Petrol v diesel.

frobisher

On a like for like basis what are the differences in everyday use between petrol and diesel engines?

mike65

One uses 30% less fuel and requires 30% fewer gearchanges.

Mike.

frobisher

mike65 wrote:

One uses 30% less fuel and requires 30% fewer gearchanges.

Mike.

Which one?

Stark

Diesel.

colm_mcm

diesel cars are more likely to accellerate from low speeds in high gears than petrol cars, as the engines generally develop more power at lower revs.

Turbo diesels generally have a power band in which acceleration is quite powerful. usually from 1500rpm to 3500rpm. unlike petrol cars, power dies off at high revs.

crosstownk

Diesel cars nowadays are nearly as quick as their petrol counterparts. I would sooner a Passat 2.0 TDI over a 2.0 Petrol version - ditto with the BMW 320i & 320d.
Diesels are bit noiser though and do require more gear changes. I've an auto 1.9TDI Passat at the moment and it's quite good - I had doubts about the Diesel/Auto line up but now I'm all for it.

jimmycrackcorm

I had a standing start off in a petrol saab 93 1.8 against a diesel tdci mondeo. The Saab was completely outrun..

Big Nelly

Had a 1.6 Primera, changed it last year to a 1.9Tdi 90 Bhp Passat. The difference in milage was huge and it was alot quicker once I got used to the revs compared to Petrol, now have swapped it for the 1,9Tdi 130Bhp and I love it. Alot faster than any petrol I have driven.

conor_mc

crosstownk wrote:

Diesel cars nowadays are nearly as quick as their petrol counterparts. I would sooner a Passat 2.0 TDI over a 2.0 Petrol version - ditto with the BMW 320i & 320d.
Diesels are bit noiser though and do require more gear changes. I've an auto 1.9TDI Passat at the moment and it's quite good - I had doubts about the Diesel/Auto line up but now I'm all for it.

Surely you mean less gear changes for a diesel?

A TDi will pull from about 1500rpm, so overtaking from say 50mph in fifth gear is a doddle.

A petrol engine would probably need to be in fourth gear at least, if not dropped to third for some engines!

crosstownk

conor_mc wrote:

Surely you mean less gear changes for a diesel?

A TDi will pull from about 1500rpm, so overtaking from say 50mph in fifth gear is a doddle.

A petrol engine would probably need to be in fourth gear at least, if not dropped to third for some engines!

That's one way of looking at it. However, a diesels RPM range is considerably less than that of a petrol so I find I have to change up in a diesel more often. I suppose it really depends on driving style.

Mc-BigE

crosstownk wrote:

That's one way of looking at it. However, a diesels RPM range is considerably less than that of a petrol so I find I have to change up in a diesel more often. I suppose it really depends on driving style.

also must take turbo lag into account in diesels (and petrols) when at low rev's

phoenix_nights

Diesel are more noiser if you are not in a new bmw,passat etc.

maidhc

phoenix_nights wrote:

Diesel are more noiser if you are not in a new bmw,passat etc.

I dont know about the BMW, but the 1.9 in the Passat isnt quiet, it is very very loud. The PSA and Toyota diesels are so much quieter.

The narrow power band is the biggest disadvantage of diesels. Modern diesels have also lost the ability to pull from about 800rpm. Probably more gear changes are needed.

Having said that I love diesels, and have hardly ever driven a petrol!

Moanin

VW Diesels are not common rail whereas PSA and toyota diesels are.I believe VW are designing a new diesel

Mc-BigE

Moanin wrote:

VW Diesels are not common rail whereas PSA and toyota diesels are.I believe VW are designing a new diesel

BMW 320d is common rail from around 2002 (150bhp)onwards i think. and very quiet, except for maybe 1 or 2 seconds after cooled startup.

phoenix_nights

at the moment i love a quiet engine so when i dont know whether it is diesel or not (besides having to buy a 730 diesel) then i will look into them.

but with diesels becoming more popular i wonder will the price of diesel increase more than petrol