I don't know much about diesel engines at all, other than the usual comments I've heard about them being sluggish, and, of course, I've heard the noise they make and been choked by the stinky fumes.
Most diesel cars I've seen have been 1.8 litre and above... I've now seen a little Citroen C3 that is 1.4 litre. Is that going to be much good considering it's a diesel engine?
A petrol engine uses a spark plug to ignite the fuel, whereas a diesel relies upon compression, after the induction stroks, to fire. Not sure about the Citroen, though.
You see there are diesels and there are turbo diesels. The 1.4s are turbo diesels, turbos squeeze more air into each cylinder and more air = more fuel can be added. This means the power from each explosion is considerably greater. Diesel is hard to ignite, but upon combustion generates a lot more force than petrol, this has side effects. Namely diesel engines have to be built much stronger than the average petrol, making them heavy and the cars slow. Turbos add a lot more power for very little weight, helping make the power-to-weight ratio acceptable and comparible to that of a petrol engine.
Oh and if you're wondering how a turbo is powered, it uses the exhaust gases from the engine to spin a turbine (at about 150,000 rpm) which spins an air pump, which in turn pumps air into the engine.
Small turbo diesels are always as far as I know bigger than the average small petrol engine, at least 1.3litre normally 1.4. In terms of speed, some of them are really well suited to small cars, especially those who spend time on the motorway. To give you some figures -
The Citroen C2 1.4HDi generates 70bhp and 118 lb ft of torque with a top speed of 103mph and a 0-62 of 13.5 seconds. A Citroen C2 1.1 generates 61bhp and only 69 lb ft of torque with a top speed of 98mph and a 0-62 of 14.4 seconds.
The Diesel does combines 65.7 mpg, the petrol only 48.7 with the diesel able to do up to 76mpg on motorways etc.
As you can see, the small diesel is perfectly well suited to a small car with better fuel economy than the petrol, much greater ability at coping with hills, motorway overtaking and carrying loads and a longer lifespan.
Some of the other 1.4s have even bigger outputs - the VAG 1.4 produces 80bhp and 148ftlbs of torque in the Fabia.
I have said before that diesel does not suit everyone and suggest that you test drive as many different ones as you can, petrol and diesel, and make up your own mind - do not listen to anti-diesel stuff you see on here - be original and make up make up your own mind.
Petrols naturaly tend to be low in torque high in horsepower, Diesels the other way round. Torque is useful in certain situations, horsepower often plays the greatest role in acceleration and some others. It depends on gearing and all kinds of other factors.
Turbo-diesels are really the only option for the diesel buyer today. Turbos introduce about 30-40% more power to a diesel engine and modern diesels almost all of which are Turbo models aim to have similar or the same acceleration as petrol cars. Standard diesels (SDIs) are almost always very very slow, but there are only a few on sale nowadays.
The best judge is the 0-60 or 0-62 time. Check the car manufacturers site, they almost always quote the 0-62 times. Engines vary between makes and models, check up reviews and similar if you're interested in one specific car with a certain engine.
If you are for example towing a Caravan or carrying lots and lots of people you'll almost certainly want a torquey engine, which will probably be a diesel. Ditto if you fancy smooth driving/overtaking on the motorway or if you want brilliant fuel economy. If you want something super fast the worlds supercars remain petrols for a reason. Diesels are no longer slow, they're more than adequate for the average driver, but they'll never be as fast as the best petrols.
The Citroen C2 1.4HDi generates 70bhp and 118 lb ft of torque with a top speed of 103mph and a 0-62 of 13.5 seconds.
ok thats a diesel,but... compared to a petrol 1.5 in the colt czt, which has more than double the bhp (147) and a load more torque than the diesel (155lb ft) and a 0-62 of 7.7 seconds. hmmmmmm which performs better the petrol or the diesel.
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Some of the other 1.4s have even bigger outputs - the VAG 1.4 produces 80bhp and 148ftlbs of torque in the Fabia.
again even with a turbo the diesel is beaten by petrol in both bhp and torque. and the fabia turbo does 0-62 in 13.4 seconds. still a mile off 7.7 seconds from the 1.5 petrol colt czt.
....... There's got to be a hundred reasons why i should listen to diesel owners, but right now, i can't think of any.
The Colt turbo is a performance hatch, which neither of the diesels quoted here are - it also costs £16k, and has considerably poorer fuel consumption and emissions. Not really like for like, is it?
That's like me saying diesels are better cos the BMW 535d outperforms a 1.8 Mondeo....
I've been running the wife's Yaris diesel to work recently, it's 1.4 Direct Injection, pulls fine, sits happily at motoroway speeds and most importantly does 64mpg.
Not sure how well it'd do in a C3, a mate had a 307 1.4 HDI and thought it was pretty slow - simply underpowered, I'd be more inclined to go for a bigger derv engine if you're doing big miles, or a 1.6 petrol.
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Originally posted by Mindmatter: Hi
I don't know much about diesel engines at all, other than the usual comments I've heard about them being sluggish, and, of course, I've heard the noise they make and been choked by the stinky fumes.
Most diesel cars I've seen have been 1.8 litre and above... I've now seen a little Citroen C3 that is 1.4 litre. Is that going to be much good considering it's a diesel engine?
