Both cats.

[ashclio5]

Had the centre silencer chopped out on my car other day and I'm looking to have the car decated now will the flat spot get any worse? And would it pop and bang abit more too ? Or is it pointless having it done as it won't make it pop or bang more tHan it's already doing?

 

[DS197]

There is a possibilty of the decat making the flatspot worse. However to get the full advantage of a decat the car should ideally be remapped afterwards. The remap will not only take full advantage of the decat but should also be able to reduce if not totally get rid of the flat spot already present.

The car will definitely pop and bang more by just removing the secondary cat. By removing both it would probably sound like a machine gun. As you probably know you won't pass the emissions test with both cats out unless you know a friendly mot tester.

 

[johnbr6]

And they are becoming hard to get !

 

[Warren]

I have my secondary cat removed, manifold one is still in place. Fortunately I have an MOT tester next door to work who loves his cars so he won't question it removed although it still passes on emissions perfectly fine with just that one removed. If the manifold was also gone it'd probably be a different story so you'd need someone friendly, a fair few none mainstream MOT testers don't question it anyway at least not where I live.

 

[Foxspeed]

you need it re-mapped if both are removed as it will screw the fuelling up