I had my mot today so i thought id share the results of the smoke test.

I have been running my car on shell vpower diesel for the past 12 months and its amazing what difference it has made

Last years

This years

There are a number of potential influences on the MOT smoke test (on non-DPF equipped cars).

 

A good thrash just prior to the test can also see the variances you have seen.

 

Can you be sure it is down to the fuel?

Had my MOT just under a couple of weeks ago. Drove it 'cold' from home straight to garage (approx 4 miles) at a normal pace and the 'opacity' value was 0.03%. Test from first year I had it was 0.14% and last year was 0.12%. Usually it just gets 'normo' morrisons but I always add 25-50ml (depending on how many litres I'm adding) of MIllers ecomax. DPF still in place,no surprise with a result that low. 

Looks like it passed both so you might aswell use normal diesel.

 

Can you be sure it is down to the fuel?

I was useing supermarket fuel last year and done the same gentle drive of 5 miles to the mot centre from cold