Installed: F-Sport Rear Sway Bar...
06-23-17, 01:59 PM
#31
Can anyone comment on this? I'm selling my '09 IS-350 on which I'd installed the F-Sport rear sway a few years back, but I'd like to swap it over to the new 2011 IS-F *only* if it truly makes sense to do so! I've read about a bunch of IS-F owners doing it, but with the revised suspension in 2011, it's not clear if it's an actual upgrade for 2011's and later... Thoughts?
06-23-17, 02:41 PM
#32
I measured the bar on my '14 and it seems to be around 17.5mm. I used a digital caliper, but without lifting up the car so there is some room for error.
My F-Sport bar is on backorder through my local dealer. Hoping to hear back with some news next week.
My F-Sport bar is on backorder through my local dealer. Hoping to hear back with some news next week.
06-23-17, 03:56 PM
#33
^^^^I compiled the attached chart a few years ago. I went to a Lexus and crawled under a few IXX50 vehicles. I measured the bars on my F. And Yes, IMHO, it's an improvement for any model year. While the suspension changed over the years, the diameter of the rear sway bar remained constant.
Lou
Lou
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isfvss (06-23-17)
06-25-17, 06:09 PM
#34
Tech Info Resource
iTrader: (2)
The cars intentionally understeer from the factory as a safety measure for drivers on the street. Then F-sport bar that was sold for the IS250 AWD is a perfect compliment for the rear of the ISF. I have one on my 2008 since 2009 and it has been terrific. That coupled with the RR Racing USRS lower control arm bushing/bracket and the car is a blast to take through corners. No exotic suspension necessary.
If I recall correctly the part numbers for the '08 swayer and later years were the same.
If I recall correctly the part numbers for the '08 swayer and later years were the same.
06-27-17, 01:32 PM
#35
Installed mine last night. It could be placebo effect, but I felt an immediate improvement in stability and a reduction of understeer in long, sweeping turns. I am no racer, nor experienced on the track, but the F-sport rear sway + USRS feel great in unison.
06-27-17, 04:53 PM
#37
06-27-17, 11:35 PM
#38
Pole Position
This is interesting because a friend and I were discussing how something related to this. He is a development engineer at a particular OEM for automotive suspensions and we were having a discussion on actual peak performance and customer "feeling". He was saying how he was doing some final suspension adjustments that included sway bar selection. The car was a moderate performance type car for street not a track day monster like a ZL1 or Viper ACR. He told me how he was wrestling with the fact that the car performed best "at the limit" during track testing with a set of softer sway bars than previously on the vehicle. He wanted to recommend this but he was concerned about customer perception and usage. I asked him what he meant and he said customers that never approach the peak performance of at the limit handling often feel that stiffer bars are better because they do help the car "react" quicker in street usage. He continued to say that a car that feels great on the street (taking a on ramp or back roads) may feel like trash at the limit (probably on track) with the same setup but because consumers like the feel of a stiffer bar over increased mechanical performance he would probably have to choose that direction.
I guess my point is, you are probably not having a placebo effect, and the car probably does react quicker or give the feel of decrease understeer in a street situation. The sway bar is a compromise made for street vehicles and a fine tuning tool for some race cars. For a street car a sway bar allows you to decrease body roll using a temporary spring rate increase during roll. It is used because you are limited to properly tune the actual springs and shocks to the optimal mechanical performance due to issues with NVH and daily driving. A sway bar is good for NVH because it is has no impact on how the car interacts with "bumps” or the road surface when the car is not turning. It is a very good bandaid for a common street car and what you feel is that increase in spring rate when the sway bar is functioning during a turn. A proper track or race car will have the actual spring rate and dampers perfectly before adding a sway bar into the equation, then the sway bar may be added for fine tuning if necessary, usually if things are designed and tuned correctly a sway bar is unnecessary. I have commonly seen the sway bars of street based race cars removed or disconnected pending the setup or race conditions.
06-29-17, 10:19 PM
#41
^^^^It's actually not needed. But the F-Sport bar has thicker walls and is heaver see this thread, Post #2:
https://www.clublexus.com/forums/is-...-an-is350.html
Lou
https://www.clublexus.com/forums/is-...-an-is350.html
Lou
07-13-17, 06:13 AM
#43
Was there any difference in rear sway bars between '08 and '11 models (with upgraded suspension)?
