Have You Considered The Price of Gasoline?

[HBarlow]

That statement by itself doesn't say much.

There are really three operating modes for cars.

1) Cruising at constant speed - this is where cars (in terms of miles or time) spend the vast majority of their life. Nominal torque differences are inconsequential when cruising at constant speed.

2) Accelerating to merge into freeways or quick passing maneuvers. This is where the power from the engine is extracted. This is why we have high horsepower engines to begin with. No one needs a 150hp engine to cruise down the highway. Gassers massively outperform comparable diesels here.

3) Urban low speed and stop and go traffic. This is where the low end torque of a diesel shines as the car remains within the diesel's preferred zone and the torque is actually realized.

This is simply from the power perspective. Then you layer on fuel efficiency on top. But newer gas turbos have closed the gap sufficiently that the TDI (real, not fraudulent) advantage is no longer as stunning.

The Civic 1.5T (174 hp/162 lb-ft/EPA 31-42-35) does a 6.7s 0-60 while the 2.0L Jetta TDI (150hp/236 lb-ft/EPA 31-45-35) takes 8.4s.

Oh, and you have to pay a $2.5k-ish premium for a similarly equipped TDI, and diesel prices to a premium to regular gas in most parts of the country.

Once again - the math is just no longer what it used to be in terms of fuel savings.

I disagree with most of your statements.

The advantage of a turbo-diesel is that is accelerates briskly at low rpm due to the high torque generated at low rpm. Likewise the lowly little TDI engine will accelerate briskly up an acceleration ramp also at low rpm. The gas engine has to downshift, probably to second gear, to achieve the engine rpm where it makes power.

A tiny little TDI will cruise along endlessly in top gear, ordinarily 6th gear which is a very tall second overdrive, and climb grades effortlessly in 6th gear with just a little more fuel and boost added maintaining set speed without a downshift or wasteful high rpm. A large gas engine, by comparison, will downshift two or even three gears to increase engine rpm to 3500 rpm or higher where it makes power.

A gas engine has to rev and waste a lot of gasoline to maintain speed on a grade. This also accelerates engine wear and reduces longevity.

 

[sandydeb]

I disagree with most of your statements.

The advantage of a turbo-diesel is that is accelerates briskly at low rpm due to the high torque generated at low rpm. Likewise the lowly little TDI engine will accelerate briskly up an acceleration ramp also at low rpm. The gas engine has to downshift, probably to second gear, to achieve the engine rpm where it makes power.

A tiny little TDI will cruise along endlessly in top gear, ordinarily 6th gear which is a very tall second overdrive, and climb grades effortlessly in 6th gear with just a little more fuel and boost added maintaining set speed without a downshift or wasteful high rpm. A large gas engine, by comparison, will downshift two or even three gears to increase engine rpm to 3500 rpm or higher where it makes power.

A gas engine has to rev and waste a lot of gasoline to maintain speed on a grade. This also accelerates engine wear and reduces longevity.

1) This explanation only makes sense in a world where one is doing nothing but going up a grade. In the real world, most cruising is done on relatively flat highways.

2) I did point out that the TDI shines in low rpm, variable speed scenarios, such as urban driving or driving on mountain roads.

What i forgot to point out is that this also happens to be the scenario in which the emissions cheating was most blatant.

What does that say about the non-fraudulent 'strength' pf the engine??

 

[Perfectreign]

1) Doesn't the Avalanche weigh like twice as much as the Jetta????

2) I did not say downshifting is needed for lack of power. It is needed to maximize fuel efficiency.

Yeah, the AV weighs about 5500 lbs, while the Jetta weights under 3000 lbs. The HP to weight ratio is a bit better in the avalanche - 0.05 hp/lb vs. 0.03 hp/lb - but I'm sure the torque in the jetta more than makes up for it.

 

[turbobrick240]

1) This explanation only makes sense in a world where one is doing nothing but going up a grade. In the real world, most cruising is done on relatively flat highways.

2) I did point out that the TDI shines in low rpm, variable speed scenarios, such as urban driving or driving on mountain roads.

What i forgot to point out is that this also happens to be the scenario in which the emissions cheating was most blatant.

What does that say about the non-fraudulent 'strength' pf the engine??

I do see the point you make about small turbo gassers closing the performance/efficiency gap with tdi's. But there will always be diesel fans. You are free to sell your tdi and replace it with a Honda , Toyota, whatever, any time you like.

 

[HBarlow]

1) This explanation only makes sense in a world where one is doing nothing but going up a grade. In the real world, most cruising is done on relatively flat highways.

2) I did point out that the TDI shines in low rpm, variable speed scenarios, such as urban driving or driving on mountain roads.

What i forgot to point out is that this also happens to be the scenario in which the emissions cheating was most blatant.

What does that say about the non-fraudulent 'strength' pf the engine??

At any given road speed a turbo-diesel engine will hum along at much lower rpm than any gas engine can manage because of the TDI's inherent advantage of high torque at low rpm.

Are you trying to convince yourself you made a good choice? I can assure you that you won't convert those of us who understand and appreciate the numerous advantages of diesel power.

So long and good luck to you. Motor away in your gas car.

 

[Perfectreign]

I do see the point you make about small turbo gassers closing the performance/efficiency gap with tdi's. But there will always be diesel fans. You are free to sell your tdi and replace it with a Honda , Toyota, whatever, any time you like.

*sigh* If only they still made the beautiful Excursion with the 7.3...

 

[MichaelB]

*sigh* If only they still made the beautiful Excursion with the 7.3...

There are very good reasons why they don't. #1 it's a fuel suckin' pig.
Diesel or not!

 

[JRSYJET]

D-2 price moves, too. Should a viable C/I option become available, I'll consider.

 

[turbobrick240]

There are very good reasons why they don't. #1 it's a fuel suckin' pig.
Diesel or not!

Clearly they aren't for everyone. But if you need a vehicle to haul your wife, four kids, RV, and camping gear across the country, it might fit the bill nicely.

 

[MichaelB]

Clearly they aren't for everyone. But if you need a vehicle to haul your wife, four kids, RV, and camping gear across the country, it might fit the bill nicely.

Why do you have a NEED for all that? Need vs Want? That is a problem in a society that thinks what they want is a need. Read King Lear and you will know what I mean.

 

[turbobrick240]

Why do you have a NEED for all that? Need vs Want? That is a problem in a society that thinks what they want is a need. Read King Lear and you will know what I mean.

I don't have a need for all of that. But I do have a need for a vehicle that can plow two foot deep snow and haul an equipment trailer loaded with 4 tons of farm machinery. And my 4x4 F250 with 7.3 diesel does the job admirably. You could argue that none of us really need autos of any kind. As americans we expect more than mere survival.

 

[MichaelB]

I don't have a need for all of that. But I do have a need for a vehicle that can plow two foot deep snow and haul an equipment trailer loaded with 4 tons of farm machinery. And my 4x4 F250 with 7.3 diesel does the job admirably. You could argue that none of us really need autos of any kind. As americans we expect more than mere survival.

OK I get that but that is not what you used as an an example of need. You used a family pulling a RV trailer happily across our great nation as a need. So that is justification (need) to own a fuel sucking SUV. There are other ways to see America.

 

[sandydeb]

I don't have a need for all of that. But I do have a need for a vehicle that can plow two foot deep snow and haul an equipment trailer loaded with 4 tons of farm machinery. And my 4x4 F250 with 7.3 diesel does the job admirably. You could argue that none of us really need autos of any kind. As americans we expect more than mere survival.

Whenever prople bring up this 'needs vs. wants' argument, they usually peg human 'needs' at their personal (north american global top 5%) wants, and then proceed to criticize all whose needs exceed that.

 

[HBarlow]

Why do you have a NEED for all that? Need vs Want? That is a problem in a society that thinks what they want is a need. Read King Lear and you will know what I mean.

Who is it a problem for? I don't feel that I have any right to approve or disapprove of what someone else chooses to drive as long as it doesn't endanger me or my family.

What another man or couple believe they need to meet their transportation goals is only a problem to those who wish to control the lives of others.

 

[sandydeb]

At any given road speed a turbo-diesel engine will hum along at much lower rpm than any gas engine can manage because of the TDI's inherent advantage of high torque at low rpm.

Maybe we are having this argument simply for the lack of factual information? Why don't you figure out what RPM a Civic 1.5T logs while cruising at 80mph relative to the 2.0TDI in a Jetta?

Hint: You seem to believe that there is a difference of 2000 rpm, it is more like less than 100rpm. Or in other words, nothing that anyone would even notice. In fact, without a tach, someone would 'feel' that the gasser was logging lower rpms given NVH advantages relative to the diesel.

