Diesel and petrol engines

[t_marat]

What are the advantages and disadvantages of both of those engines? Apart from the fuel economy of the diesel one.

I notice that nearly everybody here has a petrol engine, very few diesels. Not many diesel E34s?

Which engine has a longer lifetime, diesel or petrol?

[joshua43214]

As a general rule, deisals last longer for several reasons. They rev lower, so less extreme running wear. They tend to run a bit cooler. The fuel itself is a lubricant. They have far simpler engine management. Until recent breakthroughs in deisal construction, they had far less power.In the past deisals had higher emisions as well.

the main reason for a predominance of gas engines is supply and demand. MB easily cornered the market for high line Euro car diesals. The low power of diesals make them less popular for buyers, and most of the people willing to deal with diesals buy MB.

Modern diesals have far more power, but I don't know if that has come at the expense of longevity. They also require imressive catylitic convertors to meet fleet emision standards.

Diesal fumes stink like holy hell, they sound like they are self destructing when they run, Only model cars and planes should have glow plugs, and the oil stains you hands badly. torquing the head bolts on a diesal will make you feel like a real man. I saw a MB diesal with almost 900k mi, and when I worked on MB, we had quite a few knocking right along with over 400k.

I hate diesals.

[BillionPa]

Diesel works by injecting the fuel and air at very different ratios depending on engine load.

A gasoline engine will always try to maintain a 14.7:1 air fuel mass ratio, with a slightly "richer" ratio during acceleration.

A diesel engine idling can have a ratio of 100:1 using almost no fuel in the process, and during acceleration, 2:1.

Diesel fuel is easier to ingite and slower to burn, and it gells at low temperatures. Adding acetone increases the burn speed a bit, allowes higher efficiency of the fuel burn with lower emissions, and keeps the fuel slightly more fluid at pre gel temps.

since diesel engines use more air and fuel during acceleration, they produce more exhaust, and adding a turbo gives a significant kick to the engine power.

If you are looking at a diesel car, get dual turbo (big and small) and add acetone to the fuel. Also stay out of freezing weather with it!

[BillionPa]

well i really didnt explain the diff between a gas engine so here it is.

gas engines have much better acceleration because of the fast burn speed of the gas vapors, but poorer economy during low rpm low load situations since it needs to maintain a fairly constant ratio of fuel to keep the engine within emmisions standards

if there is too much fuel it produces carbon monoxide, and too little fuel and it produces nitrogen oxides.

most gas you buy at a pump doesnt contain much lubrication, but you can add it to your gas fairly cheeply, increasing the lifespan of the fuel pump and injectors.

in a "high performance" situation like racing, gas engines consume much less fuel than a diesel engine and produce much more horse power (although usually less torque) than diesel, which is why you normally see diesel in vehicles that travel for longer distances with fairly constant velocities.

[kyleN20]

i think bmw put a deisel car into some lemans thing and took the win because they dident have to stop for fuel as much.

[BillionPa]

the only recent win is the McLaren BMW GTR in 99.

you might be thinking of the Mazda quad rotor car which was BANNED from lemans for being too good after it won by a very large margin.

[kyleN20]

maybe not lemans, but i am sure that i saw something on tv where bme put a deisel car in some race, maybe nurinberg and won the thing

[BillionPa]

LMR sorry, the GTR was in 97.

The only fast diesel BMW has is the Z9 concept which uses a 3.9L V8 turbodiesel (less than 300HP but lots of torque)

[rob101]

its not the catalytic converters that have made the biggest difference with new diesels but the "particulate filters" which trap the soot particles and when these meet with some diesel they burn the particles thus reducing their size and ensuring new diesel do not produce the black smoke of their predessors. also now that their is a common rail direct injection there is a pre and post-combustion injection event, the pre-injection ensures pressure increase in the cylinder is more gradual than before which reduces the rattle of the engine and the post delivers diesel to the particulate filter to burn off the soot.
i don't think diesels in the past have had throttle for the air, the only way they controlled power was by injecting more or less fuel.... not sure about the new ones though.

We recently got a 400 kW Liebherr Diesel, very quiet and smooth you can't feel vibration from the engine unless you are standing on top of it. its actually quieter than a new isuzu diesel with one quarter of the power!

[BillionPa]

NB 24 hour race yes, that was like, 9 years ago or something though in a 3 series.

[BillionPa]

8 years

http://bmw-motorsport.com/ms/en/fascination/history/distance/cars/bmw_320d.html

[ajt3nc]

Doesn't BMW market a v10 twin turbo diesel in Europe? I read a review of it and fell in love, whether it was a one off or production I do not know.
I had a 524td and loved it. It was sleddish from lights but would run with the average gas burner at highway speeeds. Lincoln used this motor for a year or two.
As soon as the US switches to the world standard clean ULSD diesel we will get an onslaught of awesome euro diesels. How about a hybrid diesel/electric camry pulling vw tdi mileage? I think the VW v-10 suv was a teaser.

