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Pete. Thanks for all this good info always. Based on the Shocks/Springs each year being the same for RWD to RWD F Sport vs Base/Lux AVS. Is the difference in the chart we are seeing perhaps the Steering ECU difference? F Sport ECU vs Lux ECU. Both having AVS.
The Non Tapering 13 Springs would be the stiffest springs imo. Also the KYB's can be ordered and found on Amazon, and purchased with a warranty for Free replacement option if anyone wants it.
Yes, Luxury and F Sport trims use the same spring, same shock absorber and same roll bar part numbers, however, the software mapping between Luxury is F Sport trims are deliberately different on Sport+ mode; on Normal mode, the Luxury and F Sport trims have the same AVS software mapping.
Depending on month/year, the Luxury/F Sport duo have different part numbers too.
200t/300/350, AWD and 450h have different part numbers again.
Although 200t/300/350 use the same suspension part numbers.
All so complicated.
I have never driven the AWD version, but I wouldn't be surprized if it was softer than RWD.
What sort of damping rates/control are you after?
Are you after a floaty, or intermediate balanced, or very controlled ride?
For a floaty ride, go for 2016-20 dampers.
The 2013 dampers will probably give you an intermediate/balanced body control.
While the 2015 dampers will probably give you "tied down" body control!
The early and late 2014 dampers would probably fall between 2013 and 2015.
The KYB aftermarket dampers are less than half the price of Lexus OEM.
However, like you say, the KYB aftermarket only seems to have the "one" damper body control rate - which is said to be firmer than the OEM 2013 according to jgscott, but is it as firm as 2014 and especially the 2015 OEM?
The ECU ROM chip and software control of the valves inside the shock absorber?
For a start, my Luxury trim has softer software shock absorber computer mapping than the F Sport trim in Sports+ mode.
2013-15 vs 2016-20? I wouldn't be surprized if the original versions had firmer software mapping than the midlife update.
Too difficult for me to fiddle with the ECU because it controls the engine as well.
Both Luxury and F Sport trims in Normal mode:
Luxury trim in Sport+ mode:
F Sport trim in Sport+ mode:
Also remember that you have the 2018 F Sport which uses the 2016-20 body structure with twice as many laser weld points for greater torsional rigidity and bending stiffness, so this stiffer body structure will force the coil springs to compress more and be more compliant than the original 2013-14 body structure.
The 2015 body structure is a little more rigid than the original 2013-14 body structure thanks to special new adhesive used in the bonding of the front and rear windscreens.
I have both the OEM RWD 2015 front coils with 2013-15 RWD rear coils.
I retrofitted OEM RWD 2013-14 front coils.
The 2013-14 RWD front coils are "non-tapering", hence they are stiffest - far left photo below.
The 2015 RWD front coils have a tapering end, which enables the first 1/2-1.0" of compression to be more compliant - in the middle of the photo below.
According to my measurements, the 2013-14 RWD has the exact same thickness and axial height as the 2015 RWD front, however the 2015 has a progressive "tapered" finish for initial compliancy.
Interestingly, the 2013-15 RWD had rear coils with a "tapering" finish all along - right in the photo below.
In other words, the 2013 RWD started out with "constant" wire coils at the front, and "tapered/flat end" wire coils in the rear; by 2015, the 4GS RWD got "tapered/flat end" coils at the front too.
My original 2015 RWD OEM suspension handled "almost" like a compact sedan!
However, for me only - it was a tiring ride.
I'm looking for the firmest OEM set-up of springs and dampers. Basically, if I'm going to keep this car, it needs to be as OEM firm as possible. Let me know which dampers that would be. My 2018 has a production year of 03/2018. Looking at the graph, and given your experience with the 2015 RWD, I'm guessing the firmest AWD dampers would be: 48520-80443, 48510-80766 and 48530-80759. My last two cars were both Infiniti's... a Q50 Red Sport and G37x. Both of them felt like sports cars by comparison. I kick myself for not looking at 13-15 model year GS's, but who would've thought there this many differences throughout one generation? Also, given how soft the 2016-2020 models are (compared to 2013-2015) I wouldn't be surprised either if Lexus softened the ECM programming software too. There is another post her on CL where a member had traded in his 13-15 F-Sport for a 16-20 F-Sport (both AWD's) and noticed quite a bit of differences between the two--especially in suspension, handling and drive mode feel. Looking at the still pics you provided from the 2013 GS video, I wouldn't be surprised if my 2018 F-Sport has the 2013-2015 Luxury Sport+ setting.
I'm looking for the firmest OEM set-up of springs and dampers. Basically, if I'm going to keep this car, it needs to be as OEM firm as possible. Let me know which dampers that would be. My 2018 has a production year of 03/2018. Looking at the graph, and given your experience with the 2015 RWD, I'm guessing the firmest AWD dampers would be: 48520-80443, 48510-80766 and 48530-80759. My last two cars were both Infiniti's... a Q50 Red Sport and G37x. Both of them felt like sports cars by comparison. I kick myself for not looking at 13-15 model year GS's, but who would've thought there this many differences throughout one generation? Also, given how soft the 2016-2020 models are (compared to 2013-2015) I wouldn't be surprised either if Lexus softened the ECM programming software too. There is another post her on CL where a member had traded in his 13-15 F-Sport for a 16-20 F-Sport (both AWD's) and noticed quite a bit of differences between the two--especially in suspension, handling and drive mode feel. Looking at the still pics you provided from the 2013 GS video, I wouldn't be surprised if my 2018 F-Sport has the 2013-2015 Luxury Sport+ setting.