I used to own an extremely high strung 1.8L Toyota Celica gasser, which redlined at 8800rpm and the extra torque from the VVTIL kicked in only after like 6000 rpm or something. Even that car turned only 2600 rpm cruising at 80mph.

The reason for this was covered in my earlier post, the one that you totally disagreed with. Maintaining a car at a steady speed +/- minor undulations on the road does not take much torque,and hence even substantial torque differences are not relevant. The torque comes into play only when there is a significant and extended change in grade at constant speed, or there is an attempt to increase speed substantially. Neither applies in highway cruising.

 

[sandydeb]

Are you trying to convince yourself you made a good choice? I can assure you that you won't convert those of us who understand and appreciate the numerous advantages of diesel power.

So long and good luck to you. Motor away in your gas car.

I do not wish to convert anyone. OP made the argument that low gas prices are making people forget the original reason for buying a TDI - the substantial fuel efficiency advantage. I pointed out that that argument no longer holds true.

I bought a TDI when the math made sense. Based on updated information, it no longer does. So I won't any more.

At the end of the day, these are dull mass market economy cars designed for mundane commuting. If that is what it takes to excite someone - sure, why not.

So for me, it is a dollars and cents argument - cost+mileage+reliability+resale+operating efficiency in most likely driving scenario.

And for the record, I am still driving my TDI and will hold on to it till the late 2018. The dollars and cents logic makes it crystal clear that there is no rationale for turning in a car early when its depreciation has been halted. VW is paying me to drive the car for 2 years. I don't see why I should not.

 

[bhtooefr]

I really should get a ScanGauge and put it on my Prius on a freeway cruise.

Would it be cheating to set the cruise for 71 MPH, and go down a hill, when showing the ScanGauge's report of engine RPM (the Prius doesn't have a tach, you see)?

 

[APT]

At any given road speed a turbo-diesel engine will hum along at much lower rpm than any gas engine can manage because of the TDI's inherent advantage of high torque at low rpm.

It is not the fuel source providing that benefit. Any late model turbocharged direct injection high pressure gasoline engine offers the same peak torque benefit as a turbocharged direct injection high pressure diesel engine. In fact, the flat torque curve for gasoline engines is even broader, like 1500-5000rpm.

One benefit that diesels have traditionally have is peak toque available within the cruising speed of the engine, as suggested in this thread of 1500-2500rpm. It takes less time to spool a turbocharger than downshift 2-3 gears to get a naturally aspirated gas engine to its peak torque of about 4500rpm. Modern turbocharged gas engines offer this same benefit. They do tend to use more fuel in the real world when that boost is used vs. diesels, though.

 

[turbobrick240]

Let's not discount the physical properties of the two fuels. I met a very nice woman at my town office a couple weeks ago. She was badly burnt and facially disfigured from a car accident that erupted into flames. Sure, it may not happen often, but trust me, you don't want those scars. Diesel fuel is much less volatile and unlikely to ignite if the tank ruptures in an accident. Someday people will look back at gasoline cars and wonder what the hell we were thinking.

 

[sandydeb]

I do see the point you make about small turbo gassers closing the performance/efficiency gap with tdi's. But there will always be diesel fans. You are free to sell your tdi and replace it with a Honda , Toyota, whatever, any time you like.

Oh I most definitely plan to

And TDIs will go back to being an oddity. Given that Mazda went as far as announcing a diesel for the 6 but never managed to launch it tells me that VW cannot make it work absent fraud. The additional cost no longer makes sense given that gas turbos are within striking distance of actual (non-fraud) TDI fuel efficiency.

So you will be left with with a small subset of the current TDIs that do not get turned in for enthusiasts to toy around with.

Finding good fuel will also start becoming more challenging. Gas stations had started offering diesel as there was increasing demand from passenger cars. Most of these stations were not relying on bus and truck business, as those folks fill up cheap-ass dirty diesel that works just as well for their rugged diesel engines. Fragile (relative to those) TDIs need better fuel. But that will no longer matter.

 

[chadbag]

Finding good fuel will also start becoming more challenging. Gas stations had started offering diesel as there was increasing demand from passenger cars. Most of these stations were not relying on bus and truck business, as those folks fill up cheap-ass dirty diesel that works just as well for their rugged diesel engines. Fragile (relative to those) TDIs need better fuel. But that will no longer matter.

