Diesel Sports Cars and Performance Cars
Tom Martin
There is a conversation in response to our coverage of the Audi TT TDI that suggests a diesel sports car doesn't make sense:
http://www.nextautos.com/audi-mileage-marathon-we-drive-audi-tt-20-tdi
Having driven many diesels, I can see the attraction of diesels in a sporting chassis. For example, this coverage of a possible Cadillac CTS with V8 diesel sounded attractive to me, especially if it had CTS-V underpinnings:
http://www.nextautos.com/cadillac-considering-v-8-diesel-option-cts
My view would be that in real world (not track day) driving, the diesel torque curve is fun. In addition, for a given level of torque a diesel will have better fuel mileage. The latter isn't such a big cost savings, but it feels good. Alternatively (as in the Caddy) I can have 15-25% more real world torque with no fuel penalty. That sounds good to me, too.
Are "diesel" and "sporting vehicle" incompatible?
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Mena
I think they're quite compatible and the only way future car enthusiasts will be able to get their combustion engine fix before they go by the wayside entirely. Diesels can be fun to drive although not necessarily fast, they give the impression of being fast with the quick ramp up of torque. Great for city driving especially. I like diesels because of their near bulletproof engines and the relative ease if getting big power and huge torque. I don't like them because of their narrow powerbands.
Tom Martin
Here's a perfect example of what would work:
http://www.nextautos.com/report-next-mercedes-benz-slk-come-with-diesel-...
Mena
It needs 50 more hp but it's a start.
Tom Martin
I'm not clear that 50hp is really needed. I can easily imagine a market, to steal your words, that would prefer the impression of being really fast over the reality of being just fast.
Mena
I can imagine that market too but some of us are still going to want substance. Oh well, there's always the aftermarket or the lottery.
Tom Martin
I'd have no beef with that, except that I don't understand why hp is substance and torque isn't.
Mena
Sorry, I guess I'm not being real clear here. I'm not interested in the "feeling" of power in certain situations (at mostly low rpm), I'm interested in all around power (all around performance to be specific). Diesels, have narrower power curves (if you graph hp and torque throughout a cars rpm range) than gas engined cars. A 250hp gas car will be faster than a 250hp diesel car, all else being equal, irregardless of the diesels torque advantage because the diesel makes less overall power and torque in a given rpm range. HP is a function of torque. (torque x rpm) / 5252 = HP. Raise rpm, you raise hp given the same torque number.
What would you rather have? 300 lb-ft of torque from 4000-7500 rpm or 300 lb-ft of torque from 1200-3000 rpm. You and others would like the latter from what I've read but massive low end torque does nothing but roast tires. Current tire tech can't put a massive amount of torque to the ground at lower rpms but can put down massive torque gradually induced over X rpm range. And if you modulate your foot to keep from roasting the tires then you make less torque and might as well drive a gas car. I like diesels, don't get me wrong. I like them for towing and gas mileage. You can get around most of its shortcomings with gearing but at higher rpms, it will fall flat on its face.
I'm actually discovering that my Solstice's powerband doesn't suit my driving style. Small turbo spools up quick for lots of low end torque but falls on its face at higher rpms. When I'm driving spiritedly, I'm at higher rpms and the turbo is already out of steam in my fun area. There is a fix, just need a slight modification to the stock turbo (cough Audi RS6 cough). Diesels perform similarly (more torque though). Leave the light spiritedly, feel that wash of low end grunt, just when it starts to feel good, the turbo (diesels are turbo'd) falls on its face, the minivan that you left for dead catches up and you're reminded that you're still driving a VW
Tom Martin
I don't disagree that some people would like to wind their cars out to high rpm and like a broad power band. That's fine. I have an M3 and I understand the draw of this approach. I simply think there is another legitimate approach, and isn't necessarily "substanceless".
Your question highlights the issue. You ask if I'd rather have 300 lb.-ft. of torque from 4000-7500 rpm or 1200-3000. Either could be interesting, but given the power advantage of the former, I'd take that. But that isn't the choice we have in the real market. It more like this (real 4 cylinder examples):
Turbo Diesel: 204 hp, 369 lb.-ft.@ 3000 rpm
Gasoline: 237 hp, 162 lb.-ft.@ 6800
Gasoline Turbo: 260 hp, 260 lb.-ft. @5300
Now it isn't so obvious which engine (assuming all three were in the same vehicle) would be faster or has more substance. And, as I think you might agree, it isn't obvious which would be more fun. Certainly the gas example (S2000) is the choice if you love to wind your car our to high rpm. But for part-throttle passing and suburban fun, the diesel (SLK 250) could be the choice.
