Liking the new(ish) MOT

[kalniel]

So the A3 had it's first MOT today, which incidentally is my first MOT for a car newer than 2012 - and I never knew you got such interesting breakdown of figures. The brake test especially - now I know the exact real world weight of the car (plus the tester I guess), weight distribution, braking force and distributions etc. Fascinating

Car weighs 1314kg, distributed predictably poorly at ~58:42 (though presumably heavier engined A3s are worse). Road friction tells me how much I'm losing due to rolling and mechanical resistance, which is about 54 kgf or about 1/15 of the friction when braking. The friction distribution is interesting at 54:46, telling me that despite more weight being on the front axle, there's not the same proportional increase in rolling resistance, so either the mechanicals are smoother (which you wouldn't expect, given complexity of drive and steering) or the tyres have better rolling resistance (which would tally - Michellin PS4 on the front, ContiSport5 on the back). Brake force distribution is 61:39, pretty much as you'd expect and presumably more front-loaded than the weight distribution both for safety and to account for force transfer, though as this is only measured to wheel locking you presumably have to account for differences in tyre performance.

Emissions same as always, and as expected for a young car, beautifully clean - though a bit on the lean side which isn't superb for life of the cat. Will have to see what it's like next year as a comparison.

[DanceswithUnix]

Is that the actual measured weight, and not the registered kerb weight?

[kalniel]

Is that the actual measured weight, and not the registered kerb weight?

Yes, broken down per axle too. Manual says kerb weight is 1300kg (no doubt with smaller wheels, no spare wheel, none of my bits and bobs still in the car or the full tank of fuel I had )

[spacein_vader]

The best bit of the newer teat regime is being able to see the entire MOT history of a car by putting the reg into a government website.

Certainly helps decide when looking at used cars.

[DanceswithUnix]

Interesting, I wonder if that affects the handbrake test. My kit car has a registered kerb weight rather higher than the actual weight, but the handbrake has to be able to hold the registered weight which it always struggled with.

[kalniel]

Interesting, I wonder if that affects the handbrake test. My kit car has a registered kerb weight rather higher than the actual weight, but the handbrake has to be able to hold the registered weight which it always struggled with.

Interesting. According to this test the parking brake just has to apply a force equal or greater than 16% of the actual measured weight. This is an electronic brake though so maybe it's different.

[DanceswithUnix]

Interesting. According to this test the parking brake just has to apply a force equal or greater than 16% of the actual measured weight. This is an electronic brake though so maybe it's different.

My kit car has never been weighed, but holding 900kg and holding the something like 1200kg declared weight is some difference.

[Xlucine]

The best bit of the newer teat regime is being able to see the entire MOT history of a car by putting the reg into a government website.

Certainly helps decide when looking at used cars.

That's been a thing for a while - I can see MOT records for my car (first registered 04) going back to 07

[ik9000]

That's been a thing for a while - I can see MOT records for my car (first registered 04) going back to 07

dare i look..... :s

[Ttaskmaster]

Manual says kerb weight is 1300kg

And you're carrying 14kg extra?
Wow, all those pens, flip flops, bottles of sunscreen, loose pennies, newspapers, Ginsters crumbs, half eaten sandwiches and other car junk really add up, don't they?

Kerb weight should include all consumables, usually including full tank. Everything (including user manuals, ice scrapers and first aid kits) it comes with as standard and needs to make it go, apart from a driver.

[Xlucine]

If you include a full fuel tank you make cars with bigger tanks look "worse" (since they're heavier, what with the extra fuel). I say include the fuel & such needed for 100 miles of driving without damaging the engine, that way you're encouraging efficient engines without penalising the convenience of a bigger tank

[kalniel]

Thread revival.. for fellow geeks who like to see how these things vary

This time I only had half a tank of fuel, which is largely responsible for the recorded weight of 1282kg (cf 1314kg).

The PS4s on the front are down to 3.4mm, and the brake force before locking has increased. New Primacy 4s on the rear (can give a review on those separately if anyone wants) are also better than the conti sport 5s from the previous test. Total brake force before locking is up nearly 200 kgf (23% better), which combined with the reduction in vehicle weight means brake efficiency is up to 75%, compared to 60% before. So a tip I'll take forward is definitely have a less than full tank when testing since the brake efficiency has to be equal or better than 58% to pass.

Lambda still right on the absolute limit for leanness, which given the accuracy of the test leads me to believe this is engineered by design, as you might expect to improve economy.

[Lowe]

Where do you find this info? Can’t say I’ve seen in on my sheet?

[kalniel]

It's one of the sheets of info I get back from the MOT - I get an invoice, an emissions sheet, and this third sheet of roller results. I don't suppose they *have* to give you a copy, but there should be one somewhere if you ask for it.