Prius FAQ: Snow and Ice vs Traction Control
#21
04-10-2008, 08:42 AM
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Re: Prius FAQ: Snow and Ice vs Traction Control
I seem to be the only person that had experiences with both TRAC setups on the same car.
Here's the background info in case you haven't been following me on PriusChat:
2005 Prius bought in Oct 04.
The first winter, I got stuck pulling out of the curb. We had a good 10-15cm of snow. I decided to test the Prius' TRAC since it's the first winter and snow events around here (esp. with 10+cm) are few and far between (they usually melt within days). As expected (at the time), the wheels spun and the TRAC cut all power. No amount of prodding on the acccelerator would produce any forward movement at all (can't imagine rolling on momentum if the power was cut while making a left turn).
Anyway.. that was my one and only time with the TRAC cutting all power. Next year (winter 05/06), there was that ECU update. My Prius tech fried my engine ECU so my poor car was at the dealership for a week and a bit.
I found out the TRAC changed its behaviour by accident actually. I was backing into the garage (we're on a slope) and I noticed this weird sound... it was like the engine was revving up and down. I thought it was weird but figured it was the TRAC doing its thing. Then I noticed the blinking Slip Indicator. Ok, so it was TRAC. I had regained grip by then so I ignored it. I knew it was a bit icy in the alley. So I continued to back up and then it happened again. It was then it strucked me. The tyres were spinning! I stopped the car then intentionally tried to get the wheels to spin and it did. The engine was just revving up and down as the power was fed in pulses by the TRAC in an attempt to regain traction.
I posted my findings online and we couldn't figure out why I had the old "cut all power" TRAC behaviour before and now it was exhibiting the "slip and grip" behaviour. I thought it might have something to do with the ECU update but a wife of a Prius tech said her DH wasn't aware of any changes done to the TRAC.
I hope you can delve deep into this issue and maybe find out how I managed to get it changed and help those that have the old TRAC setup, update to the new one.
Here's the background info in case you haven't been following me on PriusChat:
2005 Prius bought in Oct 04.
The first winter, I got stuck pulling out of the curb. We had a good 10-15cm of snow. I decided to test the Prius' TRAC since it's the first winter and snow events around here (esp. with 10+cm) are few and far between (they usually melt within days). As expected (at the time), the wheels spun and the TRAC cut all power. No amount of prodding on the acccelerator would produce any forward movement at all (can't imagine rolling on momentum if the power was cut while making a left turn).
Anyway.. that was my one and only time with the TRAC cutting all power. Next year (winter 05/06), there was that ECU update. My Prius tech fried my engine ECU so my poor car was at the dealership for a week and a bit.
I found out the TRAC changed its behaviour by accident actually. I was backing into the garage (we're on a slope) and I noticed this weird sound... it was like the engine was revving up and down. I thought it was weird but figured it was the TRAC doing its thing. Then I noticed the blinking Slip Indicator. Ok, so it was TRAC. I had regained grip by then so I ignored it. I knew it was a bit icy in the alley. So I continued to back up and then it happened again. It was then it strucked me. The tyres were spinning! I stopped the car then intentionally tried to get the wheels to spin and it did. The engine was just revving up and down as the power was fed in pulses by the TRAC in an attempt to regain traction.
I posted my findings online and we couldn't figure out why I had the old "cut all power" TRAC behaviour before and now it was exhibiting the "slip and grip" behaviour. I thought it might have something to do with the ECU update but a wife of a Prius tech said her DH wasn't aware of any changes done to the TRAC.
I hope you can delve deep into this issue and maybe find out how I managed to get it changed and help those that have the old TRAC setup, update to the new one.
Forward traction, pulling away for the curb, vs reverse traction, backing uphill into your garage.
Since your Prius had no reverse gear it uses only the "electrics" for reverse drive and therefore there is no need for frictional braking to restrain wheelspin/slip. I would also suspect that the level of torque the electrics can produce for reverse "motion" is artificially restricted, certainly so once wheelspin develops in reverse. In any case the electrics cannot easily produce the level of torque for reverse motion as can be had with both the ICE and electrics providing "forward" torque.
