No front anti-sway bar=a better ride

[KoolBRZ]

I'm currently running with just the stock front sway bar. For suspension I have the HKS Hipermax GT IV's with 6k springs in front and 4k springs in back, the back springs need a lot of preload to keep from bottoming out, so I'll probably upgrade the rear springs to 6k. It corners well on the streets with just a front sway bar, but has a lot of oversteer when pushed to the limits. I figure having a softer, (81% of stock) front sway bar will reduce the oversteer, as well as having a softer, (79% of stock) rear sway bar.

The biggest change however will probably be changing the rear springs to 6k. Using 6k springs front and rear, and softer sway bars should provide a balanced, softer, yet responsive, street handling machine, (by that I mean "pothole handling" machine).

As I mentioned earlier, I had an air suspension setup on my car, but just could not get it adjusted right to give me a good ride. I won't go back to air for one simple reason. Air suspension doesn't have adjustable preload, period. Any attempt to adjust preload just raises the car up, limiting the shock travel, worsening the ride. Sad but true for all types of air suspension.

[Hyper4mance2k]

Originally Posted by KoolBRZ

I'm currently running with just the stock front sway bar. For suspension I have the HKS Hipermax GT IV's with 6k springs in front and 4k springs in back, the back springs need a lot of preload to keep from bottoming out, so I'll probably upgrade the rear springs to 6k. It corners well on the streets with just a front sway bar, but has a lot of oversteer when pushed to the limits. I figure having a softer, (81% of stock) front sway bar will reduce the oversteer, as well as having a softer, (79% of stock) rear sway bar.

The biggest change however will probably be changing the rear springs to 6k. Using 6k springs front and rear, and softer sway bars should provide a balanced, softer, yet responsive, street handling machine, (by that I mean "pothole handling" machine).

As I mentioned earlier, I had an air suspension setup on my car, but just could not get it adjusted right to give me a good ride. I won't go back to air for one simple reason. Air suspension doesn't have adjustable preload, period. Any attempt to adjust preload just raises the car up, limiting the shock travel, worsening the ride. Sad but true for all types of air suspension.

Did you ever try swapping the springs, or was there not enough adjustment in the coilovers to account for the different spring lengths?

[mike156]

Going softer in the front will give MORE front grip...which will produce MORE oversteer.
Going stiffer in the back will REDUCE rear grip...which will produce MORE oversteer.




You don't seem to understand the changes you are making.

[KoolBRZ]

Originally Posted by mike156

Going softer in the front will give MORE front grip...which will produce MORE oversteer.
Going stiffer in the back will REDUCE rear grip...which will produce MORE oversteer.




You don't seem to understand the changes you are making.

I understand completely. You're failing to take into consideration the effect of the track links the frs/brz's have in the rear suspension. Body roll affects the track links, causing them to change the toe angle of the rear wheels, which causes oversteer. Increasing spring stiffness only reduces body-roll-induced oversteer, it would still increase grip-induced oversteer. Your answer is right for the track, but my answer is right for the street.

There is also the fact that softer sway bars allow more body roll, so once again, stiffer rear springs will help reduce oversteer, by reducing body roll, and still allow for more independent suspension which can more easily soak up the potholes, ruts, dips, and other street surface problems not usually found on a racetrack.

[KoolBRZ]

Originally Posted by Hyper4mance2k

Did you ever try swapping the springs, or was there not enough adjustment in the coilovers to account for the different spring lengths?

I swapped the 4k springs to the front, but couldn't stop it from bottoming out, no matter how much preload I used. The 4k springs would be fine in the back, except I haul about 150 Lbs of extra weight in the back. I have the vertical, hidden, receiver hitch, computer tools, parts and tow hitch insert. That extra weight is just a little too much for the 4k springs.

[Kostamojen]

"This message is hidden because KoolBRZ is on your ignore list."

Solves all the things

[wparsons]

Originally Posted by KoolBRZ

I'm currently running with just the stock front sway bar. For suspension I have the HKS Hipermax GT IV's with 6k springs in front and 4k springs in back, the back springs need a lot of preload to keep from bottoming out, so I'll probably upgrade the rear springs to 6k. It corners well on the streets with just a front sway bar, but has a lot of oversteer when pushed to the limits. I figure having a softer, (81% of stock) front sway bar will reduce the oversteer, as well as having a softer, (79% of stock) rear sway bar.

The biggest change however will probably be changing the rear springs to 6k. Using 6k springs front and rear, and softer sway bars should provide a balanced, softer, yet responsive, street handling machine, (by that I mean "pothole handling" machine).

If you honestly believe that increasing rear stiffness is going to make it understeer less, you need to go back and start at the basics all over.

Originally Posted by KoolBRZ

I understand completely. You're failing to take into consideration the effect of the track links the frs/brz's have in the rear suspension. Body roll affects the track links, causing them to change the toe angle of the rear wheels, which causes oversteer. Increasing spring stiffness only reduces body-roll-induced oversteer, it would still increase grip-induced oversteer. Your answer is right for the track, but my answer is right for the street.

