charlieton

Am I qualified to write a review? Probably not. What I do know is this: I like to drive and I drive a lot. My 9-5 commute is 61 miles one-way (mostly on the 5/405/10 freeways) and once a week, I commute all the way up to Santa Barbara. That leg to Santa Barbara is 136 miles one-way (mostly 5/405/101 freeways). And, I wanted to share my experience and hopefully help someone else down the road looking to made the same upgrade.

The percentages below are already posted in the forum, but I wanted to put them in here for completeness of the review.

F-Sport Sway Bar stiffness increase against OEM
IS250-RWD
Front: 46.6%
Rear: 42.8%

IS250-AWD
Front: ---
Rear: 42.8%

IS350
Front: 6.3%
Rear: 151.5%

How do sway bars work?
"So you're driving down the road and you go over
a bump that goes across the entire lane. The sway bar
does nothing. Both sides compress normally. You go around a
corner and the chassis starts to lean and compress the outside
suspension and now it's as though you have a bigger spring
out there, so the car remains more level. That's the good part.
Here's the bad part. You hit a bump with only one side, and it
behaves the same way, as though you have a stiffer spring,
so you feel uneven bumps more. You feel it crossing anything
diagonally as well, such as coming into or out of a parking lot
or driveway curb. "
read the entire article @ http://www.stealthtdi.com/SwayBars.html

I read that article before I installed the sway bars and thought "cool'; the explanation not really sinking in. I bought my IS250 in April and since then, have put about 7k miles on it. When I'm in commuter mode, I average about 28-29mpg. On a couple of tanks I coasted that number all the way up to 31mpg. After I purchased the car, I've been feening to modify it. I had been saving up for coilovers. As life goes, something came up and I have to dedicate a large portion of my next couple of paychecks to something else. I'm like Oh no, it's going to be forever until I can buy coilovers. I decided forget it, I need something to hold me over until I can get coilovers. This past Saturday, I bought a Joe-Z intake from L-tunedparts.com. Suffice to say the Joe-Z intake is nice, sounds pretty good and is a good buy. But it didn't quench my thirst.

I was heading over to Lexus of Westminster (what's up kerry and pete!) for an oil change. On my way there I was like hmmm what can I buy to fix the bug I'm ailing of. When I got there I looked up at the F Sport Wall and saw the sway bars. "That should do it!" I thought. Kerry was very knowledgeable and seemed pretty cool. After I made the purchase of the set (front and rear sway bars), he handed me off to Pete. Both of these guys ride IS' and both commented on how much they enjoyed their sway bars. Installation didn't take too long, I think it was right about an hour with the oil change.

I was so giddy after the install, I was like a kid in a candy store on his birthday. Like the newbie I am, with two new mods on the car, I was gunning it to the 22 freeway. What a let down I thought. I remembered on the forums how people were saying it was a night and day difference and I couldn't really tell. Can you say instant "buyer's remorse"? I was thinking what a joke this is, that was my initial impression. After that I needed to wallow in my remorse and headed over to Phan-Tastik cafe to re-read the reviews and see how much moo-la I could recover in the secondary market if I sold my sway bars.

After drinking my Cafe Sua Da (in a clear to-go cup, don't trust those glasses), I hit the road again. This time though, with much less enthusiasm and a lighter foot. This is when I really started to notice the improved handling characteristics of the sway bars, earlier I was pushing it just too hard.

The sways bars do make a notable difference in handling. I would say the greatest difference is felt on long freeway banks and lane changes. On Wednesday, I had to head up to Santa Barbara. There is a section of the 101 where its just a huge uphill battle, I would say probably like 10 miles long and then after that a huge downhill course. I remember riding stock, taking this downhill grade at about 80 MPH, it was very scary making lane changes. With the sway bars, it is much more confidence inspiring and the car really does hug the road. The lane changes were much more direct; I would describe it as much less "floaty" feel to it. In 90 degree cornering, the ride is definitely flatter with less lean. Just don't expect to make right handed 45mph turns w/ no lean. If you guys know the 5 N to 22 W interchange, there's a great switchback right to left with an uphill incline and a slight peak at the end. I can confidently take that interchange at about 10mph faster than usual with zero worries.

Is it a night and day difference? Unfortunately, no. I think that it may be more noticeable if you upgrade the rear first, ride it for awhile and then upgrade the front. Is it an improvement? Yes. Would I have purchased coilovers before I bought the sway bars, if I had to choose all over again? I can't say for sure, as I haven't bought the coilovers. But I would have to say I am leaning towards the coilovers.

More importantly, would I recommend this upgrade to friends with an IS250? Yes!

charlieton

I would've put pictures up, but you can't really see the sway bars after they are installed. If you guys want them, let me know.

JDKane527

iTrader: (10)

If you pushed it hard to the point where you broke traction in turns before, chances are you'll still do the same now. It's in going wide smooth turns that you can feel the difference of how flatter it is. Try the 5S to the 10E junction that was fun too before the bumps.

gocubs08

Seems like majority of people who say the sways arent worth it as much drive the 250, everyone who says its night and day have a 350... I wonder if there is difference in suspension between cars??

syzygy

There necessarily has to be a difference if you consider the two following facts -

Fact #1: F-sport sway bars (front and back) are identical for both the IS250 and IS350

Fact #2: Percentage increases in stiffness going from stock front and rear bars to F-sport sways are different for the IS250 and IS350.

If you get a 42.8% increase in stiffness for rear sways with the IS250 RWD, and a 151.5% increase in stiffness for the rear sways with the IS350, and the F-sport rear sways are identical, then the conclusion is that stock IS250 rear bars are stiffer than stock IS350 rear bars.

Similarly, stock IS350 front bars are stiffer than stock IS250 front bars, and stock IS350 front bars are nearly identical in stiffness to F-sport front sway bars.

I think a better question is - why are stock IS250 rear bars much stiffer than stock IS350 rear bars (and vice versa for front bars - where front IS350 stock bars are much stiffer than front IS250 stock bars)?

Edit:

Some quick math -

let F = stiffness for F-sport rear sway bar
let x = stiffness for stock IS250 RWD rear bar
let y = stiffness for stock IS350 rear bar

x + .428x = F
y + 1.515y = F

1.428x = F
2.515y = F

1.428x = 2.515y
x = (2.515/1.428)y
x = 1.761y

The conclusion is that IS250 RWD stock rear bars are 76% stiffer than stock rear bars for the IS350

JDKane527

iTrader: (10)

Hmmm...selling IS250 REAR SWAY BAR!! =D

Cali2is

How much?? lol...

JDKane527

iTrader: (10)

https://www.clublexus.com/forums/is2...ml#post5644484 Someone's gotta be interested haha
I have a feeling though I may be able to get the same amount if I just get it recycled.

gocubs08

Sell it just to be the first person to do so! Then I wanna see if a 350 owner feels a difference!! LOL

brociouz

iTrader: (65)

Something seems wrong about putting an OEM IS250 part into an IS350...

alan003

thanks for the detail info carlx. there's one thing that is misleading from lexus is that the part#s for the sway bars are the same. if one is stiffer than the other, shouldn't lexus make two separate part#s?

Jetfire

iTrader: (3)

for IS 250 the understeer/oversteer shouldn't change too much, just that it has less body roll.

for the IS350, you have a lot less understeer with the f-sport sways and less body roll. so that's why it's more night and day.

JDKane527

iTrader: (10)

This supports IS250 having stiffer sway bars from factory than IS350...interesting.

brociouz

iTrader: (65)

+1 This is what the numbers would support.

uz07lex

iTrader: (14)

great info. I loved the story. you made me feel to go out now and buy sways.