Leo Levine cited some numbers that compare like cars, different engines;
MB S350, 268 hp, 258 lb.-ft., 0-100 mph: 19.5 sec
MB S320 CDI, 210 hp, 400 lb.-ft., 0-100 mph: 20.5 sec
This suggests that the broader power band of the gasoline engine makes up for the lower torque at low rpm. But only by a little and in a test that makes good use of max rpms.
Mena
Unless the S320 and S350 have the same weight, same CD, same frontal area, the same hp and the same gear ratios, you can't really compare them. Also, the numbers you gave are peak numbers and never tell the entire story. You need graphs of both powerbands. That's where you'll see the differences. Example: you quoted the numbers for the Solstice GXP above. 260 lb-ft at 5300 rpm. If you graphed that cars hp and torque curves, you would notice it makes the entire 260 lb-ft of torque from 2500 to 5300 rpm. The car hits peak at a much earlier rpm, giving you a big torque boost over a pretty decent range. And you'll still make good power/torque outside of that range too. In the Solstice, both trail off big time after 5800 rpm as the turbo goes outside of its efficiency range.
It sounds like I'm bagging on the diesels but I just want people to know that big torque doesn't mean a fast car.
Tom Martin
Well said. Just as big horsepower doesn't mean a fast car. As you say, if you want to do this with specs, you need the hp or torque curves. The problem is thus twofold:
-- if speed were the goal, diesels and gasoline engines have very different torque curves, so it is hard for a layman to compare them and know what the implications are. The point of the MB comparison is that these cars are pretty close to the same weight, same CD, same frontal area (you wouldn't gear two completely different engines the same way, and in the real world you don't get to match peak hp). I think this suggests that the modern gas engine of roughly the same displacement will slightly out-drag a modern diesel when run flat out. It might be interesting to get more data to see if that hypothesis holds up.
-- as I originally suggested, speed isn't actually the goal for some drivers, and the difference in torque curves suggests different driving experiences. I think the big torque, narrower power band characteristic of the diesel fits well with the way some sporting drivers actually use their cars -- which is to say, not wound out to the redline very often, but rather accelerating at part throttle from one speed to another. One other thing we can say is that in the band where diesels make more torque, they will accelerate harder all other things being equal.
There is then a final issue that we haven't covered, but is the reason I posted this in Unguzzle: how would these results look if we equalized mpg rather than displacement?
Mena
Great points!!! Some aren't interested in all out speed. Some just want a car to feel peppy. Diesels would make lots of people happy even if their cars really aren't that fast. And I'll be more than happy to remind them of this fact. :P j/k
Ducati Minor
The TT is a tough call. Audi has a proven track record with diesel--literally. The R10 TDi has defined the Audi image in Europe. The problem with a TT TDi is that it's a TT TDi. The TT is a hard pass as a genuine sports car. It's a front-drive machine with a hefty curb weight for a compact two-seater. If Audi could incorporate a diesel engine into a more clearly defined sports car, you wouldn't have the problem of perception being pervasive. An SLK320 CDi could be more reasonable, even though it's actually a pretty heavy vehicle as well. But the SLK-class tends to be more accepted because of its fixed open-top, rear-drive layout.
Tom Martin
The TT weighs 2965 lb. If you're coming from a Lotus Elise I guess that's hefty, but it is less than a 911 and about like a Boxster. I can see FWD as a drawback,, but it looks like we're working overtime to say things aren't sports cars. Or maybe we need a definition of a "sporting" car -- one that is fun to drive and quick on the street and attractive, but doesn't have to live up to purist definitions?
Ducati Minor
Thanks for making me feel stupid, Marty.
I was recalling the previous ragtop, which I further mistook for bearing a similar weight to the front-drive Alfa Spider, which weighs in around 3,700 lbs. I completely overlooked Audi engineers use of aluminum to reduce weight. The current drop-top weighs in at over 3,100 lbs, down from a little over 3,200.
