StanNH

I've been driving this car for over a month now and still can't quite figure out exactly what the traction control on the C6 does. I've driven with it on, and I've driven with it off. It still doesn't seem to behave like any other traction control system I've ever used.

First, when I pull hard from 1st or 2nd gear, I expect the TC to modulate the rear brakes to prevent tire spin. Instead, I just get a lot of axle hop....and I mean A LOT of axle hop.

I tried a hard acceleration run from 1st today with the TC disengaged, stability on. The car went into a quick right side 180 degree spinout which I easily corrected by backing off the throttle. No axle hop that time, but no obvious tire spin (that I could hear) either. I was expecting rear wheel spin, certainly before the rear end came around. The rear tires obviously lost traction or it wouldn't have come around, but how come I never heard it?

Can you just put down a straight line of rubber with this car? No, I'm not doing any "boy racer' tricks here, just trying to figure out a more stable way of getting off the line quickly.

Ambient conditions today were 17 F outside temperature, with dry and level road conditions. The car was well warmed up and the tires were warmed up with over 20 minutes of driving. The car is set up with the Z51 package and 6 speed manual.

Alex Levy

I do agree.. the TC is much different in the C6 then my M3.. the TC seems to kick in during laterals then normal linear driving. I can only get the TC to kick on in a straight run on wet surfaces.. On dry i can chirp in the first 3 gears and the TC does nothing. Im wondering what "Competition" mode does.. Well guess we will find out at limerock soon enough

C64BC

Stan, i can't offer any help since i don't have my car yet, but...I have a friend with a C5 and his car can often light up the tires and the rear end come around with no tire squeal whatsoever...just the most awesome engine and exhaust sound. I think sometimes it depends on the road, because other times it make the standard sound of screaming tires losing tread!!

I'm anxious to read what other owners say here so i can put into practice hopefully in a few days!

SellingBMWforC6

Wheel hop blows! I can't believe you are getting this with TC engaged. And not sure why it disappears with TC off, either. Had to put traction bars on my '70 Chevelle SS to stop the wheel hop. Are traction bars still a necessary mod to correct this problem? Nothing ruins a driving experience quicker than wheel hop.

elh0102

Stan,

Both rear tires were spinning when you did your 180. And I'm not surprised that you heard no tire noise, which comes more from lateral force than high rpm spinning.

If you feather the clutch a bit, coming off the line more conservatively, you should see evidence of two, straight tire marks. If you dump the clutch, both rears are going to totally lose traction, and the driveline torque will cause the rotation you experienced.

I don't know the intricacies of how these systems work. But, I think the TC will cut ignition and/or throttle to limit rear wheel spin, not brake, which probably explains the axle hop. The Active Handling will apply specific braking as required to limit the yaw, or lateral movement, but will not limit rear wheel spin from throttle input. At least that is my perception of how they work, but I'm sure others are more knowledgable about these things, and will offer a more expert answer. (I'm still getting over no carburetor and ignition points).
Ed

Vespa-Vette

C6 EMT SC tires spin easily and quietly. I've tried burn-outs several times and it's no fun because you can't hear it.

crabman

Different tires were talking about but mine are very quiet spinners. In the wet with the stereo on I have had em spinning and had no clue until I notice the rear end starting to move or noticed I was increasing revs but not speed. Its been both wet and cool in this neck of the woods so thats a factor but even when its dry they are pretty quiet while spinning. More so than any tire I have experienced so far. I cant launch this car worth a damn, keep going into wheelspin and when I do its hard to drive out of it smoothly without chopping the throttle so much that the launch is totally ruined. I know that too much throttle is the primary factor there but as I launch I keep feeling like Im just not getting it right. Im either launching to soft or into wheelspin, not the middle ground I have been trying for. Tips welcome.

FLC6

It's so hard to launch the C6 6 speed.

I can burn rubber all day long with the auto.

My 60 foot times are below 2 as well.

David Lasic

Put her in Competition Mode or completely shut off the system entirely.

Then, just hang on. Tire sound?? It depends on the tire, Z51 vs base.
Also depends on the surface composition.

But, they will spin. No wheel hop whatsoever.

When powershifting, I'll get first, second, and third gear scratch on the shifts. Going too fast for fourth gear. I like using the Competition Mode the best so far. No track times yet either. May never do that. This car is plain fast. For me, its enough to get used to the car's limits, then just enjoy the ride.

Dsob15

So...the other day in the rain I was attempting a U-turn...After going around the turn I go pretty easy on acceleration up until about 20 or 30, when I lay into it and realize I'm not going anywhere. I have the auto 3.15. It actually took me a few seconds to realize what was happening. Luckily no traffic was coming... TC was on.

cbecker

I've also noticed that the stability control does not kick-in until you are well out of control. With everything turned on I've ended up almost 90 degrees sideways before the system kicked in and I'm not sure that my moving off the throttle didn't happen before the system ever kicked in. It is actually a bit scary.

I must say, however, that in high speed turns...it is so easy to drive at the edge of traction and stay there that I can't imagine an easier car to drive fast! This car lets go almost in slow motion and you can drop throttle slightly and feel everything hook-up again. I need a dash cam to see the expression on my office collegues faces as I drive them around my personal test tract in the Denver Tech Center! I take this one turn after a short full throttle burst and they all go stiff thinking that we're not going to make the turn and the tires don't make a sound at .90G-.91G.

shopdog

The tires are remarkably quiet during a burnout. I don't know why. If both wheels spin, traction control modulates engine power. This can feel like wheel hop. If only one wheel spins, traction control does differential braking. Stability control works off accelerometer readings. In other words, you have to be slewing *hard* before it kicks in. It won't act if you're just in a gentle slide.