My dad has the Fiesta with the same engine. For a driving instructor's car its fine, for wanting to overtake anything in a hurry it's pants! Fuel economy is excellent - he does mid to high forties when teaching.
As I've said before, an engine is only as good as the car it sits in. A poor gearbox/transmission, poor driver or heavy car will make any engine slow and unhelpful.
And as has already been said, all very nice talking about the 1.5 in the Colt but that's a performance engine, tuned and designed for speed. Small diesels are designed for economy, cheapness, and average to good but not excellent ability.
You want to compare engines? BMW 320d - 50mpg, 1995cc 0-62 8.3seconds. BMW 320i 40mpg (20% less efficient) 1995cc, 0-62 9 seconds. And the diesel will be able on the motorway, the petrol with get loud and unpleasant and run out of steam on overtakes.
How about we take a look at Fiat diesels, new Grande Punto has a 1.3 (1248cc) Multijet diesel 90PS 0-62 in 11.6 seconds- top speed 109mph, 61mpg. The 1.4 (1368cc) Petrol takes 12.9 seconds on the 0-62 and has only 65PS. Furthermore it achieves only 46mpg.
We could go on all day. The diesel is a perfectly reasonable choice, personally I'd go for the 1.6hdi, there's nothing between it and the 1.6 petrol in the range and it's a lot more economical. The 1.4hdi makes a lovely engine for the C2 as it has a lot more guts than the majority of the petrols allowing the car to cope with the motorway, hills and heavy loads.
Makes as much sense as comparing a petrol hot hatch with diesel city cars half the price, just because they both happen to have a turbo...
If you want to compare a Colt turbo with anything diesel, then try an Ibiza Cupra TDi, they're broadly aimed at the same market, and the Ibiza has a list price a shade over £15k.
I ain't on the warpath, I'm just out to right some wrongs and give a little balance...!
Forgive me, must dash, have to go rescue some children from a burning orhpanage across the street....
whats the best performance diesel then? whatever it is there will always be a petrol engine that has more bhp AND more torque than the diesel produces.
take a mitsubishi evo 8. 405 bhp 355 lbft 2.0 turbo petrol
not sure of a "good" diesel to compare it with but you could have the same capacity bmw 320d 160 bhp 251 lbft 2.0 turbo diesel
....... There's got to be a hundred reasons why i should listen to diesel owners, but right now, i can't think of any.
my arguments are to do with performance only. i just hate it when people say diesels are more advanced than they used to be and they are about the same or even better in terms of power/performance than the same sized petrol engines. its just not true. and its not true they have more torque than a petrol, if you compare the best "sporty" diesel to the best "sporty" petrol.
....... There's got to be a hundred reasons why i should listen to diesel owners, but right now, i can't think of any.
Originally posted by pantherd90: As I've said before, an engine is only as good as the car it sits in. A poor gearbox/transmission, poor driver or heavy car will make any engine slow and unhelpful.
And as has already been said, all very nice talking about the 1.5 in the Colt but that's a performance engine, tuned and designed for speed. Small diesels are designed for economy, cheapness, and average to good but not excellent ability.
You want to compare engines? BMW 320d - 50mpg, 1995cc 0-62 8.3seconds. BMW 320i 40mpg (20% less efficient) 1995cc, 0-62 9 seconds. And the diesel will be able on the motorway, the petrol with get loud and unpleasant and run out of steam on overtakes.
How about we take a look at Fiat diesels, new Grande Punto has a 1.3 (1248cc) Multijet diesel 90PS 0-62 in 11.6 seconds- top speed 109mph, 61mpg. The 1.4 (1368cc) Petrol takes 12.9 seconds on the 0-62 and has only 65PS. Furthermore it achieves only 46mpg.
We could go on all day. The diesel is a perfectly reasonable choice, personally I'd go for the 1.6hdi, there's nothing between it and the 1.6 petrol in the range and it's a lot more economical. The 1.4hdi makes a lovely engine for the C2 as it has a lot more guts than the majority of the petrols allowing the car to cope with the motorway, hills and heavy loads.
Reasonable points, it seems like some Manufacturers are now playing down their Petrol models in favour of Diesels. Amazing what a few more PSi on a Turbo will do.
My 1.6 petrol can go up virtually any hill in 4th, if not sometimes fifth, with two people in the car aslong as I get the revs to 2000 RPM. Once at 2000rpm, the car will pull it's self up most things in fourth quite happily without bogging down at all, quite often I change upto fifth and still keep going.
Some Diesel people really seem to think Petrol cars have rubbish torque - they DON'T, Diesels just have an excessive amount!
Originally posted by beach: my arguments are to do with performance only. i just hate it when people say diesels are more advanced than they used to be and they are about the same or even better in terms of power/performance than the same sized petrol engines. its just not true. and its not true they have more torque than a petrol, if you compare the best "sporty" diesel to the best "sporty" petrol.
This is exactly right, Beach, and was the exact point I was making on the other thread. However I made the mistake of using my own car as a comparison, therefore attracting the "mine is bigger than yours" comments.
I would like to see a Diesel produce 202.5 bhp a litre!
