Needing some help with suspension set up on C6 Z51
03-16-2007, 08:42 AM
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Needing some help with suspension set up on C6 Z51
Is anyone running the T1 bars with the factory wheel sizes and the Hoosier A6 tires close to the factory tire. I have heard the rear bar on stock width tires can cause the back to get loose.
Also how about any upgrades with the shocks?
What effect does lowering the cars have on handling. I have read different opinions on this change.
What alignment specs work best for Autocross and 3 or 4 track events per year.
This year like last year for me is about seat time I just want to get the car to handle as good as possible more for safety reason's than being competative.
Also how about any upgrades with the shocks?
What effect does lowering the cars have on handling. I have read different opinions on this change.
What alignment specs work best for Autocross and 3 or 4 track events per year.
This year like last year for me is about seat time I just want to get the car to handle as good as possible more for safety reason's than being competative.
03-16-2007, 11:31 AM
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Is anyone running the T1 bars with the factory wheel sizes and the Hoosier A6 tires close to the factory tire. I have heard the rear bar on stock width tires can cause the back to get loose.
Also how about any upgrades with the shocks?
What effect does lowering the cars have on handling. I have read different opinions on this change.
What alignment specs work best for Autocross and 3 or 4 track events per year.
This year like last year for me is about seat time I just want to get the car to handle as good as possible more for safety reason's than being competative.
Also how about any upgrades with the shocks?
What effect does lowering the cars have on handling. I have read different opinions on this change.
What alignment specs work best for Autocross and 3 or 4 track events per year.
This year like last year for me is about seat time I just want to get the car to handle as good as possible more for safety reason's than being competative.
Here is an old thread on the effect of lowering
Cars response to lowering
What is happening is the roll center has been lowered so that the moment arm that goes from the roll center to the CG is longer so there is more body roll that you are trying to compensate with bigger springs. You could do what the Porsches do, i.e. compensate for incorrect geometry by having obscenely high spring rates. Some of the Porsches have 1800/2200 lb/in springs so that the geometry does not matter (watch the bouncing baby Porsche). If you do that, your shock damping has to go up as proportionally.
The only cheap thing I can think of is to put in stiffer bump rubbers on your shocks so that when you are at full bump the spring rate is higher and it limits the travel. Shock bump rubbers (actually they are urethane) are available in various stiffness. At least the tires won't hit as often.
Gary Hoffman.
...the overall diameter of the tire.
This may not help much, but a C5 with stock fender openings (regardless of tire size) needs a measurement from the spindle centerline to wheel well opening lip of at least 14" or the front roll center will be too low. By using the spindle centerline to fender lip measurement, you take the tire/wheel size out of the equation. For those with modified fender openings, you will need to come up with your own fudge factor for your fender openings.
The roll center calculator that I use is from Performance Trends, Inc. It is a slick little software package that allows you to see graphically what different ride heights, Dive and Roll do to your roll centers.
As a side note with little regard for roll centers: I usually set up the faster C5s to be between 14 1/4 to 14 1/2" up front and 14 3/4 to 15" in the rear, depending on which track we are running and which springs they are running. Go any lower and you will need shorter shocks and much stiffer springs and anti sway bars to keep things in check.
Mark "Beer" Stein
Email - Mark@motorsportimage.com
http://forums.corvetteforum.com/show...41&forum_id=23
Stock Ride heights ranges:
round to just behind the jacking puck points.
Front - Right and Left 5 3/4"
Rear - Right and Left 6"
Measured at the jacking points on the frame...
Front (Left and Right) 5 1/8"
Rear (Left and Right) 5 3/8"
What is happening is the roll center has been lowered so that the moment arm that goes from the roll center to the CG is longer so there is more body roll that you are trying to compensate with bigger springs. You could do what the Porsches do, i.e. compensate for incorrect geometry by having obscenely high spring rates. Some of the Porsches have 1800/2200 lb/in springs so that the geometry does not matter (watch the bouncing baby Porsche). If you do that, your shock damping has to go up as proportionally.
The only cheap thing I can think of is to put in stiffer bump rubbers on your shocks so that when you are at full bump the spring rate is higher and it limits the travel. Shock bump rubbers (actually they are urethane) are available in various stiffness. At least the tires won't hit as often.
Gary Hoffman.
...the overall diameter of the tire.
This may not help much, but a C5 with stock fender openings (regardless of tire size) needs a measurement from the spindle centerline to wheel well opening lip of at least 14" or the front roll center will be too low. By using the spindle centerline to fender lip measurement, you take the tire/wheel size out of the equation. For those with modified fender openings, you will need to come up with your own fudge factor for your fender openings.
The roll center calculator that I use is from Performance Trends, Inc. It is a slick little software package that allows you to see graphically what different ride heights, Dive and Roll do to your roll centers.
As a side note with little regard for roll centers: I usually set up the faster C5s to be between 14 1/4 to 14 1/2" up front and 14 3/4 to 15" in the rear, depending on which track we are running and which springs they are running. Go any lower and you will need shorter shocks and much stiffer springs and anti sway bars to keep things in check.
Mark "Beer" Stein
Email - Mark@motorsportimage.com
http://forums.corvetteforum.com/show...41&forum_id=23
Stock Ride heights ranges:
round to just behind the jacking puck points.
Front - Right and Left 5 3/4"
Rear - Right and Left 6"
Measured at the jacking points on the frame...
Front (Left and Right) 5 1/8"
Rear (Left and Right) 5 3/8"
