what should my next suspension mod be?
08-13-2014, 08:35 AM
#11
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Understand that roll and squat motions of the car do not cause the load transfer (somewhat incorrectly aka "weight transfer"). It's the other way around, and a firm bump setting will increase the loading during the time that that corner of the car is moving downward. At equilibrium - think midcorner on a long sweeper being the best approximation - shock damping effects are at a minimum because there is little suspension movement happening.
I copied and pasted the Koni guide from another forum, which was faster than trying to find my own file. The boldface at the end is mine, because it's applicable for "tweaking to suit".
FWIW, there are some even more specific tuning tweaks that are done in the circle track world . . . all you have to do is translate things intended to help fix issues turning left only into working for lefts and rights. I haven't yet seen any table of what those guys do to set up their shocks for Watkins Glen and Sonoma (Sprint Cup) or Mid-Ohio (Nationwide).
KONI shock tuning guide
Suggested Adjustment Procedures For Road Racing Use
(from the KONI NA Factory Tuning Guide)
Adjusting The COMPRESSION (Bump) Damping Control (Very Important to do this FIRST!)
Bump damping controls the unsprung weight of the vehicle (wheels, axles, etc.). It controls the upward movement of the suspension as when hitting a bump in the track. It should not be used to control the downward movement of the vehicle when it encounters dips. Also, it should not be used to control roll or bottoming.
Depending on the vehicle, the ideal bump setting can occur at any point within the adjustment range. This setting will be reached when "side-hop" or "walking" in a bumpy turn is minimal and the ride is not uncomfortably harsh. At any point other than this ideal setting, the "side-hopping" condition will be more pronounced and the ride may be too harsh.
STEP 1: Set all four dampers on minimum bump and minimum rebound settings.
STEP 2: Drive one or two laps to get the feel of the car. Note: When driving the car during the bump adjustment phase, disregard body lean or roll and concentrate solely on how the car feels over bumps. Also, try to notice if the car "walks" or "side-hops" on a rough turn.
STEP 3: Increase bump adjustment clockwise 3 clicks on all four dampers. Drive the car one or two laps. Repeat Step 3 until a point is reached where the car starts to feel hard over bumpy surfaces.
STEP 4: Back off the bump adjustment two clicks. The bump control is now set. Note: The back off point will probably be reached sooner on one end of the vehicle than the other. If this occurs, keep increasing the bump on the soft end until it, too, feels hard. Then back it off 2 clicks. The bump control is now set.
Adjusting the REBOUND Damping Control
Once you have found what you feel to be the best bump setting on all four wheels, you are now ready to proceed with adjusting the rebound. The rebound damping controls the transitional roll (lean) as when entering a turn. It does *not* limit the total amount of roll; it *does* limit how *fast* this total roll angle is achieved. How much the vehicle actually leans is determined by other things such as spring rate, sway bars, roll center, ride heights, etc.
It should be noted that too much rebound on either end of the vehicle will cause an initial loss of lateral acceleration (cornering grip) a that end which will cause the vehicle to oversteer or understeer excessively when entering a turn. Too much rebound control in relation to spring rate will cause a condition known as "jacking down." This is a condition where, after hitting a bump and compressing the spring, the damper does not allow the spring to return to a neutral position before the next bump is encountered.
This repeats with each subsequent bump until the car is actually lowered onto the bump stops. Contact with the bump stops causes a drastic increase in roll stiffness. If this condition occurs on the front, the car will understeer; if it occurs on the rear, the car will oversteer.
STEP 1: With rebound set on full soft and the bump control set from your earlier testing, drive the car one of two laps, paying particular attention to how the car rolls when entering a turn.
STEP 2: Increase rebound damping three sweeps (or 3/4 turn) on all four dampers and drive the car one or two laps. Repeat Step 2 until the car enters the turns smoothly (no drastic attitude changes) and without leaning excessively. An increase in the rebound stiffness beyond this point is unnecessary and may result in a loss of cornering power. Note: As with the bump settings, this point will probably be reached at one end of the car before the other.
However, individual drivers may find it desirable to have a car that assumes an oversteering or understeering attitude when entering a turn. This can be easily "dialed-in" using slightly excessive rebound settings at either end.
Suggested Adjustment Procedures For Road Racing Use
(from the KONI NA Factory Tuning Guide)
Adjusting The COMPRESSION (Bump) Damping Control (Very Important to do this FIRST!)
Bump damping controls the unsprung weight of the vehicle (wheels, axles, etc.). It controls the upward movement of the suspension as when hitting a bump in the track. It should not be used to control the downward movement of the vehicle when it encounters dips. Also, it should not be used to control roll or bottoming.
Depending on the vehicle, the ideal bump setting can occur at any point within the adjustment range. This setting will be reached when "side-hop" or "walking" in a bumpy turn is minimal and the ride is not uncomfortably harsh. At any point other than this ideal setting, the "side-hopping" condition will be more pronounced and the ride may be too harsh.
STEP 1: Set all four dampers on minimum bump and minimum rebound settings.
STEP 2: Drive one or two laps to get the feel of the car. Note: When driving the car during the bump adjustment phase, disregard body lean or roll and concentrate solely on how the car feels over bumps. Also, try to notice if the car "walks" or "side-hops" on a rough turn.
STEP 3: Increase bump adjustment clockwise 3 clicks on all four dampers. Drive the car one or two laps. Repeat Step 3 until a point is reached where the car starts to feel hard over bumpy surfaces.
