Prius facts to hang your hat on

Take two cars with empty fuel tanks and put them side by side. Put exactly the same amount of fuel in each and run them on the same course at the same time until they are out of fuel. When this happens I'll believe the story. Any other comparisons are not valid due to all the different variables. Just ignore the stories.

 

<div class='quotetop'>QUOTE(jkash @ Jan 20 2007, 09:07 AM) [snapback]378217[/snapback]</div>

See my post #12 in this thread:
http://priuschat.com/index.php?showtopic=28578&hl=

All the serious studies of the issue that I found showed that hybrid gas vehicles significantly outperform the equivalent diesel-powered vehicles in terms of overall wheel-to-well efficiency.

 

A whole lotta folks pitching their 2 bits on this thread, so here's mine:

Calculated mileage for life of car ('07 Prius) is 44.8 mpg.

Calculated mileage between 'fillups', varies quite a bit (35 to 60 mpg). The 'rubber bladder effect' of the fuel tank probably accounts for most of this.

Computer mileage (around town) between 43 (winter) and 46 mpg (summer).

Best computer mileage 53.1 mpg (on trip between Santa Cruz and Arizona border, heading for Grand Canyon). Worst computer mileage 38 mpg (Arizona border to Williams, AZ), mostly due to markedly superior highways to those in CA and the 75 MPH posted speed limit (I found myself driving 80 to 85 MPH over this stretch. The highways in AZ seem to be engineered on purpose to make this speed feel 'natural'.) (BTW: It looked like trucks outnumber cars (at least on the the AZ Interstate) better than 10 to 1, and more than a few were driving 'very conservativly' at around 65 mph.)

Here in Santa Cruz, CA, better than 2% of vehicles on the road (incl. busses, trucks and motorcycles) are Prius's (Prii?).

Santa Cruz is an expensive place to live (median home price nearly 1/2 million $). More than a few folks here can afford to buy a Prius, so I rather imagine that there is a nearly corresponding reduction in the number of SUV's and BMW's being driven around here for every Prius I have seen on the road.

As far as mileage goes.... One can truely buy a much less expensive car that gets not too much less mpg than Prius. I think it is really great that more and more folks are putting fuel efficiency higher up on the list of criteria for their next car purchase, no matter what make or model they choose.

As far as bio-fuel.... what works,.... works. However the stuff bio fuels are made of is getting more expensive. (Among other things, every acre of corn that goes into a tank is many less sacks of 'surplus' corn (or wheat) stenciled with a great big 'USA' that has been 'traditionally' shipped off to help feed the unfortunate people in other parts of the world suffering from drought, natural disasters and war. The USA loses quite a bit of PR. What's kinda' worse is that (in my view, at least) the average (?mostly illiterate?) folk in those areas (because of the www, satellite TV, etc.) now have a better idea why they may be suffering more than they would otherwise.

Note: A (the only?) bio-diesel station in Santa Cruz just closed 'cause they couldn't afford to buy the next tanker load of fuel. Note: This enterprise was not established to 'make money' (charging only 10 to 25 cents per gallon over cost). It's purpose was to promote local use of bio-diesel. Unfortunatly, their markup couldn't keep up with sudden rise in wholesale cost. They hope to reorganize as a membership cooperative.

OK... 4 bits... But now I am finally tired enough to go to sleep (now 3 AM).

Gary...

 

+1000000

lets get all these myths over with, i want to shut all the haters up

 

The other problem with the initial "experiment" is that the cars should have been driven at the same time in the same manner in the same direction.

In tests where the conditions are held as similar as possible (EPA or even the recent Edmunds test), the Prius does better than the diesel.

 

and to add to that -- take in consideration cost of diesel II vs regular 87 octane gas.

 

Not intending to be smug There's a slight learning curve for driving a Prius most efficiently, these people who drive a Prius once and compare a Prius mpg to another car are just going about it all wrong. In addition, we all know that mpg will go up with time due to both the driver and the car breaking in, probably more so than a "normal" car. Also there are very simple things to increase the mpg even more such as raise the TP a little, get an ebh, and a Scangauge so you know for sure when the ice shuts off.

