[Cozy]

Question: Will an N54 BMW 335i pass an MOT with Catless downpipes but with it's original N54 catted mids still installed?

We all know it still passes with mid-cats removed and factory downpipes still remaining but I fear the N54 mid-cats are not as robust.

Obviously straight up Catless throughout is a fail so, those who are totally Catless, how do you tackle your MOT?

[windymissile]

A warm engine will sail through with DP cats removed and mid cats installed. Fully catless is an obvious fail. I guess the mid cats will have to be slaved back in for MOT time. Or find a friendly mot tester who will stick his car on the emissions tester instead of yours..

WM

[phil200tdi]

Previously true.

But now there is a visual inspection for the cats. Mine sailed through fine, but if the tester goes looking its pretty obvious they ain't there.

I'm tempted by a VRSF cat back exhaust, the lack of mid cats for MOT is a worry though!

[nicktyler]

I'm pretty sure it will pass with catless DP's. The primary cats are pretty much there to keep the emmissions down during cold start AFAIR.

I have supersprint DP's and there is a welded on plaque at the bottom that says 'not for road use' so I'm pretty screwed in terms of visual inspection.

[Cozy]

Thanks guys. I'm pretty much residing myself to the fact that I'm going to have to once yearly drop catless midpipes off the car and reinstall the N54 mids if I'm set on squeezing everything out of this car. I could probably live with leaving the N54 mids in there if they did anything to control rasp but I don't think they'll do much compared to a properly resonated section of pipe.

[Phil325i]

Originally Posted by phil200tdi

Previously true.

But now there is a visual inspection for the cats. Mine sailed through fine, but if the tester goes looking its pretty obvious they ain't there.

+1

Sadly it's no longer just a question of passing the emissions test. As I understand it, new MOT rules mean removal of any OEM emissions device is an automatic fail.

[windymissile]

Guys, if your MOT guy is worried about all the original "emissions control equipment" being there. You need to find a new place!!
The mid cats free up negligible performance. Just ditch the dp cats and leave the mid ones in.
WM

[mike07s]

Considering how difficult it is to see the primary cats compared to the secondary even on a visual test surely most MOT testers would just pass it through.

[idnan]

Take your MOT tester out for a run in your car beforehand and I'm sure he'll be more understanding! Worked for me

[Bee Pee]

The sighting of catted or decatted DP's just fwd of dual flanged connection is pretty obvious, even with plastic undertray in place, once car is up on the ramp.

DP with gutted cats will pass the visual and combined with hi flo cats or oem cats in situ on mid pipes will still pass the emissions test.

Otherwise, one to one and/or test drive with tester has to worth a punt !

[Drrncour]

Where in Surrey are you, I know a Catless friendly MoT centre. :-)

Just had the Decatted Audi with down pipes done there no issues.

[Cozy]

Thanks for the replies guys. If the MOT tester wanted to be picky and look beyond the under tray then I'd definitely fail but here's hoping not and good idea regarding a test drive

Originally Posted by Drrncour

Where in Surrey are you, I know a Catless friendly MoT centre. :-)

Just had the Decatted Audi with down pipes done there no issues.

I'm in the Reigate area, is it anywhere near? I'm willing to travel when the time is due.

[AlanYoro35i]

Originally Posted by Drrncour

Where in Surrey are you, I know a Catless friendly MoT centre. :-)

Just had the Decatted Audi with down pipes done there no issues.

I would like to know too please. i'm in camberley