There are three definitions in current use: --U.S. liquid gallon is 231 in³ (exactly) or 128 U.S. fluid ounce (exactly) or 3.785411784 litres --U.S. dry gallon 4.404 884 L --Imperial (UK) gallon is 160 imperial fluid ounces (exactly), or 4.54609 L (legally). That is approximately 1.201 US gallons">.
..."Yes, a diesel would be a slug without a turbocharger -- it needs it to function decently.
In contrast, a gas engine runs well enough without a turbo. But it loses fuel economy that it would have if it had a turbo.
When discussing the differences, don't ignore the benefit of the turbocharger. A chunk of the fuel economy gain in a diesel belongs to the turbo, not to the type of fuel used in the engine to which it is attached. "...
Might be a reason why a turbo diesel is used.
In contrast diesel will run without a turbo. Diesel will get the fuel economy it gets.
The benefit of the turbo charger is included. fuel type is also a component. You just need to put %'s to it since it bothers you so. But all this is nothing new. And if you stay in this vane without you assigning those numbers you will be stuck in an endless loop and not making any power.
You also need to drop this engine size by cylinder head displacement. A turbo in effect increases displacement due to increased amounts of air being forced into the cylinder. The actual size of the entire engine may surprize you. The weight is more important with respect to output. Diesels are heavier due to stronger engine designs needed for higher compression values. So forget about displacement and go by vehicle overall size. vw jetta tdi to vw jetta 2.0 or MB E320 CDI to E320 v6 gasser.
"That might be your take, but you are twisting what was said. Is 31 mpg better than 49? YES or NO? You don't answer that straight away because you are twisting what was said. So you ignore what is being said and make believe interpretations."
For the reference I made, no you have it totally wrong. 31 US vs 49 US., answer the question which is better? You can't and wont!
So forget about displacement and go by vehicle overall size. vw jetta tdi to vw jetta 2.0 or MB E320 CDI to E320 v6 gasser.
Not a legitimate comparison. Again, you are comparing turbodiesels to non-turbo gas engines and you are ignoring the performance loss of the diesel.
The fact that a diesel has to be larger and heavier is one of its disadvantages. You are trying to ignore this disadvantage, when it is clearly one of the most significant disadvantages of diesel motors. There's no good reason to ignore that a turbodiesel has to be 40-50% larger than a turbo gas engine to be similar in output and performance.
If the 49 mpg is supposed to be US EPA, then you have it misquoted it. According to fueleconomy.gov, the Jetta TDi gets 36/41 (manual) and 35/42 (automatic), which is well below 49 mpg.
"Not a legitimate comparison. Again, you are comparing turbodiesels to non-turbo gas engines and you are ignoring the performance loss of the diesel.
The fact that a diesel has to be larger and heavier is one of its disadvantages. You are trying to ignore this disadvantage, when it is clearly one of the most significant disadvantages of diesel motors. There's no good reason to ignore that a turbodiesel has to be 40-50% larger than a turbo gas engine to be similar in output and performance. "
Then you are using an illegitimate comparision unfairly comparing the unfair comparison. To be fair the gasser should have the heavier iron just like the diesel.
To be fair the gasser should have the heavier iron just like the diesel.
The gas engine doesn't need the weight and wouldn't benefit from adding it. Are we now supposed to tie anchors to gas cars in order to help your comparisons?
Now your being foolish. A car is the sum of it's parts, and how well it performs for what is was designed. A diesel non-turbo charged engine can be made without a turbo and still perform just as well. It would be more expensive but can be done. There are many ways of getting air into the cylinder but which is the most cost effective for the application is whats most important. You believe what you want but diesel powered vehicles are more economical. Why would the Over the road truckers use them?? The fuel tax is higher but the maintenance and fuel economy is better. Plus they last longer, Engines & Transmissions!!! The lower rpms help both the engines and transmission. Now back to better discussions.
Right. And because the diesel needs to be heavier to produce the same result, that's to its disadvantage.
A diesel non-turbo charged engine can be made without a turbo and still perform just as well.
Not true. As is true with a gas engine, a diesel without a turbo will produce far less power. The difference is that where the turbo is a nice option for a gas engine, it's effectively a requirement for a diesel, given the relatively low power output of naturally aspirated diesels.
Perhaps this link that explains turbos will help: "A turbo can significantly boost an engine's horsepower without significantly increasing its weight, which is the huge benefit that makes turbos so popular!"
I take no issue with that particular comparison, although it doesn't make ruking's numbers for his Jetta any more accurate. Nonetheless, by all counts, the 335d is supposed to be a great drive and the fuel economy is impressive, we'll see if those benefits find their way into more typical cars.
"Not true. As is true with a gas engine, a diesel without a turbo will produce far less power. The difference is that where the turbo is a nice option for a gas engine, it's effectively a requirement for a diesel, given the relatively low power output of naturally aspirated diesels."
Here you need to do some homework. It's cheaper to use a turbo. The older engines used blowers or increased the intake openings with longer strokes.
"A turbo can significantly boost an engine's horsepower without significantly increasing its weight, which is the huge benefit that makes turbos so popular!"
The Key work here is "can". Oh! So I don't confuse you a blower is also called a supercharger.
There isn't really much reason to bolt a turbo onto an passenger car engine if your goal is not to get power from it. The general idea is to use a smaller turbo motor to in place of a larger normally aspirated, less fuel efficient motor with similar power output.
And the link was about turbos, not superchargers. Different type of forced induction.
Earlier, I pointed out the advantage as being about 20-25%.
This exceptional 335d, allegedly the most powerful 6-cylinder passenger car diesel in the world, gains 28%, which is pretty close to 25%.
All of those figures are well shy of your 37%. My issue was with your exaggeration, and that remains my basic point. Using imperial gallons in comparisons to US gallons is just another example of making apples-to-oranges comparisons that don't help the discussion.
If you are asking whether diesels get better fuel economy than comparable gas cars, then the answer is "yes", as I've repeatedly stated.
But it is NOT to the extent that you claim, you are overstating it by a factor of 50% or more. If you were simply more straightforward in your use of stats, I'd take no issue with it. It's the exaggeration that is the issue here -- just being straight up with the numbers and making fair comparisons would be sufficient. You won't get there by comparing slow cars with fast cars, turbos with non-turbos, and US MPG with UK MPG, as if these factors don't make a difference.
Honestly, I don't know "question" you are referring to. If you can identify the post where this question was raised, I will address it, but I don't know to what you are referring.
I've provided support for my figures. Where did you get the 49 mpg figure for the Jetta TDi?
GOd I said I Wasn't going to post on here anymore but there are just so many errors here...
