Road Race Suspension///

[jayel579]

Koni Yellows, Strano Adjustable front sway bar end links. Very good alignment and R-Comps!

New setup is KW Clubsports with Strano Sways front and rear but much more to come as I build the car.

 

[Whiskey11]

Well, nothing "exciting" to see on my car, but I'm happy with how it does!

Car/Class:
2009 Mustang GT 4.6L 3v V8
#11 STX in SCCA Solo II/Autocross

Suspension:
Tockio D-Specs
Steeda Sport Springs
Steeda HD Mounts
Strano 35mm Front Bar
Strano 25mm Rear Bar
Strano/Competition Endlinks
Fays2 Watts Link
Dunlop Direzza Z1 Sport Star Specs (245/45/18 on all 4 corners)

Brakes:
Bone Stock

Engine/Drivetrain:
K&N Drop In Filter for stock air box
Rest is stock (down to the 3.55 gears on the stock T-Lok)

Aerodynamics:
None

Other:
Non-Rusty rear axle
Hopes
Dreams
Desire to succeed

Car seems to do fine in autocross. I'm frequenting the top 25% of drivers in Overall PAX (usually around 100 entrants each event) so she can't be doing too bad! Driver still needs a lot of work though regardless of overall PAX location. Only 3 events with the car set up this way, I think on 11 or 12 total events now.

 

[neema]

KW Clubsports
ST adjustable front sway, fixed rear
Steeda X11 ball joints
MM panhard
1.9° camber in the pics below
Square 285/35/19 Kumho Ecsta XS
19x10 et43 rear, et 28 front
FRPP brake duct kit


Needed:
brake fluid
new rotors (stock ones are warped)
track pads? i'm okay with switching pads for a trackday. don't feel like going through extra effort to change rotors as well
braided lines

Wanted:
Steeda bumpsteer kit
try Grand-am spring rates (450 front, 175 rear)
rear axle geometry correction (adjustable links, relocation bracket)--could use input here

 

[stang389]

omg i can't wait to run on that track!!! looks awesome man^^

 

[hunterwiley]

Wanted:
try Grand-am spring rates (450 front, 175 rear)
rear axle geometry correction (adjustable links, relocation bracket)--could use input here

Those spring rates seem very low for grand-am rates, perhaps those are your current spring rates? I was told by a grand-am crew chief they ran ~450-700 up front, 300-450 in the rear, depending on the track and what bars they run. My car will be setup with 600 front, 350 rear, then adjust from there, but it's a full on race car....

If your car is lowered but otherwise stock, then your rear could use some help. You want the rear LCA's to be horizontal at ride height, or even better, have some upward slope from the axle to the chassis mount. Invest is some dropped brackets and you'll find more grip off the corners.

 

[Norm Peterson]

For the height to set the LCAs in the relo brackets, you'll want to consider the axle rollsteer in addition to antisquat/SVIC. Too much antisquat will make the car too loose in the turns.


Norm

 

[Whiskey11]

For the height to set the LCAs in the relo brackets, you'll want to consider the axle rollsteer in addition to antisquat/SVIC. Too much antisquat will make the car too loose in the turns.


Norm

Kind of related Norm but maybe you can answer this. With the UCA mounts with multiple mounting holes, is it possible to change the %antisquat without messing too much with roll steer? I know Steeda now has an UCA mount for the 11+ S197's that has 4 or 5 different mounting holes (Linky) but they don't go specifically what it is all for. I'm assuming that since the Antisquat % is a function of the SVIC and the line that runs through the contact patch and it's relation to the CG height and distance from the contact patch, that changing the UCA's angle down or lengthening it would reduce antisquat and changing it higher and shortening it would improve it?

Is that right or did I get that backwards? I ask because, as you know, in autocross we can't mess with the LCA's until Street Modified and can't relocate them until C-Prepared, that there needs to be another way to get some of the forward bite back. I figure since the UCA contributes little to nothing to roll steer that it may be an easier option to get back some of the antisquat lost when dropping the car.

 

[Norm Peterson]

In a 3-link suspensioon, tweaking the UCA inclination is exactly how you tune A-S without affecting the rollsteer.

Changing the UCA length changes the rate at which the UCA inclination varies with ride height, which ultimately affects the rate at which antisquat varies. I think sometimes how the A-S varies with ride height is nearly as important as what it is to begin with. The thumbnail pic illustrates that neither rollsteer nor A-S remains constant. Changing the length of the UCA changes the curvature of the A-S plot.