I will choke out some defense of my mistaken point: the Boxster weighs under 2,900--or, more accurately, 250 lbs. less than the base TT cabrio (according C&D). I am surprised the SLK-class is listed as having a base weight of just north of 3,200.
Perhaps a TDi or CDi option could work. I'd still rather see it in an A3 Quattro.
Tom Martin
Happy to be of service. Actually, apologies. No offense intended.
Anyway, I think the point isn't about the TT per se, but whether diesels could work in a certain kind of sporting car.
dieselhead
While I think diesel sports cars and diesel performance cars in general would be great, one advantage of gasoline engines is that they sound better. That advantage isn't going away, from what I've heard.
BillS
I think you're right, though I would say that the quietness of diesels even when pushed hard yields an effortless quality to acceleration that is beguiling in its own way. Kind of like a big V-8, only more so.
Anonymous
Here is one more example of two similar cars, one diesel and one gas:
BMW 530i, 0-60: 6.9 sec (232hp, 221 lb.-ft.)
BMW 535d, 0-60: 6.5 sec (272hp, 413 lb.-ft)
The diesel in this case delivers 20% better mpg. Is it fast enough to be sporting? I'd say its on the edge, but in a car that weighed less (and a Z4 for example would weigh about 400 lb. less) it would be pretty quick.
Ducati Minor
The better comparison would be with the 535i. Edmunds reports a 0-60 time of 5.5 sec. and a 300 hp twin-turbo inline-six making 22.5 mpg combined.
dieselhead
Ducati's and Mena's comments seem to be trying to answer the question: are diesels as faster or faster than gasoline engines? I think it is pretty clear that the answer is no. With all the effort of the past 10 or more years that went into making super high performance gas motors, the answer is generally that we can find gas engines that are faster when it comes to all-out acceleration. Sometimes a lot faster.
But, in the modern world of $4 or $5 gas (along with concerns about global warming), I don't think that is the question for some people anymore. Some of us would like a sports car, with good gas mileage. If the price of 20%-40% better fuel consumption is less maximum acceleration but similar acceleration from 1500 revs to 4000, then that seems like an attractive package.
Mena
dieselhead,
It's really not about "all-out acceleration". I like a well rounded car and prefer grip and handling to straight line speed. If I cared about just the straightline aspect, I'd be driving some muscle car, GT car, or something similar. I prefer sports cars. I get great handling, tons of grip, and straightline speed. I don't require 40 mpg gas mileage although it would be a "nice to have". My car gets 30 mpg and that's good enough for me plus it's a fun as hell, convertible sports car. Didn't have to compromise much. There are other cars that get similar gas mileage and performance in a more practical chassis (Cobalt SS turbo sedan, HHR SS turbo). BTW, the new Cobalt SS is friggin awesome!!! Compromise would be the interior appointments.
It pains me to see car enthusiasts feeling like they have to give up a LOT of their passion for a little practicality. I'd rather keep the passion and have a smaller house. LOL! Just me.
dieselhead
I'm with you that another way to get decent mileage is to get a smaller car. I'd just like that smaller car to have a sporty suspension setup and a diesel torque curve. If I read you and Ducati right, you want to argue that such a car isn't as fast as a some gas version of that car (true enough) and therefore can't be a sporting car. But then you say it isn't about "all-out acceleration". In which case, who cares about how fast some gas version with lower mileage is?
I'm not saying you shouldn't have your gasonline-engined sports car. That's fine. You have lots of choices and I hope those continue. I'm disagreeing with what seems like reasoning that talks out of both sides of your mouth about diesels not being suited to sporting cars. I think diesels are well-suited as a choice for sporting cars because I think a) for a given mpg level, a diesel will be faster and much more importantly b) the diesel's acceleration superiority will show up in spades where it can be used safely on the street. I just want the choice of having those advantages in a car very much like the one you drive (other than the engine).
