Why do C7 Z06's pull to the right violently when breaking loose...WTF
03-31-2018, 12:44 PM
#401
Race Director
Member Since: Jul 2007
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Tell us what a driver can be doing when holding the steering wheel straight and flooring it that can cause the rear end to fly sideways... steering into the skid is irrelevant - we're simply discussing why the car is apparently incapable of going straight whilst the tires are spinning.
without a controlled test surface it's really all just hearsay and anecdotal. most roads don't allow you to launch, turn around and park your rear wheels in the same exact spot and launch again and compare.
I am not saying the car doesn't fishtail, it has done it to me several times but so have pretty much all the other 150 cars I have owned so....I call it normal.
once in a while my race car will kick the rear out during a burnout if there's a bit more water under one tire than the other and that's with a line loc, locked rear end, solid axle, etc with perfectly measured geometry.
03-31-2018, 12:57 PM
#402
Team Owner
Sure is it 150 and not just 149? 12 cars 1 a month times 12 years equal 144 that would be 1 month. That's a busy owner right there! 
03-31-2018, 01:19 PM
#403
Melting Slicks
Sounds like an alignment problem. IMO
Also, with that new suspension firmware/software update they can install on the c7's at the dealer, does that change any of the ediff settings too?
Also, with that new suspension firmware/software update they can install on the c7's at the dealer, does that change any of the ediff settings too?
03-31-2018, 02:23 PM
#404
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not everyone brags in every post about having two corvettes. some of us can own lots of cars and make it no one else's business....and your reply is exactly why that is.
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03-31-2018, 11:09 PM
#405
Le Mans Master
I ordered and took delivery of 2 new Z06's in early January 2018. I have been driving them slowly for their 500 mile break-in period. My wife's car is an automatic, mine is a stick. I'm 54 years old, and have had Lamborghini's, ZR-1 Corvettes, and driven highly modified cars my entire life. I just got done with my wife's 500 mile break in, had the oil changed, and finally hit the throttle on her auto Z06. What I got was something I've never experienced in any of my sports cars .....EVER. The rear end swung out violently towards the left in 2nd gear with about 1/2 throttle, just mildly engaging the supercharger for the first time. I let off the gas and the car recovered, no problem. I then repeated the situation 2 more times, and both of them had the same results, rear end pushed HARD to the left, car swinging right.
I used to look at all the "idiots" on Youtube wrecking their C7 Z06's and think how can they be such bad drivers? Well, after experiencing the violent ***-swing for myself, I have to say their is definitely something wrong with the car. I don't know what it is, and haven't had a chance yet to drive in other modes, with and without traction control on, and in warmer weather (it was about 60 degrees on the day this happened to me). Breaking traction and have the rear end fishtailing, have done it thousands of times, mostly on purpose, but never had something like this happen. It feels as if someone has attached a cable to the left rear end side of the car and suddenly "pulled" the rear end to the left. I read on this thread that some people are saying it's just because their is so much torque and horsepower, but I've driven supercharged cars with over 900 horsepower, and this just doesn't happen. Sure, fishtailing, rear end loose...all very normal but NOT this pulling. Something else is at work here, and it is dangerous.
While a lot of the YouTube drivers may very well be inexperienced in driving high horsepower cars, I don't believe the fault lies with just the driver in some of these cases, the car is definitely experiencing some sort of problem enabling some of these accidents to take place.
I'm going to wait until the weather warms up and then test the car out in a large parking lot to see if the pull happens in all modes, and with/without traction control on. My 69 Stingray has a Lingenfelter 420ci small block Chevy Bowtie racing engine in it, 620HP with no traction control (obviously) and I can spin the tires in all 5 gears, but the car never pulls one way or the other, just a nice smooth fishtail until you let of the throttle.
To be continued once it warms up a bit more in Michigan... And test out my manual Z06 once I get the 500 miles on it.
