Why do C7 Z06's pull to the right violently when breaking loose...WTF
02-19-2017, 12:28 PM
#342
Intermediate
02-19-2017, 12:31 PM
#343
Burning Brakes
Mordeth I usually find your post 100% on the mark. But on this one I have to disagree. You are probably right about it's a shadow, but the video shows clearly that the driver got out of dodge after the spin. Did the driver checked out his corvette or for that matter driving surface at the accident site during the video? To assume to be true without conclusive evidence.
02-19-2017, 01:14 PM
#344
Melting Slicks
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2018 C6 of Year Finalist
St. Jude Donor '10, '17
Mordeth I usually find your post 100% on the mark. But on this one I have to disagree. You are probably right about it's a shadow, but the video shows clearly that the driver got out of dodge after the spin. Did the driver checked out his corvette or for that matter driving surface at the accident site during the video? To assume to be true without conclusive evidence.
See here:
1) https://www.corvetteforum.com/forums...post1593625569
rikhek post #192: "I guarantee there was NOTHING on the road. The shadows make it look like there is tar or oil or something, however, road was good. I spent a lot of time examining as I couldn't figure out what happened and thought it had to be something on the road.
Yes, I wasn't pushing at all, just cruising through the corner due to limited line of sight on corner entry through mid corner. I was such a surprise is was one of those WTF moments.
Then here:
2) https://www.corvetteforum.com/forums...post1593619538
rikhek post # 168:
" Road surface was not a significant factor. No dirt, rocks, oil, water, inundations, surface material, etc. Shadows incorrectly suggest oil or tar on the road. The road is slightly off camber but nothing unusual."
Also here:
3)https://www.corvetteforum.com/forums...post1593619538
rikhek post #177:
"I immediately went back to that section, parked the car and spent significant time walking the road. I looked at the road very carefully. Nothing there..."
Last edited by Mordeth; 02-19-2017 at 01:16 PM.
02-19-2017, 07:45 PM
#345
Now if you were to take that same VW 10-15 MPH over the posted limit you may get excessive body roll, the tires may squeal and maybe start to slip a little, maybe even spin out? At some point you will reach the mechanical limits of that design.
The C7Z has much higher mechanical limits than the VW and all I was trying to say is the car should be able to handle 14 MPH over the posted limit like a breeze and without issue.
Based on what I've read in the post and saw in the video, the driver did nothing of note that would cause the car to behave in that manner.
Edit: Actually now that I think about it a bit more it may be lift-off oversteer but impossible to tell from where I'm sitting.
Last edited by donato; 02-19-2017 at 07:57 PM.
02-19-2017, 07:54 PM
#346
Safety Car
Please very carefully look at the entry to the turn along with the G meter. Note that at turn in (indicated by the g force meter ball moving to the right) there is still 2 than 1 red block lit indicating the brakes were on. That is a classic trail braking maneuver. It is ok if the car is aligned well AND IF the throttle is applied soon enough and agressively enough to replant the rear OR an aggressive counter steer is applied as the rear end steps out. That latter step likely would not have kept the car on the road simply because the rear caster alignment made the rear incredibly skittish.
In my view simply a bit of trail braking that would not have normally caused a problem except exacerbated by the alignment.
In my view simply a bit of trail braking that would not have normally caused a problem except exacerbated by the alignment.
02-20-2017, 10:33 AM
#347
Burning Brakes
Please very carefully look at the entry to the turn along with the G meter. Note that at turn in (indicated by the g force meter ball moving to the right) there is still 2 than 1 red block lit indicating the brakes were on. That is a classic trail braking maneuver. It is ok if the car is aligned well AND IF the throttle is applied soon enough and agressively enough to replant the rear OR an aggressive counter steer is applied as the rear end steps out. That latter step likely would not have kept the car on the road simply because the rear caster alignment made the rear incredibly skittish.
In my view simply a bit of trail braking that would not have normally caused a problem except exacerbated by the alignment.
In my view simply a bit of trail braking that would not have normally caused a problem except exacerbated by the alignment.
The OP of that video states in a post, and agrees just two months after the spin out. That Michelin gave him a bad batch of tires and was Warranty a new set. Just too many variables on this topic to jump to a conclusion. Just look at all the pilot cup 2 tires stored in Michigan lots outside in below zero conditions??
