de cat'ing

[turbojolt]

people are telling me more and more that de-cating your cars exhaust is not good for it as it reduces your cars back pressure to much


i understand why this may be but is it true and if so how come so many tuning companies sell decat pips are they just making new from are stupidness :cry: :cry:

[brainsnova]

i de-cated my nova 1.2 and it felt faster

[turbojolt]

did it not run rough

[craig green]

It all depends on the model of engine etc. Many engines from the early 90's were simply adapted to run a cat by means of Lambda controlled ECU fuelling. But more modern stuff has been developed for a cat in the exhaust. It shouldnt cause any harm but sometimes cars do run rough when decatted if systems pick up wrong readings etc.

[FUSION X16XE]

You also have to bare in mind MOT time. Also i only have a rear silencer, no CAT or mid boxes and man its sooo loud lol My next system will be cat and 2 silencers but hi-flow.

edit- Thats on a X14XE with some mods and it is over fueling, so lots or pops and bangs lol

[Adam]

"Loosing Backpressure" is really a bit of a myth tbh.
Any backpressure your engine needs is developed in the manifold/downpipes where the gases are still very hot and expanding.

Removing the cat will gain a few bhp, but its not going be hugely noticeable.

[mowgli]

we decatted our omega 16v because the old one failed & I wouldn't spend out on a new one. it made it go a hell of a lot faster. but it got traded in before mot time........

[craig green]

An engine with no back pressure in the exhaust would make less power than an engine with some back pressure in the exhaust.

[brainsnova]

did it not run rough

nope it ran sound and the exhaust sounded louder :cool: