Danger
10-12-2021, 03:45 PM
#1
Danger
Can a member who owns 2017 Z06 explain to me why car flys to the other lane when accelerating from dead stop .Cambers are right on factory specs, I have seen many videos of this happening to other Vetts too?
10-12-2021, 04:40 PM
#2
Racer
Rear caster aligned?
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BearZ06 (10-12-2021)
10-12-2021, 06:21 PM
#4
Burning Brakes
I had my car on a Hunter machine once that had the right rear off by 3 deg toe. Machine showed it as ~0 but was actually 3 deg in. Put some strings on it to double check toe and make sure you've got the rear caster correct as well.
10-12-2021, 06:45 PM
#5
This happened to my car when it was stock; the rear caster had 1 wheel positive while the other wheel was negative. It caused a really bad kick out to the driver's side from dead stop/low speed.
Last edited by SladeX; 10-12-2021 at 06:45 PM.
10-12-2021, 08:09 PM
#6
Racer
Mine was like this too. One positive, one negative, but "technically" within GM spec. After getting them both aligned to 0.0 the problem went away.
10-12-2021, 08:15 PM
#7
GM’s alignment is made for handling as it should be. Problem with that is it makes the car twitchy under acceleration because the camber is setup to take turns. Once I had an alignment done by a trusted shop, I can now accelerate with over 1khp spinning the tires with a manual trans and is very controllable. Whole different car.
10-12-2021, 09:40 PM
#8
z06 does that all the time,punch it and car jerks left.make sure when you punch it the wheels are straight or you will get into trouble fast.
10-12-2021, 10:08 PM
#9
Tech Contributor
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Camber isn't the same as Caster. The C7 has a Rear Caster setting. Alignment machines can't measure the rear caster. To measure the rear caster you need separate angle gauges and an adapter that plugs into the rear knuckles. The purpose of the rear caster adjustment is to make sure that as the rear camber is changed the caster can be adjusted back to 0.0 degrees.
However, the rear caster setting can only account for some of the issues. The Circle of Friction clearly shows that when a tire is spinning it will slide in any direction that applies a force to the tire, forward, rearward, sideways, etc. Gravity comes into play when the car is on a crowned road. Spin the rear tires and the rear of the car will slide down the crown as gravity pulls it in that direction. That is how a number of people lose control of their cars. Another problem is most drivers' lack of experience in controlling a car in a low grip situation which is what you have when the tire is spinning.
Bill
However, the rear caster setting can only account for some of the issues. The Circle of Friction clearly shows that when a tire is spinning it will slide in any direction that applies a force to the tire, forward, rearward, sideways, etc. Gravity comes into play when the car is on a crowned road. Spin the rear tires and the rear of the car will slide down the crown as gravity pulls it in that direction. That is how a number of people lose control of their cars. Another problem is most drivers' lack of experience in controlling a car in a low grip situation which is what you have when the tire is spinning.
Bill
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10-13-2021, 09:31 AM
#10
Safety Car
Camber isn't the same as Caster. The C7 has a Rear Caster setting. Alignment machines can't measure the rear caster. To measure the rear caster you need separate angle gauges and an adapter that plugs into the rear knuckles. The purpose of the rear caster adjustment is to make sure that as the rear camber is changed the caster can be adjusted back to 0.0 degrees.
However, the rear caster setting can only account for some of the issues. The Circle of Friction clearly shows that when a tire is spinning it will slide in any direction that applies a force to the tire, forward, rearward, sideways, etc. Gravity comes into play when the car is on a crowned road. Spin the rear tires and the rear of the car will slide down the crown as gravity pulls it in that direction. That is how a number of people lose control of their cars. Another problem is most drivers' lack of experience in controlling a car in a low grip situation which is what you have when the tire is spinning.
Bill
However, the rear caster setting can only account for some of the issues. The Circle of Friction clearly shows that when a tire is spinning it will slide in any direction that applies a force to the tire, forward, rearward, sideways, etc. Gravity comes into play when the car is on a crowned road. Spin the rear tires and the rear of the car will slide down the crown as gravity pulls it in that direction. That is how a number of people lose control of their cars. Another problem is most drivers' lack of experience in controlling a car in a low grip situation which is what you have when the tire is spinning.
Bill
Someone's engineering cap is on point this morning.
Along with what Bill said though, my 650rwhp Z06 would walk all over the road when going to WOT. I bought the rear Caster tools and when I took the car in for the alignment I had the shop set the rear Caster to 0°, took the camber from 1.3/1.4 and they set it to 1.1°. Since then the car has been rock solid stable when going WOT.
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LagunaSecaZ06 (10-21-2021)
10-13-2021, 11:05 AM
#11
You will also need adjustable toe links to get the caster back to zero after changing the camber where it should be IMO for street driving. The alignment shop I used couldn’t quite get caster to zero with the factory ones. I think this was a combination of setting camber/caster while also lowering the car on stock bolts. If the car was still factory ride height I don’t think I would of needed adjustable toe links. Either way, the factory alignment is not optimal for straight line acceleration. No question.
10-13-2021, 11:35 AM
#12
Melting Slicks
Find yourself a really good alignment shop. My 2015 was the same. After I got mine aligned correctly it is a new car under hard acceleration. Much more predictable
10-13-2021, 12:15 PM
#13
My street/track alignment on the rear used a 0.3 caster with a -1.3 degree camber and -0.05 toe (toe-in). On punching it, the car goes straight and has little drama to it, if you break the tires loose, the kick out is gentle and very controllable, even on roads with a crown in it. You can be in tour mode on the highway trigger traction control trying to punch it and the only thing you notice is that the traction light is flashing and you didn't accelerate like you wanted. The point is when setup correctly, the car should be very manageable.
Last edited by SladeX; 10-13-2021 at 12:17 PM.
10-13-2021, 12:43 PM
#14
Melting Slicks
Agree with all of the above. My car totally changed its character once the rear castor was set. As others stated, most dealerships dont have a clue how to do this.
Last edited by atljar; 10-13-2021 at 12:44 PM.
10-13-2021, 05:21 PM
#15
Safety Car
You will also need adjustable toe links to get the caster back to zero after changing the camber where it should be IMO for street driving. The alignment shop I used couldn’t quite get caster to zero with the factory ones. I think this was a combination of setting camber/caster while also lowering the car on stock bolts. If the car was still factory ride height I don’t think I would of needed adjustable toe links. Either way, the factory alignment is not optimal for straight line acceleration. No question.
You do not need adjustable toe links, I had my Caster set to 0°/90° when they set my camber with no issues.
10-20-2021, 08:52 AM
#17
Burning Brakes
My 2016 Z had the same issue, after rear caster was set, issue improved. I had to get adjustable toe links to get the setting to 0 degrees. However this is not a cure all, the driver still has a great deal of input to control the car, over confidence and lack of ability will still crash the car.