Zero tax V12
Author
Discussion

cml

Original Poster:

727 posts

292 months

Tuesday 12th November 2013
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Car Makers:

How about - decoupled cylinders as standard - car is delivered with only two or four cylinders connected. Activating the other six to ten (for towing a heavy caravan sir) would require a quick bit of spanner work - Bingo, a zero-rated V12.

The VED CO2 system can't last much longer can it? A flat £100 a car per year, or something similar would be quick, simple, and stop the current wave of odd engineering going on (gear ratios chosen for a lab test, not actual road use - automatics getting better results than manuals etc. etc.)



KingNothing

3,345 posts

183 months

Tuesday 12th November 2013
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Should be on the cost of fuel, you use more (pollute more rolleyes), you pay more, would make a government agency who's sole responsibility it is to send out a throwback to the 1920's (see: tax disc); redundant, surely that'll save some money not having them on the books? Will never happen though.

kambites

71,565 posts

251 months

Tuesday 12th November 2013
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I don't think anyone has ever made a car engine with decoupling (as opposed to deactivating) cylinders. I suppose the fuel savings wouldn't be worth the complexity when they can get the same power by adding more boost to a small engine.

davepoth

29,395 posts

229 months

Tuesday 12th November 2013
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There are easier ways.


anonymous-user

84 months

Tuesday 12th November 2013
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Why would "decoupling" a few cylinders make a zero tax car?

(most of the things that make a low CO2 car are not to do with the engine)

J4CKO

46,958 posts

230 months

Tuesday 12th November 2013
quotequote all
It would be horrendous to try and do, an engine is a complex and has critical timing requirements, effectively locked in its operation, varying anything once on the move is difficult, ok there is variable valve timing and lift but little else, to decouple it would mean having a crankshaft that is split in some way and most of the strength in an engine is through the crank, even having less main bearings to support it drastically reduces its strength so having a break in it would be pretty difficult.

The only possible way would be six two cylinder, three four cylinder or two six cylinder engines in a shared block, but then you have to scale everything up for the highest duty and that adds weight so thats where the emissions come from, to move a certain mass you need to use a certain amount of energy.

Good thinking though.

996TT02

3,342 posts

170 months

Tuesday 12th November 2013
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You could clutch them in.

You would need two balanced half-engines however.

But the reality is that the power-split principle is being used nowadays, in hybrids, you do have two engines only one is electric.

Ian974

3,202 posts

229 months

Tuesday 12th November 2013
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TBH, even if it managed to get zero VED, I think that'd be the last of the issues in the way of me buying something new with a V12 engine. £500 isn't going to make much of an impact on a £100k+ car wink

cml

Original Poster:

727 posts

292 months

Wednesday 13th November 2013
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My thinking was really that you would just run it uncoupled for the EU test figures - get a zero rate, or at least a low one because your 2 cylinder car is more frugal - and then couple it all back up permanently for road use, rather than have a system that could be uncoupled on the move or anything (that would get complicated for sure) - basically cheat a bit for the test just to get a low tax bracket.

True, it doesn't make much difference for the first buyer (a few hundred on lots of thousands), but down the line after the value has dropped like s stone it does start to count. With big old Jags and Mercs the annual tax can equal a good proportion of the cost of the car.

It is a test which lends itself to such tomfoolery


anonymous-user

84 months

Wednesday 13th November 2013
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Just buy a P1/918/TheFerrari and the jobs already done for you.............

kambites

71,565 posts

251 months

Wednesday 13th November 2013
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It would probably be easier and cheaper to just sell the car with small diesel engine, then sell a conversion kit to change it for a V12.