I have a friend who has a 1.4 TSI Twincharged engine (I assume this is the engine you refer to Avant) in the lower state of tune (around 150 bhp) and he is disappointed with it and wishes he had bought the Diesel (2.0 TDI).
I think the Twincharge engine is technically fascinating but I would not want to fix it if it went wrong!
YouTube link to the video.
tinyurl.com/5mj8b2
Edited by Pugugly on 08/11/2008 at 20:24
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Thanks very much, Mattbod. The film sounds convincing (although there are a lot of rubber belts it seems) and in theory, if reliable, the engine should deliver the combination of torque and economy that people are looking for, who currently go diesel.
Do you know why your friend is disappointed with his?
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My mate has the 150 bhp version but they also do a 177 bhp version that is featured in the video. He just feels that he should have gone for the Diesel as it responds better low down as it has a lot more torque. He test drove the 177 bhp version featured in the video as well but couldn't afford it so there may be some sour grapes as well! It should be noted that to get the emissions down VW have re-calibrated this engine to 160 bhp in the new Golf. John Simister in Evo magazine was very disappointed with this latest version in comparison with the 177 bhp. It seems therefore that if you want a TSI the 177 bhp spec is the one to go for.
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As more and more folk are moving to diesel engines, the price differential between the two will just keep widening -- evidently the UK exports petrol to the States and has to import diesel.
As long as a typical 1.8l petrol car is cheaper to buy than a diesel, and diesel remains 15%+ more expensive than petrol per litre, I will continue to buy petrol cars. Yes, the diesel is more economical, but the newer, sweeter engines fitted to Mondeo-class cars are, ironically, much less economical than the older tractor-engines, and they need to be at least 15% more economical to break even, 30% more economical to make back the extra outlay for a typical 12,000 mile pa driver on a newish car over a reasonable period (say three years), and that is before you consider the potential problems with the newer diesel cars.
Yes, the diesels may well be nicer to drive, but this is an entirely separate question to the economics.
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No one has explaned how diesels cost more to service than petrol cars. I reckon they cost less, no plugs to change for one.
Is this a myth, like Rolls Royces never going wrong?
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As to economics, all the costs need to be considered, including the largest cost, which is not fuel. Which, by the way, can vary according to demand for various fractions of the crude. What costs 15% more currently may not in 2 years time. All in all, go for the engine type you prefer.
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When our company ran something like nine BMW diesels,ranging from 320ds to 530ds, the received wisdom from the business manager was that they was a saving of around 15% over the equivalent petrol fleet. Not insignificant - when I ran my own diesel BMWs, certainly found that the servicing costs were comparative with what people say on here their Fords/Vauxhalls etc were costing to service. I think that the "cost more to service" is a little bit of a myth.
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When I said diesels cost more to service I was referring to the older models (mine) having a shorter service interval than the equivalant older (mine) petrol vehicle :-(
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When I said diesels cost more to service I was referring to the older models
How old are you talking, CC? I had a couple of Austin Rover Di diesels back in the early 90s and they were 12k intervals... more than my previous Astra Petrol... and all the others have been 10k, same as the equivelent petrols...
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Hi b308
It's a '95 Cherokee TDSport, 6k service intervals.
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It's a '95 Cherokee TDSport 6k service intervals.
Ah, I had a Maestro and Montego diesels and a '93 Astra 1.7D all with 10k and above service intervals... I take it the one at 6k was an oil/filter change?!
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Yes, every 12000 it's grease up steering rack and wheel bearings. Old school.....don't you just love 'em? :-/
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No one has mentioned the fun factor either. I know it's difficult to have fun driving these days but I can't say I've ever really enjoyed driving my diesels. Yes, they've been economical, they've been torquey and quite quick to be fair (Golf 110s, 130s, 93 TiD 150s). They've also been reliable.
However, compared to an Astra VXR and a Golf GTi Mk5 I recently test drove there's no comparison. Yes, I know these are a lot more powerful but I spent the whole test drive with a big grin on my face. I can't imagine feeling like that with a Golf 170 diesel with a big heavy lump in the front affecting its handling. I've also driven the Astra with the 150 diesel in and yes, it was quick but, again, it didn't make me grin.
Yes these petrols are extreme examples but I think I've got to the middle age where I want to stop being so practical and get some fun out of driving before it's too late. And sod it if it costs a few bob more!!!
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Absolutely fair comment, but the question you're perhaps failing to ask yourself is "Am I buying toy or transport"?
I don't have the luxury of choice and I know which prime mover does the better job of moving my goods and passengers.
659.
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I know what you mean akr. I'm in the slightly odd situation of using two similar cars both for highish mileage purposes. As I mentioned above, the oddest thing now is that their fuel costs are identical despite one being a 2.0 diesel and the other being a 2.2 petrol.
The diesel Ghia X Mondeo estate is quite the most relaxing and practical car I think I have ever had. Supremely comfortable and just seems to eat the miles without trying, leaving you fresh as a daisy even at the end of long day's work on the road.
