Modified cars and the MOT

Modified cars and the MOT

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FreeLitres

Original Poster:

6,051 posts

178 months

Sunday 26th July 2009
quotequote all
Noobish question -

I have never modified a car before but have wondered what happens when it comes to the MOT?

Imagine upgrading a GTi with a massive turbo and uprated injectors for example. Wouldn't the car be producing more emmisions that a stock version? So Mr MOT tests it and finds the emmisions are way too high for "a GTi", so it would fail the MOT, right? Similarly, if you transplant a V6 engine into an MR2, wouldnt the MOT assessor expect the emmisions of a smaller 2.0 4-pot?

It's probably a simple answer, but how do you get around these issues?

FreeLitres

Original Poster:

6,051 posts

178 months

Sunday 26th July 2009
quotequote all
Thanks for your reply.

I think.

FreeLitres

Original Poster:

6,051 posts

178 months

Sunday 26th July 2009
quotequote all
Ok, so it takes into acount Hydrocarbons as part of the measurement. Hydrocarbons could be unburnt fuel, right?

So what about a highly modified Evo running anti-lag? Wouldn't this be throwing more hydrocarbons out of the exhaust pipe than a standard Evo?

Also, would you expect 4.5 litre Cerbera engine to produce the same amount of hydrocarbons as a 800cc hatchback? I just find that surprising.

FreeLitres

Original Poster:

6,051 posts

178 months

Sunday 26th July 2009
quotequote all
I see what you are saying about percentage of emission, rather than absolute volume.

The thing that confuses me is that I can practically smell the petrol coming out of a TVR when they drive past. Do TVRs really release the same percentage of petrol vapour out of their exhaust pipes as a basic Corsa?

FreeLitres

Original Poster:

6,051 posts

178 months

Sunday 26th July 2009
quotequote all
Thanks jagracer - your response came as I was typing so please ignore the last question.

FreeLitres

Original Poster:

6,051 posts

178 months

Sunday 26th July 2009
quotequote all
Ok, so I think I have this now...

So if I transplant a pre-cat TVR engine into a brand new Fiesta, it would have to be tested as a pre-cat TVR, rather than a Fiesta... Not that I am planning on doing this of course!

As for my mods - nothing planned for my current car (3.0 X-Type). Any more power will likely strip the delicate chocolate transfer box. For my next car though, supercharging a S2000 could be of interest.

FreeLitres

Original Poster:

6,051 posts

178 months

Sunday 26th July 2009
quotequote all
Very informative responses! Thanks for taking the time to explain this to me.