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MG MGF Technical - Cat Bypass Legalities

Hi there,

I've just read all the archive threads on Cat Bypass, including the performance tests, so am conversant with the arguements. I have a 96 MPi with Vader induction and standard exhaust so think it's probably worth it bang for bucks.

My question is regards legalities, particularly insurance, I'm with A Plan (recomended for modded F's BTW). I can do any mod with the execption of forced induction and nitrous, but the car must remain 'road legal'. I'm happy to pop the cat back on for MOT's but wouldn't want to have invalidated my insurance in the event of an accident.

I've listed all previous mods for them but wondered if anyone has experience or knowledge of whether I'd still technically be insured with a bypass fitted?

Hope you can help.

Thanks, Russ
Russ68

According to Rob Bell's site the bypass gives mixed results - slight gain on MPi, slight loss on VVC - see http://www.mgf.ultimatemg.com/ - Technical - Cat bypass.
You could stay legal and not be missing much oomph!
Mike Cunningham

Thanks Mike, as mentioned seen the dyno tests know the arguements and really don't want to get into that now. Opinion is divided and I don't want to open that can of worms!

If anyone is aware of the legal / insurance implications of cat bypass, i.e. had an accident, wrote one off, or roadside emmision test with one on etc?

Would it be damn unlucky to be busted for it or asking for trouble from the off?

Thanks, Russ
Russ68

I have no personal experience of this, but would have thought that insurance is dependent on having a roadworthy, taxed and MOT'd car that meets the Construction and Use regulations. I suspect that a cat bypass might not pass the emissions part of the MOT thereby giving an out to an Insurance company if so minded. The fact that many owners have a cat bypass fitted doesn't make it legal or right! (And I'm not saying it is or it isn't!).

For the sake of a phone call it's got to be worth asking the Insurance Company "what if..."
Mike Hall

Cheers Mike, I've been open with the insurance co about all the other mods so will clear it with them prior to making a final decision.

If anyone else has direct experience, I'd like to hear it.

Thanks, Russ
Russ68

As far as I know, the insurance can only be invalidated if the modification bears some blame in the event - e.g. bald tyres on car unable to stop v.s. bald tyres on car rear ended at lights - in the first case the tyres could share some of the blame, in the second not.

I don't see how the Cat bypass could take any blame (although the insurance company will try it on with any difference to stated spec if there is enough money in it)

Will Munns

No legal requirement for the car to have a catalyst - it had to be sold with one of course, but so long as the car passes an MoT you can happily run without one without falling foul of the law - so long as the exhaust is not too loud.

Insurance would count this as a modification, so I would declare it as such - although as it isn't really a real performance modification as such given an otherwise standard engine, there shouldn't be any significant premium penalty.
Rob Bell

Thanks everyone, I've just cleared this latest mod with my insurance co and they have no problem or loading for the cat bypass. So happy days, I look forward to getting it ordered and fitted :)
Russ68

Hi, my cat was adrift inside so I knocked the internals out and the remounted it..perfomance improved as the insde bits had been blocking the outlet as for the mot it still looks original.... and it met the emmisions requirements.
e holloway

This thread was discussed between 16/07/2010 and 21/02/2011

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