Fuel won't be an issue. The diesel pickup truck market is the main driver of the availability of diesel fuel in many parts of the country at regular gas stations. Those are only becoming more popular with the Dodge 1500 and the Nissan Titan joining the 3/4 and 1 ton crowd.

 

[IndigoBlueWagon]

sandydeb, the world of diesel isn't coming to an end because of this one issue.

I've been driving diesels for a long time and I can count on my thumbs the times I've had difficulty finding fuel. The number of diesel models in the US is on the rise, regardless of what VW chooses to do. Maybe you could call them an "oddity," but they're a good one.

Those of us who've always enjoyed driving diesels will continue to do so, regardless of what happens to VW or to fuel prices.

 

[turbobrick240]

Oh I most definitely plan to

And TDIs will go back to being an oddity. Given that Mazda went as far as announcing a diesel for the 6 but never managed to launch it tells me that VW cannot make it work absent fraud. The additional cost no longer makes sense given that gas turbos are within striking distance of actual (non-fraud) TDI fuel efficiency.

So you will be left with with a small subset of the current TDIs that do not get turned in for enthusiasts to toy around with.

Finding good fuel will also start becoming more challenging. Gas stations had started offering diesel as there was increasing demand from passenger cars. Most of these stations were not relying on bus and truck business, as those folks fill up cheap-ass dirty diesel that works just as well for their rugged diesel engines. Fragile (relative to those) TDIs need better fuel. But that will no longer matter.

Clearly you aren't a diesel fan. That's fine. Why you choose to spend your time on a forum for diesel fans is beyond me. Mazda' s skyactiv diesel never materialized here. That absolutely does not mean new passenger diesels can't meet the regs. BMW, Mercedes, and GM have diesel cars that do meet the regs. VW could have too. They were just too cheap to license the SCR technology from mercedes.

 

[IndigoBlueWagon]

As do Land Rover, Jaguar, and Ram. And I doubt we know why VW chose not to meet the regs, although they have been loathe to pay for technology in the past.

 

[oilhammer]

...

So you will be left with with a small subset of the current TDIs that do not get turned in for enthusiasts to toy around with.

....

Oh man I cannot wait for a return to that after all this BS blows over. I just hope the haters go away and stay away and let us enthusiasts continue to have fun with our little odd cars.

 

[Driximus]

Gas engines have narrowed the gap in the last few years. there is still more BTU's of energy in diesel and that will always be a constant. The operation of a diesel having to compress it to ignition makes it more efficient compared to a gas engine having to spark to ignite.

diesel enthusiasts will always be around. Heck diesel engines were the first alternative fuel engine, diesels have been setting trends before it was thought of.

 

[sandydeb]

sandydeb, the world of diesel isn't coming to an end because of this one issue.
I've been driving diesels for a long time and I can count on my thumbs the times I've had difficulty finding fuel. The number of diesel models in the US is on the rise, regardless of what VW chooses to do. Maybe you could call them an "oddity," but they're a good one.
Those of us who've always enjoyed driving diesels will continue to do so, regardless of what happens to VW or to fuel prices.

I don't see a scenario where tractor trailers will disappear from the nation's highways so of course, there will never be a scenario where you cannot find diesel.

But most of that will be cheap, cr*p diesel, the sort that doesn't matter to the hardy tractor trailer engine but will wreak havoc with the relatively fragile TDIs.

 

[Perfectreign]

There are very good reasons why they don't. #1 it's a fuel suckin' pig.
Diesel or not!

Nah, the 7.3 and 6.0 models got around 18 highway. Love that truck! I keep wondering if I should have gotten that instead of the Avalanche. Still I enjoy the ride of the Avalanche, which is slightly smaller than the Excursion.

 

[chadbag]

I don't see a scenario where tractor trailers will disappear from the nation's highways so of course, there will never be a scenario where you cannot find diesel.
But most of that will be cheap, cr*p diesel, the sort that doesn't matter to the hardy tractor trailer engine but will wreak havoc with the relatively fragile TDIs.

I don't know why you keep trying to talk about tractor trailers. And they have ever more stringent regulations to follow and probably need just as good of fuel.

The small truck (pickup truck) market for diesel is growing and they need the same good quality fuel as the TDI. Diesel fuel at your local station is not going anywhere.

 

[oilhammer]

But most of that will be cheap, cr*p diesel, the sort that doesn't matter to the hardy tractor trailer engine but will wreak havoc with the relatively fragile TDIs.

Well it seems clear you know very little about big commercial diesel engines in the modern sense.