Suspension mods for autocross, where do I begin?

[clutchkick]

Trying to decide between getting pedders sway bars or BMR 1.25 lowering springs with eibach struts as a little holiday gift to myself, which would have a bigger impact on autox times since the prices aren't that far off? Currently on stock FE4 suspension with a 275/315 staggered setup, and it understeers on the 180s way more than I would like. I know biggest mod is the drivermod but I wanna upgrade the car while I'm working on that too.

[larry_g]

An adjustable rear bar will give you a way to tighten the rear end and bring the balance more neutral.

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[Rusty Shackleford]

I'm right there with you. Did a track day in October and learned just how bad the under-steer is on mine (aftermarket wheels but with factory 275/245 staggered setup). I've bounced off of every wall trying to decide the best course of action. Just too many options. I've considered just throwing the kitchen sink at it, then reeled myself back in to something a little more conservative to start with while I, too, work on my driving. I'm not trying to build a racer-car, but do want to make some improvements to maximize my fun time at the track.


Before my next outing I'm going to put an adj rear bar on it and it'll be on a squared 275 or 285 setup using dot/track 200tw tires.

[acammer]

Originally Posted by Rusty Shackleford

I'm right there with you. Did a track day in October and learned just how bad the under-steer is on mine (aftermarket wheels but with factory 275/245 staggered setup). I've bounced off of every wall trying to decide the best course of action. Just too many options. I've considered just throwing the kitchen sink at it, then reeled myself back in to something a little more conservative to start with while I, too, work on my driving. I'm not trying to build a racer-car, but do want to make some improvements to maximize my fun time at the track.


Before my next outing I'm going to put an adj rear bar on it and it'll be on a squared 275 or 285 setup using dot/track 200tw tires.

#1 handling mod for a 5th gen SS - get the tires square. Understeer will be dramatically reduced. At very low speeds, it's still a big heavy car, so you'll still find the understeer, but overall the balance moves much closer to neutral - pay attention the first time you get into a high speed chicane as the car is gonna rotate a lot easier and faster with the same amount of input!

[cdb95z28]

Your tire sizes aren't helping. 285 square or 285/305 is a better choice along with a performance alignment. Then hone your skills. Developing your driver skills is tough when you are parts swapping all the time.


Going bigger, the 1LE suspension, wheel and tire sizes and a bigger rear adjustable bar would be a nice setup. Solid rear cradle mounts (AFE/Pfadt) are a great upgrade too.

As far a drop springs, they don't make as big improvements as people think other than looks. But a matched setup, with the drop springs and matching anti roll bars, goes along way to having a good baseline. Detroit Speed has drop springs and matching adjustable anti roll bars.

[FASTFATBOY]

Modding the car for track days or autocross does not do the same as modding the car for the drag strip.

You'll learn this the easy way or the hard way.

Seat time makes you faster in these realms, not modifying the car.

Put a square tire setup on it and learn that before any other changes.

[clutchkick]

Originally Posted by cdb95z28

Your tire sizes aren't helping. 285 square or 285/305 is a better choice along with a performance alignment. Then hone your skills. Developing your driver skills is tough when you are parts swapping all the time.


Going bigger, the 1LE suspension, wheel and tire sizes and a bigger rear adjustable bar would be a nice setup. Solid rear cradle mounts (AFE/Pfadt) are a great upgrade too.

Thanks for the info guys. Wound up getting some EBC Yellow pads and rotors, as I was getting some signs of warping/runout. Maintenance before mods lol.

Probably going to do wheels/tires as my next mod, I bought the car with the current wheel/tire sizes on it, so that wasn't really my choice for the 40mm stagger. My current plan is to get a pair of 20x10s to match the rear and ditch the 9" wide fronts to run square 285/35 20, unless I can cram something larger up front but 285 seems like the go to.

[Rusty Shackleford]

Well I installed the 32mm Pedders rear bar under my car about a month ago and it definitely eliminated a lot of body roll. The car feels more neutral now but I have yet to push the car hard enough to see just how much. I have a track day in two weeks so I'll know more about it then. Since the staggered tire setup is my baseline I chose to stick with that for now, but I did move the 275/40's up front and got wider wheels with 305/35's out back, so I added 30mm of tire width to each corner. Theory there being, more overall grip but equally applied so it shouldn't mess with the actual balance a lot.



We'll see what the results are and I'll make a decision moving forward from there.

[morepowerjoe]

Originally Posted by Rusty Shackleford

Well I installed the 32mm Pedders rear bar under my car about a month ago and it definitely eliminated a lot of body roll. The car feels more neutral now but I have yet to push the car hard enough to see just how much. I have a track day in two weeks so I'll know more about it then. Since the staggered tire setup is my baseline I chose to stick with that for now, but I did move the 275/40's up front and got wider wheels with 305/35's out back, so I added 30mm of tire width to each corner. Theory there being, more overall grip but equally applied so it shouldn't mess with the actual balance a lot.



We'll see what the results are and I'll make a decision moving forward from there.

Did you ever make it out to the track and if so what were the results?

[Rusty Shackleford]

Wow, dredging this one back up from almost a year ago.



But yes, I did make that next track day. and the rear bar helps significantly. Under steer was diminished a bit but still very present on entry. The car definitely rotates better from center off though.



