Disco 2 V8 Cats

Sure this will have been asked somewhere before but apologies, can't find any relevant thread...

Has anyone removed the Cats from a V8 Thor system? Have just got the engine out after a couple of days lying over the engine bay with my legs in the air and noticed the cats are looking elderly. As the Disco runs on LPG I believe the MOT won't be an issue but wanted to check if anyone has had any issues with the ECU throwing up errors?

Any other info also welcomed.

Thanks.

MOTs and Cats has been mentioned just a few time over the years.

Your MOT will be an issue because the catalytic converters are not fitted at the time of the test. All u need to know on the MOT can be found on the www.
LPG only means that the engines exhaust emissions won't be an issue... if your lucky.

discool said:

MOTs and Cats has been mentioned just a few time over the years.

Your MOT will be an issue because the catalytic converters are not fitted at the time of the test. All u need to know on the MOT can be found on the www.
LPG only means that the engines exhaust emissions won't be an issue... if your lucky.

Click to expand...

Sorry, why won't it pass it's test without the Cat? The MOT checklist states quite clearly that a vehicle will fail if a catalytic converter is missing when was fitted originally but only if the vehicle is subject to a full cat test. As the Disco is on LPG my understanding is that it's not subject to a full test.

As for emissions, the Thor system is a closed loop system with target Lambda 1 so can't see why emissions will suddenly become an issue especially as LPG burns significantly cleaner and produces far less hydrocarbons than petrol.

I appreciate any evidence you have to the contrary as I might well be reading the MOT checklist wrong! Thanks.

Follow the flow charts in the MOT testers manual and through the successive production years. Later petrol D1s and petrol D2s are subjected to the CAT test, prior to that its a BET test, but there is also a test for non-cat.

Thank you for that, I've the same file and have followed it through such that the vehicle has to be tested to pass the emissions based on either the specific limits or the default limits dependent on whether you argue that running on LPG provides an exact match for the vehicle. Both however are irrelevant as it does not say that the vehicle must have a Cat fitted, merely that the vehicle must pass either the specific or default emissions. As the Disco will be on LPG this does not concern me whatsoever. So I'm still looking for evidence that says a Cat must be fitted. Looks like I need to have a chat with the guy who'll be doing the MOT as it's his interpretation that's important.

Where the vehicle might fail is if the ECU detects a fault from the Lambdas and goes into open-loop potentially increasing the emissions at which point the vehicle is more likely to fail, so if anyone has any experience of a modified exhaust and has any feedback, it'd be most welcome.

Thanks.

The above is the only info stating a cat should be fitted if a standard fitment I've seen.

In case anyone is in a similar situation I've just had clarification this afternoon on the issue from the authority that counts. As the Disco is presented to the MOT station running on LPG the vehicle is not subject to a full cat test therefore the presence of cats is not required. It may however fail should there be a significant increase in volume (dependant on how deaf the tester is feeling that day and as he regularly passes the 90 with an Aeroturbine 25 I'm not remotely worried). If I were to present it running on petrol, it would fail if the cats were missing (although as it has a 4.6 in it, this removes it from being an exact match in the analyser database).

As always though, don't try and use this as proof in court but instead talk to the actual person who'll be testing the vehicle before making any modifications.