Gen 4 Staff Manual (In Japanese) =/ Specs/Design/Other Info

I think it may have been either "lost in translation" (they saw cheaper, lighter, more efficient, 20% and connected the dots) or Toyota over-promised and under-delivered, so when they realized they had backpedal on it. Later more likely.

The only car in recent history which did loose 20% is Mitsubishi Mirage, but to get there in addition to usage of weight saving materials and design optimizations, they had to re-think packaging completely.

 

please link an article from a toyota official stating gen IV prius will be 20% lighter, finished product. until then, it seems the lie's may be coming from the haters.

 

your link says 'eyeing to trim the weight', not guaranteed to. the headline is typically misleading.

 

let's pretend for a moment that 20% was never mentioned. Maybe they didn't tell that it will be lighter? Because it definitely isn't.

 

maybe, i have no idea. actually, weight doesn't concern me anyway. i'm more interested in mpg's and features. if mpg's are up, i don't even mind if it weighs more.

 

FHA studies had shown that reducing weight improves MPG, performance or both. Just by reducing weight by 20% they would have improved MPG by 8%; by 12% if they downsized engine. YMWW. It will be 8-12% less.

 

i can't argue with that. i'm just more interested in the finished product, but i do appreciate your thought provoking questions. you have a way of stimulating discussion. i just find it frustrating not to have many facts to go on.

 

Weight is important but even more important is where the weight is.
For MPGs, the most important place is on the wheels. The difference in weight between an alloy rim and a stell rim is not so much, but the difference in MPGs is noticeable.
At the same time, I didn't notice any difference in MPGs when I drive alone than when I drive with all my family, and that's 150 kg difference, 10% of the car weight.
A downsized engine has two other advantages that can result in higher mpg, not only weight: they heat in less time and usually less fuel is needed to keep them at minimum rpms.

 

I gather you're saying alloys weigh less. In my case the opposite is true, lol: have the OEM 17" alloys, and use 15" Corolla steel rims with snow tires.

 

I've heard about that very effective medication... I think it was called placebo.

 

We alternate between 215/45R17 Michelin Pilot HX MXM4 on OEM rims, and 195/65R15 Michelin X-ICE2 on Corolla steel rims. Last year I'd swapped over about a week earlier, asked my wife how they were feeling. She'd completely forgot, guess there wasn't much difference. I could feel a difference, mainly just the cushier, higher profile ride I think.

Where I really did notice a difference was in test drives (or at least I've convinced myself on this), first a model with 15" alloys, then the 17", which we ended up buying. Like the steering feel better, feels more planted or something.

 

The different steering set up for 15" and 17" models might be part of the difference you felt when buying.

 

There was an external combusion engine in Stanley Steamers, but they're fairly rare on the roads nowadays. So why do some folks feel the "I" is still needed to make clear they're not talking about one of those? If you're too lazy to type out all 6 letters of "engine," how 'bout just "e" for an even easier acronym?

 

20% less friction is NOT the same as 20% more efficient, not even close. For (purely hypothetical) example, if a mechanical device is originally 90% efficient, 20% less friction would make it 92% efficient. 20% more efficient would be 118% efficient, which is highly improbable.

 

Oh most definitely. At least that's my feeling.

 

Or could be tires. When we swapped tires to different brand the difference was night and day, and they both were the same size. Add on top of that 20mm wider and 25mm lower sidewall

 

it's easy to say ice. ce is more difficult to pronounce.

 

they certainly did not say Prius will be 20% lighter... you seem to be confusing things left and right.

 

so you seem to be confused between official PR about new platform and whatever blog added on their own as their conclusion... PR says TNGA platform weight will go down by up to 20% and then blog makes up Prius being produced in the USA and being 20% lighter. Its not being produced in the usa and its not 20% lighter.

Pretty obvious they decided to make Prius better car and invested whatever weight savings TNGA got, into that... suspension, interior, sound proofing,, etc, etc, it all weights more. I am certainly glad they didnt decided to strip it all down to the basics like before. I like the fact that it is a lot more rigid than Lexus GS and that door slams a lot nicer than CT200h. Base equipment will likely be much better than before too.

I do hope that it isnt slower than before, especially in crucial mid-range thrust. Apart from looks, thats my main concern right now.

As to the weight, i just checked Auris 1.4d and 1.6d weights, difference is 95kg, apart from the engine, there is also torsion beam vsdouble wishbone difference.