Yes, your guess regarding the 2015 AWD dampers being the firmest is about right.
Will be interesting to see how your car turns out after the retrofits.
I have a 2015 Luxury retrofitted with 2019-20 springs, and 2016-20 shock absorbers, plus 18" Series 45 downsized on soft touring Pirelli Cinturato P7's, though still on the original 2015 thinner front and rear roll bars - but somehow it still feels firmer than an OEM 2019-20 - so I have always suspected the 2019-20 OEM's have softer computer software mapping of the valve control in the shock absorbers.
Too hard for me to change the ECU's because the 2016-20 engines are slightly different.
However, the newer 2016-20 body structure with more laser weld points for greater torsional rigidity and bending stiffness will always force the springs to deform more for a softer ride.
I am also shocked that they changed the suspension settings this many times within one generation.
Normally, at most, they only change the suspension tuning once at midlife refresh.
Had I done my homework more thoroughly and test driven the vehicles longer and properly, I may have ended up bypassing 4GS for the softer riding ES350, however I don't like ES's long front overhang, and cheap plastics inside, plus so many grabs of the steering wheel to counter understeer.
Yes, your guess regarding the 2015 AWD dampers being the firmest is about right.
Will be interesting to see how your car turns out after the retrofits.
I have a 2015 Luxury retrofitted with 2019-20 springs, and 2016-20 shock absorbers, plus 18" Series 45 downsized on soft touring Pirelli Cinturato P7's, though still on the original 2015 thinner front and rear roll bars - but somehow it still feels firmer than an OEM 2019-20 - so I have always suspected the 2019-20 OEM's have softer computer software mapping of the valve control in the shock absorbers.
Too hard for me to change the ECU's because the 2016-20 engines are slightly different.
However, the newer 2016-20 body structure with more laser weld points for greater torsional rigidity and bending stiffness will always force the springs to deform more for a softer ride.
I am also shocked that they changed the suspension settings this many times within one generation.
Normally, at most, they only change the suspension tuning once at midlife refresh.
Had I done my homework more thoroughly and test driven the vehicles longer and properly, I may have ended up bypassing 4GS for the softer riding ES350, however I don't like ES's long front overhang, and cheap plastics inside, plus so many grabs of the steering wheel to counter understeer.
Thanks again Pete for all this excellent information. Since you indicate that the ride is still firmer vs. 16-20 models (even with 16-20 dampers on your 2015), is it feasible that all the differences between 13-20 simply comes down to springs and ECU software mapping? I’ve often thought about disconnecting my AVS altogether, removing the actuators and setting everything manually on the damper to the firmest setting and calling calling it a day.
Thanks again Pete for all this excellent information. Since you indicate that the ride is still firmer vs. 16-20 models (even with 16-20 dampers on your 2015), is it feasible that all the differences between 13-20 simply comes down to springs and ECU software mapping? I’ve often thought about disconnecting my AVS altogether, removing the actuators and setting everything manually on the damper to the firmest setting and calling calling it a day.
IMO, the final handling/ride will be the interplay between many factors including: body structure torsional rigidity/bending stiffness where a stiffer structure forces the coil springs to compress, spring rates for compliancy, shock absorber [damper] rates for the control of float to dissipate vertical oscillation energy, and roll bars where the stiffer the roll bar, the more the vehicle behaves like a non-independent beam/dead axle, and wheels and tires where smaller lighter wheels accelerate faster with superior fuel efficiency.
If we disconnect our AVS actuators, then the dampers will default to their firmest position.
IMO, the final handling/ride will be the interplay between many factors including: body structure torsional rigidity/bending stiffness where a stiffer structure forces the coil springs to compress, spring rates for compliancy, shock absorber [damper] rates for the control of float to dissipate vertical oscillation energy, and roll bars where the stiffer the roll bar, the more the vehicle behaves like a non-independent beam/dead axle, and wheels and tires where smaller lighter wheels accelerate faster with superior fuel efficiency.
If we disconnect our AVS actuators, then the dampers will default to their firmest position.
So if I simply disconnect the wire connector from the AVS actuators, (regardless of whether the vehicle is on or off) the dampers will go to their firmest mechanical setting? Or, does the vehicle have to be on or off when doing this? And/or in a particular drive mode? On the flip side, if I then reconnect the actuators, will the AVS system reinitialize the dampers correctly back to normal drive mode (as this is the default). I take it there isn’t a dedicated fuse for the AVS system that can be pulled to deactivate everything?