Mena
You're reading WAY too much into my posts. I wasn't saying it wouldn't be a sporting car, I wanted to point out that a big low rpm torque number isn't a replacement for big high rpm torque number (HP). And I do care about how fast the gas version with worse fuel economy is. LOL! Performance is a higher priority than fuel economy FOR ME and 30 mpg is pretty damn good considering what performance I get. In frugal mode, I can get as high as 35 mpg (off boost, on freeway it's just another 4 cylinder). I don't need the extra 5 mpg or so at the expensive of 85% of my performance because high gas mileage trades a TON of performance for it.
the diesel's acceleration superiority will show up in spades where it can be used safely on the street
Which will promptly get you to speeds that are too fast for city streets, screeching tires along the way. You misreading my posts aside, diesels are fine, diesels in sports cars are fine, and I may end up with one eventually (or maybe a hybrid like HCCI). No one's taking away your choices (although eventually mine will be). Have fun.
dieselhead
That's cool. Sorry I misunderstood.
Ducati Minor
No one's questioning whether it could be applied, just the problem of image. You would need to have an image-changer. Audi could pull it off by linking a sports car to its award-winning track stars. Audi has a proven formula. But you have to alters the consumers' attitudes towards the key component for that formula. That's easier in the EU than in the US.
The R8 TDi could have pulled it off, but there were a number of factors against it. The diesel V-12 concept was projected to cost four times the amount the V-8 petrol retails. The combined mileage in the mid-twenties was impressive, but the 5.0+ sec. zero-to-sixty time didn't warrant a $400K or $500K exotic.
The best shot would be to have a diesel-only product, so the features shape the vehicle. It doesn't sound pretty, which is a lot of what makes a sports car fashionable. I think Audi, more than Mercedes or Porsche, is able to pull this off. Acompletely diesel exotic would work if it could manage to appear "blue," as in clean-diesel Europe, than "brown" as in the 1980s US.
chuck goolsbee
I am and always have been, a "car guy." To me, the ideal car is a sports car. Small, 2 seater, open topped, fun. I own a vintage sports car from the 60s that used to belong to my dad.
Additionally half of the cars I've owned in my lifetime have been Diesel powered. Either VW or Volvo. Every one of them has been a compact car, either a sedan or a hatchback (except my wife's Liberty CRD). All have been practical and long-lived. The most recent two run almost entirely on fuel I make myself at home!
I would KILL to have a Diesel-powered sports car. A TT TDI, an Alfa Spider JTDM, an Elise with a VW 1.9 TDI shoved in... anything PLEASE.
The thing everyone seems to miss, is that "sports car" does NOT mean "Performance car". They just have to be FUN, not necessarily FAST, just FUN. Look at an old Triumph or MG. More fun that you can have on four wheels... you can not help but grin from ear to ear while driving an old roadster on a twisty backroad. Speed? Speed is irrelevant in such a car. Horsepower? Bah! Those old car delivered TONS OF FUN, and most weighed in well UNDER 100 HP! All of them under 2 liters of displacement. You do NOT need triple-digit HP numbers to have fun! Those "LBCs delivered smiles per mile along with pretty damn good miles per gallon too.
0-60 times? Who cares? How big is the smile on your face, that is the only meaningful metric.
Diesel is honestly the best possible technology to bring back that class of automobile. Small. Light. Fun.
--chuck
Mena
0-60 times? Who cares? How big is the smile on your face, that is the only meaningful metric.
Although I keep getting pegged with the straightline crap, I could care less about a cars 0-60 although I do look at 1/4 mile numbers to judge straightline performance. I had a Sentra with 180hp and 180 lb-ft of torque. It weighed about 2700 lbs. It had a 6 speed tranny and a LSD. Grippy tires, big rear aftermarket sway bar. Sufficiently quick but difficult to use all of the grip (FWD). It actually has more grip than my Solstice. I really liked that car. It was fun but this one blows the doors off of it and that's with the top still up. Much crisper handling, easier to drive at the limit, RWD with the added bonus of having another 80hp and 80 lb-ft of torque. AND a turbocharger stock (with a cheap, reliable 50hp increase for under $400). It looks FAR better than my Sentra although looks are not a priority with me. As long as I like it I could care less if anyone else does.
And who are you to say how I enjoy my car? I like what I like and you like what you like. I prefer a mountain road to a long freeway nowadays but occasionally I like to explore that side of my cars performance too. Sports cars are awesome like that. They have more than one aspect to them. That's why I like them.
