Does it use less fuel to change gear or let the turbo kick in?

[mattie]

Indeed - diesel is just shit tappety noise.

If you want a diesel to perform the same as petrol (e.g. huge aceleration and top end performance), then you end up with the same mileage per gallon.

If you just want to bimble along at a crawl with acceleration that would traumatise a snail, then by all means purchase a diesel.

Diesel and petrol have different specific energies (essentially the inherent amount of energy you'd get by combusting it), amongst other things, and you will always get higher useful work from a unit volume of diesel than petrol.

Hence the mpg will be lower for equivalent performance.

 

[not-bono-ever]

Indeed - diesel is just shit tappety noise.

If you want a diesel to perform the same as petrol (e.g. huge aceleration and top end performance), then you end up with the same mileage per gallon.

If you just want to bimble along at a crawl with acceleration that would traumatise a snail, then by all means purchase a diesel.

yer not kidding - I bought an ealy 80's 300 D merc auto estate . massive and heavy - I took it to the local garage concerend that its glacier like acceleration meant it was doomed, only to be told it was good for another 300K miles

 

[madzone]

Indeed - diesel is just shit tappety noise.

If you want a diesel to perform the same as petrol (e.g. huge aceleration and top end performance), then you end up with the same mileage per gallon.

If you just want to bimble along at a crawl with acceleration that would traumatise a snail, then by all means purchase a diesel.

Doesn't sound like my car at all

 

[8ball]

Doesn't sound like my car at all

Would your car's acceleration not perturb a snail unduly?

 

[madzone]

Would your car's acceleration not perturb a snail unduly?

My car accelerated from 60 -90* in 5th gear while going up a fairly substantial hill the other day. I enjoy overtaking men in flash cars as well

*of course as soon as I realised I was doing 90 I slowed down to within the national speed limit *salutes*

 

[keybored]

I always thought a diesel turbo was pretty fuel-hungry and that changing down a gear will allow you to accelerate faster anyway...

I'm pretty certain turbo diesels are more powerful and more fuel efficient than a regular diesel engine. Someone else said the turbo runs all the time on a diesel; mine kicks in noticeably at around 2000RPM. I get around 45mpg on a mix of urban and rural roads and around 60mpg on the motorway.

Cobbles, you've clearly never driven a modern turbo diesel.

 

[Cobbles]

Cobbles, you've clearly never driven a modern turbo diesel.

I've driven several that coleagues have inflicted on themselves.

I was quite interested in a 3 litre Jag that a colleague had (apart from the awful "spanners in a bag" noise) but it was no better than a 3 litre petrol V6 when pushed in terms of making reasonable progress.

Diesels are great for running power plants or bulk carrier ships but they're shit for generating fun (consumption-wise).

 

[keybored]

I've driven several that coleagues have inflicted on themselves.

I was quite interested in a 3 litre Jag that a colleague had (apart from the awful "spanners in a bag" noise) but it was no better than a 3 litre petrol V6 when pushed in terms of making reasonable progress.

See, diesels have made some progress. You've gone from "bimble along at a crawl with acceleration that would traumatise a snail" to "no better than (equivalent) petrol" in less than 2 hours.

 

[madzone]

I'm pretty certain turbo diesels are more powerful and more fuel efficient than a regular diesel engine. Someone else said the turbo runs all the time on a diesel; mine kicks in noticeably at around 2000RPM. I get around 45mpg on a mix of urban and rural roads and around 60mpg on the motorway.

Cobbles, you've clearly never driven a modern turbo diesel.

Me too.

 

[Pingu]

tbh i am not recognising that either

i have a 2.5 litre bmw turbo diesil that is pretty silent, returns 42 mpg round town and about 50 on mways. accelleration is good too