Nearly passed an emission test today

[V8HSV]

Thought this might be of interest as I have no catalyst/muffler in my exhaust system, just a back box.

The MOT tester said that it was only about 2% above on CO and at points on a 30 second run it passed, it also passed the other 2 items for an MOT.

So I think I'll have a go at an MOT test next month as they reckon if I come in real hot it might just pass, otherwise a new system or cats.

So the blower does help with cutting emissions then?

[stevieturbo]

Any modern efi should easily pass the 3.5% CO and 1200ppm HC emissions test for a 93 up car. In fact, thats still all the ( government run ) MOT centres test for over here. They still dont test for a functional cat, although some may fail if they see that it is not present.

An engine would need to have a very poor "tune" or have some wild camshafts in order to fail the above emissions requirement. Either that or have some seriously large injectors, but I think that even at around 800cc or 75lb they will still be fine in most cases.

Just for reference, a CO level of 3.5% is an AFR of approx 13.2:1 which is a very rich idle. Lambda sensors closed loop operation should keep this at 14.7:1 or 0.1% CO

Even my old rover engine would idle at around 14.7:1, cant remember what the HC were, but they werent high. it was happier around 14.0:1 though which is about 1.3% CO. Still well under the MOT's 3.5%