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Clogged or Blocked Catalytic Convertor - Induction/Turbo/Chargecooler/Manifold/Exhaust - The Lotus Forums Jump to content
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Clogged or Blocked Catalytic Convertor

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I'm posting this up as the symptoms of this are similar to three very recent posts on here, all of which people have assumed to be Turbos myself included.

Ok firstly the issue I answered in the last post was not a sticking wastegate.


The car would start absolutely fine and run as normal until it got to temprature, then at approx 3000 rpm a loud whooshing and high pitch screaming noise with no boost at all. It would bearly make 50-60mph in 3rd, 4th or 5th. The car accelerated if throttle pushed very lightly but the minute the pedal was pushed as in normal driving conditions there was no power.

Turning the car off and then letting her cool would result in the car operating normally, boosting as normal and reving as normal. The second she was up to temprature no power again.

After removing and inspecting ALL Turbo hoses both intake and exhaust side and checking vacuum line to waste gate capsule there was no explanation, she even reved to redline in neutral with no load as normal. Weird thing is no checklight will come on so bear that in mind.

It was only when I pulled into the garage yesterday they noticed no pulses coming out of the exhaust. When I reved her still nothing coming out but a loud screeching noise (sounds similar to bearing failure in turbo). Anyhow seeing as i'm running a straight through exhaust this did not seem right so the garage removed the rear silencer and still no gasses coming out of the CAT.

This issue has been intermittent on my car for a while now and the symptoms of a blocked CAT are noticable/sudden loss of power when hot, car momentarily cuts out or has a hesitation when flooring it on acceleration.

I've just ordered a High Flow Cat off SJ's

Forgot to mention the Catalysts insides were 100% intact so no rattling and no obvious braking up of the core.

Edited by waynef

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Hi Wayne,

Shame you have already ordered your Cat. I do 200 Sports cats and could probably beat SJ prices. They only take a few days to make and looks great. I don't have a proper picture of them but they are the same as my V8 CAT's. The next one I do I'll take some pics for my site.

Let us know if this makes a difference and also if there are any performance improvements!


David Walters

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