STEP 4: Back off the bump adjustment two clicks. The bump control is now set. Note: The back off point will probably be reached sooner on one end of the vehicle than the other. If this occurs, keep increasing the bump on the soft end until it, too, feels hard. Then back it off 2 clicks. The bump control is now set.
Adjusting the REBOUND Damping Control
Once you have found what you feel to be the best bump setting on all four wheels, you are now ready to proceed with adjusting the rebound. The rebound damping controls the transitional roll (lean) as when entering a turn. It does *not* limit the total amount of roll; it *does* limit how *fast* this total roll angle is achieved. How much the vehicle actually leans is determined by other things such as spring rate, sway bars, roll center, ride heights, etc.
It should be noted that too much rebound on either end of the vehicle will cause an initial loss of lateral acceleration (cornering grip) a that end which will cause the vehicle to oversteer or understeer excessively when entering a turn. Too much rebound control in relation to spring rate will cause a condition known as "jacking down." This is a condition where, after hitting a bump and compressing the spring, the damper does not allow the spring to return to a neutral position before the next bump is encountered.
This repeats with each subsequent bump until the car is actually lowered onto the bump stops. Contact with the bump stops causes a drastic increase in roll stiffness. If this condition occurs on the front, the car will understeer; if it occurs on the rear, the car will oversteer.
STEP 1: With rebound set on full soft and the bump control set from your earlier testing, drive the car one of two laps, paying particular attention to how the car rolls when entering a turn.
STEP 2: Increase rebound damping three sweeps (or 3/4 turn) on all four dampers and drive the car one or two laps. Repeat Step 2 until the car enters the turns smoothly (no drastic attitude changes) and without leaning excessively. An increase in the rebound stiffness beyond this point is unnecessary and may result in a loss of cornering power. Note: As with the bump settings, this point will probably be reached at one end of the car before the other.
However, individual drivers may find it desirable to have a car that assumes an oversteering or understeering attitude when entering a turn. This can be easily "dialed-in" using slightly excessive rebound settings at either end.
I do want to take it on the track more so I am planning on upgrading my brakes. I just don't know if I should do an EBC setup or just keep saving and do a brembo/wilwood/baer full upgrade
Norm
08-15-2014, 10:57 PM
#12
2nd Gear Member
Thread Starter
Join Date: Apr 2011
Location: NJ
Posts: 410
I realize you have independent bump and rebound adjustment capability.
Understand that roll and squat motions of the car do not cause the load transfer (somewhat incorrectly aka "weight transfer"). It's the other way around, and a firm bump setting will increase the loading during the time that that corner of the car is moving downward. At equilibrium - think midcorner on a long sweeper being the best approximation - shock damping effects are at a minimum because there is little suspension movement happening.
I copied and pasted the Koni guide from another forum, which was faster than trying to find my own file. The boldface at the end is mine, because it's applicable for "tweaking to suit".
FWIW, there are some even more specific tuning tweaks that are done in the circle track world . . . all you have to do is translate things intended to help fix issues turning left only into working for lefts and rights. I haven't yet seen any table of what those guys do to set up their shocks for Watkins Glen and Sonoma (Sprint Cup) or Mid-Ohio (Nationwide).
Do not get brakes intended for drag racing. Consensus is to use plain rotors, and you'll get a variety of pad suggestions. Me, I like the Carbotech XP's so far, they've held up to what my 4.6L and I have been able to dish out and are still streetable in terms of acceptable cool/cold bite and low rotor wear rates. Noise and dust, you'd have to be able to tolerate.
Norm
Understand that roll and squat motions of the car do not cause the load transfer (somewhat incorrectly aka "weight transfer"). It's the other way around, and a firm bump setting will increase the loading during the time that that corner of the car is moving downward. At equilibrium - think midcorner on a long sweeper being the best approximation - shock damping effects are at a minimum because there is little suspension movement happening.
I copied and pasted the Koni guide from another forum, which was faster than trying to find my own file. The boldface at the end is mine, because it's applicable for "tweaking to suit".
FWIW, there are some even more specific tuning tweaks that are done in the circle track world . . . all you have to do is translate things intended to help fix issues turning left only into working for lefts and rights. I haven't yet seen any table of what those guys do to set up their shocks for Watkins Glen and Sonoma (Sprint Cup) or Mid-Ohio (Nationwide).
Do not get brakes intended for drag racing. Consensus is to use plain rotors, and you'll get a variety of pad suggestions. Me, I like the Carbotech XP's so far, they've held up to what my 4.6L and I have been able to dish out and are still streetable in terms of acceptable cool/cold bite and low rotor wear rates. Noise and dust, you'd have to be able to tolerate.
Norm
Do you think the GT500 brembo upgrade kit is worth it? the wilwood superlites i figured were for drag racing but maybe a different wilwood kit
08-16-2014, 08:23 AM
#13
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
The 14" GT500 brake swap has been a pretty successful one, and I think it's what the very fast Vorshlag Mustang has been running (and setting all kinds of lap records in NASA's TT3 with). Terry Fair (Vorshlag owner and primary driver) gives the brakes incredibly hard use/abuse.
It's almost certainly the kit I'll go with when I start feeling that I'm being held back by my GT's OE brakes.
Norm
It's almost certainly the kit I'll go with when I start feeling that I'm being held back by my GT's OE brakes.
Norm
Last edited by Norm Peterson; 08-16-2014 at 08:27 AM.
09-17-2014, 11:42 AM
#14
Join Date: Dec 2011
Location: Texas
Posts: 9
The best bang for your bucks in brakes is the OEM 14" Brembo front brakes and the 13.8" GT500 rear brakes. Add some ducting and proper pads and fluid and you have a very capable brake setup.
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