Filed under: Diesel, Hybrid, BMW, Toyota
Toyota Prius is a gas guzzler compared to the BMW 520d
When it comes to getting great fuel economy, there is definitely more than one way to skin a cat. The Prius may be thrifty but it certainly isn't the be all and end all. Just to demonstrate that the Times of London decided to go for a little a road trip with a Prius and a BMW 520d. While the 535d that we tried out a couple of months ago is a mighty machine, it's only the tip of the iceberg for 5-series diesels. Starting things off is the 520d with a 2.0L four cylinder diesel with 177hp. In a large sedan the size of a 5-series that may not seem like much but the diesel torque still manages to get it to 62mph in a respectable 8.3 sec. That's more than enough to easily merge onto highways without feeling like you're about to get run down by that oncoming truck. That's also about 2.7 seconds faster than a Prius. But of course the Prius is specifically designed to have a minimal thirst for fuel. So how did they do? On a jaunt from London to Geneva, that specifically included an extra 100 miles of city driving just to let the Prius shine, the Prius managed 40 mpg (U.S.). The 520d on the other hand managed 41.9 mpg, all in real world driving conditions. So who says GM has to cancel all their rear wheel drive programs to meet the 35 mpg standard?
[Source: The Times of London, TTAC]
Reader Comments (Page 1 of 2)
Richard 10:03AM (3/17/2008)
More importantly, that's very comfortable performance for the vast majority of folk driving a 5-series (at least in my neighborhood). Good mileage, a comfortable, "normal," heavy sedan, seating for five, and reasonable acceleration. What's not to love?
Apart from the price, of course, but that's just endemic to BMW :)
When doing diesel reviews, perhaps quoting torque numbers (in lb-ft) would be better than comparing horsepower ratings?
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mike k. 10:04AM (3/17/2008)
Very interesting. The point GM says about canceling RWD programs for fuel economy has always been a croc. Its not about the RWD that makes it less fuel efficient its what they want to put in to drive said RWD platform.
My only problem with this article is its apples to oranges. Things like price of Diesel vs. 87 octane unleaded gas.. or the emissions impact of that same mileage between the two cars past just the fuel consumption... etc..
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Richard 10:11AM (3/17/2008)
BTW, the BMW was priced at 1.3x the Prius (its meaningless to directly translate from Euros/Pounds to Dollars). Of course, the Prius was probably hit with more import taxes than the BMW in Europe, whereas they're both hit over here in the 'States, but for only 30% more cash I think I'd take the 520d too.
As for fuel prices - does it seem odd to anyone else that diesel is now 20-30% more expensive over here than gas? Just a few years ago it used to be a few cents cheaper than regular unleaded throughout the country. Is there a good economic reason for this, or is it just due to oil companies trying to make fuel-sipping diesels less attractive? Normally I avoid the conspiracy theories, but this one makes me wonder...
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joe cross 10:22AM (3/17/2008)
Hopefully we will soon have a closer comparison between the Camry diesel vs Camry hybrid.The real advantage comes when you factor in the toxicity involved with the manufacture and recycling of 400 lbs of batteries.Toyota will be forced to include clean diesels in their portfolio as soon as people get to drive the Accord and Maxima diesels here.I want a RAV4 diesel.
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Snowdog 10:28AM (3/17/2008)
ULSD increased the price of diesel to some extent, there may also be refinery limitations, so a tight supply.
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Mattias 10:36AM (3/17/2008)
#4: Why should one directly compare diesels and hybrids? Both excel in completely different usage scenarios. Diesels win on typical long and smooth commutes with relative few stop-and-go situations. In city traffic, they are sometimes even worse because of the heavier weight. Hybrids can score in typical traffic jam, short commutes or stop and go traffic in the cities. Besides that, regarding NOx it makes more sense to use hybrids in the city.
Of course a comparison could tell you exact numbers, how many miles per year make diesels more efficient and what percentage of city traffic makes hybrids better. And yes, diesel hybrids would combine both advantages, but they would alos combine both premium prices.
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Taser 10:42AM (3/17/2008)
First, BMW needs to get that diesel certified for U.S. emissions, then we'll talk.
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Hank 11:16AM (3/17/2008)
"So who says GM has to cancel all their rear wheel drive programs to meet the 35 mpg standard?"
It'll probably be California, who doesn't seem to want clean diesel technology.
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MikeW 11:26AM (3/17/2008)
I don't believe that a 2nd generation ZF 6 speed automatic should bring mileage down that much. Maybe it is still the first generation ZF 6 speed auto.
