De-catted

[arcbeer]

I had the cats removed last weekend as the ones on there were overheating causing smoke to enter the cabin via the handbrake and also coming up under the bonnet in front of the windscreen. The car has also had a throttle pot replaced and the air and fuel set-up checked (overfueling was thought to be the reason cats were overheating).

What a difference! It really flies now. The acceleration seems harder and more immediate (probably due to the throttle pot replacement and the fact one of the cats was blocked).

It is however very loud. I am running a standard exhaust minus cats. Some of the baffling seems to have come loose causing a very loud rattle (hammer against a metal bucket sort of noise ) and the vibration also seems to have loosened something on the gear-stick which is making a plastic rattling noise.

Does anyone else have the same set-up. Have you experienced a lot of vibration? There is a fair bit of resonance around 2.5 - 3 revs. Do you experience the same thing?

Many thanks

[trooper1212]

Can't really help you, but I will hijack your thread

your overfuelling, did this result in smoke from the exhaust under hard throttle/high revs? I've currently got this problem and I need to drop it into topcats to get them to look at it when i can be bothered.

As an additional question, has anbody had a decat done after driving around with a sports exhaust for a while. I'm thinking about decatting while the cerb is in the garage, but i'd like to know how much louder it will be than a catted sports?

[kojak69]

simonhayes has resonance, see thread from a week or two ago.

www.pistonheads.com/gassing/topic.asp?t=66546&f=6&h=0

[arcbeer]

Thanks.

I get a cough of black smoke from the exhaust under very hard acceleration. I think pretty much all cars do this.

I'd read the resonance thread it's not quite the same thing. My question is more, does de-catting cause more vibrations?

[andy4200]

There was a thread a few weeks ago talking about decat and sports exhaust.
Don't know if it answers all your questions.

decat and sports pipes

[davidd]

Decatting will involve removing the middle section of the pipes (the cats) and replacing them with other pipes (cat bypass pipes or as we call them, pipes).

It is probable that when they were put back together they were moved slightly and so now rattle against the underside of the car a bit at certain revs (they live in the tunnel so can catch either side).

Take it back to where you had them fitted and get them to adjust..

Good luck and keep us posted.

D.

[RUSSELLM]

Mine's in today having the cats by passed, if they remove them, what happens to the old ones ? Are they of any use to anyone who still has them fitted ?

[crazycats]

RUSSELLM said:

Mine's in today having the cats by passed, if they remove them, what happens to the old ones ? Are they of any use to anyone who still has them fitted ?

Stash them away, for MOT time.

[arcbeer]

You need to keep them for your MOT unless they're completely knackered and then you'll need a new one or two.

Just need to find an understanding garage who will swap the cats in, hopefully you pass the emissions test for the MOT then swap them out again.

Let me know what your noise levels are like and if you experience any other adverse effects