Prius Hybrid vs. VW Diesel (new tech)

<div class='quotetop'>QUOTE(SB2 @ Sep 5 2007, 11:49 AM) [snapback]507433[/snapback]</div>

How do you "know" this?

Even if the claim were true, per http://www.autoblog.com/2006/11/10/domesti...nsumer-reports/ and many other reposts of Consumer Reports data, VWs still have poor reliability. For the worst predicted 07 model reliability, the Jetta, 4 cylinder Passat and Touareg (not surprisingly) made it in the least reliable column. If you want to see the gory details, get an online subscription to Consumer Reports, look at their cars guide at a bookstore or look at the April 07 auto issue.

They also did badly at http://www.jdpower.com/corporate/news/rele...aspx?ID=2007130.

 

We have two extremes in our family. My wife drives like a race car driver with many short trips so she gets about 51 MPG. I am a very conservative driver with only 25 min work commutes and get around 70 MPG.

I like the new VWs but reliability was a concern for me. The Prius has been very very low maintenance. Just oil changes, gas, and tire pressure. The tires are so cheap ($40 ea) that I do not even both rotating them. Just cheaper to buy new ones but so far the wife's is on 40k miles and no uneven wear.

I hate the Prius seats. I think seats were an after thought. The enginerds after marveling at the Prius' greatness thought, "Oh yeah someone has to drive this, just toss a seat in there."

The plug in option is at least 2 years away OEM and for early adopters for after market (expensive too ranging from $10k-$40k).

You would get more throwing PV and water solar arrays on your roof than getting the plug-in option unless you just want to be the cool kid on the block.

The car is more than transportation to the American. Drive what you like and can afford. If you get the Prius and are unhappy with it then you will hate dring, likewise for a VW. Follow you gut feeling. At least both of your choices are fuel efficient.

 

Toyota represents the highest in automotive engineering, probably in the world. If that's not good enough then buy a VW. Just remember, you'll be driving an inferior vehicle and likely more troublesome especially with "new" technology. VW isn't exactly known for great electronics. Just because they can create a diesel engine that is reliable (why wouldn't they be able to, it's old technology), doesn't mean the car is reliable in other ways. I would stay away from their new technology with a ten foot pole. It's more than just driver preference, Toyota is superior overall. The electronics alone in a Prius....I wish other car makers were this good. My Prius is too reliable, my brakes are practically barely used....the car is a marvel really.

 

I had the VW Rabbit diesel for several years when they were the craze. The city mpg was much less than Prius. The engine used a timing belt. Many parts had to be replaced within 30K, like the brake rotors and glow plugs. The highway mpg was closer to Prius but not equal, about 5 mpg less, both driven the same way. Using diesel fuel involves worry about the fuel filter and water in the fuel. Cold starts are more polluting and noisy. Acceleration is more polluting and nasty to everything. I will never again buy a diesel engine car. If I am behind a diesel truck or car I can smell the exhaust and try to avoid them.

 

I've owned a 2000 VW since 1999. Biggest mistake I ever made. I'll never buy another VW again.

I suggest going to http://www.carsurvey.org and http://www.myvwlemon.com/ to read what people are saying about them. I wish I knew about these sites before I bought mine!

Even if VW has greatly improved over the years, they've lost me as a customer forever.

 

<div class='quotetop'>QUOTE(Mr.Vanvandenburg @ Sep 6 2007, 10:58 AM) [snapback]507947[/snapback]</div>

Since you called it a rabbit, that means that it was model year 1974 to 1984. You are talking about a car that was made more than 20 years ago! The 5th generation Golf, called the Rabbit in the US has not been available with a diesel. Your experience with a more than 20 year old diesel is irrelevant to today's modern, electronically-controlled diesels with pollution controls.

Your experience with diesel trucks is irrelevant as well. Trucks, both medium duty (F350, GM 3500) and heavy duty (semis, buses) have completely different and much less stringent emission regulations than light-duty diesel vehicles (cars).

 

SB2,

The only regret I have about my TDI is not getting the Wagon I testdrove more than 11 years ago.

The Prius will definitely provide you better city MPG, 49 on my wife's errand-running with the kids. But since you said majority of your driving is highway, you better take it slow (below 65) to go above 50MPG.

My 96 Passat TDI sedan has over 300K miles on it. Still in original motor (block and head), transmission and clutch. It beats my Prius on my 30+ mile one-way daily commute in Northern NJ when I drive normally.

I experimented with the Prius and followed the advice I read from this forum with my normal commute. The best I got was 52.1 MPG on that tank in less than a week at 510 miles. I really had a hardtime doing this. Staying below 65, a lot of pulse and glide, coasting very far from intended stop. I'm not in the plains. There's quite a bit of hills and valleys.

After that, I performed the same experiment on my 300K mile TDI. I managed to put over 600 miles and still have a little under half a tank left. I went back to my old driving habit on the TDI and refueled with over 900 miles on the same tank. It calculated to about 55.3 MPG (it didnt come with the nice FE computer like the Prius did, so I actually have to wait til the next refuelling to find out). I wondered how well my TDI would have done if I continued my experiment on the whole tank.