Anonymous
It seems to me that most of the posts here, if not all, are from people living in the US where the availability of diesel engined cars is pitifully limited. As such most of the arguments being made are based on the writers notional interpretations of what the stats on diesel cars must translate to in terms of actual performance. The fact of the matter is that there is an actual serious gulf in the notional interpretation of the data and the actual driving experience. I have driven most of the latest generation of high performance direct injection turbo diesels and form my experience I can tell you that once up and running they are easily as quick and in most cases quicker than their equivalent naturally aspirated petrol powered siblings. The latest BMW 330d is actually quicker in all performance benchmarks than the 330i and still returns nearly 50mpg.
I have owned and driven modified Imrezas for the last 7 years and now drive a modified Audi TT 2.0 Tfsi. All were quick cars but none of them could live with a BMW 335d out on the open raod. That's a fact not some conceptual argument based on imagining what engine power stats must translate to as a driving experience. You can bore the pants off everyone with all the formulas you like to try to justify your arguments but the proof of the pudding is in the eating and in the real world some of the latest diesel sports cars are viable alternatives to petrol powered sports cars. When you get to drive enough of them back to back with their petrol powered siblings this becomes glaringly obvious. With the planned roll out of performance tdi's from BMW, Audi and Mercedes in the new year in the US more people than ever will get a chance to take one for test drive and make their own minds up. Only then will you be sufficiently informed to make actual comparisons and when you do finally get a chance to take something like a BMW 335d or even a BMW 123d I'm sure you'll be shocked at just how good they are to drive and especially own and run.
Frawls
Mena
I, like other Americans have never driven a diesel car. We also can't intepret hp/torque graphs and bow in eternal appreciation to our new, self appointed leaders, The Europeans. Thank you for enlightening me. My IQ was raised 20 points just from this discussion.
Hans
Dear Mena:
Are you running out of arguments when presented with real experiences? Are you ashamed of letting us know which diesel-powered vehicles you have actually driven? If you have just driven, by instance, diesel-powered pick-up trucks, and then you extrapolate your experience, you certainly can use the hands-on driving experiences of other people to better understand what is really going on.
I personally live in Guatemala City, a mile high town, and I have driven the Isuzu Trooper, the Mitsubishi Montero and the Totota 4d4 Hilux Pick-up truck. All of them will give support of your theory of diesels falling flat on their faces at high RPMs. On the other hand, I have driven a 2008 BMW 530d wich is a very different story. Its prodigious amount of torque available from idle lets you use whatever small opening in traffic is available, lets you come out of turns as the proverbial bat out from hell if you are in a twisty road and let you accelerate from 160 km/h (around 100 mph) to its electronically limited top of 255 km/h with authority, like some other cars feel when accelerating in second gear, not just looking at the speedometer's needle creep up. Couple that with outstanding brakes and very capable cornering capabilities and more often than not the limit to your spirited driving is imposed by your personal limits, not the car's.
So, besides reading, you should do some driving too and then write if you really want to be taken seriously. I do not have the means for buying my own 530d but was lucky enough to have a friend who does. A test-drive could fit the bill if none of your friends have one yet. You certainly write well, so it would be quite interesting to hear what you have to say after a hands-on experience with a top-of-the-line Diesel-powered car.
Mena
Once again, I bow before ye, oh Lord. Knower of all that I have experienced. How mucheth must I prostrate myself before ye?
Hans Thiel
You are missing the point again. I asked before and ask again: tell us, please, which diesel-powered vehicles you have driven, so that we may know if your arguments are based on theory or on actual driving.
I think that none of us want to offend you, so if you cannot take criticism lightly, I apologize for any involuntary offense, but then, if you are that sensitive, you should not make contentious arguments. Do not play with fire if you do not want to get burned.
Lear
Hans -- Read what he's already written: Mena says he hasn't driven any diesels. He does have a point about different power curves. I also think Mena and Ducati make the point that there are lots of gas cars that are faster than the diesels we really have in the US. That makes it seem like the technology (diesel) is much lower performance.
Hans Thiel
Lear:
I recall Mena stating that his wife has a Diesel-powered vehicle. I was wondering what kind of vehicle was that and if he had the chance of driving some other. My experience is that the newer diesels certainly are quite another story if you compare them with previous models, speaking from the spirited-driving point of view. Besides my hands-on experience, the Le Mans victory of the Audi Diesel is eloquent about what can be done with a Diesel-powered car nowadays. So, people with enough means can now a very rewarding sport-oriented driving experience using an engine that utilizes around 50% of the energy of the fuel compared with the normal 20% efficiency of the gasoline-powered engine. So, armchair drivers can also be satisfied comparing the energy efficiency together with Le mans-winning capabilities while waiting for the chance of driving some of the nicest examples of Diesel-powered sport cars.