So if I simply disconnect the wire connector from the AVS actuators, (regardless of whether the vehicle is on or off) the dampers will go to their firmest mechanical setting? Or, does the vehicle have to be on or off when doing this? And/or in a particular drive mode? On the flip side, if I then reconnect the actuators, will the AVS system reinitialize the dampers correctly back to normal drive mode (as this is the default). I take it there isn’t a dedicated fuse for the AVS system that can be pulled to deactivate everything?
Best to have vehicle off, before disconnecting or reconnecting wiring.
I've never come across a dedicated fuse for the AVS.
Best to have vehicle off, before disconnecting or reconnecting wiring.
I've never come across a dedicated fuse for the AVS.
Thanks again Pete. There is still one thing I am confused about regarding this process. However, I may have just realized it as I was typing this post...
Let me ask you for confirmation: Do the dampers always default to their firmest mechanical setting when the vehicle is turned off?
Thanks again Pete. There is still one thing I am confused about regarding this process. However, I may have just realized it as I was typing this post...
Let me ask you for confirmation: Do the dampers always default to their firmest mechanical setting when the vehicle is turned off?
Probably.
Must connect laptop with Toyota TechStream software to OBD2 port under dashboard to really find out.
703 was expert at this, but he sold his GS450h.
Also, you can try disconnecting AVS actuators to find out yourself.
However, with the engine off, the shock absorber valve position is of no significance to actual driving.
Probably.
Must connect laptop with Toyota TechStream software to OBD2 port under dashboard to really find out.
703 was expert at this, but he sold his GS450h.
Also, you can try disconnecting AVS actuators to find out yourself.
However, the valve position with engine off is not ultimately significant.
Then again, maybe it always defaults to Normal (or Eco if shut off while in this mode). See screenshot below from another thread. I know ultimately I should just try it myself to know for sure. However, I’m not certain if I will need Lexus to reset everything once I reattach everything?
Then again, maybe it always defaults to Normal (or Eco if shut off while in this mode). See screenshot below from another thread. I know ultimately I should just try it myself to know for sure. However, I’m not certain if I will need Lexus to reset everything once I reattach everything?
Just try it yourself.
I am confident everything will go back to normal when reassembled correctly.
Some people did not fit the AVS actuators properly, so it was constantly on its stiffest body control setting.
If worse gets to worse, can always get Lexus to reassemble.
If you have a bidirectional scanner, you can initiate an active test. It should go from 1 to 17, skipping 2 steps. So 1, 3, 5 ..... 17.
I found the fuse, but haven't pulled it yet. I don't have a scanner. Is the 1 through 17 the steps for the damper progression from softest to firmest? Seems to me that if I pull the fuse with the car off, the dampers will stay at either Normal or Eco as those are the only two drive modes that remain when turning off the car, then back on again. However, if I leave the car on, put it into Sport+ mode, then pull the fuse, will it leave the dampers in it's firmest setting? Or, will the system assume the vehicle has been turned off and default back to Normal again?
I found the fuse, but haven't pulled it yet. I don't have a scanner. Is the 1 through 17 the steps for the damper progression from softest to firmest? Seems to me that if I pull the fuse with the car off, the dampers will stay at either Normal or Eco as those are the only two drive modes that remain when turning off the car, then back on again. However, if I leave the car on, put it into Sport+ mode, then pull the fuse, will it leave the dampers in it's firmest setting? Or, will the system assume the vehicle has been turned off and default back to Normal again?
The valve has 17-positions, but there is a "spring" against the valve, so that when there is no power, the spring returns the valve to its firmest default position for safety.
Hey Pete, question….Can you install AVS Front Struts on a Base Non-AVS model? I’m wondering if other than the module on top if there would be any actual differences/issues preventing from doing so. My logic is if possible, you would have manually adjustable struts.
Hi Charlie, you could most probably install AVS front struts to the base non-AVS model, however with possibly no electronic sensors and no AVS valve control wiring, the AVS struts will default to their firmest damping setting for a very controlled but tiring ride - caused by the return spring on the valve.
The AVS struts have an electromagnetic solenoid which progressively opens the shock absorber valving in 17-different positions for electronically variable damping rates, based on data input from speed, acceleration, deceleration, steering angle, Pitch, Roll and Heave etc, and the ECU's software mapping.
However, without any electrical signal from AVS wiring, the spring-loaded return valve will default to its firmest damper setting.
If you want manual adjustment to vary the single fixed damping rate, there are aftermarket shock absorbers with manually adjustable valving via a screwdriver.
The last time I drove a 2013 non-AVS with a 2013 AVS back-to-back, was back in 2012-13; some 11-12 years ago.
The non-AVS damping was too firm for me, with too much body control, resulting in a hi frequency of vertical oscillations, which handled well, but it was tiring.
The Luxury fitted with AVS had a much more pleasant ride, with less body control and more float - for a lower frequency of vertical oscillations, which was less tiring, but the AVS version would automatically firm up with speed, acceleration, deceleration and lateral acceleration input.
The AVS version would also manually firm up if the Sport+ mode was selected.
01-17-24, 03:54 PM
