The owners manual mentions it a little (ie, its there). I'm wondering if it operates differently depending on driving mode selected. Reason I asked is that a local road is in disrepair (lumps and bumps). I "think" when I drive over it when in standard mode, it is bumpier and noisier than when I drive over it in Sport. But, I could also be imagining that there is a difference.

 

Why yes, it does change dampening depending in the mode. However, it should get more stiff when you change to a sportier mode, not vice versa.

 

Mine does not have the F-AVS, but this is based on what I have read from the documentation. There are two major level of damping with the F-AVS, One is the standard (soft) mode in ECO, NORMAL and the other is the stiff mode I believe in SPORT and SPORT+. There are 30 levels of adjustments as per Lexus even when it is in SPORT+, it is constantly dynamically adjusting to balance between stiffness and smoothness.

 

Stiff doesn’t always mean better (giggity). Rally suspension is not always stiff (giggity).

 

Thanks. I infer that "to me" the stiffer suspension dampens the rough road more effectively than the standard suspension setting. So I wasn't imagining a difference. I guess that I could have answered my own question since the custom drive mode selection gives you the option of standard or sport for the suspension. Just as an aside, for city driving around town I selected Eco drive train, sport suspension and normal A/C now that I know I prefer the sport suspension on that particular road that I must travel on.

 

I personally think having a more stiff suspension in sportier modes is mildly a gimmick, it does do something as a stiffer suspension can transfer weight faster but as you said, stiff does not always equal better. I genuinely prefer just standard fixed suspension

 

From what I know, the 2015 - 2016 fixed suspension is like the F-AVS in stiff mode except it is more choppy over uneven surfaces while the F-AVS is dynamic even in stiff mode always adapting to the surface conditions. I have heard from someone who owned both in RCF that the F-AVS is smoother than the non-AVS ones, but the non-AVS is more predictable over the surface conditions.



Yes, that makes sense. It is dynamic adjustment of compression/rebound I mentioned above when it is in SPORT/SPORT+ as the speed/surface conditions change. When it is soft, the chassis rigidity works against the softness of the dampers so the chassis would project harshness of the road conditions more into the cabin as the dampers are soft so it will have faster compression and slow rebound. The soft compression stroke at higher speeds will project the vibration to the chassis, which in turn will project it into the cabin.

 

yes, operates differently depending on drive mode starting for 17+. based on an AVS link in this document and your question about normal vs sport...i believe there is no difference. it's when you go to sport+. this is my experience as well (at least my in chair exp) from both my prior 17 and now 21. if there are avs ride (i.e. suspension, not throttle, etc) changes in sport vs normal i don't feel them. def feel them once going to sport+. i only go into sport + on smooth track like roads. it's here that you can really feel the difference...like it's on rails. the rebound damping is too aggressive on non smooth roads imo, esp the edition models where it's even more aggressive in sport+ than non edition.

ECO, NORMAL, and SPORT S modes, the Drive Mode Select system prioritises ride comfort while contributing to greater handling stability, based on driving operations and the road surface conditions.
In SPORT S+ mode, the focus of the damping-force control is handling stability. In addition, the SPORT S+ mode automatically switches the powertrain, electric power-assisted steering and VDIM to Sport mode.

 

See, now, that's what prompted my original query. I thought I felt a difference in noise and smoothness on the same road, same speed between normal and sport modes. The custom mode gives the option to change the "chassis" (sic) from normal to sport but it (the owners manual) doesn't discuss what changes in the AVS between those two options (if anything-but if nothing changes, why the option?). There isn't even any information as to the particular species of AVS is installed (pneumohydraulic? and is it the same in all years of RC F?). Similar to the other discussions in the MPG tread about when the engine enters or leaves the Otto or Atkinson cycle. Certainly wish there was a better technical manual available for the car. Granted, these things aren't needed to operate the vehicle, but some of us would like to go beyond the advertising copy and see how the systems actually work instead of being flim-flammed with rhetoric.

 

The word 'chassis' can be misleading. Only the AVS you have is what they refer to as 'chassis'. All of the 2017 - 2022 RCF have the same AVS damping programming through the modes. Have not seen any notes on the updates over the years. The only exception is, the RC track edition, which has the same basic suspension except the rebound stroke on the AVS is stiffer in SPORT+ mode than the non-TE versions.

One thing I found is different in 2020+ RCF, are the bushings on the front end/steering are 150% stiffer than the 2015 - 2019 RCF bushings while the rear end bushings are softer than the 2015 - 2019 RCF. The front end stiffer bushings give it more stiffer steering feel and more resistance to bump steer while the softer rear bushing make the rear end of the RCF a bit more "relaxed". It must be because the 2015 - 2019 RCF rear can feel twitchy so the softer bushings on the 2020+ in the rear make it more predictable and stable.

Another subtle difference, the rear springs of the RCF with carbon fiber/TVD are different from the RCF with LSD. Not sure why they are different, though.

 

I think this is the case. In looking at shock replacement on Utube on an IS 350 Fsport with AVS I see that the shock is equipped with a solenoid which is likely activated in sport modes and not activated otherwise. This idea is further supported by noting that the custom mode offers two choices for chassis setting, sport and normal. So, it seems the species of AVS on the RC F is solenoid activated and not pneumohydraulic.