A full set of new MPSS ZP at DT was $1,750. Michelin was surprised I only got 4,700 miles out of a set and said maybe I got some out of a "bad" batch. I said, yeah, that must be what happened....
They stood behind their warranty and paid $970 towards the new set. I paid $780. Kudos to Michelin.
They stood behind their warranty and paid $970 towards the new set. I paid $780. Kudos to Michelin.
Last edited by 360Lemans; 02-20-2017 at 10:40 AM. Reason: TYPO
02-20-2017, 03:08 PM
#348
Tech Contributor
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Bill
02-20-2017, 03:16 PM
#349
Intermediate
He said he checked the road surface after the incident. The other thing about the incident was he wasn't nailing the throttle like the people who started this thread state causes so many problems. All Corvettes since the C5 model came out have some trailing throttle over steer characteristics to them. Trailing throttle for non performamce people means taking your foot off the gas. Rikek is an experienced driver who isn't sure what happened but one thing we know for sure it wasn't from him nailing the throttle.
Bill
Bill
02-24-2017, 08:02 AM
#350
Safety Car
The OP of that video states in a post, and agrees just two months after the spin out. That Michelin gave him a bad batch of tires and was Warranty a new set. Just too many variables on this topic to jump to a conclusion. Just look at all the pilot cup 2 tires stored in Michigan lots outside in below zero conditions??
I spun in a yellow 2015 C7Z. The tire joke was made about my current 2017 C7Z with 4,703 miles. The Michelin rep couldn't believe someone could go through a set of tires in 4,700 miles as I did. As such he threw out an off the cuff comment that it had to be a bad set of tires to which I jokingly posted, "Yeah, that's the ticket".
And as stated multiple times the road was clean and clear. I walked the road for a significant time to analyze the incident. The road was good.
You might find the following thread about my 2017 C7Z alignment as delivered from the factory:
https://www.corvetteforum.com/forums...tting-sad.html
Here is the first post I wrote to start that thread:
I just took my 2017 C7Z in for its 500 mile oil change and alignment. I wanted to see the rear caster setting as shipped from the factory and to have it aligned to my specs. I did not trust the factory delivered alignment.
The factory recommended rear caster setting is 0.0 degrees. The "best" rear caster/performance alignment settings as determined by Mike Levitas/TPC Racing who did extensive testing on his C7Z was +0.8 degrees.
My car was delivered with the right rear set at 0.0 degrees and the left rear at -0.8 degrees. Really disappointing and dangerous that GM built such a good car but does a pitiful job on setting the alignment properly. FWIW, Porsche's come from the factory dead on perfect.
Just my luck that the alignment machine my guy used had a broken printer so I don't have the other as delivered factory settings. I do know what the rear caster was as I specifically asked the tech to make note of it.
For those interested I went with the specs in the thread above recommended by Mike/TPC Racing. These were the settings I had on my 2015 which totally transformed the handling and stability of the rear end. No longer twitchy and prone to snap oversteer when driven aggressively. Haven't gotten to drive the 2017 hard yet but I imagine it will be as good as my 2015.
Front - Both Left and Right:
Camber -2.0
Caster 7.1
Toe -0.03 degrees - toe out.
Rear - Both Left and Right
Camber -1.7
Caster +0.8 degrees
Toe -0.03 degrees - toe out. Yes, toe out. Read above thread...
Rick
Last edited by rikhek; 02-24-2017 at 08:04 AM.
02-24-2017, 10:28 AM
#351
Burning Brakes
Come on man, I was making a joke about the warranty. You might note the "recent" comment/post on the "bad tires" were made about a different car.
I spun in a yellow 2015 C7Z. The tire joke was made about my current 2017 C7Z with 4,703 miles. The Michelin rep couldn't believe someone could go through a set of tires in 4,700 miles as I did. As such he threw out an off the cuff comment that it had to be a bad set of tires to which I jokingly posted, "Yeah, that's the ticket".
And as stated multiple times the road was clean and clear. I walked the road for a significant time to analyze the incident. The road was good.