Mind you, 5-speed B4 Passat sedan has an 18.5 gallon tank while the prius has 12. Normally I get between 750-830 miles per tank on the Passat and 425-475 on the Prius cruising at 70MPH. I usually refuel when the fuel guage needle hits the 2-gallon mark.

CR rated my passat as having poor reliability. It didnt develop any squeek nor rattle until the muffler rutted out. My prius however is only 20 months old with 29K miles and there is already a rattle on the driver side door and under the radio.

 

Can anyone honestly say it's irrelevant with respect to clean air? I mean, honestly, I pull over and find a place to "idle" in my Prius whenever I'm behind a diesel truck. There's just no way anyone can convince me that it's okay to have that violating my airspace.

Clean diesel or no, it is the same with old gassers that really shouldn't pass emissions. I'll stop, and pull over (or hit recirc if my windows are up) to let the polluter get far away.

Now, here's a scenario: a hybrid is belching smoke...doesn't do the hybrid "image" very good. Same with diesels for the past 20 years...how do you get around that image? Very slowly...until that image is "cleaned up", then the hybrid clean marketing will win.

 

Don't forget to take emissions into account. Its great that it gets good mileage (good for CO2) but you need to make sure and consider what else is coming out of the tail pipe. Check out this thread, where we've been trying to get a handle on this issue:

http://priuschat.com/index.php?act=ST&...=38289&st=0

According to my latest calcs, the 2006 Jetta Tdi puts out 25X more smog forming emissions than 2006 Prius, and 374X more than the 2.5L Jetta low emission version. Hopefully the 2008 will be a big improvement, buts its got a lot of ground to make up.

Rob

 

<div class='quotetop'>QUOTE(Rob Smith @ Sep 6 2007, 01:28 PM) [snapback]508022[/snapback]</div>

Actual Data from 2006 EPA Testing: (http://www.epa.gov/otaq/crttst.htm)

Car---Engine --------------------------CO-----NMOG---NOx----PM----Total (g/m)-----Standard----2008 EPA Mileage
Jetta 2.5L Gas (GVWXV02.5257)--0.41--0.0033--0.000----N/A------0.4133--------T2 B2---------19/22/28
Jetta 2.5L Gas (GVWXV02.5253)--1.26--0.0290--0.029----N/A------1.3034--------T2 B5---------19/22/28
Jetta 2.0L Gas (5VWXV02.0224)--0.77--0.0205--0.012----N/A------0.8025--------SULEVII-------21/24/29
Jetta 1.9L TDI (6VWXV01.9238)--0.04--0.0194--0.310---0.046-----0.4154--------T2 B10--------30/33/37
Prius 1.5L Gas (6TYXV01.5MC1)--0.10--0.0090--0.010-----N/A-----0.1190--------SULEVII-------48/46/45

 

<div class='quotetop'>QUOTE(finman @ Sep 6 2007, 01:00 PM) [snapback]508004[/snapback]</div>

It is not irrelevant to clean air, but is irrelevant to compare diesel truck technology or a 25 year old, first generation diesel rabbit to current diesel car technology. It is no more useful than comparing a 1st generation Civic to a current Civic.

You are correct that diesel has an image problem in the US because when people think of diesel they think of an old non-regulated semi (pre-2006) leaving a huge cloud of smoke behind them or an old Mercedes or VW car doing the same thing. However, I am quite certain that if I put you inside a 2007 Mercedes S-Class or E-class and asked you if it was diesel or gas you couldn't tell the difference. BTW, the diesels are quieter at highway speeds. (I've been in diesel versions of both in Europe)

 

I like to see a similar video from a Diesel owner doing this.

23.1 miles trip with the Prius fully loaded and I floored it once on an uphill highway merge. I still got around 70 MPG. For those curious ones, see the route on Google Map.

Can you do that with a VW Diesel? Can someone with a Diesel provide similar video documentation?

 

<div class='quotetop'>QUOTE(usbseawolf2000 @ Sep 6 2007, 03:01 PM) [snapback]508090[/snapback]</div>

No you can't do that with a VW TDI. From looking at your video you seem to spend the vast majority of your time in stop and go traffic. The maximum speed I saw on your speedo was 55 mph and it looks like your average speed was about 25 mph. That is EXACTLY the conditions that a hybrid is made for. I don't think you will get very many people that will argue that a diesel is better than a hybrid for stop and go city driving. I won't.

However, the OP is going to do a long highway commute. These are ideal for a diesel and where the hybrid system of the Prius doesn't do a whole lot of good.

To throw out another irrelevant challenge, I drove a C-Class CDI on the autobahn from Stuttgart to Munich and back. I averaged about 95 mph, with a top speed of 150 mph. I got 30 mpg. Sorry, no video. Can your Prius do that? Mine can't.

 

Here is a summary of some numbers on the few available 2007 diesels. Improved over the older ones, but still pretty far off the hybrids as far as I can see. Guess we'll have to wait and see what VW comes out with....

