Who has done their recall?

Exactly

Mike

 

Yeah, but I have a different take on this. Look at it this way: Push the pedal to the metal. Let's say that the power dissipation in the boost transistors goes to max, instantly. Now, the transistor has thermal mass and a really good connection to the heat sink and such, which also has thermal mass. Whatever the heck is going on, the temperature of the transistor is going to rise along the lines of an equation,

Ttranny = Tinitialtranny - (Tinitialtranny-Tfinaltranny)*(1-exp(-t/tau_tranny))

where tau_tranny is some time constant, t is time, and "exp()" is raising "e" to some power. (Like 10**2 = 10*10, etc.)
Note that in the above equation, at t=0 the temperature is Tinitialtranny; at t=infinity the temperature is Tfinaltranny.

The heatsink that the tranny is connected to has coolant on one side, it's own thermal mass (much bigger), and a really good connection to that transistor. When the pedal hits the metal, it's going to have a similar equation,

Theatsink = Tinitialheatsink - (Tinitialheatsink - Tfinalheatsink)*(1-exp(-t/tau_heatsink))

Now, the big idea when the transistor and heatsink are mated is that their rates of thermal expansion/contraction should be about the same. When we're in steady state (before 0 or after infinity ) the temperatures are very close, the materials in question are designed to expand and contract because the thermal expansion rates are the same, or Really Close, so the physical stress of the area of the heatsink under the transistor is small.

But what I'm guessing is that the tau_heatsink and tau_tranny, the coefficients involving thermal mass, are different enough so when we look at the difference in temperatures, assuming that the final and initial temperatures are very close, we get

Ttranny-Theatsink = (1-exp(-t/tau_tranny))-(1-exp(-t/tau_heatsink)) = exp(-t/tau_heatsink)-exp(-t/tau_tranny).

Put in different values for tau_tranny and tau_heatsink and you'll get an equation starting at zero, going up to some value, then back to zero again. Public, meet second order effect: Second order effect, meet the public. This is what I've meant by differential expansion: Difference, expansion, get it?

I'd rather expect that tau_tranny and tau_heatsink are very close, since the two devices are soldered together. But the difference won't be zero. Further, it's a good guess that this was all simulated and tested.. But the difference between a models program and real-world production can be more than one might expect.

My guess is that both time constants are in the 1-2 second range, although I'll take corrections from any thermal engineer sitting around. My guess is that Toyota slows down the rise in boost voltage (remember, it's only been the boost transistors that have been showing problems, not the motor drive transistors) during a floor-it onset in order to guarantee a maximum differential heating, the better not to pop the transistors off the heat sink. If this is true (and if you haven't seen handwaving before, you're watching it now) the most likely effect would be an initial slow down in acceleration - but after that one second (wild guess), you'd be up to your normal neck-snapping G forces. Or not, these are Priuses we're talking about.

A year or so ago somebody took a Prius and put it on one of those dynanometers, along with the BWM series 5s and such. A lot of laughter then ensued, but it'd sure be interesting to see what, if any, differences there are between a pre-updated and post-updated Prius .

KBeck

 

My butt dynamometer tells me that there isn't a discernible difference. If there is, I don't really care, just as long as it keeps getting 0 to 60 while passing the gas pumps. It ain't rocket science... Is it ?

 

Is the highway speed acceleration the same or darn close to what you remember? That is my concern that they turned the car into a freakin turd.

tnx,
Mike

 

I had my recall work done this week...and I've driven about 50 miles since then. I can feel no change in the car. Accelerates the same. FE the same. Still rattles in the dash (oops! Never mind)

 

I just noticed they added a little sticker on the underside of my hood saying they did the recall. It lists 2 service numbers as well as "E0E Recall".

 

Not to worry. They didn't perform a turdarectomy. It's fine.

 

That's cool. Don't need the torque reduced with my larger wheels. My car already is slower accelerating than a Prius with 15's.

Mike

Somewhere on my phone ;-)

 

My car felt noticeably peppier today but I think that was the result of the temps finally getting into the 30's after weeks of sub-freezing.

Honestly, I've put over 250 miles on the car since having the recall done and I haven't noticed any changes.

 

I'm with you BZzap. My outlook is the same as you'rs.

 

I made an appointment yesterday for 7 a.m., and they were done by 7:45 a.m. Haven't noticed any differences yet.