There is a 2.0T TURBOCHARGED 4 cylinder in the new jetta.
There is also a 1.8T TURBOCHARGED 4 cylinder in the old jetta.
Thats the reason you two are gettnig confused. The old jetta TDI which was discontinued mid 2005 got 38/46 mpg according to the EPA. Old jetta scroll down to the bottom
The new Jetta TDI which was introduced as a 2005.5 model gets the 35/42 automatic and 36/41 manual EPA raiting.
The epa doesn't recognize the 2005.5 designation on their guide since that is kind of an audi/VW thing.
You need to look up the 2006 Jetta or pick the correct engine choice in the 2005 Jetta to see the differance in MPG. The new Jetta is signficantly larger then the old Jetta which I guess explains the drop in MPG.
Go to the fueleconomy.gov site and compare a 2004 Jetta with the 1.9 TDI diesel motor to the 1.8 turbo motor and you will see numbers. The 46 highway mpg for the diesel and the 31 highway mpg for the 1.8T motor. That is about a 48 percent differance.
Granted 46 mpg is not 49 mpg but it is pretty easy to flip a 6 around and see a 9.
OK, if you want to compare the older Jetta 1.9TDi (I was making reference to the 2006 model), that's fine, but that car was even slower than the current one.
The older motor had 90 hp, and produced a 0-60 time of 13 seconds. Among cars in its class, that was surely one of the slowest on the market, given that its rivals achieve 0-60 times of less than 9 or 10 seconds.
As I have been pointing out from the onset, for a given displacement, a diesel will offer better fuel economy that comes at a price of performance. You shouldn't compare a 1.9 liter Jetta to other sedans in that class and simply ignore that it needs a good deal more time to get to highway speed than its rivals.
Go to the fueleconomy.gov site and compare a 2004 Jetta with the 1.9 TDI diesel motor to the 1.8 turbo motor and you will see numbers. The 46 highway mpg for the diesel and the 31 highway mpg for the 1.8T motor. That is about a 48 percent differance.
To quote our former president, "There you go again." The old 1.8t gas motor needed about 8 seconds to get to 60 mph; the diesel needed 13 seconds. These are not comparable at all -- the diesel is more than 50% slower.
As I've pointed out throughout this thread, it's dishonest to focus on fuel economy and to completely ignore the performance loss. A 13 second 0-60 time puts the Jetta toward the bottom of the pool, and it's no secret that there is a trade-off between fuel economy and performance. You won't be seeing 37% differences when you compare similar cars -- even the 335d didn't accomplish that.
It is consistently wrong to point out that folks ignore performance in the discussion of fuel economy. Folks understand there are certain trade offs. It is dishonest to point to a straw man and continue say it is dishonest.
While steadfastly refusing to do the math, the other point is while the BMW 3 series diesel is certainly geared more towards PERFORMANCE and perception; it is ONLY ONE diesel model. For the MAJORITY of other OEM diesel models (European diesels) 37% is conservative, even as the BMW diesel does NOT achieve it. Again, BMW makes the decision to trade off the 26-37% ( on up) or 11% in favor of performance. No big or new news here. It of course shows; good and bad.
As for the trade offs between toward fuel economy rather than performance, it is done every day, whether one likes it or not. That is one reason why BMW bills themselves as the ultimate driving machine. (despite the hype and fluff) Since most folks do not own a diesel car, and the BMW 3 series diesel has not been allowed into the USA, heretofore, it is pretty theoretical anyway which is probably why gassers owners have so many misconceptions about it.
Been reading the ongoing posts with interest and some amusement. Just for interest, the current European engine line-up for the Jetta comprises 5 units; 3 gassers and 2 diesels. The gassers are :
Interestingly, the Golf gets a new gasser engine which is :
1.4TSI, 170/177, 6spd, 7.9
This engine is both turbocharged and supercharged, hence the output from a relatively small-displacement unit. Haven't given any economy figures as our testing protocols are probably v different. You can, of course, see more on the VW UK site. Will it finds it's way across the Atlantic ? Would anyone buy it if it did ?
There is another interesting discussion, where to me diesel in the USA is of advantage and the taxing authorities scarcely appreciate this. Actually they hope folks do nothing. UPSHOT: cost per mile driven is cheaper. tax per mile driven is also cheaper. (I think that is why there is talk of a BTU equivalency tax)
When this is compared and contrasted with European prices of unleaded regular and #2 diesel, the advantages really hit you between the eyes like a 2x4.
Use any of one's own figures, so one doesn't get wrapped around the axle like some folks do on the percentages and numbers, etc, etc,.
We can't say we came away very impressed. During a week of stop-and-go mixed with some highway driving, we ended up with an average of 32 miles to the gallon. This is better than 24.9 mpg that a comparably equipped, gasoline-powered Jetta 1.8T GLS we recently drove provided, but south of the EPA mpg estimate of 34/45 for city/highway driving. If fuel economy is of primary concern, we'd recommend the manual transmission, which has a 42 city/49 highway rating. While gas stations that sell diesel weren't lacking during our daily commute, it was still an effort to look for the green diesel sign.
One of the main advantages of a diesel engine is the availability of low-end torque, which is why it's so popular in heavy-duty truck applications. Rated at 90 horsepower at 3,750 rpm and an impressive 155 pound-feet of torque at a low 1,900 rpm, takeoff provided from the 1.9-liter engine is still on the weak side, and merging onto the freeway requires more planning than its 1.8T counterparts. Volkswagen states that zero-to-60 mph acceleration runs should be completed in a leisurely 14.9 seconds. Again, this engine would probably be vastly better suited to the five-speed manual, which better enables drivers to take advantage of increased revs. Indeed once the TDI reached midrange revs, we were pleased by its broad power band and lively passing performance. The powerplant still retains a trademark rumble at idle, but then smoothes out upon pressing the right-hand pedal.
You continue to make the invalid comparison of a fuel economy vehicle ( 1.9 TDI ) with a performance vehicle ( 1.8T gasser ).
From Edmunds review of the 2002 1.8T GLS...
So how much of a difference does the additional power make? Quite a bit, according to VW the 2002 Jetta will be able to sprint to 60 mph in just 7.7 seconds. And if you're worried that the higher peak power results in a loss of this jewel's flat power band, fret not. Peak torque still arrives at less than 2,000 rpm (1,950 rpm, to be exact) and stays up there until the tach's needle reaches 5 grand. The result is that this engine feels like the "old" 150-horse unit in terms of its flexible power delivery; it's just stronger throughout.
