Toyota Prius proves a gas guzzler in a race with the BMW 520d

Re: Another Prius hating web site?

The regenerative braking on the BMW runs the alternator during braking, using it to charge the battery, instead of steadily running during normal cruise. It is a simple yet effective way to squeeze a little more economy out of a normal power plant.

Tom

 

Re: Another Prius hating web site?

Great test:

• just highway - "welcome to the streets of . . . " said the Prius to the BMW
• manual transmission - the standard diesel 'test' configuration

Personally, I think the best answer is to let those taken in by this faux test suffer their just rewards.

Bob Wilson

 

Having spent some time on one of the diesel boards lately having this same discussion, I can definitely say this is a pretty sedate conversation by comparison. They do seem to get very worked up and defensive about the topic. There are some good arguments for diesel vs. gas, and plenty the other way too. I think for now hybrids give the gas vehicle a definite advantage for most peoples needs. We'll see if a diesel hybrid can help level the field again, a lot will depend on how well designed the system is. As we've seen from some of the recent entries, all hybrid systems are not created equal. VW seems to be shooting for a 35% improvement over the Euro 1.9L, which is pretty aggressive but should be doable with a good design.

The price of diesel certainly isn't helping, this weeks US average is $3.28 for regular and $3.97 for diesel.

Rob

 

here in the EU i drove a toyota corolla verso almost 4000 rpm on the highway
manual speed at 120kmph
i really don't like that car

and the lowest rpm at normal highway speeds ( 120kmph ) any manual car i have driven was 2600rpm

and thats not droning!! or any unpleasant

i also drove a american automatic and it when towards 2500rpm
v6 3,8liter. 4 speed manual.

 

BMW 520d got 50.3 MPG while Prius (Touring Edition?) got 48.1 MPG. The route was definately designed for diesel's advantage -- 350 miles highway and 100 miles city.

Effiency wise, Prius beat the diesel. 50.3 vs 48.1 is only 4.6% difference. The energy density between gasoline and disel is about 15%. Therefore, Prius is at least 10% more efficient than 520d even on the highway. If you add in the aerodynamic and size in the equation, you can conclude they are about the same.

That's a good thing because Atkinson cycle gas engine is as good or better than Diesel at partial load driving.

Do another test with 350 miles city and 100 miles highway and see the results. Prius can easily double the 520d mileage.

 

I don't blame you, the corolla is a bit... crappy.

I've driven an Aura, and at 70mph it was turning ~2400rpm, which isn't bad.

I suppose the answer is, I don't care? I was just pointing out that assigning a static value of 2700rpm at a certain speed to all automatic/manual transmissions cars is a bit absurd. Chill dude, chill.

FYI -- I don't think the Prius *often* dips below 1200 rpm at those speeds... mine, for sure, was more on the droning side of things at speeds over 65mph.

 

Maybe not 1200rpm, but lots of muscle cars are geared very tall in top gear to get good freeway mileage. Corvettes turn around 1500rpm @ 60mph. V-8 Mustangs and Dodge Magnums are also in that 1500-1700rpm range.

 

Re: Another Prius hating web site?

As mentioned in another thread, the guy driving the Prius wasn't do it any favors either. He managed to average 40mpg US, and then threw in all that baloney about not using the radio and AC just to squeeze out every possible mpg. Even at 70-75mph on the highway I usually average 48mpg.

Rob

 

Re: Another Prius hating web site?

the guy driving the prius screwed himself when he floored the gas to break the boredom.

 

Re: Another Prius hating web site?

Saw this one too,

Maybe somebody else also noted it:

Is it possible that a Hummer's better for the environment than a Prius is? - By Brendan I. Koerner - Slate Magazine

 

its not for good mileage is for high speed!
when you drive 60mph and rpm is 1700 then at 5000 rpm you can go a lot faster then when you go 60mph and 2700 rpm
when you paddle to the metal then it stopt with 6500rpm

those engine are also a lot bigger to you can let the rpm go lower because there is more torc at lower rpm so it Will not stall that easy

you comparing a 1.5 4 cyl engine with a v8 5 liter ?

 

I guess my reply was more toward Per. My point was that CVTs are not created equal. HSD achieves CVT-like functionality with a simple power split device and it is superior to any other CVT out there. HSD can take ICE RPM where even the manual tranny can not as well.

 

The gearing maybe for high speed, but it also gives good fuel economy in the hands of someone trying for it.
The econo trim of the Volvo C30 uses taller gears for better fuel efficiency.
Hypermilers will swap out gears and differentials to get below 2000rpms at cruising speed with 4 cylinders. You don't need much torque once you are at speed.

 

Wow! Are you sure about that?
You mean a Prius has a higher "top gear" than a six speed Corvette with a 6 liter, 400 ft.-lb., 400 hp V8?
That's amazing!
No wonder the Prius gets such good highway mileage!

Okay, seriously now, of course I know that my Prius doesn't always operate at that gear ratio. But when I listen very carefully I can hear that it immediately goes into "super-overdrive" at every opportunity, such as when going down a gentle slope or during gradual deceleration. That saves a little gas compared with conventional transmissions which force the engine to run at unnecessarily high rpm's under those conditions. And when more power is required, it immediately changes the effective gear ratio to precisely the optimum required, whereby it has a practically infinite number of ratios to choose from.


PS for those not familiar with Prius' Hybrid Synergy Drive (HSD). The Prius has an electric-CVT (Continuously Variable Transmission) which has less friction than the conventional mechanical-CVT's found in some other cars. Also, the power split device (PSD)(a simple planetary gearset) transfers only about 28% of the engine torque through the e-CVT, and the rest is transferred directly through conventional fixed gears to the wheels.

 

Re: Another Prius hating web site?

Even so, I've driven long highway trips at 75-80mph with bursts to 85-90mph and still managed low 40s. If his city driving was of the accelerate hard, slam on the brakes type driving, that would also contribute to the low fuel economy, but if it was of the slow crawling type of city driving, that should have significantly boosted his fuel economy.

I find that whenever I get stuck in traffic on the freeway that mostly just crawls along with gentle starts/stops, fuel economy goes up significantly. But in stop-light to stop-light driving where you are pressured to race towards the next stop light, fuel economy goes down significantly.

Anyway, all they've proven is that the two cars can return similar fuel economy, but the diesel still emits a lot more pollutants. Let's re-run the test with vehicles that emit the same amount of pollutants and lets see who comes back with better fuel economy.

 

Re: Another Prius hating web site?

Actually, I think they also mentioned that the BMW is faster. Added to that it handles better, stops quicker, and is more comfortable, altho more expensive... but at least the Prius manages to match it on economy.

 

Re: Another Prius hating web site?

LOL, good point.

 

WRONG.

The gearing on a Corvette Z06 in 6th gear is so high that it goes faster in 5th gear than in 6th. In 6th gear the engine rpms are so low it never hits its horsepower peak. In 5th gear the rpms are high enough for the engine to hit the horsepower peak, so it will do 196 in 5th but only 180 in 6th. It's pretty common for high performance cars with tall top gears to not reach max speed in top gear.