 

Got me a '13 Prius rental today It has the software update sticker on the door jamb. So far it seems to drive normal in PWR mode but I haven't driven a Prius since I put mine away last season so who knows Got the tires aired up to 44 psi all around. Going to drive it from Minneapolis to Cleveland in the morning and back to Sheboygan & Green Bay Wisconsin later in the week then back home. I should have some idea how it drives then. The battery meter is staying 2 bars from the top, mpg's are mid 40's but I was driving 70 or so mph from the airport to home (45 mile trip) Wish it was summer so I could line it up side by side with mine down the quarter. Oh well...

Mike

 

I just registered today. I went to the dealership to service my 2010 Prius that I just recently purchased 2 weeks ago. My radio has a quirk where it won't play music out of the front speakers but navigation prompts play just fine. When I took it in the service advisor told me they had to do a recall on it. He wouldn't tell me what it was, so I did a Google search and landed here. It took 2 1/2 hours to do the recall and find out my Jbl amp is fried. I didn't get a car wash, though However, I put 160 miles on my Prius today, mostly Highway but a little in town driving and a 10 minute death crawl through a McDonald's drive thru. I ended the day tonight with a 54.6 mpg average. It was mostly in the 50's and 60's today and since I am in Florida it is mostly even terrain. I can't say I noticed any difference in performance but Highway cruising at 71-74 mph yielded mostly over 50 mpg overall. My battery charges pretty fast as others have noted, but I rarely saw it go more than 2 bars from the top in the battery display. I also noticed that on the highway, even when getting on it, the ICE is really quiet now. Overall, not a bad update. I had a 2009 Civic Hybrid before this and when they did a IMA update, my mpg crashed hard since Honda' "fix" for failing battery packs was to dumb down the electric assist and make it rely mostly on its ICE. I love my Prius. Never thought I'd own a Toyota.

 

Welcome to the Prius addiction Dave I just got back from spending a month down there getting a suntan & house shopping, but I was driving my Kia Soul as my Prius is taking a winter nap

Mike

 

Toyota Australia is treating the recall as an important issue. Received a letter from them - attached is the envelope to show how they have treated the issue.

The contents of the letter is much the same as the details reported above in this thread. They say the effort will require approx 1 hour, which seems to be the average time as reported. Now need to get the car booked in for the work to be done.

 

Does anyone know where toy techs are supposed to plug to do the upgrade ?
I'd like to put something to be sure they really do the update, and don't just take the car without working on it :/

 

They will connect the Techstream computer to your OBDII port. This is at the base of the steering wheel about where your left knee rests.

 

870 miles driven today with updated software. mpg's running 76 mph show 43.xx on the display when powering down. The car struggles to accelerate from 70 to 90 mph. I surely remember rental Prii easily accelerating to 90 and over 100 mph real easy. Initial acceleration from say 60 mph seems weak at first then a few seconds it appears to be cranking up the electric torque. B mode takes a similar delay before it really slows the car down. Regen braking seems weak now. Much more pedal effort to get strong braking. Cruise control sags 2 mph on hills at first then overshoots the setpoint by 1 mph then settles in at the setpoint after a few seconds delay. I did not think to bring my ScanGauge II to check the boost voltage. I have a feeling the full boost voltage is delayed a few seconds after the Go Pedal is mashed to the carpet. Overall I would have to say the car feels slower. Surely the big rush off the line at a stoplight is gone. It rolls on with that delay feeling. Weaker I have a feeling my Plus Performance would be a frustrating turd with this software. The rental Prius is sufficient enough for regular not in a hurry driving. It is real slow for passing and I would not go for it on a 2 lane road if I needed to pass a vehicle. More info tomorrow if I feel it us worthwhile to post...

Mike

Somewhere on my phone ;-)

 

I haven't noticed any difference in performance out of my 2010 Prius. I've put about 300 on mine since the recall. I do notice a nice difference in mpg according to the trip computer. 76 mph today on I-95 for a 6 mile stretch and I was seeing 50.3 mpg on the display. I can't wait until they start selling the summer blend gas and I eventually ditch these OEM Yokohama Avid S33s.

 

I had my recall done on Saturday (it took full 2 hrs).

Subjectively, the acceleration feels slower indeed. I always try to accelerate at the very top of ECO zone, just before the POWER zone. If I accelerate now at that very setting, it feels slower. If I accelerate by the feel of the pedal I catch myself well in the POWER zone. Now, this is the first day of driving, so need to test it more. The good news is MPG is as good as before.