Now if you say that fuel economy is the most important consideration and that performance is of little concern then the TDI is the choice. If you want superior performance then the TDI isn't even in the picture. You first have to define your frame of reference before doing a comparison.
Anecdotal, but from the above note that Edmunds finds that the TDI delivered 32 mpg in every day driving and the 1.8T 24.9 mpg in every day driving ( a 28+% difference ).
Well the Jetta has three models the 1.8T., 2.0 and the TDI. So if you think it silly or invalid, you might have an issues with VW or whatever oem you wish to vilify. And you would probably have issues with Edmunds.com as they did do a ("silly") compare/contrast. I am just a selector for my .02 cents. (consumer)
While this is probably neutral to your point, but germane to me as a selector (consumer), I probably would not have selected the Jetta if it only had the 1.8T or 2.0. The majority of the unreliability and durability issues have been with those engines.
See my post about the (NON) sacredness of the numbers. Do the numbers, report the results. I am perfectly fine with their test reports and your math of 28%. Mine (being an actual TDI DRIVER) and a 5 speed manual is higher and that is what I said (reported).
As a matter of fact if MINE did get 32 mpg average, I'd sell it in a heartbeat. Especially since it sells at a used car premium. It also sells for a good % more than either the used 2.0 or 1.8T. In addition my Civic gets 38-42 in a 54 R/T commute, and at 12564 is 5,436 dollars cheaper. So 32 mpg is WAY less than the Civic. But if we follow PCH's logic to compare the TDI to the Civic is an unfair comparison. YOU/HE might want to think I need a 0-60, 4 second performance parameter in the 54 mile R/T daily commute, but assure you,I surely do not. have you also been missing the fact that I have been defining what I have been using the car for? Does a 54 mile R/T commute not meet the definition of defining? If you go back over my past posts ya might see it repeated many times. Does it need to be repeated again? AGAIN?
So in that very same commute the TDI gets between 48-52.
Further, the TDI went on a 6500 mile R/T from the San Jose, CA to near Daytona Beach, FL. This thing is a very able road car. Crusing (up to 95 mph) was no problem. The mpg range with the AC all the time between per fill up was highest 52 mpg to lowest of 46 mpg. avrage of the 13 or so fill ups was 48/49. So to repeat I got it and happened to put the majority of miles as a commute and road car.
Will I race it from stop light to stop light against a VW 1.8T? Heck no, the 1.8T is faster.
A lot of infos about the Jetta TDI which is correct on paper to cetain extent but do not tell the whole picture. My 2006 TDI (auto) start out about 32 mpg around town brand new and going up steadily from there. I took a trip to from Texas to Colorado in Summer with 4 persons, trunk full of luggage and golf club and average around 44 mpg on the highway when the car had around 9000 miles. Now my car has around 18000 miles on it and I am getting 38-39 mpg around town and I am sure I can get 50 mpg on highway trip.
Diesel car take a long time to completely break in and my car probably won't be completely break in until 25000 to 30000 miles.
It you launch aggresively, one car magazine achieved a 0-60 time around 10.2 seconds. You can also chipped or put a tuning box which I have used since the car was 1 week old. With the additional power add on, I am sure I can beat a VW 1.8T and my car is indeed faster than my friend VW Jetta VR6.
..."Diesel car take a long time to completely break in and my car probably won't be completely break in until 25000 to 30000 miles. "...
Like you say YES and NO. That is why I usually qualify what I say. So in regards to your quote. Yes, it does take a long time. NO not at 25,000 to 30,000 miles. It is actually longer than you think, at 50,000 to 60,000 miles. Specifically you would be looking for 550 full compression. If you measure it 25,000 to 30,000 miles it will be probably be in the neighborhood of 425-475. So yes, 44/50 mpg with an auto on a longer trip is WAY cool. (so to the naysayers, I say, I do not know this poster) 32/39 is probably due to the fact you have a automatic. My last utter and total city bogging stop and go for 3 hours gave me 46 mpg with the A/C on (5 speed manual). FUN? Far from it.
Definitely if there is a choice, drive it more aggressively rather than so called passively like you would if you were trying for good fuel mileage in a gasser. All the best.
Yo! Here is news for you. They both do the same thing but use different sources of power to drive the units. A blower is better for low end performance while the turbo is for high end performance. I have seen engines with both but it starts to get expensive. If you want to take this discussion further throw in the rotary engines.
What you don't seem to understand is that a gas motor with 90 hp installed in your Jetta would get much better fuel economy than the other gas engine choices. You are trying to attribute fuel saving benefits to the diesel that come from the fact that it is a weak engine.
And if the VW did have a 90hp gas engine, it would be a fair bit smaller than 1.9 liters, particularly if it had a turbo. You shouldn't attribute benefits to diesel technology that are unwarranted.
The only reason that you don't find 90 hp gas-engine VW's in the US is that nobody would want them. Such cars are offered in Europe, but there are few car buyers in today's market in the US who have a tolerance for the sluggish performance that comes from that lack of power.
I don't know what rotaries and superchargers have to do with any of the above, or why you're trying to change the subject.
The point being made is that using turbos allows automakers to use smaller, more fuel-efficient and lighter engines in place of larger ones, and that turbo motors will achieve better fuel economy than larger engines with the same power output.
This is true for both gas and diesel engines. If you want to compare the engines with each other in the context of discussing the alleged benefits of the diesel technology itself, then the fairest comparison is to compare two naturally aspirated or two turbocharged versions with each other, instead. And you won't be finding these 37% differences cited previously.
If you understand how turbos work, then this should be fairly obvious. These are the reasons that they are used in the first place.
It might be interesting to wonder out loud why in Europe the diesel passenger vehicle fleet is 50% and GROWING!!??
Because European countries have higher taxes on gasoline than on diesel, and higher prices overall, which makes fuel efficiency more important to the average European consumer. Hence, they drive smaller cars with smaller engines, and are more likely to use diesel.
There are gas engine cars in Europe that get better fuel economy than your diesel. But there is almost no demand for these sorts of cars here, so you don't find them on US roads. Americans simply want more power and larger vehicles.
It you launch aggresively, one car magazine achieved a 0-60 time around 10.2 seconds.
The enthusiast car magazines all launch their test vehicles aggressively, while IMO, VW tends to be a bit conservative in its claimed 0-60 times. FWIW, Car and Driver got to 60 mph in 10.3 seconds. In contrast, the 2.0 liter turbo GLI reviewed by Car and Driver has 97 (almost 100%) more horsepower, and gets to 60 mph in 7.1 seconds.
With the additional power add on, I am sure I can beat a VW 1.8T and my car is indeed faster than my friend VW Jetta VR6.
