Brakes applied in turns... not touching pedals

[fbov]

I had an odd and unsettling vehicle response yesterday, and I don't see anything similar in a search, so...

 

Coming down a slight grade to an acute right turn, after a battery-draining straight. I (re-gen) braked a little at the entry, and went around with feet off pedals, but carrying a lot of speed. At about the mid-point, when I had maximized lateral acceleration and was diving toward a late apex, I felt the left front wheel start to lock up. It released very quickly, but I had a definite stab of braking, nothing like the gentle re-gen braking.

 

The only positive out of the experience is that the front tire didn't slide at all. No steering correction needed, no change to the arc. Felt like an extraordinarily brief gust of headwind, but it was a calm day and I was in a bit of a hollow. My butt told me it was the LF wheel, but cornering this hard, most of the car's weight is on the LF so it's possible other wheels were involved, but were not loaded enough to impart noticable force to the driver.

 

This is a commuting route, so I'll try again, but I was curious if anyone else has seen anything like it. Remember, I had just taken my foot off the brake pedal, headed for the gas pedal, so I'm sure I didn't apply the brakes by accident.

 

HAve fun,

Frank, who is finding the greatest challenge is to exit a spirited turn in EV...

[fotomoto]

Check your owners manual:

 

 

The AdvanceTrac with Roll Stability ControlTM (RSC) system helps you keep control of your vehicle when on a slippery surface. The electronic stability control (ESC) portion of the system helps avoid skids and lateral slides and roll stability control helps avoid a vehicle rollover. The traction control system (TCS) helps avoid drive wheel spin and loss of traction. For details on TCS operation, see the Traction Control chapter. 

 

You can download a more convenient digital copy here:  http://fordcmaxhybridforum.com/topic/1603-on-line-owners-manual/?p=14268

[fbov]

Well, this kind of thing ruins a great love affair...

 

RSC is "disabled when the transmission is in position R." Not an option

 

When activated, it de-stablizes the vehicle. Not a desirable option; what was Ford thinking?.

 

If it's activated by driving at the limits, well wait until winter... half the fun of living where you get 8' of snow is driving in it. ABS acts at my request. I've held on to RWD cars for a reason...

 

Anyone here perfoprmance-minded enough to find a work around?

 

HAve fun,

Frank, who downloaded the manual a month ago, but didn't realize Ford was on a roll... my fault as they did rate it at 47 mpg, so the warning were there.

Edited August 22, 2013 by fbov

[wab]

Welcome to the wonderful world of lawyers, DoGooders, and people who will gladly think for you.

 

Disclaimer: This IS NOT a Mini CooperS or any other front wheel drive car that handles!

 

Take a look at this:

 

Left 4 way/ok steering wheel control

 

Left arrow till you see Settings at the bottom of the left screen

Down arrow to settings

OK

right arrow on Driver Assist

OK

left arrow on Traction Ctrl

arrow down to OFF

OK

Left arrow, left arrow, etc.

 

Problem: you will have to do this every time you start the car.

 

Good luck, drive safe and within YOUR limits, let us know if this improves your driving experence.

 

wab

[HotPotato]

The Focus ST uses Torque Vectoring Control too -- that's why it handles so well. Our C-Max is a tall car with a short wheelbase -- bad news without electronics to make it safer and more fun to carry unwise speed through corners.

[armoredsaint]

my previous prius did that a lot in the winter time when turning, at first it was quite unsettling.

[fbov]

Thanks for reading; I found a lot on Ford's RSC problems in the F-150 forums. Seems it kills brakes in snow plow applications, so those guys pull the fuse... and disable the ABS. I find that unacceptable, for reasons other than the "wonderful world of lawyers." ABS only has a couple disadvantaged scenarios (eg. deep snow), and it's of great advantage in low traction conditions. RSC needs a SW switch like traction control. Turning off traction has no effect on RSC; you have to take out ABS, too it appears.

And what's with "traction control" that traps cars on flat-but-slippery surfaces? The menu option to disable is not there for looks!!

I'm also surprised at the presumption of poor handling from the C-max, as I find nothing of the sort. Mini's I've seen have more body roll, even though they're shorter. Have you tried rocking a C-Max? This thread started because I was able to activate RSC in a situation where the driver was in complete control of the car. This thing is very nicely balanced at the limit, no excitement until the hammer hits.