Reverse drive torque controlled via the electrics, no need for braking control, no "threat" to rotor warpage from overheating, no engine dethrottling required.
Apples...and Oranges.
#22
04-10-2008, 08:55 AM
Re: Prius FAQ: Snow and Ice vs Traction Control
I use Michelin X-Ice tires on all my cars. While I am sure the Nokians you mentioned are a very fine winter tire, the Michelins remain one of the best. I have my own experience over a good number of years to vouch for it and they hit FE as much as they stick even in weeks worth of -40C weather.
With that said, I want to re-emphasize that it did not happen to me nearly as often as it happens to the owners of earlier models in my area. Jayman (also a local) may totally hate his and he even swears by studded tires. Frankly, I don't think studded tires are needed when we use good winter rubber instead, at least on the 2007 models. But what I am also saying is that it still happens to a minor but yet undeniable degree. I am not crazy and neither are some who own post 2006 models.
Cheers;
MSantos
#23
04-10-2008, 03:29 PM
Re: Prius FAQ: Snow and Ice vs Traction Control
You appear to be making an "apples and oranges" comparison.
Forward traction, pulling away for the curb, vs reverse traction, backing uphill into your garage.
Since your Prius had no reverse gear it uses only the "electrics" for reverse drive and therefore there is no need for frictional braking to restrain wheelspin/slip. I would also suspect that the level of torque the electrics can produce for reverse "motion" is artificially restricted, certainly so once wheelspin develops in reverse. In any case the electrics cannot easily produce the level of torque for reverse motion as can be had with both the ICE and electrics providing "forward" torque.
Reverse drive torque controlled via the electrics, no need for braking control, no "threat" to rotor warpage from overheating, no engine dethrottling required.
Apples...and Oranges.
Forward traction, pulling away for the curb, vs reverse traction, backing uphill into your garage.
Since your Prius had no reverse gear it uses only the "electrics" for reverse drive and therefore there is no need for frictional braking to restrain wheelspin/slip. I would also suspect that the level of torque the electrics can produce for reverse "motion" is artificially restricted, certainly so once wheelspin develops in reverse. In any case the electrics cannot easily produce the level of torque for reverse motion as can be had with both the ICE and electrics providing "forward" torque.
Reverse drive torque controlled via the electrics, no need for braking control, no "threat" to rotor warpage from overheating, no engine dethrottling required.
Apples...and Oranges.
It has done the slip/grip going forward too, what's your point?
#24
04-10-2008, 09:16 PM
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Re: Prius FAQ: Snow and Ice vs Traction Control
My point...??
I was responding to/with the information you gave us. If that information was wrong or incomplete...
But, under the circumstances you described in your post my point was well made.
I was responding to/with the information you gave us. If that information was wrong or incomplete...
But, under the circumstances you described in your post my point was well made.
#25
04-13-2008, 10:44 PM
Re: Prius FAQ: Snow and Ice vs Traction Control
Fair enough... and now I've completed it. It acts in an identical manner forward or in reverse.
#26
01-09-2009, 09:55 PM
Re: Prius FAQ: Snow and Ice vs Traction Control
"I have an 04 and I live in Colorado Springs. Never had this problem. In fact, my Prius is the best snow car I've ever driven in my entire life, and that's with all weather tires."
Ok genius, stop the car in the middle of a snow covered hill, like we have in Iowa, and then try to make it up the hill. Maybe the snow in Colorado is different from the snow in Iowa? We live on a hill and if it's snowing the car will not make it up the hill. It's like fighting Mike Tyson with my hands tied behind my back. Beside this death-trap feature, I love the car.
Traction control and anti-lock brakes were designed for people too stupid to actually drive a car.
Ok genius, stop the car in the middle of a snow covered hill, like we have in Iowa, and then try to make it up the hill. Maybe the snow in Colorado is different from the snow in Iowa? We live on a hill and if it's snowing the car will not make it up the hill. It's like fighting Mike Tyson with my hands tied behind my back. Beside this death-trap feature, I love the car.
Traction control and anti-lock brakes were designed for people too stupid to actually drive a car.