Sorry, but I wouldn't buy either that or that famous bridge that always being offered for sale. Chipping typically adds perhaps 25% more horsepower, which would make yours about 125 hp. That would still lag behind a 1.8T with 180 hp or a VR6 with 174 hp...and of course, you could chip the 1.8T to put even more distance between you.
Yo babe. If you put a 90 hp gas engine in the jetta you may stall it if you tried to take off from a start under a load even with a turbo. The turbo doesn't help until the exhaust pressure is high enough to turn the turbo. This occurs above 2500 rpms on most gas engines. The diesel has enough torque at low rpms to allow the use of a 90 hp engine to get better FE. Remember the old VW bug. It's gas engine was around 30 hp. It got about 30 to 35 mpg and was extremely light. Also had no emissions systems. put that same engine in a Jetta of today and it would only get about 20 at best with all the emissions requirements of today pulling the weight of a new jetta. You could put a turbo on it and get about 50 hp but then your mpgs would drop if you spooled up that turbo. You would have a slow car which could not pull any weight. (Top speed would be about 65 MPH.)
A barrel of crude oil contains about twice as much gasoline as it does diesel fuel. If a barrel of oil is refined straight, then perhaps what the article intimates might be true. However, since refiners extract more gasoline out of barrel than a barrel contains the article does not address that. What I am speaking of is cracking. That takes lots of heat and pressure to make gasoline and/or diesel fuel from the heavier fractions of crude oil. Since the majority of vehicles in the United States are powered by gasoline, and it takes more heat and more time to makes gasoline from the heavier fractions of crude and with that in mind think about how much greenhouse gas gets dumped into the atmosphere. It takes less cracking and heat to make diesel from the heavier fractions.
As to Ruking's 37% efficiency improvement and a comment you or someone else made about gearing, I have to sort of disagree with both of your points of view. In their own right, diesel engines are significantly more efficient than gassers. There are plenty of articles and studies that show that. In several respects, they are also environmentally friendlier too in spite of what larsb's article says. As to the gearing issue, there is little truth to that. For the Jeep Liberty be it the gasser (V-6) or the diesel, both use the same rear end gear ratio of 3.73:1. For the gasser, which has a four speed auto, the overdrive gear ratio is 0.69:1 while for the diesel, which uses a five speed auto it is 0.67:1. The difference in gearing is insignificant in this case. For Mercedes, the E320 CDI uses the same trans as the other E class small block V-8's. Gearing is the same in the trans as well as the rear ends. So how do you account for the increased fuel economy of the diesel powered vehicles? I would attribute most if not all of it to the engine.
The diesel has enough torque at low rpms to allow the use of a 90 hp engine to get better FE
This is true of any car.
Yo babe. If you put a 90 hp gas engine in the jetta you may stall it if you tried to take off from a start under a load even with a turbo.
Er, VW sells Golfs (Rabbits)in Europe with 1.6 liter naturally aspirated gas engines with 79 hp. It's a slow car, just slightly slower than the 90 hp diesel model, but it works.
On the subject of adequate power: The VW Sciroccos had a 70 HP engine and were very quick. They were lighter than the current Jetta by about 1000 lbs. My 1982 Volvo non turbo gas/4 speed OD auto had 101 HP when new and still performs adequately in all areas except hill climbing when it has to go down to 3rd. It still pegs the speedometer at 85.
What hp rating are you using? bhp or hp gross or net? Put that 1000 lbs in your Sciroccos and it will have trouble accelerating. The 82 Volvo was most likely bhp if you put it on a dyno would test out higher. The engine was most likely torque heavy as was the Saturn 1.9 four cylinder used in the early 90's. The torque and horsepower curves determine the shift points for the best performance.
You guys need to learn so much more about diesel. With a box, I have above 140 hp and 250 torque and I can spank a VR6 all day long. There's plenty of TDI out there with more agressive chipping and running drag race. Have you even ever tried a chipped TDI?
I am not saying chipped gaser is not faster but my car run fast and getting 38 mpg on city and 50 mpg on the highway which is a unbeatable combination. There is also why VW TDI is in high demand.
Any motor with a turbo can be chipped for horsepower gain. The benefit of chipping goes to any turbocharged motor, both gas and diesel.
As for getting 140 hp out of a 100 hp motor, I don't frankly believe that, those figures are the tuners' equivalent of snakeoil. You don't typically get those benefits from chipping, and if you do, you probably won't get it without compromising drivability and reliability. You are not beating VR6's with a 1.9 liter TDi.
Yes this is the thing about the diesel. Between the TDI and Civic there is a weight difference of 436#'s 2950-2514=. the epa 42/49 vs 29/38. Using the same 54 mile commute the TDI gets 48-52 and the Civic gets 38-42. both with one person. 90 hp/155# ft and 115 hp/110# ft. Honda gasser has 25 more hp. So here's an EASY softball pitch. To equalize the weight factor, one person in each car will still commute but the Honda Civic needs 436#s or 3 extra people. So will the mpg be less or more? Will the car handle better or worse? This leaves the TDI to take 4 more people and the Honda one more.
Adding the 1000 lbs brings the Scirocco to about the same power to weight ration as the 90 HP VW referred to. The Scirocco was, for its day, considered a "Pocket Rocket"
The HP ratings referenced are BHP. BHP is measured at the flywheel; any ratings on the dyno at the rear wheels will bring far lower numbers as we learned in the 60's testing factory delivered "street racers" - their dyno ratings were 20/30% lower than their BHP ratings.
Auto trans shift points are adjustable, and were factory set to arrive at a compromise of economy and general performance based on geographical destination. I have stepped my shift points up slightly.
Another term for motive power that avoids direct references to either HP or Torque alone is BMEP; Brake Mean Effective Pressure.
The best real world performance snapshots seem to be the zero to X, X1, X2 and so on. Passing time required for 45 to 65 is also a very useful one.
I'm not sure where you're going with this. As a general rule, VW-Audi is building relatively heavy cars compared to its rivals, while Honda has tended to build lighter ones.
If anything, VW needs to put its cars on a diet, because their products outweigh the competition across the board, with no apparent benefit. The solution is not to change drivetrains, but to find ways to remove excess bulk from their platforms.