Regardless, time for the ZF 8 speed automatic. Show that stick who is boss!
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Mark 11:40AM (3/17/2008)
I have never, NEVER, gotten less than 45 mpg for a tank in over 70,000 miles of driving my Prius. That includes all day trips down the interstate at 75mph+.
You'd have to work at it to do that badly.
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Mr Dennis 1:39AM (7/28/2008)
Are you relying on the Prius' inbuilt computer for that, or actually measuring the economy yourself? By all accounts the inbuilt computer seems to way underestimate the true fuel consumption.
KarenRei 12:28PM (3/17/2008)
A sample size of one is statistically meaningless.
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wxman 12:39PM (3/17/2008)
#6 Mattias -
I agree that each excels in different usage scenarios.
However, limiting NOx in urban areas generally will not help ground-level ozone (smog), and in some cases, can actually make it worse, since urban/suburban areas in the U.S. are nearly exclusively VOC-limited.
The only way to decrease GLO/smog levels under these conditions is to limit VOC emissions.
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rgseidl 12:49PM (3/17/2008)
First off, miles per gallon of what exactly? Comparing MPG numbers that are based on different fuels is a total mug's game because they feature different energy density. Either compare miles per unit of energy (GJ), total CO2 emissions or, miles per unit of currency - depending on what you care about.
Second, even with the inclusion of 100 miles of city driving, this test run was skewed toward freeway miles at fairly high speed - something the Prius wasn't optimized for. The conclusion consumers should draw from this test is the same as the one from all the previous tests: gasoline hybrids are better if most of your miles are in stop-and-go traffic, diesels are better if you spend a lot of time cruising at freeway speeds.
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smog 12:53PM (3/17/2008)
I have never, NEVER, gotten less than 50 mpg for a tank in over 70,000 miles of driving my Jetta TDI. That includes all day trips down the Highway at 90mph+.
and it's a seriously tweaked out Jetta putting 200hp and 360lb.ft @ 1800 rpm
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daniel billinton 1:10PM (3/17/2008)
It has been widely reported that the Prius in real world conditions doesn't achieve the claimed 55mpg(US) and achieves more like 40mpg(US).
This is almost certainly because the test drive cycle is so slow and has many stop starts and so favours hybrids.
The Prius is a step in the right direction but is very heavy due to the batteries and is a triumph of marketing over reality in our binary world. i.e. Prius good, SUV bad
I would have thought that the BMW 318d SE is a fairer comparison to the Prius in terms of size and performance - and it achievs around 52mpg(US) and 123g CO2/km - and BMW will gradually be introducing them to America as they comply with NOx regulations
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T2 1:59PM (3/17/2008)
re RWD effiency.
A FWD 3:1 single stage spur gear reduction has a loss of 7%.
A RWD 3:1 hypoid gear stage which simultaneously has to turn the power through 90 degrees has a 30% loss. That is the reason why the rear transmission has a particular oil type to cope with the higher temperatures generated by those losses.
T2
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Earl 3:02PM (3/17/2008)
40 MPG? You'd have try to do that badly in a Prius. I've never got below 50 mpg for a tank of gas. By the way, anyone else notice diesel is at $4.00/gal? I'll stick with my $3 gas+hybrid combination over a diesel anyday of the week.
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Warner Young 3:05PM (3/17/2008)
40mpg seems a little low for a Prius. I don't drive very carefully in mine, and it's mostly highway driving, and I've been averaging 48mpg over the last 6 months or so, at roughly 200+ miles per week.
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Snowdog 4:35PM (3/17/2008)
Bah!
Everyone breaks out the personal anecdotes in the BS war between Hybrids and Diesels. Here is long term test of both to give some real world numbers to both and make both sides whine, Edmunds known to beat the crap out of the cars for over a year with multiple drivers.
PRIUS:
http://www.edmunds.com/insideline/do/Drives/LongTerm/articleId=101393/pageId=66588
Current Odometer: 40,687
Best Fuel Economy: 50.1 mpg
Worst Fuel Economy: 33 mpg
Average Fuel Economy (over the life of the vehicle): 41.4 mpg
VW Beetle TDI:
http://www.edmunds.com/insideline/do/Drives/LongTerm/articleId=44033
Final Odometer Reading: 32,406
Best Fuel Economy: 48 mpg
Worst Fuel Economy: 21.5 mpg
Average Fuel Economy: 36.5 mpg
Both sides can put that in their pipe and smoke, but particularly the "Diesel better than hybrid in the real world" crowd.
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