Since I bought mine a little over year ago I've never had less than a 49 mfd mpg tank, the first tank after I bought it was 52 with dealer tp and not knowing anything, probably just due to knowledge gained by lurking here in PC for a month before buying it. My average is in the sig, last 6 tanks have been over 58 mpg. I'm commuting using the same route I've used for 10 years, mixed freeway and stop and go. Give ME another car to compare over the same course for a tank of gas, and that would be a fair comparison for my commute. Other's mmv.

 

that video was sweet...thanks for showing it to us.

 

your welcome

according to that video the PRIUS still reigns SUPREME over its so called "competitors"

 

Despite their attempts to downplay it, looking at the numbers definitely made Prius the winner. Best in overall fuel economy (only 1.3/1.2 mpg worse than the TDI on back roads/highway, but 19.9 mpg better in city), best in emissions, and best in cost of trip. Seems like to me there was a clear winner, despite their statement saying otherwise.


Anyone else a little surprised by the backroad numbers? I would think that cruising from 50-65 mph would have netted above 50 in the Pirus, but maybe it was the terrain?

 

Or the wind, or the temperature, etc.

Even in a test like this, driver technique would have an effect; was the Prius driver savvy enough to take advantage of gliding, or did they just keep it on cruise control?

 

i'm willing to bet the driver of the prius didn't even know how to take advantage of the pulse, glide and warp stealth. otherwise 50+ is a simple feat.

someone mentioned earlier that our prius's must be driven with proper techniques based on experience. you simply cannot hop from a gas driven vehicle and expect to get ballistic mpg's right away. put some of the experienced drivers behind the same test..............GAME OVER.

PRIUS WINS BIGGER!!!!!

 

THANKS KANDY for the video. sweet.

 

Yes this is the major error in the whole 'test'. It was so grossly anecdotal and biased as to be rendered useless.
It was not done in parallel, using the same route, at the same time, with randomly alternating drivers.

In fact the diesel was driven from NW to SE generally with the prevailing weather and the Prius was driven SE to NW generally against the prevailing weather. One of the key fuel economy factors all the 'real world' testers ignore is the effect of weather on all vehicles. Wind and inclement weather can reduce the same vehicle's fuel economy by as much as 15% over the same route.

However there is no denying that the diesels are in their element on long highway trips. However they are no better than mediocre in slow city-type driving. Combined they fall short of the hybrids in fuel economy.

If one has a 90% Highway drive, and that will never vary, then the diesels are a very valid choice for using the same or less fuel than the hybrids. However as we see now at a 20-25% cost premium diesels have no cost advantage over a similarly sized hybrid.

1) the diesels use about the same or slightly less fuel than a similar hybrid on the Highway
2) the diesels use 50-70% MORE fuel than a similar hybrid in the City
3) the cost of diesel fuel is normally 10-25% higher than gasoline.

That's all that can be said, do your personal calculation.

 

not to mention that Diesel currently costs more then Gasoline.

 

I agree but would add that for an accurate test, it would be best to use a small auxiliary fuel tank. Stock fuel tanks usually can't access all the fuel in the tank due to the position of the fuel pump.

The test should also take place on a track with the vehicles driven at a steady state with one starting half way around the track so they are always positioned 1/2 a track apart. (You can't have one follow the other due to the reduction of drag for the following car.)

I just attending an event where Adam and Jamie did a question and answer session and showed some behind the scenes and non-released video from Mythbusters. From what they said, in general, they have about a week to set up and shoot a myth. That would explain why some of their tests aren't that scientific.

I also found it interesting that they both said that they generally don't like each other and don't interact except on the show. (Adam used to work for Jamie but quit but didn't last too long working together due to the different personalities)

 

the video test was all done together in their controlled environment all at the same time going the same route in the same weather side by side
although driving technique would have made the Prius win by a larger margin, it was NOT necessary...clearly the prius wins hands down regardless of what the "commentator" said