Next on the list is pretty much a complete poly bushing replacement front and rear, and will probably add a bigger front bar then too.

[cdb95z28]

Originally Posted by Rusty Shackleford

Wow, dredging this one back up from almost a year ago.



But yes, I did make that next track day. and the rear bar helps significantly. Under steer was diminished a bit but still very present on entry. The car definitely rotates better from center off though.



Next on the list is pretty much a complete poly bushing replacement front and rear, and will probably add a bigger front bar then too.

All poly is the wrong choice if you care about handling and excellent chassis dynamics. Poly tends to bind when stressed at a suspension joint. And in doing so it can add wheel rate, essentially making the suspension feel stiffer. But that is not how you really want to stiffen the suspension. Do it with springs and bars. Now there are some areas poly is ok, like anti roll bar mounting. But, your Camaro may already have some OE spherical rose joints. I do not recall what a '12 SS has compared to the ZL1 or 1LE, or Z/28 for the matter. If you do have some of the shared performance variant items, and they are still tight, keep them. The only arm worth changing to aftermarket on a Gen5 is the rear toe arm. No poly. Get the spherical adjustables with the eccentric bolt lock out. I had Detroit Speed on my '14 SS 1LE. Easy toe adjustments and OE quality sphericals. Also, Poly is not maintenance free. Once the lube starts to be pushed out you'll start to hear them. And it will deform. Not good.

After that, if there are any rubber bushed arms that can be upgraded to the 1LE/ZL1/Z/28 arm, that would be a better choice. FE6/FE5/FEA. Again, you may already have some these arms. The OE rear setup on those three are excellent for autox or track days. Some of them are spherical joints. They may "look" cheap but the GM engineers did excellent. Light, strong (in the intended loads) and cheap. Especially the additional parts the Z/28 had. Up front, the radius rods (diagonal arm) are all the same on the Gen5s except of the three mentioned above, the Z/28 had a hard Delrin insert in the rubber bushing. I recall your SS may not have a rubber insert in your OE arm. The ZL1 and 1LE radius rods had a small rubber insert at the ends of the bushing. Try to find those Z/28 arms or Delrin inserts. It won't really help with grip, but it will help with keeping that bushing stable under heavy loading and it also helps under heavy braking. The other front lower control arm has a rubber bushing. The 1LE and ZL1 shared this arm and the Z/28 has a little harder rubber bushing. Again, look for the Z arm but lots of the Z/28 stuff is hard to find. Otherwise the 1LE/ZL1 arm is plenty capable.

I tracked my '14 SS 1LE for about 6 years before I moved onto a Gen6. It was extremely capable. I ran with the OE 1LE parts for a long time and the car was amazing on track. I then moved onto the Detroit Speed rear toe rods. Then I bought some of the Z/28 parts. Arms more so for helping with tire wear and a little bit of response. The only other aftermarket arm/joint I had was a non adjustable UMI rear trailing arm with their big Johhny shperical joint. That one was not really worth having. The AFE rear solid cradle mounts were a massive increase in the feel and stability of the car. That made such an impression on me that the first part I bought for my '22 SS 1LE was the ZLE solid rear cradle mounts.

Stick with the simple stuff and work on the driver mod. I mentioned in an earlier post, the 1LE suspension would be perfect for your car. Tweak with the rear bar. Yeah, a front bar can help with some turn in response but a bigger front bar will almost certainly create more understeer. There are rare occurrences when adding a bigger bar actually helps create more front grip. Alignment matters too on with balance. The 1LE stuff might be hard to find, especially the shocks Stick with Koni adjustables or Bilsteins for a good balance of performance, durability and cost.


All I have on my Gen6 SS 1LE is a Hotchkis front bar, BMR rear bar with my custom rear mounts (BMR's mounts suck), SPL adjustable endlinks and the ZLE cradle mounts and ZLE front radius rod (more durable when using 100TW SC3R tires). The car is amazing on track. I even went back to the OE rear toe rods after having the SPL toe rods.. Keeping it simple!

1LE based suspension, struts/shocks/arms/front bar
solid rear cradle mounts
bigger rear adjustable bar
adjustable spherical rear toe rod
285/35-20 square....Gen5 or even Gen6 SS 1LE wheel setup. Same wheel size between the two Gens. Offset is a minor change between the two.
200TW tires.....tires make a massive difference!

[Rusty Shackleford]

Thank you for the informed response. Everything you say makes sense. My reasoning behind planning the change to poly was more based on looking under the car, seeing all the arms and bushings, and thinking two things.

1) stacking all of the potential flex from bushings, and I'm struggling to find the correct term here, but might not maintain a good dynamic alignment under load. An alignment is in the plans before it sees another track day.
2) if the bushings are moving around then the car would likely get more responsive after tightening all of that stuff up. Not that I have any big issues now. Just figured it couldn't be a bad byproduct.


So basically I was coming at it from the approach of stabilizing the platform before taking any other swings at it.



At this point I doubt I'll be changing anything before a late spring track day this year. Life is getting in the way of hobbies right now, and I'm signed up for the Big Bend Open Road Race in April. So I might get in one or two track days before the summer break.

[Bretts]

I went with a suggested set of specific parts from jdps with the other things like ccw spa16 285 35 19 setup, did very well with a 55 car rally group ata road course event with a side autox event, slow build as you go but coilovers will get you flat also in those tight apexs