My mot is due on the octy in a few months. I've got a Blue flame full system with no cat (obviously my engine mgt light is always on grrr... )

Will the de-cat result in a failed emissions test? Some people say yes, others just say turn off the air con, with a warm engine and it will still pass (just).

Which is true?...... and if it fails how much money is a 100 CEL BF sports CAT?

Thanks

It should fail.

Mine Blueflame sails through with the 100 cet sports cat, and without will almost certainly fail the MOT.

Blueflame were quoting about £350 for the sports cat and downpipe, but why not ring Blueflame and ask them.