I can't find the specific gear ratios for the rfe545 used in the liberty crd. I don't know if the info for these liberty transmissions are specific or general for these vehicles. I found the horsepower and torque curves for the two engines. The 3.7 makes 160 hp at 3600 rpm while the 2.8 crd makes 160 hp at 3800 rpm. The torque for the 3.7 peaks at 235 lb-ft between 3600 rpm to 4400 rpm. The peak hp for the 3.7 is at 5200 rpm. They are pretty close in the hp curve between 800 to 3500 rpm range. The 3.7's hp curve is more linear while the crd's peaks earlier then drops off above 3800 rpm. The crd has greater torque earlier but drops off at higher rpms. If you look at these curves you would see why the CRD has five speeds with torque converter lockup in the last two and the 3.7 only needs 4 speeds to accomplish the same thing. The final gear ratio is not really important after looking at these two engines torque and power curves. The 3.7 engine should have a much higher top speed then the crd. But below 85 mph they should be close. The CRD makes more hp up until about 3500 rpm. Gobbs of more torque at lower rpm means more hp in the beginning.
This should show why gearing of the trans is important to compliment the engines performance curves. More torque at lower rpms gives more hp earlier which will accelerate you faster at lower rpms but the diesel will run out of rpms faster so you put more gears closer together to compensate for this. (Sorry about the graph. This system doesn't tab to well)
A barrel of crude oil contains about twice as much gasoline as it does diesel fuel. If a barrel of oil is refined straight, then perhaps what the article intimates might be true. However, since refiners extract more gasoline out of barrel than a barrel contains the article does not address that. What I am speaking of is cracking. That takes lots of heat and pressure to make gasoline and/or diesel fuel from the heavier fractions of crude oil. Since the majority of vehicles in the United States are powered by gasoline, and it takes more heat and more time to makes gasoline from the heavier fractions of crude and with that in mind think about how much greenhouse gas gets dumped into the atmosphere. It takes less cracking and heat to make diesel from the heavier fractions.
This was my own thought but being unfamiliar with the entire process I have no way to estimate what is done to the 'residuum' through cracking to make it produce other petroleum products. Maybe these are individual trade secrets. All the 'net exposes is what one bbl of oil produces through distillation; twice as much gasoline as diesel. Since gasoline is more volatile it is an easier product to produce through distallation, diesel require more heat and energy.
When the residuum is processed by cracking how much of one product or another also seems to be a trade secret. It would seem though that gasoline again being more volatile would be an easier and less costly by product than diesel/fuel oil. Again this is only supposition. I have no data to support it.
Actually very easy. The TDI engine would perform even better across the spectrum in a minus 436# environment: mpg, acceleration, braking, handling, components lasting longer, etc.
I would also agree a lot of Euro makes like BMW, Porsche, etc. need to go on so called "diets". But it is NOT likely as how those very same oem's are some of the most profitable, dollar and % wise.
The TDI engine would perform even better in a minus 436# environment.
So would a gasoline engine. Obviously, an engine that has less work to do, such as weight to carry, will use less energy than one that has to do more work.
Lower vehicle weight and turbocharging benefit both engine types. Putting a "chip" into a turbocharged motor of either fuel type can be used to increase horsepower. These truisms are not unique to diesels.
Again you miss the point. With the Honda Civic BEING in the lighter environment the TDI (in the heavier environment) STILL gets better MPG across the spectrum.
The other thing is the durability of parts is far less in the Honda than the VW, despite the extra weight. Tires in the Honda will probably not last as long. Brake pads and shoes wear faster, shocks and struts will probably need replacing sooner, etc.
Comments
Perhaps this link to Wikipedia will help (Types of gallons):
There are three definitions in current use:
--U.S. liquid gallon is 231 in³ (exactly) or 128 U.S. fluid ounce (exactly) or 3.785411784 litres
--U.S. dry gallon 4.404 884 L
--Imperial (UK) gallon is 160 imperial fluid ounces (exactly), or 4.54609 L (legally). That is approximately 1.201 US gallons">.
In contrast, a gas engine runs well enough without a turbo. But it loses fuel economy that it would have if it had a turbo.
When discussing the differences, don't ignore the benefit of the turbocharger. A chunk of the fuel economy gain in a diesel belongs to the turbo, not to the type of fuel used in the engine to which it is attached. "...
Might be a reason why a turbo diesel is used.
In contrast diesel will run without a turbo. Diesel will get the fuel economy it gets.
The benefit of the turbo charger is included. fuel type is also a component. You just need to put %'s to it since it bothers you so. But all this is nothing new. And if you stay in this vane without you assigning those numbers you will be stuck in an endless loop and not making any power.
For the reference I made, no you have it totally wrong. 31 US vs 49 US., answer the question which is better? You can't and wont!
Not a legitimate comparison. Again, you are comparing turbodiesels to non-turbo gas engines and you are ignoring the performance loss of the diesel.
The fact that a diesel has to be larger and heavier is one of its disadvantages. You are trying to ignore this disadvantage, when it is clearly one of the most significant disadvantages of diesel motors. There's no good reason to ignore that a turbodiesel has to be 40-50% larger than a turbo gas engine to be similar in output and performance.
The fact that a diesel has to be larger and heavier is one of its disadvantages. You are trying to ignore this disadvantage, when it is clearly one of the most significant disadvantages of diesel motors. There's no good reason to ignore that a turbodiesel has to be 40-50% larger than a turbo gas engine to be similar in output and performance. "
Then you are using an illegitimate comparision unfairly comparing the unfair comparison. To be fair the gasser should have the heavier iron just like the diesel.
The gas engine doesn't need the weight and wouldn't benefit from adding it. Are we now supposed to tie anchors to gas cars in order to help your comparisons?
I'm looking at the fueleconomy.gov website, which is operated by the US EPA. Is there a better source for EPA fuel economy data?
Feel free to follow the link to 2006 Jettas, and you'll see that it matches what I provided above: fueleconomy.gov
Right. And because the diesel needs to be heavier to produce the same result, that's to its disadvantage.
A diesel non-turbo charged engine can be made without a turbo and still perform just as well.
Not true. As is true with a gas engine, a diesel without a turbo will produce far less power. The difference is that where the turbo is a nice option for a gas engine, it's effectively a requirement for a diesel, given the relatively low power output of naturally aspirated diesels.
Perhaps this link that explains turbos will help: "A turbo can significantly boost an engine's horsepower without significantly increasing its weight, which is the huge benefit that makes turbos so popular!"
BMW UK 3 series Price list
Look at the 335i
Price CO2 Tax
335i SE * £30,940 Petrol 33%
Displacment Fuel Consumption 0-62 mph
2979cc 29.4 (29.4) mpg imperial 5.6
Then look at the 335d
Price CO2 Tax
335d SE * £32,995 Diesel 30%
Displacment Fuel Consumption 0-62 pmh
2993cc 37.7 mpg imperial 6.2
Both Turbocharged engines both Inline 6 cylinders in virtually the exact same car that are within three cubic centimeters of equal displacment.
