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is it because the denser hydrocarbons create a lower pitch sound wave which thuds through the engine block?
 

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To do with the compression that dervs run at, they dont need a spark to ingite fuel, as they rely on heat under extreme pressure to ingite the fuel.

Higher compression, more noise.

Although for the people who dont drive them very often, the new ones do sound extremely quiet :)
 

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Stu C said:
To do with the compression that dervs run at, they dont need a spark to ingite fuel, as they rely on heat under extreme pressure to ingite the fuel.

Higher compression, more noise.

Although for the people who dont drive them very often, the new ones do sound extremely quiet :)
I appreciate diesels for certain applications, I really do. My dad's diesel S80 is just spot on, however, it really gets on my tits when people buy new diesel focus' just because they think they will save on fuel (they wont, they arent doing nearly enough miles to make it back) and not because they enjoy driving a diesel, and these things clatter and rattle like I simply cant beleive.
Why why why, they need to be quality diesels....suppose thats true of petrol too, just some diesel development is in relavant infancy.
 

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Yeah definatly, my mom has a diesel 1.3 multijet punto, and not fast by a long shot, but nippy and does a good 55 odd mpg on her 90 odd mile a day commute.
My car is the same, if i hd a petrol id be broke at the moment! i can get from telford to swansea and back to telford again on 3 quaters of a tank provided i drive at the limits! ;)

Although the likes of BMW, Audi and Volvo are definatly catching up with the diesels, i read in the locla cafe other week an old copy of a car magazine, and they tested an S60 D5, Jag derv and new Saab 9-3 1.9 TiD and the volvo won hands down :D
 

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Diesels are loud because of the way they ignite the fuel. The compression ratio is typically around twice that of a petrol car. They squeeze air in the cylinders then inject REALLY high pressure fuel spray into the top of the cylinder. This spontaneously ignites due to the pressure and temperature and the ensuing explosion pushes the piston down. This process can happen in petrol engines also. Its called detonation and it usually results in petrol engines rapidly being destroyed by the explosions. Diesels therefore are stronger built to survive and are also therefore heavier (unfortunatly).

People like diesels not just because of the mpg figures but also because they are easier to drive. Diesels have lots of torque and so can usually "pull" in any gear. In manuvers round town you don't actually need to apply the throttle, you simply release the clutch.
 

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E_T_V said:
In manuvers round town you don't actually need to apply the throttle, you simply release the clutch.
Yeah that definatly shows when i get in a petrol car and drive it for a bit, shudder shudder rev :lol:
 

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Thats my point, you don't have to be careful in a diesel. You have to try hard to stall them!
Having driven both a diesel and a KV6 I know which is the lazier car to drive.
 

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i liked old diesels, I couldnt hear the wife in the back !!!


I now have a 75 and things are a very lot noisier !!


FROM THE BACK SEAT THAT IS !!!!!
 

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I'll second them being easier to drive:

I'm learning in an Astra CDTi, but i used to elarn in the 1.6 petrol. The derv is much easier to drive than the petrol one was, and doesn't sound like a cat being strangled when you go past 2000rpm.

They are harder to stall, (good if you are a learner) and i like their driving style (they are low-revving and often have shorter-geared transmisssions than petrol cars)
 
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