Last edited by DanFinken; 01-09-2009 at 10:01 PM.
#27
01-10-2009, 07:55 AM
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Re: Prius FAQ: Snow and Ice vs Traction Control
"I have an 04 and I live in Colorado Springs. Never had this problem. In fact, my Prius is the best snow car I've ever driven in my entire life, and that's with all weather tires."
Ok genius, stop the car in the middle of a snow covered hill, like we have in Iowa, and then try to make it up the hill. Maybe the snow in Colorado is different from the snow in Iowa? We live on a hill and if it's snowing the car will not make it up the hill. It's like fighting Mike Tyson with my hands tied behind my back. Beside this death-trap feature, I love the car.
Traction control and anti-lock brakes were designed for people too stupid to actually drive a car.
Ok genius, stop the car in the middle of a snow covered hill, like we have in Iowa, and then try to make it up the hill. Maybe the snow in Colorado is different from the snow in Iowa? We live on a hill and if it's snowing the car will not make it up the hill. It's like fighting Mike Tyson with my hands tied behind my back. Beside this death-trap feature, I love the car.
Traction control and anti-lock brakes were designed for people too stupid to actually drive a car.
The only functionality TC will have, can have, on a RWD or R/AWD vehicle is a warning, heads-up indication to the driver of adverse roadbed conditions for which the driver might have been otherwise unaware.
ABS, on the other hand, while it could use some further "tweaking"(***) is a highly desireable design feature overall, but not in all cases.
*** ABS should be revised to be "locked-out" until/unless VSC detects a "yawing" state, the vehicle is not "tracking" the desired/intended direction of motion.
Last edited by wwest; 01-10-2009 at 07:57 AM.
#28
01-10-2009, 11:54 AM
Re: Prius FAQ: Snow and Ice vs Traction Control
"I have an 04 and I live in Colorado Springs. Never had this problem. In fact, my Prius is the best snow car I've ever driven in my entire life, and that's with all weather tires."
Ok genius, stop the car in the middle of a snow covered hill, like we have in Iowa, and then try to make it up the hill. Maybe the snow in Colorado is different from the snow in Iowa? We live on a hill and if it's snowing the car will not make it up the hill. It's like fighting Mike Tyson with my hands tied behind my back. Beside this death-trap feature, I love the car.
Traction control and anti-lock brakes were designed for people too stupid to actually drive a car.
Ok genius, stop the car in the middle of a snow covered hill, like we have in Iowa, and then try to make it up the hill. Maybe the snow in Colorado is different from the snow in Iowa? We live on a hill and if it's snowing the car will not make it up the hill. It's like fighting Mike Tyson with my hands tied behind my back. Beside this death-trap feature, I love the car.
Traction control and anti-lock brakes were designed for people too stupid to actually drive a car.
VSC is a supplement, not a cure.
#29
01-10-2009, 12:12 PM
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Location: Coquitlam BC, Canada (Greater Vancouver area)
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Re: Prius FAQ: Snow and Ice vs Traction Control
"drive from side to side in a snakelike pattern"
That's a good strategy in any borderline traction situation. It's like climbing a hill via a series of switchbacks, vs taking it head-on.
That's a good strategy in any borderline traction situation. It's like climbing a hill via a series of switchbacks, vs taking it head-on.
#30
01-12-2009, 08:27 AM
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Re: Prius FAQ: Snow and Ice vs Traction Control
Did you mean "slide" from side to side...??
Or do you have really WIDE street where you live...??
"...if there's no ice underneath...""
And most of us call THAT just common everyday driving...
"...VSC is a supplement, not a cure.."
I suspect you meant TC, Track, not VSC.
TC is most definitely a "cure" for those with a handicap that does not allow them to learn to just feather the throttle "almost" up to the level of loss of traction but not beyond. No amount of wheelspin, absent "burning" the ice or snow covering away, will get you up that hill if using the appropriate level of traction doesn't.
And VSC can do things, dynamic "things", that are far beyond the powers of mortal men.
Last edited by wwest; 01-12-2009 at 08:46 AM.