I don't have any problem launching the car. Switch to "competitive driving" mode, bring up the revs while holding the brake, then gas it hard while releasing the brake, go quick like bunny. But then mine is an automatic.

lager99

Mine's parked for winter...hold on, I'll try it...I've got room in my garage...should be able to stop in time...

Yogivette

Ive only had problem with wheel hop once and the roads were cold and MAYBE damp not too sure....i havent tried launching the car yet so no advice there. Is it possible that the tires are just too soft to make noise like a harder tire would...or maybe the tread design. I havent gotten mine to chirp yet either. I was thinking that maybe its just cause of soft tires....i can even make my fathers minivan squeel so i dont know.

_crazi4speed_

wow this sounds pretty bad, i have hear of many high performance cars with well over 400hp and never heard soo much trouble with straight line gunning or while taking turns or at higher speeds...

i know no one will agree to it since you all have the car, but is this not something seriously wrong with the C6, I have spoken to few owners of C5 and they havent told me any such scary moments?

Would this only happen in winter months or will this also tend to happen in summer ? just curious..

jschindler

Stan, a few of observations.

At 17 degrees your car is making a lot of horsepower. Probably somewhere around 365 rwhp. That makes a big difference as does the cold tire and pavement (I know you said you warmed them up, but the pavement is still cold).

The C6's traction control (and active handling) does seem to allow a lot more "entertainment" before kicking in than the two C5's I had.

My C6 has yet to "axle hop". I have no doubt they will, and my C5's certainly did, but it has not happened yet. I think it has something to do with how you feed in the clutch and gas. But it's not an exact science.

Finally, I think you overstated a bit that you "saved" a 180. At 180 you are going the other direction. If you really did save a 180, you actually did a 360! (you know I"m just busting your nuts on that one!)

StanNH

There's another thread going on now about "fishtailing". Same observations about the same difficulties in getting a smooth full throttle launch. I've spoken with a few local speed shops and one pro driver (who runs a racing/driving school) about this and have reached a few conclusions.

The outside temperature is a BIG factor in how the tires behave...bigger than I would have expected. I know high performance tires lose adhesion as the temperature drops, (all tires do to some degree), but the Supercar EMTs on the Z51 package must lose them at relatively high temps.

The Positraction rear axle in the Vette will allow both rear tires to spin, rather than cut power to the side that has lost traction.

The lower gearing on the Z51 manual seems to make tire spin much easier than the auto or non-Z51 packages.

The traction control modulates the throttle to control tire spin, not the brakes as other cars I've owned. This accounts for the "wheel hop" feeling I spoke of.

400 foot pounds of torque can be a handful in cold weather, especially driving a Z51 6 speed. Now I'm really looking forward to the warm weather of summer!

Thanks for everyone's input on this....I learned a lot!

TRAIL BOSS

Good summary, thanks for the post!

Convert14

WhiteC5Vette

I do not own a C6, waiting for spring and my local dealer to accept GMS; however, I know how the ABS/Traction Control/Active Handling systems on the C6 operates, since the system is not unique to the C6, and it operates in the same manner as the system used on the C5; and other GM vehicles.

If wheel speed slip is detected, the electronic brake control module (EBCM) signals the PCM to reduce the amount of torque to the drive wheels. The PCM will then reduce torque to the drive wheels in two ways; one, retard timing; two, turn off fuel injectors.

If these methods fail to eliminate the wheels from spinning, the EBCM will apply the drive wheel brakes to eliminate wheel slip via the brake pressure modulator valve assembly.

What may be happening, as you previously stated is that since the tires are hard and cold, both rear wheels are spinning at the exact same speed for a few feet (positraction does work at times). The system operates in traction control mode (as well as ABS mode) by seeing differences between rotational speeds of the different wheel speed sensors. Since the PCM has signaled (via the "delivered torque signal circuit") that the car is accelerating, and the EBCM does not see a brake apply input, it will look at the rotational wheels speeds reported from the rear two sensors.
Therefore, the EBCM will not go into traction control, until it sees a difference in rear wheel rotational wheel speeds. Once the EBCM detects a difference in rotational wheel speeds of the rear wheel speed sensors, it will go into traction control mode.

If the EBCM detects the brakes are applied (via the brake apply input signal), it will then monitor all four wheel speed sensors to detect differences in wheel rotational speeds, and will release and/or apply pressure to the correct wheel to prevent if from locking up.
If the EBCM detects acceleration, no brake apply input, the programmed desired yaw rate is different than the actual yaw rate as signaled by the Yaw Rate Sensor, and the steering wheel position is changing via the Steering Wheel sensor, it will go into active handling mode, and pulse the brakes to prevent the car from over- or under-steering.

This is a simplified description of the operation of these three different modes, and may not explain why the TC and or Handling systems are not operating correctly. However, the statement made earlier that the TC does not control brakes as in the C5 is incorrect, or at least it is incorrect according to all the information available on the C6. This information includes the C6 service manual, knowledge on how this system operates, since it is not unique to only the Corvette.