Autoblog

I just wanted to point out the part which says some dealers have sold out their allotments. Seems like people ARE putting their money where their mouths are.

↓↑report

Everyone wants a late model VW TDI until they speak to someone who has owned one in a cold climate.

"...more time on a hook than in my driveway."

↓↑report

I have a co-worker (in Winnipeg, MB) who drives to work every day in a MKIV Jetta TDI. He doesn't have any problems with the engine in the extremely cold climate, except that it takes a very long time to get hot air in the cabin. Other than, it seems very reliable for him.

↓↑report

Bring the Polo over, VW moron management.

↓↑report

Waited two years for the Tiguan, but VW chose to price the car almost 4K above a similar CRV, and no diesel. Love the driving dynamics of german cars, willing to put up with the lousy dealerships and the little problems, but good luck to VW on the sales at the price level they think I will pay for a Golf with a little more ground clearance and poore fuel mileage.

↓↑report

About diesel in a cold climate:

If you use winter mix that helps.
BUT
An engine block heater is the only way to be safer.

I have owned one in a very cold winter and even my gas engine will sputter from time to time.

↓↑report

The internets (Jetta forums) say you can't hit 620 miles (1000km) per tank unless you drive 50mph on the highway. Is that not really true?

↓↑report

you're correct ls7 (i have an 02) - you'll need to be very progressive on throttle, keep the rpms very low, and essentially cruise between 50 and 60 if you want to manage 50mpg.

↓↑report

Have had 2000 Beetle since new and now has 195,000 miles. Gets 46 mpg around town, 51 or so on the highway at 65 mph. Average has been consistent 49 mpg overall. I've done several highway only trips and pulled a max 810 miles on a tank..although I was on fumes at fill up! No plans to get rid of this anytime soon.

↓↑report

The range doesn't mean too much without the corresponding fuel tank size. An RV with a 300 gallon capacity going 620 miles isn't as impressive as a car with a significantly smaller tank.

I believe the TDI's have the same size tank as their gas counterparts. For the Mk4 platform, that means a 14.5 gallon tank. The fuel light will generally turn on with about 1.5gal. remaining. For me, I tend to put about 13-13.5gal. into my car when I fill up. I usually go a day or so with the fuel light on before actually stopping to fill up.

So, if you got 50mpg, times a 14 gallon fill-up equals 700 miles to a tank. That's not unheard of, but should not require driving at 50mph to attain. In fact, reading those same forums(VWVortex being the largest), most seem to be able to achieve mid to upper 40's even while doing 80mpg. Doing the math and assuming a 14gallon fill-up, a 620 mile range you mentioned equals 44mpg. I think many people would be quite happy with that as an average.

For the record, I tend to average about 28mpg between fill-ups and my car requires Premium fuel. So, if I could almost double my range(I get about 350miles between fill-ups now) while paying about 15% more for the fuel, that's a large net savings for me and I'd happily do it if I were in the market for a new car.

↓↑report

You're not going to double mpg by just putting in an equivalent Diesel engine. You'd have to give up a fair bit of performance just to get to 50% better mpg.

↓↑report

Found some more mileage info. While VWVortex is the largest VW forum, TDIClub.com would be the best place for TDI-related stuff. They also have an entire section devoted to threads about fuel economy.
http://forums.tdiclub.com/forumdisplay.php?f=24

There are several threads dedicated to posts from people who have surpassed specific range goals(700mi/tank, 900mi/tank etc.) They also have a monthly MPG contest.

It's not limited to just Jetta owners though and there are several models of TDI's so the range again is related to the size of the fuel tank since Passats and Touaregs have larger tanks. Not to mention the other decades of TDI-powered vehicles VW has made over the years.

↓↑report

Quote from Why not the LS2LS7? - "You're not going to double mpg by just putting in an equivalent Diesel engine. You'd have to give up a fair bit of performance just to get to 50% better mpg."


Where was performance ever mentioned?

The same can be said of putting a less powerful engine into any vehicle. You may get increased mileage, but at the expense of performance. That said, the increased torque of a diesel engine makes a huge difference in driveability. This 2.0L has 33% more torque than my 1.8T powered car, which in itself is fairly torquey. I'm not expecting similar 0-60 times, nor should I. But, I challenge you to find another 140hp car for sale in the US which attains the mileage of the '09 TDI. The TDI is designed for economy, my GTI is designed with performance in mind.

So, what was your point?

↓↑report

My point is if VW sold a crap-slow gas version of the Jetta in the US it would get better mpg too.

As to the Diesel having more torque, you're talking about torque at the shaft. This torque never makes it to the ground because the redline on the engine is low. This requires you to shift sooner to a higher gear and this takes away the torque you speak of.

Remember, torque at the wheels is what determines performance, and since Diesel cars perform so much worse, it indicates they are making a lot less torque at the wheels. Bragging about torque at the shaft is pointless.

People talk about the payback of paying more for a Diesel engine and for Diesel fuel per gallon, but saving money in the end because overall consumption is lower. But a smaller gas engine could probably provide similar savings without having to pay more (in fact less!) up front and per gallon.