I used to look at all the "idiots" on Youtube wrecking their C7 Z06's and think how can they be such bad drivers? Well, after experiencing the violent ***-swing for myself, I have to say their is definitely something wrong with the car. I don't know what it is, and haven't had a chance yet to drive in other modes, with and without traction control on, and in warmer weather (it was about 60 degrees on the day this happened to me). Breaking traction and have the rear end fishtailing, have done it thousands of times, mostly on purpose, but never had something like this happen. It feels as if someone has attached a cable to the left rear end side of the car and suddenly "pulled" the rear end to the left. I read on this thread that some people are saying it's just because their is so much torque and horsepower, but I've driven supercharged cars with over 900 horsepower, and this just doesn't happen. Sure, fishtailing, rear end loose...all very normal but NOT this pulling. Something else is at work here, and it is dangerous.
While a lot of the YouTube drivers may very well be inexperienced in driving high horsepower cars, I don't believe the fault lies with just the driver in some of these cases, the car is definitely experiencing some sort of problem enabling some of these accidents to take place.
I'm going to wait until the weather warms up and then test the car out in a large parking lot to see if the pull happens in all modes, and with/without traction control on. My 69 Stingray has a Lingenfelter 420ci small block Chevy Bowtie racing engine in it, 620HP with no traction control (obviously) and I can spin the tires in all 5 gears, but the car never pulls one way or the other, just a nice smooth fishtail until you let of the throttle.
To be continued once it warms up a bit more in Michigan... And test out my manual Z06 once I get the 500 miles on it.
my c7z is a non z07 with the Michellen mpss. The choice of tires by gm is terrible. The mpss just feel like your driving on grease. And when it does hook for a moment more then likely then not it breaks loose and you get the violent snap.
I think on both my c6z and c7z cars it’s the tires and alignment. When an owner drives their c7z on the street the car for safeties sake it should have a street alignment and non-summer tires . Someone way up the thread mentioned they went with all weather pirelli tires and this fixed the problem. I can’t imagine how ridiculous a c7z would be running on cup tires on the street would be.
I have driven 700 hp plus cars without all the crap like e-diffs, and suspension settings of our c7z’s and these cars never exhibited this behavior. They hooked and went straight or broke the tires loose and went straight.
04-01-2018, 02:21 PM
#406
Melting Slicks
The problem with this snap situation is there are a variety of variables that contribute to the undesirable behavior.
04-01-2018, 05:33 PM
#407
Race Director
I am getting the alignment looked at soon (again) but almost feel as if it is the e-diff or something computer related because to me it doesn't happen all the time. Most of the time it plays nice and is easy to control but I have had a handful of times all of a sudden it wants to throw me into the ditch 
And before anyone says different roads, conditions etc. these are the same roads I have raced on literally hundreds of times in many different cars. From my D1SC 402 C5 (with bridgestone all seasons mind you) to my modded C6Z06 I have never experienced a car this finicky.
Last edited by tail_lights; 04-02-2018 at 03:16 PM.
04-01-2018, 06:15 PM
#408
Instructor
I ordered and took delivery of 2 new Z06's in early January 2018. I have been driving them slowly for their 500 mile break-in period. My wife's car is an automatic, mine is a stick. I'm 54 years old, and have had Lamborghini's, ZR-1 Corvettes, and driven highly modified cars my entire life. I just got done with my wife's 500 mile break in, had the oil changed, and finally hit the throttle on her auto Z06. What I got was something I've never experienced in any of my sports cars .....EVER. The rear end swung out violently towards the left in 2nd gear with about 1/2 throttle, just mildly engaging the supercharger for the first time. I let off the gas and the car recovered, no problem. I then repeated the situation 2 more times, and both of them had the same results, rear end pushed HARD to the left, car swinging right.
I used to look at all the "idiots" on Youtube wrecking their C7 Z06's and think how can they be such bad drivers? Well, after experiencing the violent ***-swing for myself, I have to say their is definitely something wrong with the car. I don't know what it is, and haven't had a chance yet to drive in other modes, with and without traction control on, and in warmer weather (it was about 60 degrees on the day this happened to me). Breaking traction and have the rear end fishtailing, have done it thousands of times, mostly on purpose, but never had something like this happen. It feels as if someone has attached a cable to the left rear end side of the car and suddenly "pulled" the rear end to the left. I read on this thread that some people are saying it's just because their is so much torque and horsepower, but I've driven supercharged cars with over 900 horsepower, and this just doesn't happen. Sure, fishtailing, rear end loose...all very normal but NOT this pulling. Something else is at work here, and it is dangerous.