I spun in a yellow 2015 C7Z. The tire joke was made about my current 2017 C7Z with 4,703 miles. The Michelin rep couldn't believe someone could go through a set of tires in 4,700 miles as I did. As such he threw out an off the cuff comment that it had to be a bad set of tires to which I jokingly posted, "Yeah, that's the ticket".
And as stated multiple times the road was clean and clear. I walked the road for a significant time to analyze the incident. The road was good.
I can tell you this Z06 handles different than my C7 did, or for that matter any sports car I have ever owned. I have always re-aligned all my cars before tracking and never put trust in any assembly line generic alignments. I have also analyzed why I spun, clear track no oil / sand. And my conclusion was on me, driver error and I chalk it up as lesson learned. I have not and will not try to analyze your video, like I stated it's just too many variables to point blame.
02-24-2017, 11:46 AM
#352
I'm throwing this out there...I'm not going to read the whole thread but maybe this might help too.
Some people here claim stock tires rubbing inside the wheel wells witnessing bad alignment too upon further inspection.
Perhaps the tire/wheel jams upon full throttle inside the well with a bad factory alignment causing what you guy's are suffering with.
Some people here claim stock tires rubbing inside the wheel wells witnessing bad alignment too upon further inspection.
Perhaps the tire/wheel jams upon full throttle inside the well with a bad factory alignment causing what you guy's are suffering with.
08-07-2017, 09:30 PM
#353
Melting Slicks
I've thought about the pros and cons of reposting my spin video and decided to repost.
The pros being it will help fellow owners by allowing viewing of my snap oversteer incident to demonstrate the issue and hopefully prevent others from a similar event.
The cons being it will divert the technical conversation of this thread to the, "you got what you deserved by endangering the public driving that fast on a public road" and the "you shouldn't drive on public streets with the nannies off"folks. FWIW, I believe I was driving at a "safe" speed as utilizing line of sight. This is why I slowed significantly for the corner.
Dave396LT states in his post above individuals who have experienced the phenomena of the car rotating violently to the right under hard acceleration in a straight line is due to driver error. I don't agree and believe many who have experienced this trait are capable drivers.
He has also maintaines that my spin was due to driver error from attempting to navigate the corner too fast.
Factual information pertinent to my spin:
1. Speed limit on the road is 50 mph. I was doing 64 mph in 3rd gear (M7) with minimal maintenance throttle application at low RPMs when it let go.
2. Tires were in great shape and hot. Ambient temp was around 90 degrees.
3. Road surface was not a significant factor. No dirt, rocks, oil, water, inundations, surface material, etc. Shadows incorrectly suggest oil or tar on the road. The road is slightly off camber but nothing unusual.
4. Driving mode was Sport 2.
I attribute the main contributing factor to be improper rear caster setting. Post incident caster was measured at 0.0 degrees on one side and -0.8 degrees on the other. Settings were as delivered from the factory. Significant testing has determined the optimum setting to be symmetrical at +0.7 degrees.
I'll let you view and make own analysis. Sharing your thoughts is welcomed, hopefully related to the technical aspects of this thread.
Rick
The pros being it will help fellow owners by allowing viewing of my snap oversteer incident to demonstrate the issue and hopefully prevent others from a similar event.
The cons being it will divert the technical conversation of this thread to the, "you got what you deserved by endangering the public driving that fast on a public road" and the "you shouldn't drive on public streets with the nannies off"folks. FWIW, I believe I was driving at a "safe" speed as utilizing line of sight. This is why I slowed significantly for the corner.
Dave396LT states in his post above individuals who have experienced the phenomena of the car rotating violently to the right under hard acceleration in a straight line is due to driver error. I don't agree and believe many who have experienced this trait are capable drivers.
He has also maintaines that my spin was due to driver error from attempting to navigate the corner too fast.
Factual information pertinent to my spin:
1. Speed limit on the road is 50 mph. I was doing 64 mph in 3rd gear (M7) with minimal maintenance throttle application at low RPMs when it let go.
2. Tires were in great shape and hot. Ambient temp was around 90 degrees.
3. Road surface was not a significant factor. No dirt, rocks, oil, water, inundations, surface material, etc. Shadows incorrectly suggest oil or tar on the road. The road is slightly off camber but nothing unusual.