The petrol Signum is an altogether different thing despite its similarity in terms of market sector. My one is fitted with the harder suspension and sports seats and of course the reasonably powerful petrol engine. Much more involving to drive and loads more fun to press on in when the mood and opportunity arises. However, not nearly as relaxing. I describe it as a harder car, a hooligan in a suit, whereas the the Mondeo is more of a faithful butler.
Depends what you want I guess.
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Almost everyone is comparing turbo diesels and similar size petrol engine's without turbo's and pronouncing the diesel a far better car. Most are not comparing like for like, and i do speak as a very long term diesel owner who remembers just how sluggish non turbo diesels were, but also the delightful low speed torque they had for traffic and reasonable driving.
Lets come up to date and compare the power and sheer brute force of say a Volvo D5 and a T5, both about 2.5 litres, one a capable and reasonable performer within a limited power band, the other a similar car that can transform into an awesome and very fast machine in the blink of an eye.
You can make the same comparisons with almost any manufacturer that makes turbo'd or supercharged petrols as well as diesels.
MB made good 3 or 3.2 turbodiesels, very powerful and smooth, but their performance pales when compared to the 3.2 V6 petrol Kompressor, performance to put many 5 litre and above petrol engine's to shame, drive a range rover with the 2.7 diesel for a lesson in diesel lag then hop into the supercharged petrol for a lesson in instant no lag brute power.
Yes modern turbo diesels are powerful and will do everything most people want, assuming they are unable hear that awful clatter on a cold morning, and i along with the vast majority here know instantly when a diesel fires up, whether i'm in it or out.
But they are still crude when compared to the silky smoothness of a 6 or more cylinder petrol engine, not to mention the black smoke that comes from almost every diesel worth driving under power. If they don't black smoke a bit under full power then there's probably some clever device waiting to hit you in the pocket preventing it.
And when overall economy is looked at, most people could buy the petrol car they want, have it LPG'd and end up with a cheaper, quieter, often faster, more refined and much more economical car than the equivalent diesel.
BM 520d or 530 LPG'd petrol, i know which one i'd want, and assuming i keep my job.... my next car will be a LPG'd 6 cyl petrol (unless of course those V8 Dodge Chargers keep dropping ..;) He says conveniently forgetting Dick Turpin's VED plans....oh well back to reality.
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{{..(unless of course those V8 Dodge Chargers keep dropping..;)
As far as I'm aware, if it's a car that isn't officially imported into this country, DVLA won't have any emissions figures for it so it falls below the radar. Should be £185 then.
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country DVLA won't have any emissions figures for it so it falls below the radar. Should be £185 then.
Now thats a nice thought, but i seem to remember checking this out before and being disappointed, but i would like someone to prove me very wrong.;) don't ask me why but those new chargers really do something for me that only a handful of cars of the last 40 years have, the new challenger doesn't..don't know why.
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Whatever you do, don't admit to liking American cars on here, I've learned that from experience. Cue the howls of derision. Inferior. Bad build quality. Don't go round corners.
Bad taste (ok, that's a matter of opinion.... the new Rolls Royce doesn't REALLY look like a vulgar brick)....
A few FACTS and figures though, from experience (not heresay)....
19 year old American car flies through last 3 MOTs without even an advisory...now there's inferior bad build quality for you
Parts availability....next day no problem, longest wait 5 days for an obscure part from the states.
Expensive to maintain....oil filter £4.50, water pump (only thing that went wrong in 4 years) £60. Wow. Transmission filter £19. Cam belt don't know it doesn't have one, thankfully, like almost all American cars.
Comprehensive insurance £172 (limited to 5000 miles a year, agreed valuation)
Don't go round corners. Oh yes, it does. Very nicely thank you.
Minimal depreciation....the longer I keep it the more it's worth ( the previous model to mine worth around 10-15% more)
Thanks to the difference in price of diesel/petrol costs pretty much the same to run as my diesel 4x4.
Champagne motoring for lemonade money. Don't see the point in spending a fortune buying a "me too" car, I like something a bit different.
There, I've nailed my colours to the mast. Anyone smell burning? ;-)
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Whatever you do don't admit to liking American cars on here
Like most other countries makers there are good and not so good.
I've had 2 in the past, a 72 mustang and a 86 camaro, both V8's both reliable and quick and refreshingly simply made.
I wonder if thats still the case.
The mustang was a straight line machine only and very basic, went like hell but couldn't stop it with non servo drum brakes all round.
The camaro was much more comfortable and useable and once i'd slung the US tyres was as good in the handling dept as any comparable RWD coupe.
Reasonable on fuel so long as you didn't use all the power all the time, and agree about parts prices, a revelation and confirmed the Rip off Britain theory about our own vehicles.