To be honest I'm a bit reluctant to change sway bar only - suspension is designed as a whole and changing single part is not the way I would go. From my experience with BMW E90 (which had very thin OEM rear sway bar), adding thicker rear sway bar made car more tail happy and it was loosing traction much easier. But it was compensated by softer springs in the rear + adding LSD.
Anybody installed it on '11+ ISF and tracked it? How is traction?
Does turn-in in slow corners (one of biggest issues of standard car according to me) really gets better?
Less under steer in tight corners?
To be honest I'm a bit reluctant to change sway bar only - suspension is designed as a whole and changing single part is not the way I would go. From my experience with BMW E90 (which had very thin OEM rear sway bar), adding thicker rear sway bar made car more tail happy and it was loosing traction much easier. But it was compensated by softer springs in the rear + adding LSD.
Anybody installed it on '11+ ISF and tracked it? How is traction?
Does turn-in in slow corners (one of biggest issues of standard car according to me) really gets better?
Less under steer in tight corners?
Also, I'd forgotten how easy it was... the entire swap took exactly 65 minutes without power tools or even jacking the car up at all, including a break for water and clean-up. Anybody looking for a really clean high-mileage silver IS350 in Texas? It has F-Sport shocks/springs, and now a stiffer (than stock) IS-F rear sway!
Last edited by Leander311; 07-13-17 at 06:21 AM.
07-13-17, 07:04 AM
#44
This is interesting because a friend and I were discussing how something related to this. He is a development engineer at a particular OEM for automotive suspensions and we were having a discussion on actual peak performance and customer "feeling". He was saying how he was doing some final suspension adjustments that included sway bar selection. The car was a moderate performance type car for street not a track day monster like a ZL1 or Viper ACR. He told me how he was wrestling with the fact that the car performed best "at the limit" during track testing with a set of softer sway bars than previously on the vehicle. He wanted to recommend this but he was concerned about customer perception and usage. I asked him what he meant and he said customers that never approach the peak performance of at the limit handling often feel that stiffer bars are better because they do help the car "react" quicker in street usage. He continued to say that a car that feels great on the street (taking a on ramp or back roads) may feel like trash at the limit (probably on track) with the same setup but because consumers like the feel of a stiffer bar over increased mechanical performance he would probably have to choose that direction.
I guess my point is, you are probably not having a placebo effect, and the car probably does react quicker or give the feel of decrease understeer in a street situation. The sway bar is a compromise made for street vehicles and a fine tuning tool for some race cars. For a street car a sway bar allows you to decrease body roll using a temporary spring rate increase during roll. It is used because you are limited to properly tune the actual springs and shocks to the optimal mechanical performance due to issues with NVH and daily driving. A sway bar is good for NVH because it is has no impact on how the car interacts with "bumps” or the road surface when the car is not turning. It is a very good bandaid for a common street car and what you feel is that increase in spring rate when the sway bar is functioning during a turn. A proper track or race car will have the actual spring rate and dampers perfectly before adding a sway bar into the equation, then the sway bar may be added for fine tuning if necessary, usually if things are designed and tuned correctly a sway bar is unnecessary. I have commonly seen the sway bars of street based race cars removed or disconnected pending the setup or race conditions.
I guess my point is, you are probably not having a placebo effect, and the car probably does react quicker or give the feel of decrease understeer in a street situation. The sway bar is a compromise made for street vehicles and a fine tuning tool for some race cars. For a street car a sway bar allows you to decrease body roll using a temporary spring rate increase during roll. It is used because you are limited to properly tune the actual springs and shocks to the optimal mechanical performance due to issues with NVH and daily driving. A sway bar is good for NVH because it is has no impact on how the car interacts with "bumps” or the road surface when the car is not turning. It is a very good bandaid for a common street car and what you feel is that increase in spring rate when the sway bar is functioning during a turn. A proper track or race car will have the actual spring rate and dampers perfectly before adding a sway bar into the equation, then the sway bar may be added for fine tuning if necessary, usually if things are designed and tuned correctly a sway bar is unnecessary. I have commonly seen the sway bars of street based race cars removed or disconnected pending the setup or race conditions.
07-13-17, 03:52 PM
#45
A few weeks in, the F-Sport sway + USRS are worthy budget upgrades if you are looking to elevate daily driving pleasures. The car is also a little more tail happy now. Track day in a few weeks' time, we'll see how that goes.