You cannot get a closer comparison these engines even share the same stroke.
The petrol model only outguns the diesel motor by 20 horsepower and the diesel engine only weighs 45 more kilos then the petrol BMW.
The diesel does make 180 more Nm then the petrol model.
You can't get two more equal engines and two more equal vehicles.
About 28% more gas mileage on the combined cycle.
Here you need to do some homework. It's cheaper to use a turbo. The older engines used blowers or increased the intake openings with longer strokes.
"A turbo can significantly boost an engine's horsepower without significantly increasing its weight, which is the huge benefit that makes turbos so popular!"
The Key work here is "can". Oh! So I don't confuse you a blower is also called a supercharger.
There isn't really much reason to bolt a turbo onto an passenger car engine if your goal is not to get power from it. The general idea is to use a smaller turbo motor to in place of a larger normally aspirated, less fuel efficient motor with similar power output.
And the link was about turbos, not superchargers. Different type of forced induction.
This exceptional 335d, allegedly the most powerful 6-cylinder passenger car diesel in the world, gains 28%, which is pretty close to 25%.
All of those figures are well shy of your 37%. My issue was with your exaggeration, and that remains my basic point. Using imperial gallons in comparisons to US gallons is just another example of making apples-to-oranges comparisons that don't help the discussion.
If you are asking whether diesels get better fuel economy than comparable gas cars, then the answer is "yes", as I've repeatedly stated.
But it is NOT to the extent that you claim, you are overstating it by a factor of 50% or more. If you were simply more straightforward in your use of stats, I'd take no issue with it. It's the exaggeration that is the issue here -- just being straight up with the numbers and making fair comparisons would be sufficient. You won't get there by comparing slow cars with fast cars, turbos with non-turbos, and US MPG with UK MPG, as if these factors don't make a difference.
I've provided support for my figures. Where did you get the 49 mpg figure for the Jetta TDi?
There is a 2.0T TURBOCHARGED 4 cylinder in the new jetta.
There is also a 1.8T TURBOCHARGED 4 cylinder in the old jetta.
Thats the reason you two are gettnig confused. The old jetta TDI which was discontinued mid 2005 got 38/46 mpg according to the EPA. Old jetta scroll down to the bottom
The new Jetta TDI which was introduced as a 2005.5 model gets the 35/42 automatic and 36/41 manual EPA raiting.
The epa doesn't recognize the 2005.5 designation on their guide since that is kind of an audi/VW thing.
You need to look up the 2006 Jetta or pick the correct engine choice in the 2005 Jetta to see the differance in MPG. The new Jetta is signficantly larger then the old Jetta which I guess explains the drop in MPG.
Go to the fueleconomy.gov site and compare a 2004 Jetta with the 1.9 TDI diesel motor to the 1.8 turbo motor and you will see numbers. The 46 highway mpg for the diesel and the 31 highway mpg for the 1.8T motor. That is about a 48 percent differance.
Granted 46 mpg is not 49 mpg but it is pretty easy to flip a 6 around and see a 9.
The older motor had 90 hp, and produced a 0-60 time of 13 seconds. Among cars in its class, that was surely one of the slowest on the market, given that its rivals achieve 0-60 times of less than 9 or 10 seconds.
As I have been pointing out from the onset, for a given displacement, a diesel will offer better fuel economy that comes at a price of performance. You shouldn't compare a 1.9 liter Jetta to other sedans in that class and simply ignore that it needs a good deal more time to get to highway speed than its rivals.
Go to the fueleconomy.gov site and compare a 2004 Jetta with the 1.9 TDI diesel motor to the 1.8 turbo motor and you will see numbers. The 46 highway mpg for the diesel and the 31 highway mpg for the 1.8T motor. That is about a 48 percent differance.
To quote our former president, "There you go again." The old 1.8t gas motor needed about 8 seconds to get to 60 mph; the diesel needed 13 seconds. These are not comparable at all -- the diesel is more than 50% slower.
As I've pointed out throughout this thread, it's dishonest to focus on fuel economy and to completely ignore the performance loss. A 13 second 0-60 time puts the Jetta toward the bottom of the pool, and it's no secret that there is a trade-off between fuel economy and performance. You won't be seeing 37% differences when you compare similar cars -- even the 335d didn't accomplish that.
While steadfastly refusing to do the math, the other point is while the BMW 3 series diesel is certainly geared more towards PERFORMANCE and perception; it is ONLY ONE diesel model. For the MAJORITY of other OEM diesel models (European diesels) 37% is conservative, even as the BMW diesel does NOT achieve it. Again, BMW makes the decision to trade off the 26-37% ( on up) or 11% in favor of performance. No big or new news here. It of course shows; good and bad.
As for the trade offs between toward fuel economy rather than performance, it is done every day, whether one likes it or not. That is one reason why BMW bills themselves as the ultimate driving machine. (despite the hype and fluff) Since most folks do not own a diesel car, and the BMW 3 series diesel has not been allowed into the USA, heretofore, it is pretty theoretical anyway which is probably why gassers owners have so many misconceptions about it.
1.6FSI, 115PS/114lb ft, 6spd, 11.1 sec 0-62mph
2.0FSI, 150/147, 6spd, 9.2
2.0TFSI, 200/206, 6spd, 7.2
Diesels are :
1.9TDi, 105/184, 5spd, 11.9
2.0TDi, 140/236, 6spd, 9.7
Interestingly, the Golf gets a new gasser engine which is :
1.4TSI, 170/177, 6spd, 7.9
This engine is both turbocharged and supercharged, hence the output from a relatively small-displacement unit. Haven't given any economy figures as our testing protocols are probably v different. You can, of course, see more on the VW UK site. Will it finds it's way across the Atlantic ? Would anyone buy it if it did ?
Thank you
Brings to mind the US/Euro compare/contrast.
There is another interesting discussion, where to me diesel in the USA is of advantage and the taxing authorities scarcely appreciate this. Actually they hope folks do nothing. UPSHOT: cost per mile driven is cheaper. tax per mile driven is also cheaper. (I think that is why there is talk of a BTU equivalency tax)
When this is compared and contrasted with European prices of unleaded regular and #2 diesel, the advantages really hit you between the eyes like a 2x4.
Use any of one's own figures, so one doesn't get wrapped around the axle like some folks do on the percentages and numbers, etc, etc,.
2003 VW Jetta TDI epa 42/49 pmd: $.0688095/.0578
2003 VW Jetta 1.8T, 2.0 epa 24/31 pmd; $.10625/.082258
2004 Honda Civic epa 29/38 pmd: $. .087931/.0671052
Example data : USA: ULR-2.55 ULSD-2.89
So for example, running a DIESEL VW vs gasser VW is 35% to 29.7% LESS, EPA.
