Diesel Engines

[Parthiban]

Could someone help me with something that has confused me for a little while? Even when fuel economy is put aside, people are always raving about how powerful diesels are, and how much torque they have, and so on..... :duh:

But don't all these diesels have some kind of forced induction? And they're always compared to normally aspirated petrol engines. The one that immediately springs to mind is that new BMW 535d, which is a twin turbo diesel, and everyone goes on about how its much quicker that the petrol 535.

My question is, that if BMW turbocharged the c**p out of the petrol 535, would it not walk all over the diesel and then some?

Any help would be greatly appreciated :)

[Kent]

Could someone help me with something that has confused me for a little while? Even when fuel economy is put aside, people are always raving about how powerful diesels are, and how much torque they have, and so on.....  :duh:

But don't all these diesels have some kind of forced induction? And they're always compared to normally aspirated petrol engines. The one that immediately springs to mind is that new BMW 535d, which is a twin turbo diesel, and everyone goes on about how its much quicker that the petrol 535.

My question is, that if BMW turbocharged the c**p out of the petrol 535, would it not walk all over the diesel and then some? 

Any help would be greatly appreciated  :)

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No technical knowledge I'm afraid but would a twin turbo 3.5 litre petrol BMW hope to get remotely close to the fuel economy of the diesel? It would probably be bringing the 535 petrol into M series territory if they twin turbo'd it and BMW don't want to produce a mainstream rival to those. Just some thoughts and not really an answer but there are some seriously technical members here who will be along soon I am sure.

[chips229]

Yea your right in what your saying if they Turbo charged a petrol version it would put out more Bhp than the diesel,not so sure it would put out as much torque as the diesel because diesels are longer stroke engines so dont rev as high as petrol,but the longer stroke gives more torque...But as to mpg the Turbo diesel will do more mpg than the turbo petrol engine.Diesel engines have come along way over the last few years.....i still prefer petrol power myself,i hate having to follow a diesel motor because of the fumes :yack:

[ColinBarber]

Yes a petrol 535 would put out much more power than their 535d. However fuel economy would get much worse which is why they don't do it. The petrol engine puts out enough power without having to introduce turbo lag etc.

chips, as for your comment on following diesel motors - I couldn't agree more. My AC seems to spend nearly all its time automatically on recirculate these days.

[TheDon]

well i am for and against diesels as i own both....

The lexus is obviously supercharged and is a bugger to drive sensibly but suffers at pulling away and has about 240 nm torque (according to tte) and does 20mpg

Where as my new 2.5 litre nissan navara does 31mpg with 174bhp TDi and had 400 nm torque.

it drives smoother and pulls realy hard (its also rear wheel drive in 2wd mode) and is less strenuous on motorways. and it also has 18,000 mile service intervals compared to 10k in the lexus.

I think the choice of diesel over petrol is all down to purpose...... but they are definately getting better every day!

[ColinBarber]

The new 2.2 unit that Lexus will use in the IS220d so meant to be good. Prespool on the turbo sounds an interesting idea to get rid of turbo lag and lack of low end performance.

[fergy]

BMW have the two turbo chargers on the 535d to get round turbo lag...small one that spins up quickly at the bottom end, and big one to give push at top end. I test drove one and the car was lovelly...amazingly quick with linear acceleration... pity to get the car the way I wanted was required silly money to be spent on extras (which dont influenec re-sale)....

Will be interesting to see hwo quick it is when they fit it in the new 3 series.. guessing not a lot of cars will be able to keep up...

[Lex-aholic]

Yea your right in what your saying if they Turbo charged a petrol version it would put out more Bhp than the diesel,not so sure it would put out as much torque as the diesel because diesels are longer stroke engines so dont rev as high as petrol,but the longer stroke gives more torque...But as to mpg the Turbo diesel will do more mpg than the turbo petrol engine.Diesel engines have come along way over the last few years.....i still prefer petrol power myself,i hate having to follow a diesel motor because of the fumes :yack:

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I owned a diesel before the Lexus.

The diesel cloud you're referring to was the best thing, especially when you have a tailgater right up yer arse. Just drop the gears and floor it - usually peed them off. :D

[ColinBarber]

The diesel cloud you're referring to was the best thing, especially when you have a tailgater right up yer arse.  Just drop the gears and floor it - usually peed them off. :D

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That's because the person behind backed off - they couldn't see where they were going through all the smoke and dirt ;)

[chips229]

The diesel cloud you're referring to was the best thing, especially when you have a tailgater right up yer arse. Just drop the gears and floor it - usually peed them off. :D

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I normally overtake,before they get to the smokey bit before they have to change up at there 4k rpm rev limit :P :D

My old man replaced a petrol engined caravanet with a old perkins diesel engine,i remember as a kid watching him get a run up for a hill...55mph flatout...to watch it die as we were going up the hill....3rd....2nd gear....1st gear 10mph in 1st to the top of the hill....when he bought a car i was amazed to go up the same hill only dropping 1 gear...

I also remember him spraying air o start into the intake to help it start :D on a cold morning.

Like i said diesels have come along way over the years :)

Bmw seem to have some Very quick diesel cars on sale.

[steveo]

Like i said diesels have come along way over the years 

Bmw seem to have some Very quick diesel cars on sale.

There was an article in the daiky mirror last week about a vw prototype coupe, it had a 1.5 ltr turbo deisel that was capable of doing 100mpg, but with a bit more weight on your right foot could take it from standstill to 60 in 3 seconds! with a top speed of 145, apparently the engine has been designed in japan??

looked quite nice to an i guess a lot of the speed could be down to it being mostly carbon fibre! They recon that prices would be around the 18k mark, and would probably be made of aly instead of cf, but still quite a quick eco sports car!

steve

well theres my tupance

[chips229]

Like i said diesels have come along way over the years 

Bmw seem to have some Very quick diesel cars on sale.

There was an article in the daiky mirror last week about a vw prototype coupe, it had a 1.5 ltr turbo deisel that was capable of doing 100mpg, but with a bit more weight on your right foot could take it from standstill to 60 in 3 seconds! with a top speed of 145, apparently the engine has been designed in japan??

steve

well theres my tupance

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I could not find the story you talk of but heres a review from the Mirror praising the new Jag diesel....0 to 60 in 7.8 secs and 35mpg

http://www.mirror.co.uk/motoring/tm_column...name_index.html

[steveo]

ok here we go try this vw ecoracer

ok seems like its actually 0-60 in 6.3 an upto 83mpg still not bad tho!

:)

[chips229]

ok here we go try this  vw ecoracer

ok seems like its actually 0-60 in 6.3 an upto 83mpg still not bad tho!

:)

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Now thats Quick and 83mpg!!!

Thanks for finding the write up ;)