Lear
I've seen Mena post on trucks, so maybe his wife has a diesel truck.
I totally loved what Audi did at LeMans. But I never knew if the LeMans rule-makers set things up so that diesels were advantaged or if this was just science in action.
I have been disappointed in Audi's follow up on LeMans in the US. Where is a diesel A4, A5, A3 or TT?
BillS
I think Ducati Minor nails it when he cites the need for an image-changer. To wit:
"Diesels can be fun but not necessarily fast"
"I don't need the extra 5 mpg at the expense of 85% of performance"
The reality, though, is that even with a little extra mpg, diesels are faster. Thats what the diesel numbers say (as mentioned above). That's what thermodynamics say. I found these diesel-gas comparables to add to the collection:
Diesel BMW 120d, 0-60 7.7 sec
Gas BMW 120i, 0-60 8.7 sec
Note: the 120d gets about 20% better mpg; thus with equal mpg it would be perhaps 25% faster not 12% faster.
The perception problem arises because in the US market the automakers remain heavily focused on using diesels to score high mpg numbers. Said differently, they aren't marketing fast diesels with moderate mpg levels (say 30 mpg combined). They aren't putting diesels in their sexiest chassis and in sedans with their best suspensions. So all the examples are of white-bread low-power miserly sedans or massive, top heavy SUVs. I think the diesel guys here, and I count myself as one of them, are asking for the car makers to go beyond this narrow view. Give us sports sedans and sports GTs with diesel power, 30 mpg and some punchy acceleration.
It is deeply ironic that the car companies all want ways to distinguish their brands. The ones with mediocre brand strength especially want this. Now here is a positioning opportunity that could capture the attention of a ready market, and a market that will pay premium prices and overlook the extra cost of diesel, and the car makers all walk away. All of them. Jaguar, Saab, Audi and Ford could all use a boost. BMW may not need it, but it couldn't hurt and this approach would be the easiest for them to do. But what we have is dead silence. Arrrrrrrrrrrrrrrrrgh!
Mena
"That's what thermodynamics say."
Really? Thermodynamics determines where an engine makes power in a given rpm range? Care to quote the formula that states this?
BMW 120i 168hp/150 lb-ft
BMW 120d 175hp/260 lb-ft
I would think a 7hp and 110 lb-ft advantage would translate to faster acceleration all else being equal. Not only does the diesel get off the line quicker, it holds its lead with the hp advantage. Oh wait. The 0-60 numbers I found put a manual 120i at 7.7 seconds and a 120d at 7.5 seconds.
http://en.wikipedia.org/wiki/BMW_1_Series
BTW, I would prefer the 123d over the 120d. More power and torque with not much of a drop in gas mileage.
120d - 49 mpg combined Euro cycle
123d - 45 mpg combined Euro cycle
BillS
Here's my understanding. Others who know more may wish to comment. It is generally accepted in what I've read that diesel engines are 25-30% more efficient than gasoline engines. Efficiency here is the ability to turn the energy stored in fuel into power. Power is the ability to do work. Acceleration requires work to be done. So, all other things being equal, in theory a diesel engine will out accelerate a gasoline engine when the two use the same amount (volume) of fuel. I believe this comes from two thermodynamic observations: diesel fuel has higher energy density than gasoline and combustion at higher compression occurs more efficiently (more of the energy in the fuel is turned into useful power).
I'm sure in the real world there are many factors that make these generalizations only approximate. But the empirical numbers seem to bear the theory out (diesels with somewhat better mpg have slightly lower 0-60 times). I don't have a bunch of Euro test data at my fingertips, so there might be contrary examples (for example how does direct injection affect these results?).
But such observations won't change the perception. That will take real cars, I think. Someone else suggested some marketing $ would help too, and I'd go with that as well.
Mena
So, all other things being equal, in theory a diesel engine will out accelerate a gasoline engine when the two use the same amount (volume) of fuel.