Reality is better or worse depending on individual results. So for my 54 R/T commute I get 48-52, or 50 avg.
EPA has recently been cited as being wildly optimistic for a lot of (GASSER) drivers.!!!?????
(so could you imagine if ULR/ULSD were PAR?)
UK: ULR $6.40 US ULSD $6.70
2003 VW Jetta TDI epa 42/49 pmd: $.1595/.1367
2003 VW Jetta 1.8T, 2.0 epa 24/31 pmd; $.2667/.20645
2004 Honda Civic epa 29/38 pmd: $.22069/.1684
It might be interesting to wonder out loud why in Europe the diesel passenger vehicle fleet is 50% and GROWING!!??
We can't say we came away very impressed. During a week of stop-and-go mixed with some highway driving, we ended up with an average of 32 miles to the gallon. This is better than 24.9 mpg that a comparably equipped, gasoline-powered Jetta 1.8T GLS we recently drove provided, but south of the EPA mpg estimate of 34/45 for city/highway driving. If fuel economy is of primary concern, we'd recommend the manual transmission, which has a 42 city/49 highway rating. While gas stations that sell diesel weren't lacking during our daily commute, it was still an effort to look for the green diesel sign.
One of the main advantages of a diesel engine is the availability of low-end torque, which is why it's so popular in heavy-duty truck applications. Rated at 90 horsepower at 3,750 rpm and an impressive 155 pound-feet of torque at a low 1,900 rpm, takeoff provided from the 1.9-liter engine is still on the weak side, and merging onto the freeway requires more planning than its 1.8T counterparts. Volkswagen states that zero-to-60 mph acceleration runs should be completed in a leisurely 14.9 seconds. Again, this engine would probably be vastly better suited to the five-speed manual, which better enables drivers to take advantage of increased revs. Indeed once the TDI reached midrange revs, we were pleased by its broad power band and lively passing performance. The powerplant still retains a trademark rumble at idle, but then smoothes out upon pressing the right-hand pedal.
You continue to make the invalid comparison of a fuel economy vehicle ( 1.9 TDI ) with a performance vehicle ( 1.8T gasser ).
From Edmunds review of the 2002 1.8T GLS...
So how much of a difference does the additional power make? Quite a bit, according to VW the 2002 Jetta will be able to sprint to 60 mph in just 7.7 seconds. And if you're worried that the higher peak power results in a loss of this jewel's flat power band, fret not. Peak torque still arrives at less than 2,000 rpm (1,950 rpm, to be exact) and stays up there until the tach's needle reaches 5 grand. The result is that this engine feels like the "old" 150-horse unit in terms of its flexible power delivery; it's just stronger throughout.
Now if you say that fuel economy is the most important consideration and that performance is of little concern then the TDI is the choice. If you want superior performance then the TDI isn't even in the picture. You first have to define your frame of reference before doing a comparison.
Anecdotal, but from the above note that Edmunds finds that the TDI delivered 32 mpg in every day driving and the 1.8T 24.9 mpg in every day driving ( a 28+% difference ).
While this is probably neutral to your point, but germane to me as a selector (consumer), I probably would not have selected the Jetta if it only had the 1.8T or 2.0. The majority of the unreliability and durability issues have been with those engines.
See my post about the (NON) sacredness of the numbers. Do the numbers, report the results. I am perfectly fine with their test reports and your math of 28%. Mine (being an actual TDI DRIVER) and a 5 speed manual is higher and that is what I said (reported).
As a matter of fact if MINE did get 32 mpg average, I'd sell it in a heartbeat. Especially since it sells at a used car premium. It also sells for a good % more than either the used 2.0 or 1.8T. In addition my Civic gets 38-42 in a 54 R/T commute, and at 12564 is 5,436 dollars cheaper. So 32 mpg is WAY less than the Civic. But if we follow PCH's logic to compare the TDI to the Civic is an unfair comparison. YOU/HE might want to think I need a 0-60, 4 second performance parameter in the 54 mile R/T daily commute, but assure you,I surely do not.
So in that very same commute the TDI gets between 48-52.
Further, the TDI went on a 6500 mile R/T from the San Jose, CA to near Daytona Beach, FL. This thing is a very able road car. Crusing (up to 95 mph) was no problem. The mpg range with the AC all the time between per fill up was highest 52 mpg to lowest of 46 mpg. avrage of the 13 or so fill ups was 48/49. So to repeat I got it and happened to put the majority of miles as a commute and road car.
Will I race it from stop light to stop light against a VW 1.8T? Heck no, the 1.8T is faster.
Off topic: for that we have a 0-60, 4 sec Z06!
Diesel car take a long time to completely break in and my car probably won't be completely break in until 25000 to 30000 miles.
It you launch aggresively, one car magazine achieved a 0-60 time around 10.2 seconds. You can also chipped or put a tuning box which I have used since the car was 1 week old. With the additional power add on, I am sure I can beat a VW 1.8T and my car is indeed faster than my friend VW Jetta VR6.
Like you say YES and NO. That is why I usually qualify what I say. So in regards to your quote. Yes, it does take a long time. NO not at 25,000 to 30,000 miles. It is actually longer than you think, at 50,000 to 60,000 miles. Specifically you would be looking for 550 full compression. If you measure it 25,000 to 30,000 miles it will be probably be in the neighborhood of 425-475. So yes, 44/50 mpg with an auto on a longer trip is WAY cool. (so to the naysayers, I say, I do not know this poster)
Definitely if there is a choice, drive it more aggressively rather than so called passively like you would if you were trying for good fuel mileage in a gasser. All the best.
And if the VW did have a 90hp gas engine, it would be a fair bit smaller than 1.9 liters, particularly if it had a turbo. You shouldn't attribute benefits to diesel technology that are unwarranted.
The only reason that you don't find 90 hp gas-engine VW's in the US is that nobody would want them. Such cars are offered in Europe, but there are few car buyers in today's market in the US who have a tolerance for the sluggish performance that comes from that lack of power.
The point being made is that using turbos allows automakers to use smaller, more fuel-efficient and lighter engines in place of larger ones, and that turbo motors will achieve better fuel economy than larger engines with the same power output.
This is true for both gas and diesel engines. If you want to compare the engines with each other in the context of discussing the alleged benefits of the diesel technology itself, then the fairest comparison is to compare two naturally aspirated or two turbocharged versions with each other, instead. And you won't be finding these 37% differences cited previously.
If you understand how turbos work, then this should be fairly obvious. These are the reasons that they are used in the first place.