While a lot of the YouTube drivers may very well be inexperienced in driving high horsepower cars, I don't believe the fault lies with just the driver in some of these cases, the car is definitely experiencing some sort of problem enabling some of these accidents to take place.
I'm going to wait until the weather warms up and then test the car out in a large parking lot to see if the pull happens in all modes, and with/without traction control on. My 69 Stingray has a Lingenfelter 420ci small block Chevy Bowtie racing engine in it, 620HP with no traction control (obviously) and I can spin the tires in all 5 gears, but the car never pulls one way or the other, just a nice smooth fishtail until you let of the throttle.
To be continued once it warms up a bit more in Michigan... And test out my manual Z06 once I get the 500 miles on it.
I used to look at all the "idiots" on Youtube wrecking their C7 Z06's and think how can they be such bad drivers? Well, after experiencing the violent ***-swing for myself, I have to say their is definitely something wrong with the car. I don't know what it is, and haven't had a chance yet to drive in other modes, with and without traction control on, and in warmer weather (it was about 60 degrees on the day this happened to me). Breaking traction and have the rear end fishtailing, have done it thousands of times, mostly on purpose, but never had something like this happen. It feels as if someone has attached a cable to the left rear end side of the car and suddenly "pulled" the rear end to the left. I read on this thread that some people are saying it's just because their is so much torque and horsepower, but I've driven supercharged cars with over 900 horsepower, and this just doesn't happen. Sure, fishtailing, rear end loose...all very normal but NOT this pulling. Something else is at work here, and it is dangerous.
While a lot of the YouTube drivers may very well be inexperienced in driving high horsepower cars, I don't believe the fault lies with just the driver in some of these cases, the car is definitely experiencing some sort of problem enabling some of these accidents to take place.
I'm going to wait until the weather warms up and then test the car out in a large parking lot to see if the pull happens in all modes, and with/without traction control on. My 69 Stingray has a Lingenfelter 420ci small block Chevy Bowtie racing engine in it, 620HP with no traction control (obviously) and I can spin the tires in all 5 gears, but the car never pulls one way or the other, just a nice smooth fishtail until you let of the throttle.
To be continued once it warms up a bit more in Michigan... And test out my manual Z06 once I get the 500 miles on it.
The instructors at Ron Fellows Driving School heavily emphasized that the car should be pointed straight when applying throttle after a turn and that it should be applied gradually and then progressively go to full throttle. Never stab the throttle they say,you will only spin the tires,lose time and possibly control.
One other point they make concerns the electronic locking differential. It is unlocked when you are off the throttle (as in a turn). When applying the throttle when in a turn, the rear diff locks and throttle steer will push the car straight. This may cause the driver to over correct and possibly spin.
To sum it all up the tires should hot, the car pointed straight, and the throttle applied gradually ,not stabbed. This is not only safer, it’s faster.
04-01-2018, 06:22 PM
#409
Melting Slicks
I am getting the alignment looked at soon but almost feel as if it is the e-diff or something computer related because to me it doesn't happen all the time. Most of the time it plays nice and is easy to control but I have had a handful of times all of a sudden it wants to throw me into the ditch And before anyone says different roads, conditions etc. these are the same roads I have raced on literally hundreds of times in many different cars. From my D1SC 402 C5 (with bridgestone all seasons mind you) to my modded C6Z06 I have never experienced a car this finicky.
Never had an issue on the track, but I am running slicks. So far when I am unwinding from a corner on the track it will warn me with some inside wheel spin which does not cause snap.
Last edited by djnice; 04-01-2018 at 06:22 PM.
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04-01-2018, 08:16 PM
#410
Safety Car
Although I have never been big on gratuitously burning up perfectly good expensive tires, I did test things out yesterday for a bit in 1st and 2nd in my A8. Everything was straight. I definitely felt the ediff moving the traction around so the rear end was wiggling a bit as it tried to keep each tire within the traction circle, but only several inches each way and then it self corrected.
I am running +0.5 deg rear caster and zero toe in the back so the toe curve doesn't get to crazy in compression. Where it is uncontrollable, I suspect a combination of the ediff not keeping up and toe out under compression due to a bad alignment. Only thing I can think of that make some of the cars a bear to control.