There are few comparos that compare cars that have comparable performance between gas and Diesel to see which really is cheaper to run. One of the few I've seen was on Fifth Gear where they compared the BMW MINI Cooper S and BMW MINI Cooper D. The Cooper D only got 9% better fuel economy and didn't perform as well despite seeming like the engine was working much harder than the gas engine was in the other car.

↓↑report

Quote from why not the LS2LS7? - "There are few comparos that compare cars that have comparable performance between gas and Diesel to see which really is cheaper to run. One of the few I've seen was on Fifth Gear where they compared the BMW MINI Cooper S and BMW MINI Cooper D. The Cooper D only got 9% better fuel economy and didn't perform as well despite seeming like the engine was working much harder than the gas engine was in the other car." -

Being that they tested the diesel against the S model, I'd have to say I'd be surprised if the gas engine was working harder. I haven't seen that comparison though so I will comment no further.

The best comparison I've seen lately was from Edmunds where they tested 4 different vehicles, a Prius, an '05 Jetta TDI, a Ford Focus, and a Smart fortwo. The Focus and the Smart fulfill the gas engine part, with the Focus probably being closest to the Jetta since the Smart is so much smaller.

http://www.edmunds.com/advice/fueleconomy/articles/126370/article.html

The Jetta soundly trounced the Focus in mileage and was better than the Smart all-around as well, only being worse(by 1.4mpg) in the city section. Over the course of the whole trip, the Jetta achieved almost 32% better mileage than the Focus.

It also compared very well against the Prius. Again, only being beaten in the city section. If it weren't for the higher cost of diesel, the Jetta would have come quite close to winning the comparison.

Either way, not a bad performance by a 3yr older vehicle using a reletively low-tech engine especially considering that the '09 is expected to be even more fuel efficient(if the EPA figures are any indication) and significantly more powerful as well.

↓↑report

Responding to LS2, etc.:

http://www.cars.com/go/crp/research.jsp?superTrim=&makeid=48&logtype=7&mode=&destURL=features.jsp&year=2002&acode=USB20VWC031F0&modelid=447§ion=features&myid=970§ion=features&mode=&aff=national

2002 Jetta TDI:

14.5 gallon fuel tank
42 mpg city
49 mpg highway
~609 miles city range
~710.5 miles highway range

As I said, my mom consistently gets in the high 40s for miles per gallon. She routinely gets near or more than 600 miles per tank. This is not by driving 50mph or any other abnormal driving. This is driving 70-75 on the freeway (often faster). The most she's ever gotten a tank of fuel is just over 700 miles, but as someone pointed out, it was running on fumes at that point.

As far as your argument that diesel engines don't get torque to the ground, you need to take a look at any dyno chart for a diesel. Of course they get the power to the ground. There is no point in quoting torque numbers if you don't get the power to the ground and there is no difference in a gas engine getting power to the ground than there is a diesel engine getting power to the ground. Just because diesel engines are engineered to run at lower engine speeds (compression ratio of 19.5:1 will dictate that usually), doesn't mean they "don't get the torque to the ground." One of the main reasons diesel engines are as efficient as they are is because they make their power down low, so you don't have to rev the crap out of it to make it up the road.

As far as proof for diesels' torque "making it to the ground, take a look at this dyno chart:

http://forums.tdiclub.com/showthread.php?t=43373

I'd say 250 lb-ft *at the wheels* is getting decent power to the ground...that would be damn close to at least 280 lb-ft at the crank.

↓↑report

Sam, LS2 is just saying that power is a figure of torque multiplied by RPMs.

-- Technically, torque isn't really the number that has anything to do with how fast you accelerate, power is. You always hear that having low-end torque makes a car have more grunt. That's true because having more torque at any RPM makes the car have more power, but since you spend more time in lower RPMs, low-end power is more accessible. The reason low-end torque feels different from high-end torque is that the *jerk* (jerk is change in acceleration) is higher when the torque is lower, so with low-end torque the power comes on faster. However, jerk is just the rate of change of acceleration, not the actual acceleration.

-- Torque times RPMs times a unit-coefficient equals power. Power is what accelerates you. If you produce the same amount of torque at 2000 RPM and 4000 RPM, at 4000 RPM you produce more power, and thus you'd accelerate quicker.

↓↑report

One of the best comparisons of torque and HP I've seen lately is this,

"TORQUE answers the question "Will it be able to do it?"
POWER answers the question "How fast will it do it?"

It's simple and easy to understand. Others include, "Torque is what gets you there, power is what you brag about" and "Torque is what gets you up to speed, power is what keeps you there".

As far as the TDI Jetta performance, surely it won't win many drag races, but it's again built with economy in mind. That being the case, it will have no problem keeping up with other similarly-designed vehicles like the Prius. The difference will be farther in favor of the TDI when the cars are loaded down with cargo and/or passengers or when the driving terrain features significant elevation changes.

It is correct that higher RPM's can allow torque multiplication and there is some validity there. But, from an economy standpoint, an engine not working as hard generates better fuel economy. So, an engine making it's max torque at a low RPM(and over a wide range), won't have to work as hard as an engine which has to rev much higher to achive higher torque figures. Again, refer back to the first comparison.

↓↑report