In a way, tuning A-S with the UCA is the flip side of how changing the PHB height affects rollsteer (and RCH) without affecting the A-S.

Changing the LCA inclination affects everything (including RCH a little bit).


Norm

 

[Whiskey11]

In a 3-link suspensioon, tweaking the UCA inclination is exactly how you tune A-S without affecting the rollsteer.

Changing the UCA length changes the rate at which the UCA inclination varies with ride height, which ultimately affects the rate at which antisquat varies. I think sometimes how the A-S varies with ride height is nearly as important as what it is to begin with. The thumbnail pic illustrates that neither rollsteer nor A-S remains constant. Changing the length of the UCA changes the curvature of the A-S plot.


In a way, tuning A-S with the UCA is the flip side of how changing the PHB height affects rollsteer (and RCH) without affecting the A-S.

Changing the LCA inclination affects everything (including RCH a little bit).


Norm

I believe I understand. My goal is a little better bite off the line, not so much out of a corner, although that will always help, I think the Watts link with the RC set at the bottom bolt hole took care of the bite coming out of a corner issue... I think!

 

[neema]

Those spring rates seem very low for grand-am rates, perhaps those are your current spring rates? I was told by a grand-am crew chief they ran ~450-700 up front, 300-450 in the rear, depending on the track and what bars they run. My car will be setup with 600 front, 350 rear, then adjust from there, but it's a full on race car....

If your car is lowered but otherwise stock, then your rear could use some help. You want the rear LCA's to be horizontal at ride height, or even better, have some upward slope from the axle to the chassis mount. Invest is some dropped brackets and you'll find more grip off the corners.

shame on me, but i just assumed from what i've been reading on vorshlag that the grand am rates were 450/175. honestly, the spring rates i have now (~550/~350) worked FANTASTIC on the track, but i would be changing them out for a little streetability. in hindsight, i may keep them on. they'll work well with hoosiers.

what's the verdict on the rear axle geometry? upper and lower controls arms w/ relocation brackets?

 

[Norm Peterson]

I believe I understand. My goal is a little better bite off the line

Within the ST* ruleset there isn't a whole lot else you can do, and even there I think you have to be careful which end of the UCA you "relocate" (I don't have the current rulebook handy). You might be able to cobble some sort of eccentric LCA bushings together which could be used to change the inclination of the LCAs slightly, and there *might* be another legal trick to buy a little more.

I think the Watts link with the RC set at the bottom bolt hole took care of the bite coming out of a corner issue... I think!

OK, you're lowered a bit, which drives the intersection of the LCA axes upward (the convergence is behind the axle). I'm assuming that the WL main pivot is lower than the midpoint of the PHB would have been, in which case both the lowering and the WL adjustment have added a measure of roll steer in the vehicle understeer direction. Depending on how much the inclination of the axle's own roll axis was changed, it'll feel a little more stable, but perhaps a little less happy about slaloming.


Norm

 

[Whiskey11]

Within the ST* ruleset there isn't a whole lot else you can do, and even there I think you have to be careful which end of the UCA you "relocate" (I don't have the current rulebook handy). You might be able to cobble some sort of eccentric LCA bushings together which could be used to change the inclination of the LCAs slightly, and there *might* be another legal trick to buy a little more.


OK, you're lowered a bit, which drives the intersection of the LCA axes upward (the convergence is behind the axle). I'm assuming that the WL main pivot is lower than the midpoint of the PHB would have been, in which case both the lowering and the WL adjustment have added a measure of roll steer in the vehicle understeer direction. Depending on how much the inclination of the axle's own roll axis was changed, it'll feel a little more stable, but perhaps a little less happy about slaloming.


Norm

Touche on the UCA "relocation". It clearly says the axle side UCA mounts can be relocated (must have been selective reading on my part) and that pretty much kills changing the UCA mount and using a different mounting hole. Sometimes I wonder about these rules which are obviously "allowed" for the Steeda 5-link for the Fox and SN95 cars and a lot less friendly towards the newer stangs. Just like my "problem" with the SFC wording about welding and how it is compared to the roll cage allowances seem so backwards. Sure go ahead and weld in a full 6 pt cage but don't you dare weld in those SFCs! I guess I should petition for some changes to make ST a bit more diverse by freeing up some pretty restrictive live axle stuff? Granted, it will likely be ignored since the pony cars are not really competitive (or proven competitive I should say) in ST anything.