4. Driving mode was Sport 2.
I attribute the main contributing factor to be improper rear caster setting. Post incident caster was measured at 0.0 degrees on one side and -0.8 degrees on the other. Settings were as delivered from the factory. Significant testing has determined the optimum setting to be symmetrical at +0.7 degrees.
I'll let you view and make own analysis. Sharing your thoughts is welcomed, hopefully related to the technical aspects of this thread.
Rick
08-07-2017, 10:48 PM
#354
Race Director
I'll have to watch the "E-LSD" display/graph. i always drive in tour as i cannot stand these roads here and sport tries to flip this car on its roof over sharp raised impacts!
08-07-2017, 10:53 PM
#355
Le Mans Master
My C5 on the Goodyears and Cups did the same thing exactly!
These guys with my turbos are always straight out. And they're relatively cheap too!
Last edited by johnglenntwo; 08-07-2017 at 11:01 PM.
08-07-2017, 10:57 PM
#356
ahhh back from the dead, this thread is alive once more. my car definately had the problem and now definately doesn't have it anymore. as a driver, I am as good or bad as ever. I changed 2 of the 3 contributing factors to the VERY REAL problem. I got a good alignment including rear castor and I got rid of the worthless stock rear tires for 19" NT05r. I am now thinking of ditching the eLSD for the RPM Transmission Wavetrack that is about to come out mostly to take the weak link (spider gears) out of the potential failure list. Other things I did that may or may not have helped my cars manners are the DSC controller and the LG Spindles that I did. My car went from rabid pit bull to labrador retriever.
The following 2 users liked this post by Adam Silver05:
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08-07-2017, 11:17 PM
#357
Melting Slicks
^^^^ yeah? I thought it is always looking to maximize grip and locks much quicker than a traditional LSD? my car instantly starts to rotate and is spinning both if i get on it to quick and the tires aren't up to temp.
I'll have to watch the "E-LSD" display/graph. i always drive in tour as i cannot stand these roads here and sport tries to flip this car on its roof over sharp raised impacts!
I'll have to watch the "E-LSD" display/graph. i always drive in tour as i cannot stand these roads here and sport tries to flip this car on its roof over sharp raised impacts!
The following users liked this post:
23/C8Z (08-07-2017)
08-08-2017, 12:41 PM
#358
I've been reading this thread for a while now. Currently own a 911 4S, which has incredible grip and control - whether on the track or in spirited driving on deserted country roads. I was really leaning towards buying a Z06 as I've always been a Vette fan (Dad has owned 10+), and I really wanted a powerful V8, which translates to a Z06. But after reading the concerns shared by what appear to be many muscle-car experienced drivers, I'm having doubts. I'm not seeing a silver bullet solution to this issue - is there one I've missed? Replacing tires makes sense (and even the 911 gets a little slippery in Minnesota cold weather around spring/fall time), but having to get an alignment on a brand new $100k vehicle seems a little absurd.
08-08-2017, 01:02 PM
#359
Burning Brakes
I've been reading this thread for a while now. Currently own a 911 4S, which has incredible grip and control - whether on the track or in spirited driving on deserted country roads. I was really leaning towards buying a Z06 as I've always been a Vette fan (Dad has owned 10+), and I really wanted a powerful V8, which translates to a Z06. But after reading the concerns shared by what appear to be many muscle-car experienced drivers, I'm having doubts. I'm not seeing a silver bullet solution to this issue - is there one I've missed? Replacing tires makes sense (and even the 911 gets a little slippery in Minnesota cold weather around spring/fall time), but having to get an alignment on a brand new $100k vehicle seems a little absurd.
08-08-2017, 03:56 PM
#360
Burning Brakes
The Snap Oversteer Monster will be along shortly to blame rear caster. Maybe it's even true - but do people who get that "fixed" no long have to worry about the rear end coming around? I'd pay for an alignment if I believed it made the car more stable in street scenarios (I have had no issues on the track, so maybe my car is randomly set up properly from the factory).
Why would the gear make a difference as to why the rear end steps out? Any theories? That part strikes me as odd, and I can't say I've experienced the same.
Why would the gear make a difference as to why the rear end steps out? Any theories? That part strikes me as odd, and I can't say I've experienced the same.
What track allows you to run a vert with no roll cage?