Smoke Opacity Analysis - what does it mean?

[pistonheadforum]

Hi,

So the e39 touring has made it through another MOT and now I have a piece of paper with the smoke opacity analysis results.

Uhhhh owkay...

What does these numbers mean and is there anything that can be derived about the general health of the lump at the front?

Opacity Values [m-1]

Acceleration 1: 2.01
Acceleration 2: 0.53
Acceleration 3: 2.63
Acceleration 4: 1.31
Acceleration 5: 0.59
Acceleration 6: 2.85

Zero Drift: 0.02
Opacity Mean Value: 2.06


Obviously the key thing is the PASS but would be interested in understanding what these numbers mean from those with the knowledge and if it's a scrape through!



Many thanks,

[pistonheadforum]

Thanks!

So as far as I can see the main blurb is:

3. After 6 free accelerations, the mean of the last 3 smoke levels is:
a. for vehicles first used on or after 1 July 2008, more than 1.5m-1 for both turbocharged and non-turbocharged engines

b.for vehicles first used before 1 July 2008:

. for a non-turbocharged engine, more than 2.50m-1

. for turbocharged engines more than 3.00m-1.[/b]

Given that this is a 2001 turbo diesel with 140,000 miles on it a result of 2.06 (and for a pass need < 3.00) seems not too shabby!



Thanks again,

[pistonheadforum]

Aye, random number generator is what that appears to be.

Had a look at two old MOT test result - single acceleration each with 0.75 and 1.34 for the results.

No idea what happened with that one - up there with bigfoot and Rongorongo.

Edited by pistonheadforum on Wednesday 29th July 21:17