I am running +0.5 deg rear caster and zero toe in the back so the toe curve doesn't get to crazy in compression. Where it is uncontrollable, I suspect a combination of the ediff not keeping up and toe out under compression due to a bad alignment. Only thing I can think of that make some of the cars a bear to control.
04-02-2018, 05:25 PM
#411
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What is important in this 20 page thread is that there is not a design flaw in the C7Z06 that causes some kind of magic "unintended acceleration to the right." It is always one of two things. From a mechanical standpoint it is most likely a poor alignment job from the factory. From a driver standpoint it also could be driver error. Some don't like to admit the latter is at all possible, but if your alignment has been checked then the latter needs to be considered. The vast majority of owners do not experience this "problem." I do suppose that it could be some flaw in the particular cars eLSD but so far nobody has diagnosed that as a problem that needs addressing.
Bill
04-03-2018, 04:45 AM
#412
Take it from an owner like me that had a car that was predictable like a pitbull on crystal meth that has since been transformed into a golden retriever. The alignment and tires WILL change the car. I did those two things and it was night and day. I still feel like the eLSD may be part of the problem and I feel that the electronic throttle by wire has possibly something to do with it. I have gotten to where the car is fun and safe and predictable so I haven't done the Wavetrac yet and dont feel any rush now.
Last edited by Adam Silver05; 04-03-2018 at 04:46 AM. Reason: typo
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04-03-2018, 07:43 PM
#413
Melting Slicks
I agree the eLSD can contributes to the problem, but have no proof.
04-03-2018, 08:23 PM
#414
What do you think drag racers mean when they say “I had to pedal it” when they get loose? Nothing new, can happen just about anywhere depending on many variables and in any high hp vehicle when you lose traction. Cars are tuned constantly in between runs to get down the road, which includes the way the car launches and reacts. People work tirelessly trying to get their cars to launch straight with as little tire slip as possible.
Last edited by Cercone; 04-03-2018 at 08:49 PM.
04-04-2018, 11:18 AM
#416
What do you think drag racers mean when they say “I had to pedal it” when they get loose? Nothing new, can happen just about anywhere depending on many variables and in any high hp vehicle when you lose traction. Cars are tuned constantly in between runs to get down the road, which includes the way the car launches and reacts. People work tirelessly trying to get their cars to launch straight with as little tire slip as possible.
1. I didn't change or improve as a driver.
2. My car was terrifying! (understatement)
3. I fixed a horrible factory alignment (that was technically within specs but rear caster on left and right very nonsymetrical).
4. I changed tires at the same time.
5. The car is totally different and 100% more predictable.
04-04-2018, 12:37 PM
#417
Melting Slicks
"Pedal it" has nothing to do with the way the C7 snaps so hard it puts the car into a sideways skid in the opposite direction of the drift. So far I find if I stay on the throttle it will straighten out after a couple of snaps each direction. I haven't had time to deal with alignment, but will do it one of these days.
04-04-2018, 01:52 PM
#418
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I will try to keep this simple and short with easy words for people that still can't grasp....
1. I didn't change or improve as a driver.
2. My car was terrifying! (understatement)
3. I fixed a horrible factory alignment (that was technically within specs but rear caster on left and right very nonsymetrical).
4. I changed tires at the same time.
5. The car is totally different and 100% more predictable.
1. I didn't change or improve as a driver.
2. My car was terrifying! (understatement)
3. I fixed a horrible factory alignment (that was technically within specs but rear caster on left and right very nonsymetrical).
4. I changed tires at the same time.
5. The car is totally different and 100% more predictable.
I never had a snap over steer issue as I knew from lots of years driving limited slip diff vehicles in low grip situations (snow/ice) how to use the throttle to control side slip (when both rear wheels are excessively spinning there is no lateral control provided by the tires, they will slide sideways in either direction depending on the outside forces being applied such as the crown of the road). You see this on paved roads all over the country where some hot dog decided to do a burn out and the tracks of the spinning tires move back and forth across the pavement.
