling sound isnt down to the unburnt fuel its just the noise you get from an engine with NO silencer on it!!
The Big BANGS are the unburnt fuel!! its this which collects in the system, usually around the baffles.

anyway, you may find that a tunned 4-2-1 manifold actuaaly quite downs the sound and turns more whinney than the cast items.

i put one on my x-flow and it got all quite and no popping!
so i leaned off the carb idle jet and now it pops a big un!!!

 

[BUTRE]

ok.. let me see if I got this right

The Big Bangs, like a race car do but they spit fire throught the backbox, I experience happens because of unburnt fuel goes to the exhaust system.

Now, to prevent this, can I use better ignition mod? Spark plugs, wire set, etc etc or can I change the exhaust system so that the unburn fuel wont sound so loud when it hits the exhaust system?

Im lost in here...

The weird thing is that never happened before... now is doing all the time when I go pedal through the metal.

 

[BenR]

well, it should only really happen on overrun when your not on the throttle. if there are bangs etc when you at full throttle then its mis-firering! get it sorted!

 

[coolspot007007]

I used to be able to make my old 1.4 bang whenever i wanted by tapping the accelerator quickly, then acclerating hard, it was overfuelling with the Hill Power chip. Used to pop all the time on overrun as well. Hopefully ill be popping again soon with a straight through centre section on my valver

 

[BUTRE]

BenR, its when Im going down gears at hard braking... above 4000rpm it just BANG. Even using the throttle to put the engine back in high rpm while clutching between gears. Once I get my foot of the throttle... BANG.

Next week going to change spark plugs, wire set, distribuir cap, take off all exhaust system to see if there is a exhaust leak.

Ill keep in touch for results.

 

[BenR]

yeah sounds normal to an extent.
but mine was making huge back fires when there was a hole in the manifold!! just gave it more O2 to burn.

 

[Nick Read]

Weird, I cant get a pop or bang out of mine however hard I try!

Even with full throttle gearchange and a launch control switch that I can use to misfire the engine whenever I want, theres not a single snap, crackle or pop to be had!

 

[BenR]

then your not runing lean nor rich!
i had to set my carb idle jet to run lean to get it to pop.

 

[Nick Read]

hehe yeah thats the problem Ben - its running exactly spot on! Whod have thought anyone could complain about that? Maybe Ill fiddle with the fuel pressure and see what happens.

How come it popped when it ran *lean*?

 

[jon16v]

when i accelerate above 4k revs then back off, and as its de-accelerating just touch the throttle is pops a big bang or a continuous pattern of little pops!! funny hey - learnt how to get it whenever i want to know - quite fun

 

[wkdlad]

just had a full mongoose system put on inc de-cat went out 2day and it pops same happens to mine pops over 4000 but does not do it under 4000.My mate who has a 5turbo has the best bang while driving he takes it to about 6000 or 7000 then turns the ignition off then back on again he has flames comming out of his and the biggest bang ever he can also do it on the spot by revving it hard the off with the ignition then back on i think its cool but it must not do his engine any good ps fuel injection cars cant do this only carb

 

[BenR]

haha, yup do that with my carbed MK1 XR2 too!
sounds like a bloody gun! people duck at bus stops ahaha!!

its not too got for the exhaust system and baffles, but who cares!

it pops when it runs lean cause when an engine runs lean it doesnt burn all the fuel, hence back fire back up the carb when the mixture inside is till burning and ignites the fuel in the fresh mixture up to the carb mouth. So this unburn fuel collects at a point in the exhaust (usually baffles) until enough is there to burn....pop