TCS or Not

[Rex]

Okay, first I searched and didn't see anything on this. My car is equipped with TCS and I understand the benefits of it for rain/wet road surfaces, though after this past winter I have my doubts about it's usefulness in snow conditions.

I guess one of the the questions I have is, does the TCS on the circa '94 Q use/apply the brakes when the rear wheel spins?

Another one is (if your car has TCS) do you turn it off under some conditions? (dry/wet/snow/ice,etc)

Lastly, do you think acceleration is better (dry/normal conditions) with it tunred off?

[maxnix]

Lastly, do you think acceleration is better (dry/normal conditions) with it tunred off?

Usually with these braking/throttle control devices, this is true. However, since the Q is so heavy, it may not make much difference unless your rear tires have a low coefficient of friction and will thus break traction in the dry on pavement.

[PalmerWMD]

I had the TCS on only one Q(a 92) and I found it useful in Minnesota winters.

Fred...

[AZhitman]

From what I can tell the TCS does NOT involve the braking system.

[Rex]

So, does the motor drag the tires down enough to make it re-act like the brakes were applied?

I have a HORROR story of a drive I tried to make from Cincy to Nashville back in early December when the roads were nasty. The car went completely sideways 3 different times while driving 40mph-ish going straight down the interstate. Ugh, it gives me nightmares just thinking about it.

[PalmerWMD]

I dont believe this is fault of the TCS, it probably would have been worse w/o.What kind of tires did u have on the car?

Fred..

PS: Thats exactly how I crashed my non TCS Q on Dec 25th...sniff:(

[Rex]

They were Bridgestone Potenza's RE's or something like that with less than 10K miles on them. Front end was alittle out of alignment. But it felt just like if you're driving on bad slippery/slick road and tapped the brakes.

You're in the Louisville area, you remember the Dec 4th winter mess? I pulled over just to the side of the road at the bottom of the hill just before E-Town.

Ugh, bad pictures of car going sideways while a tractor trailor is in the lane next to me.

[maxnix]

TCS will not really help on ice. Neither will AWD or 4 wheel drive once traction is broken.

[maxnix]

From what I can tell the TCS does NOT involve the braking system.

A bet that is why the TCS cars have 4 channel ABS and not the standard 3 channel.

That way, each rear wheel can be braked independently. And that is the end most subject to control by TCS systems in dynamic side-load situtations.

[GEOFF]

From what I understand, wheel spin is read from a circular grid at the back wheels. When spin is detected that info is sent to comp sys. I think it then retards the timing, but not sure. Oh and do not put two different sized tires on the back with TCS on, you will hardly be able to move. Overall I think I will miss the TCS from my 93Q. At that time I did not realize how few had this option up to '97.

[don85259]

I always keep it on in my 98 Q45. Of course, here in Arizona, it rains so rarely that it is really not needed. When it does rain, it can become slick and then it becomes VERY helpful. I have never driven it on snow or ice so I can't say how it would perform in those conditions.

I can tell you the Q45 is light years ahead of my last car in terms of general control and performance (the 1994 Lincoln Mark VIII I used to own with 280 horses). Although it was fast in a straight line (probably even faster than the Q), God help you if you had to turn. That thing would oversteer from hell and the rear end was very wiggly. If you were not careful (say on hard acceleration around a curved freeway onramp), you could break out the rear wheels and suddenly be going sideways down the ramp (happened to me twice--enough to scare the bejeezus out of me!).

The Q TCS system allows you to push the envelope far more.

--don

[Q45tech]

The Q viscous limited slip is a critical part of the algorithm for both ABS [less so for rear but why you can use a single channel for the rear] and TCS [requires dual channel rear]. The differential fluid temperature affects the EXACT lock up point of the viscous silicone fluild........as do warped viscous plates damaged from overheating [excesive spinning].

The oem tires min/max slip points/slip angles are programmed in..........the make/brand tires are tested and the numbers derived are added to the softwear. Some [many] aftermarket tires have wear indexes which exceed the oem 200, therefore the tire may not be able to maintain as high a friction coefficient [Mu] as designed...........thus the ABS/TCS actives early and longer decreasing vehicle performance.

Generally tires that don't meet oem specs add significant feet to braking as more time is spent with less braking pressure to avoid lockup.

Same with TCS, hard tires will increase acceleration time as they are more likely to spin at least in 1st gear.

The abs/tcs ecu is smart enough to know when things are slipping more than normal and shifts programming [attack, ramp up, release rampdown, time between pulses] to a winter/wet mode which may be even worse in achieving minimal stopping distances.

Notice that the Tire Rack Test for braking of even the Ultra/ High Performance tires show up to 10% deviation in braking distance...........some of this is the tires themselves and some is how the ABS reacts to slight differences in the tires friction coefficient!

The number one cause of bad ABS/TCS performance is owners not purchasing tires which meet the oem specifications, unfortunately to avoid liability and the Warren Mag Act oem equivalent tires are not specified or required as replacements!

The owner therefore assumes all responsibility for diminished performance when they purchase a replacement tire.

http://www.fuzzytech.com/e/e_a_esw.html

"just what Nippondenso did. When the ABS first detects blocking of a wheel, it starts to control the brake fluid valves so that each wheel rotates with a slack of 0.1. The fuzzy logic system then evaluates the reaction of the car to the braking and estimates the current road surface. Considering this estimation, the ABS then corrects the set value for the slack so that it achieves the best braking effect."

Unfortunately the fuzzy logic can't differentiate between a low friction road surface or a low friction tire compound!

[Rex]

TCS will not really help on ice. Neither will AWD or 4 wheel drive once traction is broken.

Yes, as I sat in the hotel room watching the news waiting for the roads to become passable, the State Trooper made the same point, but my horror story started prior to the ice/freezing. Nonetheless, it got severely (sic?) worse as things froze, to the point I couldn't drive the car across the street to the hotel from the gas station the tow truck dropped me off at. Actually, I had a hard time walking up the inclined drive to the hotel in my Nike ACG boots.

[elwesso]

It really helps when driving; it helps in preventing slips and spinouts, but does ABSOLUTELY nothing when on ice. I got stuck backing up my driveway. If I could by a Q again, it would be with TCS, no doubt. The traction on the Q sucks as it is, and TCS does help.

To help winter driving, put a couple 50 lb bags of sand in your trunk, and maybe get some winter tires. I got some for next season, after having a heck of a winter this year with the Q!!

Its is basically a car you only want to drive on pavement, no snow or ice.