Missing the point regarding short wheelbase (same as Focus...). Turning circle is huge like most FWD cars, but the bigger impact on handling is the weight distribution; front engine, rear battery is reminiscent of the Porsche 944 with front engine, rear transmission, and an actual short wheelbase at 94.5". The added height is a small factor at street speeds compared with placement of the drive train and battery mass to give a very low center of mass, which is what really improves handling. It's what reminds me so much of driving a Spitfire.

And yes, armoredsaint, I am not looking forward to winter of the car fighting me back when I drive. Snows may not be optional...

My bottom line is still close to HotPotato's sentiment:
"...electronics make it unwise to carry speed through corners."

Have fun,
Frank

Edited August 23, 2013 by fbov

[plus 3 golfer]

...

My bottom line is still close to HotPotato's sentiment:

"...electronics make it unwise to carry speed through corners."

 

Have fun,

Frank

My bottom line:  "other people's welfare make it unwise to carry speed through corners."   ;)   Save such "spirited driving" for the track not the highway.  

 

Have fun, but drive safely.  :)

[fbov]

Plus, it's insulting of you to presume otherwise. That's twice you've presumed in ignorance... As i said before, your objective contributions are quite valuable, but the third time, things may get ugly.

 

You should be aware that, in addition to 30 years with a license, I've got a complete set of runner-up trophys from the SCCA Solo II Nationals, have instructed at track schools and taken other people's cars home on my trailer. Autocrossing, I've had air under my right-side wheels repeatedly and never got the shiny side dirty for one very good reason. I practice in everyday driving, especially when it's snowing, and my driving record attests to the fact that I know the difference between spirited and wreckless.

 

When I make a car sllide, no one can tell besides me, as the car is not out of control... until RSC intervenes to "fix" it. RSC is too sensitive, as implemented, and the same is true of traction control. Ask your plow guy.

 

HAve fun,

Frank

[plus 3 golfer]

Plus, it's insulting of you to presume otherwise. That's twice you've presumed in ignorance... As i said before, your objective contributions are quite valuable, but the third time, things may get ugly.

 

You should be aware that, in addition to 30 years with a license, I've got a complete set of runner-up trophys from the SCCA Solo II Nationals, have instructed at track schools and taken other people's cars home on my trailer. Autocrossing, I've had air under my right-side wheels repeatedly and never got the shiny side dirty for one very good reason. I practice in everyday driving, especially when it's snowing, and my driving record attests to the fact that I know the difference between spirited and wreckless.

 

When I make a car sllide, no one can tell besides me, as the car is not out of control... until RSC intervenes to "fix" it. RSC is too sensitive, as implemented, and the same is true of traction control. Ask your plow guy.

 

HAve fun,

Frank

 

My "ignorance" is not the issue. I did not presume otherwise. I could easily surmise from your first post that you "feel" you are above most in driving skills. You've now demonstrated that with your resume.  So why the threat "but the third time, things may get ugly".   Resorting to ad hominem attacks are not arguments that supports your statement in question.  So, if a corner is marked with a suggested speed limit, are you saying that electronics are preventing the car from carrying the posted limit through a corner.  

 

My previous post simply states that my bottom line is different than yours. I understand that you like to find the limits of vehicles for the track. But you weren't on the track but a public road "testing" the C-Max and state you'll try it again.  A couple of rhetorical questions:  when is it "wise" to carry speed through corners on public roads and what makes it "wise" to go 10, 20 or more mph above the posted cornering speed limit suggestions.  I can't think of any rationale answers.   

[fbov]

If you want to be an ass, I can't stop you, but I would prefer a harmonious relationship. If you have nothing of value to add, please don't post.

 

The problem isn't that your "bottom line is different" but rather that your bottom line is better... you "can't think of any rationale answers." Your value judgments are out of place here, and will continue to be a source of conflict as long as you promulgate them in place of true added value. Please seek your ego gratification elsewhere.

 

Have fun,

Frank

[ford]

And Mr Wallenda knew a thing or two about tightropes, but he isn't with us any more..............? How about the captain of the Titanic .He was going too fast. Were is he now......?