A few months later I had got a track alignment the dealership couldn't measure rear caster so didn't bother to set it. Again, I never had control problems. Later on when I finally received my rear caster adapter and angle gauge I found left side rear caster was about +0.5 while right side rear caster was about -0.4.
As Chip Ganassi once told a reporter who asked what Chip thought about Scott Pruett crashing one of his IMSA cars, "He ran out of talent". In most cases that is what causes all of the snap over steer complaints. Drivers not knowing how to drive. They don't realize both rear wheels spinning cause lateral stability issues, they don't stay on top of the steering so get behind when the car starts moving in a way they don't expect and then completely screw up subsequent throttle positioning.
Bill
04-04-2018, 03:25 PM
#419
Melting Slicks
Yep, you need to be a "driver". Watch Randy at 6:06 and 6:54, for example.
06:33
but it can be dicey in the corners the
06:37
primary characteristic of the co six
06:39
Corvette is oversteer especially an to
06:42
oversteer and it hurts the lap times if
06:50
oversteer into the corkscrew yo this one
06:58
that is a handful it requires many
07:02
Corrections
07:03
takes a lot of driving to drive the
07:05
Corvette mask
07:08
that's a wild ride let me tell you it's
07:11
loose enough that it's a challenge on a
07:13
road course you've got to really be on
06:33
but it can be dicey in the corners the
06:37
primary characteristic of the co six
06:39
Corvette is oversteer especially an to
06:42
oversteer and it hurts the lap times if
06:50
oversteer into the corkscrew yo this one
06:58
that is a handful it requires many
07:02
Corrections
07:03
takes a lot of driving to drive the
07:05
Corvette mask
07:08
that's a wild ride let me tell you it's
07:11
loose enough that it's a challenge on a
07:13
road course you've got to really be on
Last edited by djnice; 04-04-2018 at 03:30 PM.
04-04-2018, 07:31 PM
#420
I own a 2013 Viper, same differential as the 2006 GTO, and it does the exact same thing you guys are talking about in this thread. Just a couple months ago, I was in second gear, and gunned it at around 2500 rpm, rear snapped out and went to the right. That's on Pirelli PZero Corsas. A year ago I drove my friend's 2010 GT500, same exact thing. Imo, it's not a differential, it's not something wrong with the tires. Maybe adjusting the alignment helps some, but I don't think there is anything wrong with the factory alignment.
What the culprit was in both my cases, was mashing the gas down on cars with massive amounts of torque, on cold Summer performance tires, in cold weather. I've done the exact same thing with the Viper in the summer, and it spun the tires, wiggled a little bit, but kept straight. The tires gripped faster too. Why? Because they were simply warmer, and these summer tires need heat in them to grip. My GTO doesn't do this, but it's also got a lot less torque, and it's always been riding on Michelin all seasons year long. Then again, I can't recall if I've actually gunned it hard in 1st gear during the winter time....so it might actually do it as well.
So I don't think there is anything wrong with your Corvettes, this is a natural thing that's going to happen with a car that has a ton of torque and cold performance tires.
Also of note, don't be fooled into thinking the tires are warm because the tire pressure has gone up a few psi on your digital display reading. That's what I thought with the Viper when it happened, I had drove the car around for over 30 minutes. In cold weather, that doesn't matter, the tires are still cold.
What the culprit was in both my cases, was mashing the gas down on cars with massive amounts of torque, on cold Summer performance tires, in cold weather. I've done the exact same thing with the Viper in the summer, and it spun the tires, wiggled a little bit, but kept straight. The tires gripped faster too. Why? Because they were simply warmer, and these summer tires need heat in them to grip. My GTO doesn't do this, but it's also got a lot less torque, and it's always been riding on Michelin all seasons year long. Then again, I can't recall if I've actually gunned it hard in 1st gear during the winter time....so it might actually do it as well.
So I don't think there is anything wrong with your Corvettes, this is a natural thing that's going to happen with a car that has a ton of torque and cold performance tires.
Also of note, don't be fooled into thinking the tires are warm because the tire pressure has gone up a few psi on your digital display reading. That's what I thought with the Viper when it happened, I had drove the car around for over 30 minutes. In cold weather, that doesn't matter, the tires are still cold.
Last edited by CNU_Physics; 04-04-2018 at 08:49 PM. Reason: Addition
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