Short of going to a torque arm set up (the Griggs unit is legal surprisingly enough) I am not sure how much more forward bite can be achieved without going to every extreme to get it and spending all of that money to get it and there is no guarantee the torque arm will give me what I want vs exacerbating problems that are currently very minor. Then you start getting into the cost vs performance imprivement and for someone like me there are more glaring issues (dampers, spring rate, tires (hopefully changing soon) my own driving deficiencies, etc) that should be addressed before chasing those other things that don't change the performance a whole lot compared to the price!

Yeah the rear pivot for the watts sits in the lower third of the rear diff at ride height. Sadly I don't have the number for its height above ground. The car feels really solid when slaloming. Maybe a little less willing to change directions quickly than the PHB configuration (car was stock at that point) but the car feels much more planted when slaloming than when I had the pivot bolt in the next highest position or the PHB arrangment. I think I may have a touch of steadystate understeer in constant radius sweepers but I'm affraid if I take the rear bar to the stiffest setting that it will be way too squirrely when slaloming. Tire pressures seem to be the easiest way to deal with that understeer but it is so slight anyway I just drive around it. I'm not that great of a driver and make plenty of "line" errors in corners that make the time lost from that small push seem insignificant.

Thanks again for the help Norm, its appreciated! I really should pick up some of the chassis tuning books and give them a good reading. I'm not one for complex maths for a hobby unless its absolutely necessary but I can always use a firmer grasp on the concepts and their application which is where the majority of my suspension changes have originated from. The last thing I did was take someone's word on "what am bestest handling setup" without first understanding why the recommendations have been made for those parts and what each part does to get me to my goal and how it does it! You have helped further my understanding of my suspension set up and that is greatly appreciated!

 

[Mike K]

How she sits now:

-Saleen Speedlab N2+ adjustable coilovers
-Saleen front sway bar
-Saleen front big brakes
-Motul RBF600 fluid
-FR adjustable panhard bar
-Forgestar CF10 wheels
-Michelin Pilot Super Sport tires

In the works: custom front brake ducts and rear 14" upgraded rotors, front splitter and rear diffuser.

When you do the brake ducts please do another thread as I'll be wanting these in the future.

 

[Blazer707@TBR]

Just installed Strano adjustable sway bars front and rear and wow it made a difference. Car feels sturdy and more planted out of corners.

Now just waiting for my Koni yellows to be off back order!

 

[Sharad]

Just installed Strano adjustable sway bars front and rear and wow it made a difference. Car feels sturdy and more planted out of corners.

Now just waiting for my Koni yellows to be off back order!

Swaybars made a nice improvement on my car, but the Koni Yellows were arguably the single biggest improvement on my car. I know it all works together as a system, but MAN I love those Konis.

 

[Blazer707@TBR]

I can't wait. I'm told mid August until I get mine. And when I do it's game on.

 

[Vorshlag-Fair]

2011 Mustang GT, Brembo option, 3.31 gear, 6-spd - this car was purchased new to be used as our in-house test mule for suspension development. This car is daily driven, autocrossed in SCCA ESP class, and used in NASA time trial in TTS class (with only wheel/tire and aero changes). Current race weight is 3467 pounds.

Build thread: http://www.vorshlag.com/forums/showthread.php?t=7806
Picture gallery: http://vorshlag.smugmug.com/Projects/Vorshlag-2011-Mustang-GT-build/

Suspension:
Moton Club Sport double adjustables with remotes (this car was the test mule for AST 4150s)
Vorshlag camber-caster plates
Hyperco 450#/in front, 175 #/in rears (after trying many set-ups)
Eibach adj front swaybar, stock rear
Spohn Performance upper rear control arm + panhard rod (with Delsphere ends on both)
Energy Suspensions polyurethane front LCA bushings

Power Mods:
Steeda cold air, ARH 1=7/8" long tubes, ARH X-pipe with cats, custom Vorshlag dual 3" mandrel bent 304SS exhaust, Flowmaster Series 44 mufflers
430 whp, 406 wtq

Brakes:
Stock rotors front and rear, Porterfield R4 pads (track) and R4S pads (street + autocross)
Custom brake ducting to the front rotors from the CS lower fascia fog light holes

Aero:
Custom 10" rear spoiler (autocross)
APR GTC-300 carbon wing with custom uprights (track)
Boss 302 Leguna Seca Front Splitter (street, autocross and track)

Wheels/Tires:
Forgestar 18x11" (front) and 18x12" (rear) F14 wheels
Kumho V710 tires in 315/35/18 front and rear

Cheers,

 

[Mike K]

^ that is a great setup you got on that thing. Looks mean as hell!

 

[FR500GT]

Must be nice

 

[Sharad]

mmmmm, Motons.