I understand what you're saying now and agree. I'm sure there are other factors as well. About observations, I also agree that there will need to be a perception change about diesels used in performance applications. Audi is helping to change that but only car nuts are aware of their racing diesels. A solid diesel sports car would help immensely.
dieselhead
You are so right. There definitely are other factors. One is that diesel engines tend to weigh more. Another, which I think you mentioned above is gearing. I'm guessing one reason we're seeing more 7 speed trannys is so that diesels can run more often in their sweet spot.
One could also argue that "acceleration per volume of fuel" isn't the issue. You could say it is "acceleration per $ of fuel". There is no long term reason for diesel to be more expensive per gallon, but short term supply and demand mean that in the US it has been and will be for a while more expensive. At today's prices I'd guess acceleration per $ of fuel would be a wash or slightly favor gasoline engines (especially DI engines).
And then, of course, there is all the subjective stuff: sound, shape of torque curve, throttle response.
As you can tell by my username, I'm a diesel proponent, but this isn't a case of one technology being hands down better than another.
ishmael010
Interesting comments on diesels. I've owned an '03 VW TDI for the last two years, and have had it tuned and tweaked for me by knowledgeable diesel mechanics. The VW handled well out of the box, but I improved the suspension with Bilstein gear. I don't engage in stoplight races, but the VW is plenty quick off the line. The big difference is in highway speeds, passing and accelerating from 40 to 80 mph it will absolutely knock your socks off, and with the tuning on the highway at consistent speeds I still get 50mpg. I'll take my TDI over most anything else on the road right now, and if they offer a sports car version via the Audi TTd, more power to them!
Mena
What kind of tuning have you had done? Quite frankly, I think diesels would excel more than gas engined cars in the aftermarket. Look at the aftermarket diesel trucks.
Bernie
If VW would make a TDI Eos and bring it to the US I'd buy it now. May end up with a Jetta TDI some day. . . but times are a changing. Mileage is a performance measure for me.
Rotts
Can't comment on racing applications, but one of the most thrilling and enjoyable drives I've ever experienced was running an Audi A4 V6 diesel sedan at 240KPH (145 mph) on the "63" Autobahn North toward Frankfurt a few years ago. Tremendous power (torque?) and totally stable at that speed (of course, Autobahn construction is a big factor in the stability, too). Can't wait for the new diesels in the US! I want a Jetta TDI Sportwagon!
Spark
It appears the question has been answered, yes, 'sporting' and 'diesel' are compatible. Everyone will always have their own ideas and preferences about what makes a car either 'more' or 'less' sporting, but with the advances in common rail technology the power diesels are capable of producing is now on par with most gasoline engines. If the US market ever embraces them, the technology will likely be advanced that much further.
I live in Paris now, and currently drive a 1.9L Alfa 147. It puts out a modest 150hp and about 225 lbsft, and yes, it redlines early - I have to shift around 4500 rpm's so 0-60 times are slow (around 8 sec). But it is a blast to drive point to point and no matter how heavy my foot has been I have never recorded under 43 mpg, getting over 50 regularly on long trips at 100 mph+. If I pony up a small sum and get it tuned it would see 185hp/285ft lbs and creep closer to 6.5 0-60.
It is a different kind of car than the 2.0L WRX I had in the states but no question it is 'sporting.' Add the fact that diesel is actually cheaper than petrol over here, and it's a no brainer. The only major drawback I see is sound/vibration of the engine, it takes some getting used to when compared to the non diesel counterparts (and even that is getting better).
dieselhead
Now we're talking:
http://www.nextautos.com/detroit-2009-volkswagen-bluesport-diesel-roadst...
260 lb.-ft., mid-engine, 57 mpg. Looks pretty sweet too.
Mena
I really don't think that car will get 55 mpg US even though the conversion states this. Nor do I think it will weigh 2600 lbs like that linked website states. Nice looking car though and should help to change the perception of diesels in fun cars. 6.6 0-60 mph is plenty for most people. I wonder what the handling and grip will be like. Looking forward to the reviews.
Anonymous
The diesel engines powering race cars such as the R10 and Puegot should be either banned or held to the same rules as IC engines regarding, as a minimum, displacement and turbocharging.
ukarl
I"ll drive one in a minute.....ka....