Because European countries have higher taxes on gasoline than on diesel, and higher prices overall, which makes fuel efficiency more important to the average European consumer. Hence, they drive smaller cars with smaller engines, and are more likely to use diesel.
There are gas engine cars in Europe that get better fuel economy than your diesel. But there is almost no demand for these sorts of cars here, so you don't find them on US roads. Americans simply want more power and larger vehicles.
The enthusiast car magazines all launch their test vehicles aggressively, while IMO, VW tends to be a bit conservative in its claimed 0-60 times. FWIW, Car and Driver got to 60 mph in 10.3 seconds. In contrast, the 2.0 liter turbo GLI reviewed by Car and Driver has 97 (almost 100%) more horsepower, and gets to 60 mph in 7.1 seconds.
With the additional power add on, I am sure I can beat a VW 1.8T and my car is indeed faster than my friend VW Jetta VR6.
Sorry, but I wouldn't buy either that or that famous bridge that always being offered for sale. Chipping typically adds perhaps 25% more horsepower, which would make yours about 125 hp. That would still lag behind a 1.8T with 180 hp or a VR6 with 174 hp...and of course, you could chip the 1.8T to put even more distance between you.
A barrel of crude oil contains about twice as much gasoline as it does diesel fuel. If a barrel of oil is refined straight, then perhaps what the article intimates might be true. However, since refiners extract more gasoline out of barrel than a barrel contains the article does not address that. What I am speaking of is cracking. That takes lots of heat and pressure to make gasoline and/or diesel fuel from the heavier fractions of crude oil. Since the majority of vehicles in the United States are powered by gasoline, and it takes more heat and more time to makes gasoline from the heavier fractions of crude and with that in mind think about how much greenhouse gas gets dumped into the atmosphere. It takes less cracking and heat to make diesel from the heavier fractions.
As to Ruking's 37% efficiency improvement and a comment you or someone else made about gearing, I have to sort of disagree with both of your points of view. In their own right, diesel engines are significantly more efficient than gassers. There are plenty of articles and studies that show that. In several respects, they are also environmentally friendlier too in spite of what larsb's article says. As to the gearing issue, there is little truth to that. For the Jeep Liberty be it the gasser (V-6) or the diesel, both use the same rear end gear ratio of 3.73:1. For the gasser, which has a four speed auto, the overdrive gear ratio is 0.69:1 while for the diesel, which uses a five speed auto it is 0.67:1. The difference in gearing is insignificant in this case. For Mercedes, the E320 CDI uses the same trans as the other E class small block V-8's. Gearing is the same in the trans as well as the rear ends. So how do you account for the increased fuel economy of the diesel powered vehicles? I would attribute most if not all of it to the engine.
This is true of any car.
Yo babe. If you put a 90 hp gas engine in the jetta you may stall it if you tried to take off from a start under a load even with a turbo.
Er, VW sells Golfs (Rabbits)in Europe with 1.6 liter naturally aspirated gas engines with 79 hp. It's a slow car, just slightly slower than the 90 hp diesel model, but it works.
I am not saying chipped gaser is not faster but my car run fast and getting 38 mpg on city and 50 mpg on the highway which is a unbeatable combination. There is also why VW TDI is in high demand.
As for getting 140 hp out of a 100 hp motor, I don't frankly believe that, those figures are the tuners' equivalent of snakeoil. You don't typically get those benefits from chipping, and if you do, you probably won't get it without compromising drivability and reliability. You are not beating VR6's with a 1.9 liter TDi.
Adding the 1000 lbs brings the Scirocco to about the same power to weight ration as the 90 HP VW referred to. The Scirocco was, for its day, considered a "Pocket Rocket"
The HP ratings referenced are BHP. BHP is measured at the flywheel; any ratings on the dyno at the rear wheels will bring far lower numbers as we learned in the 60's testing factory delivered "street racers" - their dyno ratings were 20/30% lower than their BHP ratings.
Auto trans shift points are adjustable, and were factory set to arrive at a compromise of economy and general performance based on geographical destination. I have stepped my shift points up slightly.
Another term for motive power that avoids direct references to either HP or Torque alone is BMEP; Brake Mean Effective Pressure.
The best real world performance snapshots seem to be the zero to X, X1, X2 and so on. Passing time required for 45 to 65 is also a very useful one.
A possibly interesting site: http://www.epi-eng.com/ET-BMEP.htm
If anything, VW needs to put its cars on a diet, because their products outweigh the competition across the board, with no apparent benefit. The solution is not to change drivetrains, but to find ways to remove excess bulk from their platforms.
2.8 CRD hp: 40 @ 1000 rpm 3.7 hp: 55 @ 1000 rpm
80 @ 1500 rpm ********60 @ 1500 rpm
115@ 2000 rpm ********80 @ 2000 rpm
130@ 2500 rpm ********105@ 2500 rpm
145@ 3000 rpm ********125@ 3000 rpm
155@ 3500 rpm ********155@ 3500 rpm
red line 160@ 4000 rpm ********177@ 4000 rpm
**************198@ 4500 rpm
**************208@ 5000 rpm
This should show why gearing of the trans is important to compliment the engines performance curves. More torque at lower rpms gives more hp earlier which will accelerate you faster at lower rpms but the diesel will run out of rpms faster so you put more gears closer together to compensate for this. (Sorry about the graph. This system doesn't tab to well)
This was my own thought but being unfamiliar with the entire process I have no way to estimate what is done to the 'residuum' through cracking to make it produce other petroleum products. Maybe these are individual trade secrets. All the 'net exposes is what one bbl of oil produces through distillation; twice as much gasoline as diesel. Since gasoline is more volatile it is an easier product to produce through distallation, diesel require more heat and energy.
When the residuum is processed by cracking how much of one product or another also seems to be a trade secret. It would seem though that gasoline again being more volatile would be an easier and less costly by product than diesel/fuel oil. Again this is only supposition. I have no data to support it.
I would also agree a lot of Euro makes like BMW, Porsche, etc. need to go on so called "diets". But it is NOT likely as how those very same oem's are some of the most profitable, dollar and % wise.
So would a gasoline engine. Obviously, an engine that has less work to do, such as weight to carry, will use less energy than one that has to do more work.
Lower vehicle weight and turbocharging benefit both engine types. Putting a "chip" into a turbocharged motor of either fuel type can be used to increase horsepower. These truisms are not unique to diesels.
The other thing is the durability of parts is far less in the Honda than the VW, despite the extra weight. Tires in the Honda will probably not last as long. Brake pads and shoes wear faster, shocks and struts will probably need replacing sooner, etc.