Installed super fat sway bars, now car is a slidey boii

[Stomachbuzz]

Wanted to modify my car, and make it "my own", you know how it goes...
Bought the car stock with Firehawk AS tires, stock size.

Installed the Eibach sway bar set (25mm front, 19mm rear, both tubular) with adjustable endlinks. Both sway bars set to most tame, and set endlinks to same length as the OEM links.

And now the car is very slidey...
I was anticipating some changes in the behavior, obviously, and was driving very cautiously until I could find the new limits of the suspension, but wow. Seriously caught me off guard in a potentially dangerous situation.

Shortly after that incident, I tested it in a more controlled environment. I went around a 90deg turn (usually a 12mph turn in a regular car, I suppose) around 18mph and the rear end still knocked loose and got wide before the aids stepped in.
I was shocked. You could be driving this car in a rather tame fashion, and the rear end would feel like it's on ice skates.

Other factors: I think it was like 45-50F temp. The rear tires have deep tread. Local roads are trash, and 1st time it broke loose, likely had lots of road debris.

In some ways, it almost seems 'worse' to drive than with stock sway bars. Previously, you had to try to break the rear loose. Either take a turn with significant speed, or slam into 2nd gear around a parking lot intentionally trying to drift.


I don't want to play the "I installed race car parts, but I don't want race car consequences!" card, but what are my options here?

Better tires? Stiffer springs/dampers?

[NoHaveMSG]

This car doesn't need much rear bar. I have been hunting for a used stock rear one, on a perrin 16mm now.

[Stomachbuzz]

Originally Posted by NoHaveMSG

This car doesn't need much rear bar. I have been hunting for a used stock rear one, on a perrin 16mm now.

At this point, it seems you would be correct.
Now that I have experience with it, I would say the 19mm Eibach bar is excessive, but that's the only size Eibach offers, and they come together in a kit, so I thought they would be appropriate.

I suppose the proper scenario is the car has a suspension setup that can justify (and use) that much stiffness in the rear.
Not sure if I should build the rest of the car to match, or install smaller bar

[NoHaveMSG]

More aggressive tire would help. Even on my 200TW setup I personally don't like a lot of rear bar.

These are the specs Perrin gives on their bars. I know you are on the Eibach but this will give you an idea of the difference in stiffness based on diameter. I'd put your stock rear bar back on for now.

PERRIN 16mm Bar Hole #1 30% Stiffer than 14mm OEM bar
PERRIN 16mm Bar Hole #2 65% Stiffer than 14mm OEM bar
PERRIN 16mm Bar Hole #3 116% Stiffer than 14mm OEM bar
PERRIN 19mm Bar Hole #1 150% Stiffer than 14mm OEM bar
PERRIN 19mm Bar Hole #2 243% Stiffer than 14mm OEM bar
PERRIN 19mm Bar Hole #3 347% Stiffer than 14mm OEM bar
PERRIN 22mm Bar Hole #1 400% Stiffer than 14mm OEM bar
PERRIN 22mm Bar Hole #2 535% Stiffer than 14mm OEM bar
PERRIN 22mm Bar Hole #3 729% Stiffer than 14mm OEM bar

[DarkPira7e]

Swaybars are suspension tuning tools. The reason cars come with body roll and suspension compliance is to avoid what you're experiencing.
Rear bar helps mostly with dialing in oversteer if the car front plows on corner entry. I'd go back to stock bar or induce compliance elsewhere if you can (if you have coilovers, maybe adjusting pre-load or damping to be softer could help)

[venturaII]

"I put the most extreme parts I could find on an otherwise stock car, and am surprised and sad that the car is now worse than before..."

[strat61caster]

http://www.ft86club.com/forums/showthread.php?t=67345

7. Tire choice

Really stiff springs with all season or OEM tires can reduce grip as you'll be quickly/easily overloading the tire. Match your spring rates to your tire choice.

Running sticky tires on soft OEM springs is a problem too, but you will still gain grip from the tire. It'll just feel sloppy and move around a lot.

Stiff swaybars isn't much different than stiff springs. If you want to keep the roll stiffness you need to match the tires to the suspension, at least decent summer tires like Michelin PS4S or Conti ECS.

[new2subaru]

Originally Posted by NoHaveMSG

This car doesn't need much rear bar. I have been hunting for a used stock rear one, on a perrin 16mm now.

The Perrin 16mm is too much? The TRD bar is 15.8mm I believe. 17+ cars are 15mm?

[NoHaveMSG]

Originally Posted by new2subaru

The Perrin 16mm is too much? The TRD bar is 15.8mm I believe. 17+ cars are 15mm?

For my taste. I like a little bit of safety understeer since I can always bring the nose in a little bit with left foot braking or trail braking.

[new2subaru]

Originally Posted by NoHaveMSG

For my taste. I like a little bit of safety understeer since I can always bring the nose in a little bit with left foot braking or trail braking.

Gotcha. I like mine a bit looser. At least for now.

[NoHaveMSG]

Originally Posted by new2subaru

Gotcha. I like mine a bit looser. At least for now.

And I wouldn’t quite call the 16mm too much. I would just like to try a stock one. I bought my car with parts on it already. The rear bar was set at full stiff.

[new2subaru]

I'd do the same just to check it out. What front bar does it have and what setting?

[NoHaveMSG]

Originally Posted by new2subaru

I'd do the same just to check it out. What front bar does it have and what setting?

Perrin 22mm in softest setting. On Tein’s with 6kg springs all around. Track tire is a 235 Z3. Street tire a 225 V12 evo which is quite understeery on this setup. Going to T2’s with 400lb main springs. Have a set off 500lb springs too I may try. Track setup has a little bit of understeer on turn in and mid corner which can be neutralized with trail braking.

[new2subaru]

Nice, let us know what happens when you switch it out.


(Can't quote you for some reason)