Biggish Cars:
vehicle---------------Total Em(g/mi)---HC-NM+NOX-COMP(g/mi)----2008 EPA Mix MPG
Mercedes E320BT-----3.46----------------------0.169-----------------------26--------------
Mercedes E350--------0.25----------------------0.01------------------------19--------------
Camry Hybrid---------0.106---------------------0.01------------------------34--------------
Accord Hybrid---------0.329---------------------0.04------------------------25--------------
Lexus GS450h---------0.118---------------------0.02------------------------23--------------

Mediumish SUVs:
vehicle---------------Total Em(g/mi)---HC-NM+NOX-COMP(g/mi)----2008 EPA Mix MPG
Mercedes GL320 CDI---0.555--------------------0.99------------------------20------------
Mercedes GL450--------0.774--------------------0.05------------------------15------------
Jeep Grand Ch CDI----0.503--------------------0.94-------------------------20-----------
Jeep Liberty CDI--------1.302--------------------1.24------------------------21------------
Ford Escape Hybrid-----0.126--------------------0.01------------------------30------------
Lexus RX400h-----------0.017--------------------0.02------------------------26------------

More details here:
http://priuschat.com/index.php?showtopic=3...mp;#entry508223
http://priuschat.com/index.php?showtopic=3...mp;#entry508260

I'm certainly not an expert on this. In fact, I was looking for a reason to get a diesel when I started looking at all this. So far I can't make the numbers look even vaguely reasonable.

Rob

 

Rob, why are you so interested in HC-NM + NOx-COMP? Neither of us knows what it means. It would naturally favor gasoline cars though if you subtract CO from NOx. Diesel have lots of NOx and little CO; gasoline cars have lots of CO and little NOx.

I've included some CARB Sheets I've found. They don't include or explain HC-NM + NOx-COMP though.

Gen 1 Prius: http://home.pacbell.net/tocho9/toyota-prius.pdf
MK IV TDI: http://home.pacbell.net/tocho9/volkswagen-tdi.pdf

Also the EPA has a interesting breakdown of the big pollutants and their sources on their website: http://www.epa.gov/otaq/invntory/overview/...tants/index.htm


[EDIT] I GOT IT! HC-NM + NOx-COMP is not some sort of weighting of pollutants. It is just another test from the form for SFTP1 and SFTP2: [NMHC+NOx(g/mi)(composite)] [EDIT]

 

<div class='quotetop'>QUOTE(jhinton @ Sep 6 2007, 04:37 PM) [snapback]508112[/snapback]</div>

Since Diesel has 15% more energy than gasoline, you just only got 26 MPG (gasoline).

You or me definately can not do 150 mph top speed but 95 mph average speed can be done in a Prius. According to the Prius Energy Use Simulator, Prius can get 35 MPG at 95 MPH with zero ambient wind causing MPG gain or loss at 75 deg F. Tire pressure set to 44/42 with summer formula gasoline on a smooth dry asphalt.

I will not make a video going 95 mph since there isn't any highway that I can go at that speed legally. :lol:

 

<div class='quotetop'>QUOTE(usbseawolf2000 @ Sep 7 2007, 11:19 AM) [snapback]508600[/snapback]</div>

A simple "No the Prius can't do that" would have been sufficient.

Just going a steady 95 mpg isn't even close to the same thing. I averaged 95 mph from having to slow down for the 100 kph regulated zones and then speed back up to about 180 to 200 kph. It is amazing how quickly that car would accelerate even at 150 kph, but once above 200 kph, the last 40 kph to 240 took quite a bit of time. I've topped out every rental car I've had in Germany but usually cruise at about 180 kph. That trip though we were late leaving and I was racing back to the airport in Stuttgart.

 

<div class='quotetop'>QUOTE(jhinton @ Sep 6 2007, 10:00 PM) [snapback]508315[/snapback]</div>

Yeah, that confused me for quite a while too. I came to the same conclusion you did, its basically Non-methane Hydrocarbons + NOx Composite. My interest in it is only that its a quantity they often report and have standards for so it seems to be of some interest to the EPA and/or CARB. I assume that it is a figure of merit for smog emissions, as these two seem to be the main two ingredients for smog.

I also do see the value of adding everything up for a total emissions number, but it worries me that EPA/CARB do not seem to do this. For this to be a valid figure of merit, you have to assume that all emissions are equally bad relative to their weight. We know this is not really the case, as each quantity has a different certification standard. Another way to look at it is, that the total we are calculating is not really the total. Just the total of the things that are measured and reported. For example, we know that all these cars are putting out 150-300+ g/mi of CO2, but thats not even measured in the US (unlike UK). If you took the UK numbers and calculated total emissions, you would have a number completely dominated by mpg, via CO2. Ideally someone would cook up a weighted score based on the relative importance of each compound and its actual measured values. Its pretty lame that the EPA doesn't seem to do this, instead just coming up with an arbitrary score based on bin.

Rob

 

Web site www.truedelta.com is compiling independent vehicle reliability data. They have data on the 2006 and 2007 Passat and the 2007 Jetta/Rabbit. Both show a high number of "trips to the shop" compared to the 2007 Prius (which is one of the best cars in that regard).