General very economical diesel

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General very economical diesel

I drive a Diesel Audi A3 2.0 TDI which I love. Regularly returns 60MPG, 0-60 in 8 seconds and top is around 130. I do journeys of around 37 miles to work and an average of 19,000 miles per year so it is perfect.

When looking for a new car for the Wife, it's a no brainer, she does lots of short trips around town as a community health worker, lots of stop starts from cold, low mileage. It's got to be the 1.2 PETROL 500 (at least that's the first option choice made :eek:)

Horses for Courses

Vic
 
Temperature of engine does not make a difference to diesels, they are equally economical from cold to full running temperature, whereas the petrols will always guzzle until they are warm, so for short trips around town you are better off with the diesel.

(BTW, this is not meant to be a diesel is generally better than petrol post);)

Good to hear people are getting good returns on their diesels at last. Mines due to arrive any day now, so I'm just hoping there won't be any hg, economy or trim faults...having nightmares about it actually!:eek:
 
Its all about which you prefer to drive.

Ive got a small car with a TDi engine and its great, by far cheaper to run than my other car (the same car but a smaller engined petrol).

IMO the 1.3 diesel is against the 1.4 engine, as its the same price, therefore cannot reallt compare to the 1.2. A 1.3 will remap too so will give near 1.4 performance, if not a little more.

Id get the diesel, as thats what i prefer to drive.

And yes, i do have a petrol stilo, but i still maintain, a diesel is a better drive - generally.
 
Temperature of engine does not make a difference to diesels, they are equally economical from cold to full running temperature, whereas the petrols will always guzzle until they are warm, so for short trips around town you are better off with the diesel.

Untrue, Deisels take much longer to reach best economy and working temperature than petrols do due to their nature of operation which is why Deisels are a better buy for higher mileage use.
 
Untrue, Deisels take much longer to reach best economy and working temperature than petrols do due to their nature of operation which is why Deisels are a better buy for higher mileage use.

I agree. Diesels rely on high compression and nice warm cylinders to get the most out of the fuel. Thats why old Diesels tend to be smokey when cold as the fuel isn't fully burning and appears as smoke.
 
Temperature of engine does not make a difference to diesels, they are equally economical from cold to full running temperature, whereas the petrols will always guzzle until they are warm, so for short trips around town you are better off with the diesel.

Exactly !
 
Sorry, but your'e both wrong. The diesel is more efficient which is why it takes so long to deliver heat to the cabin in cold weather. Yes it does use slightly more fuel when cold but not to the same extent as petrol. The high mileage equation is only used for recouping initial purchase costs, most of which will be recouped on trade in anyway as diesels are worth more. Simple as that.;)

On the other hand the particulate filter will be self cleaning more often and will use more fuel in doing so. The efficiency will still be better. Old diesels smoke more due to the innaccuracy of their injection systems, which has largely been eradicated by the advances in sequential multi stage injection... hence the multijet name.
 
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The high mileage equation is only used for recouping initial purchase costs, most of which will be recouped on trade in anyway as diesels are worth more. Simple as that.;)
The big change with modern diesels is that people would only buy diesels if it was going to make a significant saving to runing costs. Diesels were slower and noisier than their petrol equivalents. The choice is less clear cut now as a modern turbo diesel can offer similar performance to a similar size normally aspirated petrol albeit in a very different way.

The high mileage equation still holds true in which case financially diesel is the best choice. At lower mileages it is so marginal and speculative (based on estimated residuals of new models) that preference is the key. Low down torque or revvy power.

With some models (like say a Zafira) the diesel offerings are weak performance wise compared to the petrols, so the diesel teds to be choice for hign mileage users for financial reasons, whereas the stronger performing petrols are the engine of choice in the range.

With the Fiat 500 no engine seems particularly weak each having their own characteristics and performing to expectations for capacity.

So go with your gut feel, the calculator won't really help!

Cheers
Baldrick
 
Untrue, Deisels take much longer to reach best economy and working temperature than petrols do due to their nature of operation which is why Deisels are a better buy for higher mileage use.

I agree, a petrol makes a better town car generally.

I have two Arosas, one is a 1.0S and the other a 1.4TDiS. The 1.0 warms up so much faster and is lighter so better for town use. Especially the warming of the engine, in the winter this is really welcome.

The TDi takes forever to warm through and uses a load of fuel in the winter. Even on longer runs it does worse in the winter months, but loves the summer months - MPG wise.

Although saying that i still get better MPG from the diesel around town.

Really, imo, if you do a lot of miles and/or prefer the torque of a diesel then id get the diesel. Otherwise the 1.2 would probably be fine.
 
Sorry guys but I think there is a misconception about the diesels here...now, I'm no tech but I DO know that the longer a machine takes to warm up the MORE efficient it is.

EVEN modern petrol injection engines which are now called 'lean burn' still require a richer mixture in a cooler cylinder, before, when you used to have carburettors the engine used to dump fuel into the manifold when cold and when you pulled the choke (Hence that horrible fuel smell you got on early morning starts years ago!) It's NOT so bad on modern day petrols but is still glaringly inefficient this is because petrols have much less of a 'compression ratio' than diesels. Petrol 10 to 1 (variable) whereas diesel 20 to 1 (constant).

Compression ignition Diesel is not inefficient when cold because of the the high compression ration about...3000ibs per square inch. This causes the fuel to be already extremely hot and thats why its called 'compression ignition'; does not need a spark plug the glow plug is there to warm the viscous, thicker fuel before it enters the head.

On full or part throttle, diesel uses the ONLY the amount of fuel that is necessary for that amount of power but a petrol will reduce it's compression ratio and the mixture will become richer (more fuel less air) otherwise you'll stall, petrol is only at it's maximum efficiency when you're 'flat out'...(full compression ratio).
Petrols also wash the lubricating oils off the cylinder because petrol is a solvent and if its rich and not fully vapourised then it will dissolve the lubricating oil leading to engine wear, hence the shorter petrol life span in comparison to diesel.

Manufacturers use all their expertise and resources to improve this universal inefficiency problem with petrols, clever ECU calibrations, mixtures, all sorts but diesel is STILL more efficient because of it's basic and rather simple operating principles.

The ONLY element to a diesel engine which can make it negligibly less efficient when cold is the Diesel Particulate Filter and the Catalyst, which require full operating temperature to feedback to the engine more efficiently. However this part is heated FAR quicker than the engine itself because it's an exhaust management element, and exhaust leaves the engine piping hot from start.

So don't worry if you're pottering along in your 1.3 which I will be in the next 48 hrs and after 10 miles you're still not up to temperature. You will NOT be burning more fuel ( as you would be in a petrol,) you are in fact witnessing the miracle of a super efficient engine!

I now apologise if I have any of my facts wrong, I DO know that petrol injection technology and engine management systems have come a long way and I am pleased to hear high MPGs for the 1.2s however I feel that it is a common misconception that diesels behave in the same way as petrols whilst getting up to temperature and I thought I might try to explain it....Sorry if I'm mistaken in some areas.
 
Well said about the cold efficiency Baerius! I knew I wasn't talking rubbish. You managed to put very eloquently just what I was thinking...
 
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70.3...that's...well....beautiful:cry:

Er....I'm supposed to be getting mine on Friday, they 'sort of' promised me a full tank o diesel....don't think I'll be getting that now! Fuel shortage just when I take delivery of my car...tsk:rolleyes::shrug:
 
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