When the traction control kicks in on a wet surface, I've heard it's a real 'messy' kind of effect. Not smooth but choppy.

Can someone describe what the engine does when the rev limiter kicks in? Not how it does it or what rpm but, the sensation. Does it just rev up to the limit and smoothly sit there? Or, is it real 'choppy' as it revs at the limit?

thx

 

when people say 'bounce off the limiter'.. its pretty accurate... it hits the limiter, drops a few hundred rpm, heads back to the limiter, drops a few hundred rpm, etc..

id estimate a surge every 1/2 second?

try it.. it shouldnt hurt anything.. and its good to feel it once so you know whats happening.


:cheers:

 

I haven't had the traction control kick in on a wet surface yet (I avoid doing things like that in the wet weather).

The rev limiter kicking in is a little choppy since the engine power is being cut (don't know if it is fuel, spark or both). I would categorize it as noticeable, but not bad

 

When the traction control kicks in you will hear a scraping of brakes as individual brakes are applied to the highest speed wheel(s) You also will feel like the gas pedal has been disconnected and you can no longer feed the car gas.

With rev limiting, I believe, one of the banks of cylinders no longer is being fed gas and it has the sound of a gas starved engine. Or a V8 running on 4 cylinders.

 

In Utah we have a good number of roads that are many miles long and of decent construction out in the desert. At the time I wasn't aware of many of the features of my new car, the rev limit being one of them. The car was literally pushing itself the entire way up the mph gage like a war horse until it neared 165 when it just stopped accelarating completely. It didn't stutter, and to be honest I assumed it was just 'topping' out so my foot was firmly still planted on the floor. I let up and dropped off 15 mph or so and kept driving for a minute (seemed like 30 but more likely it was less then 2) at which point I pushed down to the floor once more and the car literaly pushed me into my seat as it lept forward again stopping at 165.

As soon as I got home (was meant to be picking up socks, or toiletpaper, or some other made up errand) I hopped online and learned that the car is top speed limited at 165 for an automatic. To be honest, I don't remember what the RPM's were at but I'm very sure that they weren't over 6000 where the limiter would be. So I haven't felt the bouncing effect of hitting the rev limiter in my Corvette.

But if you're wondering about the top speed limiter, it came on quite smoothly. If it wasn't for the fact that the car was accelerating strong right up to that speed it would feel like any other car that was hitting it's top speed naturally.


...so I guess writing this out I've got a few other questions. Does anyone know what the top speed is in a stock automatic without the limit enabled?

ps. I don't want to encourage breaking the law or risking life/injury to yourself/others. So let me state that this entire experience did in fact 'not' take place and/or was imagined by the myself in a daydream etc ;)


On the topic of traction control, it's with mixed emotion that I have to say this has saved my life on two occasions. Both of these times were due to road conditions and not reckless driving per se. (Reading this I'm beggining to sound like a teenage daredevil.. couldn't be farther from the truth). The traction control is a very nice feature, the couple of times that I've purposely induces a sideways slide it has kept the power off of the wheels and enable the car to recover flawlessly. I can't recall any sounds of braking, and never has the car ever screeched or made anything resembling a squealing sound from the tires no matter how sideways the car has been. Although the adrenaline does tend to deaden outside noise quite a bit. The traction control definitely makes the car recover from almost every slide, spin, etc that I've put the vehicle in whether on purpose or not.

The top speed limit and traction control system both felt 'natural' and in no way left me with that sick feeling in your belly that you feel when you see the little kid in the suv parked next to about ready to swing open that door with his feet.


(edited for typos)


[Modified by Vette-Dream, 10:09 AM 9/19/2003]

 

When the TC cuts in there is no messy efect. The car just feels like the engine stopped. The feeling is enhanced since no matter what you do with the gas pedal there is no response until the TC Active message goes off from the DIC.

When you hit the rev limiter the engine sounds like it is sputtering and you get a slight surging. Not as bad as running a 60s engine that got point bounce in the upper RPM ranges but still noticeable.

Go out and try out both of them and you will know. You are not going to hurt the car. While you are at it give the ABS a try also so you know what to expect. Make sure everything is clear around you get up to about 50 and hammer the brake pedal. It gets pretty violent but boy do you stop quick.
Bill

 

Funny you should ask; I had the pleasure of seeing "Traction Sys Active" on the DIC in the wet a couple days ago.

Basically, it feels like there's been a serious drop in power; like you should be going quite a bit faster than what your throttle position would suggest. Which is, of course, the whole point of it. :yesnod:

 

I don't think this is accurate. The traction control reduces throttle position... and does not apply the brakes. ??????

ABS and Active Handling use the brakes.

 

My '97 A4 has an aggressive traction control program. Yep, it feels like the engine quit, and the half-second or so before it goes back to normal can be agonizingly long if you are pulling out in front of a line of traffic from a gravel road, for example.

Chevy admitted to allowing some driver skill/judgement in the programming, so if you floor it on a low traction surface, the TC cuts in, and if you keep your foot planted, when TC is "released" and it starts spinning again, TC will again do its thing. Keep this up and you'll jump ahead a few feet every few seconds, and look a lot like a idiot. BTDT when it was a few days old!

Chevy's thinking was that if you got full TC by spinning them on a low traction surface, you, the wise driver would recognize the situation, and lift so that when it gave you back power the 'stupid cycle' wouldn't start again. The other option was to bring back the power gradually for the stupid foot-to-the floor driver. I'm glad they didn't go this route.

I fully agree about practicing full-on anti-lock braking on dry tarmac before you need it. My technique is 65-70 mph, clear the area, especially behind you, and mash down as hard as you can. Many folks won't hit the pedal hard enough to get ABS cycling in that condition...at least not the first time. Some never do.

After a couple of full ABS cycling stops, I suggest trying a gentle lane change DURING THE ABS CYCLING. Do it gently at first, but as you get experience you'll find that you can maneuver fairly aggressively to miss something in front of you even during ABS cycling. If you've taken a Skip Barber (or similar) driving school, you'll have tried this without ABS, which is much more of a challenge, especially when a quart of adreneline is pumping thru your system.

Doing all this on wet roads at a fraction of the speed is also good practice, but the high-speed dry road practice might prevent a lot of 'accidents'. My kids didn't get their driver's licenses until they had done this with me in the right seat.

FWIW, I used to teach folks to fly Air Force fighters. A lot of the same techniques work in driving. Do things in a controlled situation before you do them 'in anger'.

My $.02


[Modified by OldSStroker, 8:26 PM 9/20/2003]


[Modified by OldSStroker, 9:56 PM 9/20/2003]

 

:iagree:

 

AFAIK Traction control does use brakes as the sentence above states. It applies it to whichever wheel has the least traction. You can hear them scrape.