There is also the fact that softer sway bars allow more body roll, so once again, stiffer rear springs will help reduce oversteer, by reducing body roll, and still allow for more independent suspension which can more easily soak up the potholes, ruts, dips, and other street surface problems not usually found on a racetrack.

No, just no. Have you actually looked at the suspension geometry???

Here's a hint, you'll get the same change in toe (not opposite) from compression and rebound. What does that mean? As the car rolls, one side is compressed and the other rebounds... but they both toe in/out the same. To have it oversteer like you're claiming, you would need the outside to toe out and the inside to toe in (passive rear wheel steering).

You also need to keep in mind how minimal this would be compared to your HEAVILY front biased setup with softer rear springs and no rear sway bar.

It would also behave exactly the same on a track as it does on the street. The car doesn't know what surface it's on.

Originally Posted by KoolBRZ

I swapped the 4k springs to the front, but couldn't stop it from bottoming out, no matter how much preload I used. The 4k springs would be fine in the back, except I haul about 150 Lbs of extra weight in the back. I have the vertical, hidden, receiver hitch, computer tools, parts and tow hitch insert. That extra weight is just a little too much for the 4k springs.

I find that very hard to believe unless they have less bump travel than stock does.

[Ultramaroon]

Originally Posted by Kostamojen

"This message is hidden because KoolBRZ is on your ignore list."

Solves all the things

I want to look away but I can't.

[KoolBRZ]

The Cusco "soft" sway bars are installed now, and I've had some time to play around with the suspension settings.

In my opinion, these are the strength of sway bars that should have come on it from the factory. These really let the coilovers do their job. I towed my trailer with both kayaks on it last Sunday. I went all over the place trying to locate a boat launch, then i needed a discover pass to park, so I gave it a good shake-up. It seemed to handle the trailer better than it ever has. The extra weight just seemed to make the ride smoother. Driving around today I found myself missing the trailer. I guess my suspension isn't quite dialed in yet.

I would definitely recommend them to anyone looking for a smoother ride on the street. I'm definitely not setup for the track though. I have softer sway bars, stock tires, and my dampening is set 3 clicks from full soft in front, and only 2 clicks from full soft in back.

[wparsons]

Originally Posted by KoolBRZ

The Cusco "soft" sway bars are installed now, and I've had some time to play around with the suspension settings.

In my opinion, these are the strength of sway bars that should have come on it from the factory. These really let the coilovers do their job. I towed my trailer with both kayaks on it last Sunday. I went all over the place trying to locate a boat launch, then i needed a discover pass to park, so I gave it a good shake-up. It seemed to handle the trailer better than it ever has. The extra weight just seemed to make the ride smoother. Driving around today I found myself missing the trailer. I guess my suspension isn't quite dialed in yet.

I would definitely recommend them to anyone looking for a smoother ride on the street. I'm definitely not setup for the track though. I have softer sway bars, stock tires, and my dampening is set 3 clicks from full soft in front, and only 2 clicks from full soft in back.

What's the part number on those sways? EVERYTHING I've found online suggests even the softest bars they make are stiffer than stock. I'd love to see where you found mystery softer ones.

[HunterGreene]

Originally Posted by KoolBRZ

The Cusco "soft" sway bars are installed now, and I've had some time to play around with the suspension settings.

In my opinion, these are the strength of sway bars that should have come on it from the factory. These really let the coilovers do their job...

Your opinion is contradictory, namely because the car didn't come from the factory with coilovers. Please put the stock suspension back on and re-evaluate.

[KoolBRZ]

Originally Posted by HunterGreene

Your opinion is contradictory, namely because the car didn't come from the factory with coilovers. Please put the stock suspension back on and re-evaluate.

I WILL be putting the stock suspension back on, when I change back to my winter setup.

For the softer sway bars, the part numbers are below;
Cusco hollow sway bars
Front 965 311 A16 79% of stock strength
Rear 965 311 B14 73% of stock strength

[mav1178]

Originally Posted by KoolBRZ

Front 965 311 A16 79% of stock strength
Rear 965 311 B14 73% of stock strength

No, your info is incorrect.

These are 79% and 73% stiffer than stock.

http://www.cuscousainc.com/products/.../sway-bar.html
http://www.cuscousainc.com/vehicle-r...&modelname=470

The % listed is STIFFER THAN STOCK.

-alex

[celica73]

Originally Posted by mav1178

No, your info is incorrect.

These are 79% and 73% stiffer than stock.

http://www.cuscousainc.com/products/.../sway-bar.html
http://www.cuscousainc.com/vehicle-r...&modelname=470

The % listed is STIFFER THAN STOCK.

-alex

As much as I want to LOL with you, that isn't the case here.

965 311 B14 (rear) is a 14mm hollow bar. Stock is a 14mm solid bar. The hollow bar is softer.

Similarly, the front 965 311 A16 is a 16mm hollow bar compared to 18mm solid stock. The hollow bar is softer (and would also be softer if it weren't a hollow bar).