I haven't had any more recent cars from the US, but i did test drive a new shape Mustang 3 or so years ago, quick of course but very disappointed in the hard ride and extremely sad to find so much rust on the unpainted suspension on a less than 12 month old demonstrator, definately a must for full waxoyling and/or painting fully underneath. (the sales chap was most surprised when i went underneath for a butchers, does anyone buy a car without having a good poke nose around them)
As i said very few cars have that 'i really do want that car' factor for me that have been made within the last 40 years, only the Charger does that at the moment, these Euroclone flying machines do nothing at all.
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72 Mustang, can't pick a decent one up for less than 7 grand these days. The unassisted drum brake set up is one of those curious things about American cars that is down to which option boxes the original buyer ticks when they order the car. So you sometimes get air con, power seats, locks but "hey I'm not bothered about upgrading the brakes even though I opted for the 400 cubic inch V8!"
As for undersealing, they just powder coat the underside at the factory and leave the undersealing to the customer to arrange with the dealer to carry out if they wish. Strange....
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Just a quick correction: TSI in lower tune is in fact 140 bhp and the higher tune 170 bhp with 177 lb/ft of torque. That's still considerably lower than the 230 lb/ft that the 2.0 TDI produces.
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Can someone explain (in laymans terms) why, like for like,diesel engines use less fuel than petrol engines?
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Put simply, A given volume of diesel fuel contains more energy than petrol and a diesel engine converts more of that energy to work, than a petrol engine.
Edited by oilrag on 09/11/2008 at 13:37
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Not sure if this the answer but I've always imagined it was because diesels produce the torque at lower revs and to my simple mind it takes less burnt fuel to turn an engine slowly than to turn it quickly. Probably quite wrong......
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It is because they are more thermodynamically efficient. In simple terms this means that more fuel is conerted to energy than in a petrol. I am no scientist however! One of the best explanations on this subject is in Robbie Coltrane's book Coltrane's Planes and Automobiles in the Diesel chapter, well woth a read.
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And compression ratios are quite a lot higher for diesels. Typically 23:1 on the older non-turbo diesels, 18:1 on VAG 1.9 (the fuel efficient ones!) and now down to 16.5 on the CR VW diesels (the less fuel efficient ones) and the Honda 2.2 engine.
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Are diesels worth the hassle. In my book yes. I've had three in the last 5 years. No problems.
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>>Can someone explain (in laymans terms) why, like for like,diesel engines use less fuel than petrol engines?
Here's a few reasons;
1) Quality control, not quantity control - the presence of a throttle in a petrol engine
A diesel regulates how much power it produces simply by varying how much fuel is injected - the air supply is not throttled or restricted, i.e., the mixture quality is regulated. A petrol engine regulates how much power it provides by varying the amount of air fuel mixture is injested - both air and fuel are regulated, and the total quantity of mixture is controlled.
By throttling the air supply, the petrol engine must do more work against pumping when running at part load. Another way of viewing this is that the (partially) closed throttle reduces the "effective" compression ratio of the petrol engine.
2) Compression ratio - rejecting less heat to waste
The diesel engine uses a higher compression ratio than a petrol. One way to consider the advantage of this is to think about it as an expansion ratio - in a petrol engine, you might only expand the hot products of combustion 10 times, while in a diesel, you will be expanding them nearer to 20 times.
This can be demonstrated in a practical, but approximate way. If you started up 2 similar engines, one petrol, and one diesel at the same time, and placed one hand upon each exhaust manifold, you would need to let go of the petrol engine's manifold far before the diesel's. A diesel rejects less heat energy to the exhaust.
3) The density of the fuel
Diesel is heavier than petrol, and so, you get more mass, more carbon atoms per litre. This is partially offset by diesel having a lower "lower calorific value" when expressed in terms of mass.
Items 1) and 2) are the dominant factors.
Sorry if the terms aren't sufficiently "layman" - however, most "layman" explanations are at best obviously wrong, and at worst plausibly confusing.
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A fair summary as usual from my learned friend NC.
Again, in layman's terms, the crucial advantage of the diesel is that it is not committed to a constant air/fuel ratio as is the petrol engine. Most of the time, it runs very weak - this is under low and part load conditions which is how most of us use our engines on this crowded Isle. (My PD idles at about 50:1 air/fuel - most petrols at about 15:1).
Diesel fuel has a higher density, and a slightly higher calorific value per unit volume than does petrol - but it's not a lot different. The higher compression ratio of the diesel allows more work to be done per stroke; this is a key thermodynamic advantage. The diesel is not as constrained as the petrol engine is in terms of detonation - all diesels detonate to a degree when the fuel starts to burn. If you were to lower the compression ratio of a diesel to avoid this, it wouldn't generate enough heat to ignite the fuel.
It's a brilliant concept, made very acceptable by modern fuel systems. Hats off to Dr. Rudolph.
659.
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Good concept but have always understood the originator disputed and in fact Mr. Herbert Akroyd-Stuart patented a compression ignition engine in 1890 two years before the Herr Doktor and also had a high compression engine runnning reliably six years before the Herr Doktor. If that's not true I'm sure somebody here will correct it!
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