Installed: F-Sport Rear Sway Bar...
 

Well, I was getting a little tired of the body roll and understear that the stock IS-F had. I heard that the F-Sport rear sway bar was larger, 19mm vs 16mm for the stock rear sway bar, so decided to give it a shot. Sure enough it definately reduced the body roll and made the F much more neutral and straighter on tight turns. I definately recommend it for those who want to tweek the handling on their IS-F. Now I'm just waiting for some strut braces to be made by some company...Darshana S...

Wow.....sounds pretty nice I wish they have something like that for the 3GS......

How much was it installed?:woot:

So the F-sport rear bar fits the IS-F? Very cool!

15 min to install w/ a lift. Dealer most likely gonna ring it up for an hour labor.

There was another thread on this a while back. The thing that I don't understand is that if a slightly larger sway bar would make the car handle better why didn't the IS F come with it already. Can anyone explain that?

theoretically having less roll doesn't mean better handling, it's all about compensation, a bit roll can be helpful. i guess the only way is to have a real track time and see which one gives better timing (same car w/ w/o, same driver, etc...)

Thanks, Henry. There really isn't much body roll on the IS F. I bought the larger sway bar a while back but haven't decided whether to install it yet.

mark you should really try it out and give your feedback, since you do drive your cars hard and with your previous collections, i think you can give a good review

i forgot the years already, but back in a year, something like a cobra had thinner sways than the gt. that's another proof that maybe the thinner sway gave a better balance to the car

but i don't deny though, maybe for normal street driving, a thicker sway would give less rolls and thus better feeling

^^I'm with you VelvetBlue. I have it, just haven't installed it yet. I would like to hear a really good review about whether or not it makes that much of a difference, etc. etc. :)

Another point to consider is that manufacturers will always dial in understeer to their finished product regardless if it's a Cavalier or an IS-F or M3 because it's safer this way on the streets etc. It's just a question of how much understeer they want to dial in. Your mom's Cavalier will always have more understeer dialed in because it was made for mom, while the IS-F will be more balanced and hence have less understeer or understeer at the limit. This is true for almost all performance cars. Just take a bunch of reviews of performance cars from various R&T mags and the specs will always say "mild understeer".

Vehicle dynamics, engine placement, etc also have an impact on understeer. That is why cars that have the engine placed in front (or closer to) of the front suspension will naturally understeer more (VW's and pre 2008 Audi's etc.). Check out underhood pics of a Honda S2000. It is one of the best handling cars and part of that reason is because, right out of the box, the engine is almost sitting in the middle of the car. Sway bars and other suspension tricks help compensate and for these limitations or fine tune how the manufacturer wants it to behave on the road.

Cheers

Would this affect stability control (VDIM)?

I am not too knowledgeable about VDIM in the F but Lexus says it will play with the car throttle and brakes to avoid loosing control (such as prematurely leaving the tarmac) and it uses various inputs for that (such as accelerometers) and obviously a piece of software.

Am I right thinking that the software -which is probably conservative- just makes a deduction about an imminent loss of control assuming standard grip from the tires, lateral acceleration and speed? If so, when you get to reach that speed/lateral acceleration that's going to become overwhelming for your tires then VDIM acts? If I am correct then the dynamics of the car are obviously factored in the software and changing such dynamics may trick the software either way (kicking in VDIM to early or too late)?

Anyone familiar with how VDIM actually work?

Thanks.

what body roll the car is rocksolid! but, i have had understeer in sweepers and thought per haps better tires and fater swaybar would help ,but thats all id add.

Dealer said F-Sport Sway bars were in the 09' ISF?! I was questioning it and thought what else is "F-Sport" that is NOT ont he car? (ex-Brembos are already on it)

Anyone have input for a noob? Thanks ;)

As far as I know that is not correct...the only changes to the 09 IS-F are interior changes, nothing to the engine or the suspension for that matter...Darshana S...