Will A Decat Pipe Fail MOT?

[vr6_super 0]

As above lol. Had the MOT back in February and passed ok bar a bit of welding. Wanting to get a 6 branch and decat for a while to let her breath a bit more easily but just wondering if its worth leaving till after next MOT if its likely to fail?

I already have an aftermarket ss cat back system in place although its 2.5" as opposed to the standard 2.25"

Its not an old engine. Was brand new probably around 20k ago, 3 years ago. Dont know if that helps with the emissions or not.

[VR6Nat 9]

what year is the car? if it is a newer one then yes it will fail, but if its one of the early ones it should be ok.

[vr6_super 0]

Its a 96, P reg

[Daverse 175]

cars before 1992 dont need cats to pass a MOT, as cats didnt come as standard back then. so yes you will need a cat for the test..

[vr6_super 0]

ahhh, ffs

in that case, i will just leave it for after the mot next year then. cheers for the replies folks

[DrRich 1]

As I understand it, you don't actually NEED a cat at all, but you risk failing on emissions without it since the limits are much tighter for post '92 cars than pre '92. Having said that I've certainly heard and read of people whose cars have passed emissions without, but I imagine your engine would need to be in perfect shape and running well, good lambda sensor, etc.

Depending on how much work you have an appetite for, would be worth giving it a go then asking a local garage to test your emissions far ahead enough of your MOT to put it all back.

Unfortunately, without trying it for real, you'll never know...

BTW, in this month's Redline, their legal expert answers a question about decatting between MOTs and just putting it back on for the test. He says if you get stopped at the roadside and tested (have seen this happen once or twice) then you risk a fine and/or points. Food for thought...