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Not to belabor the point but simply asking a dealer to "check" your alignment will typically be an exercise in futility!!! I can't state this strongly enough.
GM allows a WIDE range of "acceptable" settings and does not require symmetry. Look up above at Post #180 of the acceptable alignment specifications for our cars provided by Bill. A dealer can check and say "you're good to go buddy" with the settings below as they are within range:
Left front caster: +8.0
Rear front caster: -8.0
Left rear caster: +0.8
Right rear caste: -0.8
Left front camber: 0.0
Right front camber: -1.5
Left rear camber: -0.5
Right rear camber: -1.7
Etc, etc, etc....
This wide range of acceptable settings is why they come set all out of wack from the factory.
These guys are not used to aligning performance cars. They're used to aligning pickups, Cruz's, Malibu's, etc. As long as the alignment heads indicate green (i.e., the settings are within the WIDE range of acceptable settings) they're generally not going to mess with it. Hell, I've had a number of dealer techs chuckle at me and state the rear caster is not adjustable.
I urge you to talk to the man who's going to "check" your alignment and question him to determine if he's knowledgeable. Also, you MUST provide him in writing the EXACT settings you want on the car. You must be convinced he understands the importance of setting the rear caster where you want as NO alignment machine provides this reading on the printout sheet. You have to trust him or be there to observe the setting for yourself. Of course, you must tell him you want a copy of the final settings on the alignment printout sheet.
Not meaning to preach to you all or talk down but this is really important stuff. It's such a big deal I had no problem paying out of my pocket to get my new 2017 "properly" aligned to the EXACT Levitas/TPC Racing specs provided in this thread at my 500 mile oil change. I'm lucky enough to have a tech who is a fellow racer and takes great pride in his work. He gets it right, unlike the majority.
Rick
Great post.
Anyone with a Z06 should do themselves a favor and get a really good alignment and corner balance at a good shop if you have the option to do so. Or seek out a good Chevy dealer that knows what they're doing (like Abel Chevrolet, etc.).
Most cars DO NOT come from the factory with the perfect/correct alignment settings.
I'm not an expert but that video didn't look too fast for the turn (except for the resulting crash). At second # 18 in the video it looks like oil or fluid on the road. Nobody will convince me (based on that video) that driver technique was the culprit. I think that video is definitely a snap oversteer situation (and upsetting to watch). If the road was indeed clean, the car 100% seems to me to be the cause - not the driver. If that road had oil at second # 18, any car would have had that spin. I do think some percentage of the C7Z has major issues with freaky behavior. BTW, I am sketched enough that I ordered 19" rear wheels and Nittos all around today to try to make my car less likely to have the evil monkey! I am hoping that softer compound, non-runflat and larger sidewall will slow down things back there.
Don't count on the Nittos to do anything but wear well. They are a crap performance tire. They don't have as much grip as the GY EMTs that came on the C6Z and lose what they have over a 20 minute track session. They aren't in the same ball park when compared to the Michelins. They aren't even in the same country. They aren't going to save your butt when it comes to snap oversteer.
Bill
Last edited by Bill Dearborn; 12-09-2016 at 06:12 PM.
Don't count on the Nittos to do anything but wear well. They are a crap performance tire. They don't have as much grip as the GY EMTs that came on the C6Z and lose what they have over a 20 minute track session. They aren't in the same ball park when compared to the Michelins. They aren't even in the same country. They aren't going to save your butt when it comes to snap oversteer.
Bill
Bill
Bill is 100% correct. They are a **** tire from a performance perspective. I tried a set on my C6Z and gave them away after less than a thousand miles. The MPSS ZP that come on the car are an amazing tire.
This thread was started to discuss the C7Z tendency to rotate violently to the right under hard straight line acceleration. I'm one guilty of diverting the discussion to the cars tendency to snap oversteer during road course usage and when aggressively driving the "twisties".
To add to the original conversation I asked Mike Levitas to discuss improvements realized in straight line power down applications with a DSC Sport Controller.
Mike Levitas who owns TPC Racing is an accomplished racer and race shop owner. His credentials include winning the Daytona 24 Hours and numerous IMSA titles. He's also a long time Corvette nut and drag racing fan. The controller website is: www.dscsport.com.
Mike's a friend of mine and expressed some time back he was frustrated with difficulty putting power down with the C7Z. Additionally, he saw room for improvement from the magnetorheological shocks on road courses. Mike's chassis, suspension and setup knowledge from an engineering standpoint is world class.
I asked Mike to contribute his thoughts to the other thread. He was hesitant as he didn't want to seen as joining the discussion to promote sales of his controller. I convinced him his contribution would be welcomed.
I thought you folks would appreciate the post Mike contributed to the other thread specific to how the DSC Controller improves the ability to put power down in straight line applications:
Mike Levitas here. I thought I would chime in and try to give a few cool details about the DSC Sport controller. There are many features of the controller. One of note is the massive improvement in grip that translates in huge improvements in 60 ft times as well any speed roll-on.
My C7 Z06 M7 was so bad stock it would blow the rear tires off in 3rd gear. Now my car barely squeaks the tire.
How this is achieved is uncomplicated. The controller has an acceleration table that is used in throttle rate of change. There is a sensitivity feature so you can time the rate of change of the throttle to the compressor bypass valve in the blower.
This triggers a table that allows tuning of the magnetic dampers so you can soften low speed rear compression to soften the blow to the tire and increase low speed front rebound to slow down weight transfer so the tires are not overloaded. The result is the car flattens out with nice transfer so you don't blow off the tires.
That being said, please understand setup is critical. You must adhere to my setup on the rear uprights. Caster is king in controlling the toe curve. I'm not sure what GM was thinking with their suggested alignment setup but the car works way better with 0.75 degrees positive rear caster. Also, try to keep eccentric in the center.
I like 1.2 camber for most street cars leaving in all control arm washers. The rear toe loves to be out -0.5mm with this caster.
The secret sauce is the DSC controller so now the shocks can go way softer than stock so you don't blow off the tire. Road racing and drag racing are a lot the same in approach. I've spent time analyzing 100s of cars. Launching a good car just leaves no drama and no big weight transfer. The car just drops and leaves same as a good car off the corner and never even turns a tire.
There is so much power in the DSC controller your imagination is your only limit or lack there of. Please remember there is still the velocity tables that allow tuning of grip to the tires.
What does "stepping out to the right" mean? The front goes to the right like the video of the Red Vette or the rear steps out to the right like the phrase would normally mean?
Mine tends to go straight with (so far) an easily controllable slight drift of the rear to the lowest part of the road.
Bill is 100% correct. They are a **** tire from a performance perspective. I tried a set on my C6Z and gave them away after less than a thousand miles. The MPSS ZP that come on the car are an amazing tire.
The rear tires that came on the car suck. I am doing NT05R (drag radial) to try to get some traction in a straight line. I am not planning on track day events that have turns.
Extremely n00b question but I don't know much about suspension geometry. I'm about to put my winter tires/wheels on. Will getting the proper alignment with that setup carry over to when I put my stock summer set back on or should I just wait till the spring for the alignment?
Extremely n00b question but I don't know much about suspension geometry. I'm about to put my winter tires/wheels on. Will getting the proper alignment with that setup carry over to when I put my stock summer set back on or should I just wait till the spring for the alignment?
So what do I do, hand the salesman a piece of paper with the caster alignments written down and tell him,
"I'll buy the car when you can show me a printout proving these alignments have been made on the car."
What will happen when I do this? I'm concerned the dealership will consider me a pain in the neck and kick me off the lot.
Is this a reasonable way for a prospective buyer to conduct himself? I'd like the deal to go smoothly, but then again I don't want to hit a tree and lose a leg because of a poor alignment.
Last edited by dead of night; 12-10-2016 at 12:06 PM.
So what do I do, hand the salesman a piece of paper with the caster alignments written down and tell him,
"I'll buy the car when you can show me a printout proving these alignments have been made on the car."
What will happen when I do this? I'm concerned the dealership will consider me a pain in the neck and kick me off the lot.
Is this a reasonable way for a prospective buyer to conduct himself? I'd like the deal to go smoothly, but then again I don't want to hit a tree and lose a leg.
First, ask them if they have the gauge and a technician that knows how to use it, then ask them to put it on a rack and verify that they do or do not have the correct alignment settings. If they do and you purchase the car mark the settings on the nuts with a paint pen. Customers Rule!
Many thanks! I'lol get it done ASAP. It should be interesting as the dealer just did an alignment so I'll get to see what they set it to when at speed shop. I'm glad I asked as I assume different size tires would effect it. The more you know...
So what do I do, hand the salesman a piece of paper with the caster alignments written down and tell him,
"I'll buy the car when you can show me a printout proving these alignments have been made on the car."
What will happen when I do this? I'm concerned the dealership will consider me a pain in the neck and kick me off the lot.
Is this a reasonable way for a prospective buyer to conduct himself? I'd like the deal to go smoothly, but then again I don't want to hit a tree and lose a leg because of a poor alignment.
They can't provide a printout of rear caster as commercially available alignment machines do not have a way of measuring it. Measuring rear caster requires special tools (a gauge and an adapter to mount the gauge to the rear knuckles). The mechanic then uses those two tools to adjust rear caster while observing the camber readings on the alignment machine. Changing caster after camber is set will change the camber so it requires some time to balance the two out. Once that is done then toe can be set.
12-09-2016, 11:59 AM