[plus 3 golfer]

So would I fbov but you simply can't respond without some sort of ad hominem attack.  This is your third offense on me and I have simply responded to them.  You may not like my opinion but there's no need for personal attacks.

[C-MaxSea]

My bottom line:  "other people's welfare make it unwise to carry speed through corners."   ;)   Save such "spirited driving" for the track not the highway.  

 

Have fun, but drive safely.  :)

 

Sorry Plus 3, this was an informative thread until the lecture: "Save such "spirited driving" for the track not the highway."  Sadly, you shut it down.  We know you meant well, but sharing & learning is what this site is about - I think.  Here's to an informative, well meaning & spirited thread - thanks Frank.

 

Nick

Edited August 25, 2013 by C-MaxSeattle

[wab]

"Welcome to the wonderful world of lawyers, DoGooders, and people who will gladly think for you."

Edited August 26, 2013 by wab

[Noah Harbinger]

Nevermind…. 

 

:arrive_alive:

Edited August 26, 2013 by Noah Harbinger

[fbov]

Thank you all for your mature responses; I'm going to like this forum!

 

HAve fun,

Frank

[PapaJ]

Funny stuff!

 

We just sold a MINI Cooper "S" and trust me, our C-Max does not reside in the same universe as the Cooper when it comes to acceleration/handling/cornering -- but then, that's not why you purchase a C-Max, is it?

[HotPotato]

The funny thing is, I find the C-Max reasonably sporty (fbov's points re. same well taken)...my shopping list otherwise consisted of hot hatches and Euro wagons, and it says something that I picked our gas-electric potato instead.

[fbov]

PapaJ, if you don't see a similarity, you haven't driven it hard enough. Granted, it's hard to beat physics, as Ford has finally admitted, so the same 3600 lb. curb weight that gives the Prius an MPG advantage also appliles to the Mini, but in spades at 2800 lb. However, factor in weight distribution, and I stand by my assertion that the C-Max has less body roll than a Mini, if you take height out of the equation. Perhaps not a Mini S... but with the required trade-offs in handling vs. ride quality befitting an "S" variant.

 

The whole point of this thread is that, according to Car and Driver's Mini S review, "By the time you get the tires howling, your passenger will be dialing 9-1-1." C-Max passengers will never call 911, the driver will. That bothers me.

 

HAve fun,

Frank

[PapaJ]

PapaJ, if you don't see a similarity, you haven't driven it hard enough. Granted, it's hard to beat physics, as Ford has finally admitted, so the same 3600 lb. curb weight that gives the Prius an MPG advantage also appliles to the Mini, but in spades at 2800 lb. However, factor in weight distribution, and I stand by my assertion that the C-Max has less body roll than a Mini, if you take height out of the equation. Perhaps not a Mini S... but with the required trade-offs in handling vs. ride quality befitting an "S" variant.

 

The whole point of this thread is that, according to Car and Driver's Mini S review, "By the time you get the tires howling, your passenger will be dialing 9-1-1." C-Max passengers will never call 911, the driver will. That bothers me.

 

HAve fun,

Frank

Hi Frank -- I just think this is a classic apples-to-oranges comparison...a sports car vs. a tall SUV-thingy. I love our C-Max and yes, it handles reasonably well up to about 7/10, but in any objective handling scenario the two vehicles are worlds apart. Edmunds tested both cars in the 700-ft. slalom; the C-Max ran it at 63 MPH (not bad), the Cooper zipped through at 68 MPH.  Don't know why anyone who likes to drive fast would buy a hybrid -- these cars reward SLOW driving, don't you agree?

[fbov]

At the same time, I never expected to make that comparison with a hybrid! This is a very well-mannered suspension, handicapped by electronics.

 

Imagine what the C-Max slalom time would have been without RSC!! Don't kid yourself that it didn't slow the car down...

 

Have fun,

Frank

[GaryM]

I am also an autocrosser, but have not been able to make races in a few years, I really do miss it. My previous car was a manual trans 2004 Camry SE. On the stock Michelin sires I would make them howl all the time, but in full control. That cat had just ABS no other driver annoyances, and I loved that about it. Only on very slick surfaces, did the ABS ever intervene. A change to BFG and then to Pirrelli tires got rid of the howling tires and raised the cornering speed quite a bit. I would run the inside lane and pass many sports cars that were trying in the outer lane. Any autocrosser with decent feel for their car can run it much closer to the limit than the average driver and be in full control. 

