Removing cats, whats involved?

[MJH500]

Hello,Very recently bought a chim 500, which is my first experiance of a T.V.R.and i love it. Its a 1993 which i beleive to be one of the first. Its a one owner car and low mileage and very clean. Can someone please tell me why there is a clicking noise coming from the speedo/milometor every 10 seconds or so. It bugs the hell out of me.. Also what is involved in removing the cat convertor.ie fuel settings,lambda sensors ect. Any comments would be much appreciated.

[shpub]

The clicking is a feature. Don't worry you have not been charged for it by the factory. Caused by an unused odometer wheel.

As for decatting - may or may not need new manifolds and the ECU will require a rechip. Does very little except make the car noisier. Will require the Insurance company to agree as it is an engine mod.

All covered in the Bible.

steve
www.tvrbooks.co.uk

[robertp]

Dont worry about click - you get used to it very quick and dont notice it especially when the V8 is 'on song'

[raceboy]

The cats can be removed, not sure whats involved if you have healthy cats but if they are shriveled up and dead anyway I believe you just cut the big centre down pipe and remove it and then pull out the pre-cats, weld it back up, and away you go, a lot louder, but no quicker
You don't have to do any re-mapping if you leave the Lamda sensors in place, but you do need to tell your insurance company, and find a freindly MOT station

[shpub]

Some cats cannot be lifted out from the manifold as they are fixed into the manifold. Breaking them out is not recommended as the stuff is pretty nasty. New manifolds are needed.

Leaving the lambdas in and not rechipping is a bit pointless as it limits how the car can be remapped. If you want noise, play with the exhaust.

Best advice is leave it as is to be honest. It is a pain as it can cause MOT problems as well.

[raceboy]

shpub said:

Best advice is leave it as is to be honest. It is a pain as it can cause MOT problems as well.

Agree with that, the only reason mines de-cat is it was either de-cat or new cat and the de-cat option was cheaper
But the noise is great

[MJH500]

Where exactly are the cats? Are they inside the large manifolds where the lambda sensors are? Anyone ever removed the main centre box just before the tail pipes? I like noise.....

[joospeed]

No probs removing the cats at all, no remapping required, the extra airflow is minimal. Best way is to burn them out, but cutting and bashing out is ok too (that's how I do it ). As yours is an early 5 litre it's rated at 290bhp rather than the griff's 320/340 bhp variants so you should have really around 230-240 bhp in real life.
Removing the centre silencer gives it real nascar bass rumble, sounds fantastic .. ask Rude Girl to fire hers up if you shoud,ever meet

[bjwoods]

Why remove them?
How do you get around the legal requirement?

?
B

[Graham]

You'll get no more power but it does improve the throttle response and lets the engine rev a bit quicker.


as for the MOT ask me later today


and as for noise,my exhaust is standard and it gives a more bassey noise whithoug being as intrusive as a sports exhaust.

G

[2 sheds]

The small manifold cats were fitted to conform with the European "bag test" basically air measured from cold start, however in the UK the MOT requirement is that the engine must be "clean when hot, the big / main cat will cope with this with manifold cats removed.
Tim

>> Edited by 2 sheds on Wednesday 5th November 19:16

[Jarcy]

My exhaust is too quiet. It's non-standard but was fitted by the factory from new (apparently). I believe the exhaust was developed for cars destined for Switzerland, who have more extreme noise regulations. On track days I've had it measured at 93dB. Now that's low for a TVR!

I have a '96 Chimaera 500. Does anyone have any experience of this exhaust system? It looks different from standard in that the tail pipes are wider and fill the recesses better. - They look quite good actually.

What I'm after is a loud car that I can calm down for track days. I've thought of changing to a sports exhaust and getting some bolt on silencers, which is a bit crude. My hope is that there's someone out there with experience of my exhaust and any experience of how to mod it for more noise. (I don't want to decat.) As I've got wide tail pipes I guess there's lots of padding that can be removed. Any suggestions welcome.

>> Edited by Jarcy on Thursday 6th November 00:52