This may be a beginners question but only had my Scooby a couple of months so still getting to grips with it all.

I will be looking to get a remap next year so am in the process of upgrading various parts prior to this. Currently the exhaust system has a Prodrive back box and a Vortex Centre Section (with resonator) but I am unsure which other cats I can remove and still pass an MOT.

I was going to get a Prodrive downpipe which is a sports cat but I understand the uppipe also has a cat in it, is it best to leave this or get a decat, and if so will it pass the MOT? Confused!

 

Currently you dont need a cat to pass an MOT test until the 2012 new regs come in.

Im not sure what cats you can get rid of before you go over the emissions threshold though, im sure others can comment on that.

Its maybe best getting a sports cat or if you want to go decat get some sort of undertray to hide the exhaust, as they wont start taking things off to check if the cat is there.

 

remove pre turbo/up cat when doing the exhaust (then remap needed), will give better spool up and just the post turbo/down cat should pass mot, most sports cat do not so don't waste your money or go full de-cat for max power/torque.

 

Are you sure on this? goes against ever over comment i've seen on cats in the past. questions the point of fitting a sports cat if there not needed and again questions why people would advertise mot friendly sports cats

 

sports cat do work, can require the car to be quite warm though before MOT

 

Surely they dont just do a visual check. You have mentioned the emissions threshold yourself which is clearly tested

 

You may or maynot have an up-pipe cat dependant on year and model of car?

 

My old prodrive sportscat passed mot no problem in fact I think the emissions were lower than when I had the STD downpipe on, think some cheap ones may have cat not correct size for the car so either need to be very hot or brand new to pass. I think milltek cat is in centre pipe so this needs car hot to pass but a good quality correctly sized cat in the downpipe should pass no problem

 

+1 on that - mine went through the other week with a Ninja sports cat. Had to be hot but the tester was a good guy and persisted till it was within limits

 

Its a 2005 WRX with PPP installed

 

Was that the only cat you had? i.e, was your uppipe decat?

 

On what?

You dont need a cat to pass the test, but not havin a cat means you are likely to fail emissions.

From 2012 theres an extra tickbox for the MOT man:
'Is the car fitted with a catalytic converter?'

So its going to be harder from next year, but if you know a friendly mot'er who will pass your emissions im sure having a decat willbe fine if where the cat should be is hidden by some sort of undertray.

 

Wilbo, have a look at this pic. It's the downpipe cat that will need to remain to pass an MOT, or be replaced with a sportscat. You can lose all of the others

 

Spot on! Thanks mate, going to collect a Prodrive Sportscat this weekend. Then will potentially be looking for a TD05 or VF35, and some bigger injectors. Then think it will be ready for a remap.