MrHarris

iTrader: (1)

I keep reading the IS350 front sway is only 6% less stiff than the F-Sport sway.

But I went to the Lexus website to view their E-Brochure and this kind of puzzled me.

http://ebrochures.lexus.com/publicat...a#/b1fade6a/20

Did Lexus misprint those #'s or am I reading the chart wrong?


If I went IS350 front sway, IS-F rear sway combination would it be a decent setup as far as sways go? I plan to upgrade to megan coilovers as well in the future.

Jetfire

iTrader: (3)

i want to know too.

Kurtz

iTrader: (1)

Those are the same numbers as currently on the F-sport web site.

Most people think it's a mistake, because the F-sport web site USED to say 6.3% IS350 front and 42.6% IS250 rear.

Then a year or so ago those numbers, and only those specific numbers, swapped... right around the same time they made other updates to the website.

So probably they made an error (maybe in printing that brochure you link to) and it has stuck around.


The reason the original numbers (6.3% front 350 and 42.6% rear 250) are MUCH more likely to be correct is simple:

If the numbers currently posted were correct then putting the F-sport bars on a 250 would make the handling significantly worse.

Since that doesn't happen those numbers can't be correct.

It certainly wouldn't be the first time Lexus made a mistake on the web and took forever to fix it.

Hell, the ML standalone option still says it includes a DVD changer, and it does not.

I got them to fix that for the 2008 models (after costing them some money because of their error), but it was back to wrong again as soon as they update the website for 2009 models and has remained wrong ever since.

Jetfire

iTrader: (3)

Are you talking about the current 46.6% Front and 6.3% rear. or the old 46.6% Front and old 42.8% rear "would make the handling significantly worse"

Can you clarify this up for me. It might be the 2 hours of sleep, but it's not making too much sense to me. More understeer?


so the present 46.6% F and 6.3% R are correct then for the IS250?

Kurtz

iTrader: (1)

Nope... the current 46.6 and 6.3 are wrong. The previous 46.6 and 42.8 are more likely correct... with the 6.3 belonging where it previously was- the front 350 bar.

If they were correct then adding those bars to a 250 would make it understeer even worse than it did stock.


Stiffer front bar=more understeer
Stiffer rear bar= more oversteer (which is the direction you wanna head with most stock vehicles since they understeer from the factory)

Jetfire

iTrader: (3)

ahh, makes sense. i was worried that if the 46.6 and 6.3 were the correct ones. i wanted to reduce body roll but not increase understeer. The stock IS250 feels great around corners.


thanks for clearing it up kurtz.

MrHarris

iTrader: (1)

Thanks. I'll be purchasing an IS350 front sway bar today to accommodate my IS-F rear sway bar.

I personally think the IS250 feels terrible in the corners stock, especially with the Bridgestone Turanzas.

flowrider

iTrader: (9)

Hold On - The Sway Bars for the IS250 RWD and IS350 are the same.

See the attached PDF I compiled.

Lou

MrHarris

iTrader: (1)

Is this for sure Lou? I'm going to buy the is350 sway in about an hour and half..

Why is it all the 350 guys just upgrade the rear?

flowrider

iTrader: (9)

It's for sure, when I was researching that paper, Lexus Corporate was of little help, but I finally got it out of them. I reconfirmed by calling two Lexus Parts Departments, and sure enough, the PNs were the same.

BTW, Upgrading the rear bar is a good idea. I have the F-Sport rear bar on my F, and I sold my old rear bar to an ISX50 owner, and he loved it.

Lou

XhyDra

iTrader: (8)

Here's a very old link where a moderator explains at the end of the post about the IS350 swaybar being stiffer than IS250

https://www.clublexus.com/forums/is2...our-is250.html

An example would be the Hotchkis rear swaybar, it is 70% to 140% adjustable in stiffness, yet it's 19mm like the F-Sport one. The F-Sport one and Hotchkis might be the same mm but the F-Sport sway is still 160% stiffer. Hence the IS350 swaybar would be stiffer than an IS250 swaybar

Kurtz

iTrader: (1)

The mod in that thread states the 250 and 350 bars are not the same part number.

Lou states they are the same.


I know Lou said he did research, but I don't see how he can be right.

If he were, since we know the F-sport bars are the same between RWD250 and 350, it would be impossible for the F-sport bars to have different "stiffness increase" numbers from each other.

They'd be exactly the same for both cars.

They aren't though.


I base this on we "know" for sure these things:

The fsport bars are the same for 250 and 350.
THe fsport bars improve handling (reduce understeer) on the 250 and 350.

Therefore:
The only conclusions that make sense from what we know are:

The 250 and 350 stock bars are not the same

The current fsport.com numbers for the 250 rear bar and 350 front bar are reversed, and the original numbers they had up (6% front 350 and 42.6% rear 250) are the correct stiffness increases with the F-sport bars.


If the 250 and 350 bars were the same OEM and Fsport both then not only would the current and original set of stiffness increase numbers have to both be wrong, they'd have to be outright fraudulent, since they couldn't possible differ in that case. Since we KNOW the F-sport bars are the same 250 and 350 therefore the OEM ones can not be the same.

If anyone has an explanation for how any of the above can be wrong given the stuff in the "we know" section please let me know your thinking.

SC3coupe

iTrader: (4)

Facts that I know:
I called Lexus parts department and I was told the IS250 and IS350 sway bar part numbers are the same. It's not that hard for the parts guy to find stablizer bar under the suspension catagory.

I measured IS250 front sway bar diameter, it checks out with Lou's PDF file, a bit over an inch or 27mm.
So I don't believe IS350 front sway bar is any thicker.
All you have to do is take off the 3 bolt plastic cover that you get to the oil filter housing and put your caliper or micrometer over it.

I do believe the 250 and 350 have same sway bar front and rear.
For the current Fsport poster to be right, the 250 front sway bar would have been quite thin, but it is not..

MiiK350

iTrader: (8)

I believe kurtz to be true. I came across this thread bc tonight, after driving my girlfriends stock 250 tonight, I noticed it handles significantly better (confident) then what Used to be my stock 350 around high speed corners near her house.

Jetfire

iTrader: (3)

went around some twisties and hairpins yesterday with some other 2ISers.

my 250 with stock sways went around them "better" than the 350 with stock sways.


mmm....(not my pic)