My old and very slow 86 jetta with 421,000+ regularly pulls down 47 mpg.

[jjw]

Well, it's not BMW that has a Diesel racer, it's Audi's new R10 Le Mans racer. And yes, it's a Diesel race car that won the 12 hrs of Sebring this year.

[t_marat]

Temps at where I live can get to minus 35-40C (about -31F) during winter. I know a guy who has 525TD (or tds, don't remember). He would not even try to start his engine while temp is so low, using public transport instead.

[rob101]

Temps at where I live can get to minus 35-40C (about -31F) during winter. I know a guy who has 525TD (or tds, don't remember). He would not even try to start his engine while temp is so low, using public transport instead.
there is actually a difference in the parrafin content of diesel sold in winter and summer. don't you live in eastern europe? kind of reminds me of the stories of the germans having to light fires under their tanks to get them to start whereas the russian's would just jump in their t34 and start it right up. my late uncle (austrian we suspect he had relatives who were in stalingrad) said it was something to do with the tolerances of the engines.

PS i am not german my german ancestors migrated in the 19th century so don't hang **** on me for WW2.

[t_marat]

I live in Kazakhstan, central asia.

[kyleN20]

i knew i wasent crazy

[Zeuk in Oz]

From a layman's point of view, IMHO, diesel engines are the future for 95% of vehicles on our roads.

I own 2 diesel engined road vehicles at the moment, but my tractor and even my lawn mower are also diesel.

My ML 270 CDI has common rail direct injection and it is this technology, so I understand, combined with turbocharging which has revolutionised diesels.

My 2.7litre, 5 cylinder, produces 125 kW of power but 400 Nm of torque.

This engine is only modest compared with newer engines - BMW's single turbo six cylinder 3 litre engine produces 170 kW and 500 Nm and in twin turbo form it produces 200 kW and 560 Nm.

All this and amazing fuel economy as well.

When mated to an automatic gearbox which keeps the engine in the optimal torque band, these things are wonderful to drive.

Land Rover and Jaguar now have a new lighter composite graphite block to reduce the weight of diesel engines.

[rob101]

yeah i used to think that, but petrol engines are starting to get the wiz bang solutions that diesel has like piezo injectors or whatever that is called. i am not so sure petrol is doomed. but i am starting to think that LPG and CNG are going to play a big role in the future as is Ethanol, the difference in emissions of LPG and CNG is huge, and also the relative price and it being almost as easy to produce as diesel.
you have a diesel lawnmower?

[BillionPa]

continuously variable transmission + twin turbo straight-6 direct injection diesel + hydrogen infusion = ....

insane insane power

[Zeuk in Oz]

you have a diesel lawnmower?
Yes, it is a 27 hp Shibaura 3 cylinder diesel - basically a small tractor going backwards, with 4 wheel drive, rear wheel steering and the smaller 60" cutting deck.

Fan-bloody-tastic ! ;)

You have probably seen heaps of these (also rebadged as Ford or New Holland) and Kubota have one as well - many contractors use them.

[rob101]

i just remembered you have the diesel F250 as well! did you know CAT's starting to sell alot of CNG engines for industrial use nowadays, it seems diesels are on the way out

[Zeuk in Oz]

i just remembered you have the diesel F250 as well
I just love the smell of napalm in the morning ! :D

[Paul in NZ]

common rail +turbo+intercooler=170 kw 3.0L and similar deisel engines....I drove a 530d and everyone says autos but i would love to try a six speed manual on the open road.I reckon the tourque and the efficiency of the manual tranny would make for effortless and economical 5th and 6th gear cruising on our hilly and winding NZ roads
Changing from the auto to the manual would almost pay for the sports kit and sunroof.....

[rob101]

yeah i've heard the autos are better, they keep the turbo spooled over gearshifts, plus all gears in those new 6 speed ZF autos (such as in the ford) have lock up in all gears. so..... i don't there would be a real difference in speed as the drop in effeciency has mainly be A. because autos had less gears in the past and B. because the torque converter was transferring the power in all gears but top gear but neither of them is the case anymore, track cars with huge turbos have to be driven around on partial throttle all the time if not then the turbo has to spin up again which means LAAAAAAAAG. which is why people recommend autos for turbo diesels

[Zeuk in Oz]

yeah i've heard the autos are better......... which is why people recommend autos for turbo diesels
Having driven numerous identical turbodiesels in both auto and manual versions I would opt for auto every time.
Just my 2c.