 

I got the C-Max for several reasons. I knew it was not going to be the best handling car on the road, but it is a huge improvement over any Prius variant. It does corner very flat, and has very quick and direct steer. I do hope to find what is limiting the steering travel and get a bit more out of it, I find myself slamming into the steering limit all the time when I am parking. My longer Camry had a much tighter circle. I have not tried too hard to run the C-Max to it's cornering limits. The energy saver Michelin tires moan and squeal way too early. Braking into a corner, with no engine sound seems to make the awful tire noise seem all that much louder. I am almost looking forward to wearing these things out to try a better tire package. I have managed to get the RSC to trigger a couple times, and I do agree, it feels like it comes on way too soon and far too aggressively. The funny this is, it happened when I did not feel I was pushing it. When I am intentionally driving it more aggressively, it made more tire noise, but I didn't feels the brakes bite. I wonder if the threshold raises when it senses a more enthusiastic driving input?? I am also curious if it uses accelerometers or just calculated slip or what. Some early ABS systems would still reduce braking at the same wheel deceleration even when grippier tires were installed. I hope that is not the case here. The balance does seem quite good with just a bit of natural understeer to keep us mere humans safe. 

 

The body may be tall and fairly short in length, but the track is wide and the wheelbase is fairly long. The true center of mass is also fairly low. With just a set of tires, and maybe spring/swaybar/shock/alignment adjustments, there is no reason this thing could not corner at .9 G's. It certainly should not get tippy at that rate. Just look how low the real floor of the car is to the ground. I have seen many stock class autocross cars exceed 1.0G with just sticky tires. Toss in some camber and my otherwise stock 1995 Celica ST recorded 1.4 G's sustained. Yes, it was a 3 wheeler at those speeds, and I would never try that on the street, but I knew I could pull off well past the Corvette 0.85 G without trying hard and no squeal.

 

Yes, we bought the C-Max to get better mileage, but we also bought it because it does not kill all the fun of driving like many other high mileage cars. And, believe it or not, if you can brake less, carry more speed through a corner, without sliding, and then use less acceleration to get back to the posted speed, you actually save fuel. We all know that braking and re-accelerating is more wasteful than coasting, so this should be a no brainer. I take a nice turn from Newhall Ave onto Railroad Ave just about every day. It goes off camber and drops down past the apex. It is a riot to take it at 30-35 mph. I have no trouble at all holding the inside lane and no tire squeal, but I think the inside tires may hop off the ground as the road drops away. The off camber makes it feel like your going way faster as it adds a fair bit of lean out. The shorter car and higher ride makes it feel more fun that it was in the Camry, but I bet I am not taking it as quickly. Never looked to see my speed before, just did it by feel. In the C-Max, I am watching the speed. I drop the Eco cruise from 42 to 36 as I hit that turn. I stay in EV the whole time. Much of that run is down hill, so I easilly get 5 miles of EV if I do not get caught by the lights. 

 

The C-Max can be very fun to drive, and even being semi aggressive on a tank, I still turned 44 MPG. Cornering at a reasonable speed can be fun and still totally safe while not sucking any more fuel.

Edited September 1, 2013 by GaryM

[fbov]

Gary, we share many of the same perceptions, however, I've yet to hear the tires squeal. A gentle moan is the most I get... not pushing har denough, I guess.

 

My autocrosser is an '83 BMW 320iS, and my era was the '80's; last National was maybe '91? I had that car up on 2 wheels twice, both times in a slalom, and both times due to low roll stiffness with the stock suspension. At 1g+ lateral acceleration, it's not hard to push a suspension close to the bump stops, and it will swing very nicely to the other side if you ask the right way. I left when it became standard practice to corner on 2 wheels - bicycling - but with inches of air, not the feet I got. It was an era when technology was leaving old cars behind as fast as the rule changes!

 

HAve fun,

Frank

[PapaJ]

At the same time, I never expected to make that comparison with a hybrid! This is a very well-mannered suspension, handicapped by electronics.

 

Imagine what the C-Max slalom time would have been without RSC!! Don't kid yourself that it didn't slow the car down...

 

Have fun,

Frank

Well it certainly stomps any Prius... :shift: :shift: