Swerve to the left
02-15-2022, 12:45 PM
#4
G.M did the job they have the special tool but still flys to the left even high speeds.I just notice a piece of rubber missing from sidewall i wonder now maybe tire is the problem will replace tires and see.
02-15-2022, 01:26 PM
#5
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Rubber missing from the sidewall shouldn't do a thing unless the actual sidewall (carcass underneath the rubber) is punctured. Does the car turn when the tires aren't spinning or is it only after the tires have broken loose? When the tires are spinning they don't really have much grip in any direction and will slide in the direction that gravity pulls them if the road surface isn't dead nuts level. Any crown, dip, or slight rise will cause a spinning tire to slide toward the lowest point. Spin the tires on the right side of a road with a crown and the rear of the car will tend to slide left, spin the tires on the left side of the crown and the rear of the car will tend to slide right. If one rear tire is spinning and the other is not spinning then the rear of the car won't slide sideways since the tire that isn't sliding sideways still has lateral grip. Lookup a description of the Circle of Friction applied to tires and you will see what I mean. A sliding tire tread has an equal grip in all directions, LITTLE to NONE. A spinning tire is a sliding tire.
In straight line acceleration, the rear caster isn't as big of a factor as it is when accelerating through a corner. Thrust angle is a bigger factor. If you had the car recently aligned do you have a copy of the printout from the alignment machine? It won't show the rear caster readings but it will show the thrust angle.
Bill
In straight line acceleration, the rear caster isn't as big of a factor as it is when accelerating through a corner. Thrust angle is a bigger factor. If you had the car recently aligned do you have a copy of the printout from the alignment machine? It won't show the rear caster readings but it will show the thrust angle.
Bill
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RocksZC7 (03-16-2022)
02-15-2022, 03:07 PM
#6
Rubber missing from the sidewall shouldn't do a thing unless the actual sidewall (carcass underneath the rubber) is punctured. Does the car turn when the tires aren't spinning or is it only after the tires have broken loose? When the tires are spinning they don't really have much grip in any direction and will slide in the direction that gravity pulls them if the road surface isn't dead nuts level. Any crown, dip, or slight rise will cause a spinning tire to slide toward the lowest point. Spin the tires on the right side of a road with a crown and the rear of the car will tend to slide left, spin the tires on the left side of the crown and the rear of the car will tend to slide right. If one rear tire is spinning and the other is not spinning then the rear of the car won't slide sideways since the tire that isn't sliding sideways still has lateral grip. Lookup a description of the Circle of Friction applied to tires and you will see what I mean. A sliding tire tread has an equal grip in all directions, LITTLE to NONE. A spinning tire is a sliding tire.
In straight line acceleration, the rear caster isn't as big of a factor as it is when accelerating through a corner. Thrust angle is a bigger factor. If you had the car recently aligned do you have a copy of the printout from the alignment machine? It won't show the rear caster readings but it will show the thrust angle.
Bill
In straight line acceleration, the rear caster isn't as big of a factor as it is when accelerating through a corner. Thrust angle is a bigger factor. If you had the car recently aligned do you have a copy of the printout from the alignment machine? It won't show the rear caster readings but it will show the thrust angle.
Bill
02-15-2022, 03:09 PM
#7
Rubber missing from the sidewall shouldn't do a thing unless the actual sidewall (carcass underneath the rubber) is punctured. Does the car turn when the tires aren't spinning or is it only after the tires have broken loose? When the tires are spinning they don't really have much grip in any direction and will slide in the direction that gravity pulls them if the road surface isn't dead nuts level. Any crown, dip, or slight rise will cause a spinning tire to slide toward the lowest point. Spin the tires on the right side of a road with a crown and the rear of the car will tend to slide left, spin the tires on the left side of the crown and the rear of the car will tend to slide right. If one rear tire is spinning and the other is not spinning then the rear of the car won't slide sideways since the tire that isn't sliding sideways still has lateral grip. Lookup a description of the Circle of Friction applied to tires and you will see what I mean. A sliding tire tread has an equal grip in all directions, LITTLE to NONE. A spinning tire is a sliding tire.
In straight line acceleration, the rear caster isn't as big of a factor as it is when accelerating through a corner. Thrust angle is a bigger factor. If you had the car recently aligned do you have a copy of the printout from the alignment machine? It won't show the rear caster readings but it will show the thrust angle.
Bill
In straight line acceleration, the rear caster isn't as big of a factor as it is when accelerating through a corner. Thrust angle is a bigger factor. If you had the car recently aligned do you have a copy of the printout from the alignment machine? It won't show the rear caster readings but it will show the thrust angle.
Bill
02-15-2022, 05:18 PM
#9
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Start rolling onto the throttle instead of using it like an on/off switch. The low rpm high torque delivered by the LT4 engine is more than likely your problem. The LT4 produces 650 lb ft of torque at 3600 rpm and about 440 lb ft of torque at 1000 rpm which is higher than a lot of other engines' maximum torque levels. NA high power engines have their power curve come in at higher rpm which means the throttle pedal can be operated more aggressively without breaking the tires loose.
Bill
Bill
02-15-2022, 06:06 PM
#10
Start rolling onto the throttle instead of using it like an on/off switch. The low rpm high torque delivered by the LT4 engine is more than likely your problem. The LT4 produces 650 lb ft of torque at 3600 rpm and about 440 lb ft of torque at 1000 rpm which is higher than a lot of other engines' maximum torque levels. NA high power engines have their power curve come in at higher rpm which means the throttle pedal can be operated more aggressively without breaking the tires loose.
Bill
Bill
02-15-2022, 07:24 PM
#11
Race Director
Check rear toe, thrust angle.
02-15-2022, 08:08 PM
#12
Le Mans Master
Mine would kick out with very moderate throttle input. Once I got the 500 mile complimentary alignment to street specs it went away and is straight as an arrow
02-16-2022, 01:29 PM
#13
Rear caster being positive on one side and negative on the other caused my car to violently break loose from low speed pulls where traction was broken.
This used to feel like the car was hit in the passenger side corner, that's how jarring the action was when the car broke loose. Rolling into the throttle did not make a difference, as soon as you hit a point where you exceeded the available traction vs power, the car would break loose the rear to the driver's side; every time.
Once it was fixed, flooring it just triggers the traction light and the car doesn't accelerate as fast. These days I just look down at the dash and say oh, I had no traction and just carry on without even lifting the pedal. It was such a night and day difference after fixing my alignment.
This used to feel like the car was hit in the passenger side corner, that's how jarring the action was when the car broke loose. Rolling into the throttle did not make a difference, as soon as you hit a point where you exceeded the available traction vs power, the car would break loose the rear to the driver's side; every time.
Once it was fixed, flooring it just triggers the traction light and the car doesn't accelerate as fast. These days I just look down at the dash and say oh, I had no traction and just carry on without even lifting the pedal. It was such a night and day difference after fixing my alignment.
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BearZ06 (02-16-2022)
02-16-2022, 01:44 PM
#14
Burning Brakes
Maybe post up the alignment numbers? Just speculation without those. They should have written the rear caster angles on the sheet for you. One note - a dealer will typically align to GM's vary broad specs, which would include a positive caster on one side and negative on the other which GM seems to think is ok. They should both be positive or zero at best for street. Thrust angle is also important to know. That should be pretty close to zero also imho.