Will this fail my MOT?

[TypeR-Fusion]

I wanted to know what is a Sports Cat back Exhaust System and will this affect my MOT. As I am thinking of putting a Cold Air Induction Kit such as the AEM from SUMOPOWER they said I would need to put the above in to make significant gains in performance. Is this necessary? Your reply would be great

 

[obi_waynne]

There is a 'Sports cat' which is a higher flow catalyst and frees up power and will still pass an emissions test . The other option is a 'decat' which removes the cat altogether this will fail the MOT :cry: .:idea: A cat back exhaust system usually implies that the exhaust starts behind the cat and goes to the back of the car but its worth asking about the cat as some people mean that the cat is included in this.

 

[96AccordCoupe]

I know this is an old thread, but in case anyone is doing the rounds like I am, figured I would contribute.

If you are going to get an exhaust for noise, a simple backbox replacement or a catback exhaust will suffice.

If you want power gains, then it would be good to upgrade the header too so everything flows out of the engine smoothly and as fast as possible.

If you get a custom exhaust, make sure you try to keep the pipe as straight as possible and if you can, get it mandrel bent, not crush bent to avoid unnecessary flow restrictions.

A lot of folks say the first engine mods to do are I/H/E. Intake/Header/Exhaust. If you are sucking in more air you are going to need to expel it more quickly to make performance gains.

Oh, to stay on topic.... doing those mods probably won't fail you on MOT. Although I wouldn't recommend getting your MOT soon after getting a new exhaust as they can smoke a little when they are new until they carbon up a bit.

 

[Prince]

The other option is a 'decat' which removes the cat altogether this will fail the MOT :cry:.

Only if it fails the emissions test.

 

[Twamgl3]

I wanted to know what is a Sports Cat back Exhaust System and will this affect my MOT. As I am thinking of putting a Cold Air Induction Kit such as the AEM from SUMOPOWER they said I would need to put the above in to make significant gains in performance. Is this necessary? Your reply would be great

Whilst there are (usually) proven gains of a few BHP by fitting a CAI on it's own (after all you're reducing the intake temperature), the combination of an upgraded induction system, cylinder head and exhaust system will reap greater benefits than any one upgraded item on it's own - if you get what I mean. A CAI on a car with no other mods may free 5BHP, a CAI on a car with freer flowing exhaust may free up 7BHP.

You may be able to find a surplus cylinder head and get it 'gas-flowed' - have any surplus metal ground away, angles reduced, etc. This was something that used to be done quickly and cheaply but I understand as people have jumped back on this band wagon and there are less 'artisans' doing the work the costs have gone up.

Regardless, this with a less restrictive exhaust will allow more gas in, through, and out of the engine and provide more power.

The very real affect of fitting a CAI alone is a difference in induction noise and anything from positive to neutral to negative affect on your power and torque curves which you really won't know without testing the car accurately, for example with a rolling road, before and after fitting.