DAMPENING (damping) FORCE ADJUSTMENT

This has nothing to do with the plug and play Bilstein Damptronic, but it's a good chart and good read so I'll repost it here. Sorry it's been a while so I don't have the link where I got this algorithm (for a coilover with independent bump/rebound adjustment), but it is from Bilstein and I will post it here as an example of how complicated suspension tuning is. It illustrates the points above, that bump and rebound (obviously) interact, and more importantly, front AND rear interact to influence understeer/oversteer behavior. Pro's will do this in their sleep, but for us amateurs, it could be a hopeless quagmire.

Take the rebound setting for example, say it has a scale of 1 to 10, 1 being softest. 1 will make the car soft and mushy, 10 will make the car lose traction over bumpy surfaces, somewhere in between there is a setting that will result in "best" traction, and it would be up to your setup person to find this sweet spot for you. Note that the point of max traction doesn't frequently coincide with the point of max comfort - another decision for you to make.

This is the reason that IMHO for the majority of amateur drivers, the plug and play Bilstein B16 Damptronic is a much better solution than manual-setting coilover such as Bilstein B16 PSS10. The pros have done the dirty work for you when you have the Damptronic. The best analogy is that when my wife needs to take a picture, I give her the small Point-and-Shoot Panasonic camera, and not my Canon 1D DSLR with the manual Contax-Zeiss lens. Complexity in the wrong hands tend to cause complex complications! :-)




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cangga, your car is beautiful. What wheels are those?

 

Excellent write up, very much appreciated and amazing level of detail. Been researching various lowering options and this thread has been very helpful

I spoke with two independent well known shops here in northern california today regarding coilovers (bilstein pss10 in particular) vs lowering springs. One of them told me they won't install anymore coilovers on 997 TTs due to the drop link issue with the Bilsteins. Specifically the fact that the drop links are not designed well and have shown significant wear over time including breakage

The second shop said they would install Bilsteins but only with separate aftermarket drop links due to the poor design and wear of the drop links that come with the PSS10 set.

These were unsolicited independent comments, I made no mention of any concerns, these shops shared these concerns completely on their own.

Informative comments are welcome
Art

 

The drop links have been redesigned but they are still not adjustable like the Tarrett ones. I would recommend going for the Tarrett Engineering drop links. That's what I'm getting this winter after BBK.

 

Hello,

I love the stance of your car, but you mention that you had to increase your camber from about -0.8 degrees to -1.1. Do you know how much faster you are going through a set of tires? If you normally get around 8K miles per set is it down to 5K or 3K? Thank you

Chris AK

 

Hi, thanks. The wheel is HRE P40, silver finish. I bought them from Wheel Enhancement, who also took my old OEM wheels as trade-in.
http://www.wheelenhancement.com/inde...lDetail&id=204

Hi Chris, minus 1.1 front camber is still fairly conservative (note that the factory-set rear camber is more, at minus 1.6) and does NOT seem to affect tire wear much at all in my car. The wear of my front tire is even across the tire on visual inspection. For example, the Michelin PSS that I have right now just seems to last forever; somewhat of a bad thing :-) because I would like for them to wear out so I could try Bridgestone RE-11 next (just for fun and experimentation - I am happy with PSS, although the sidewall is on the soft side and therefore car rolls a little more than I would like).

Increasing front negative camber is one of the most effective and cheapest ways to increase front cornering force and decrease understeer in our 4WD Turbo (which inherently has a tendency to understeer because of the 4WD). Every Turbo should have left the factory this way; try it, IMHO you *will* appreciate the change.

 

Ok. Thank you for the feedback Cangga. Beautiful Car / Wheel / PCCB / Stance Combo

 

Hi Art, thanks for the nice words and you're welcome.

1. The first version of Bilstein Damptronic was released around 2008. Many people have used the end link of first version without any problem whatsoever. My car's Bilstein is living proof: no wear, no break, no problem for 4 years.
2. A few people (very few - on this forum I would say maybe 3-4 per informal statistic, no flame pls if not accurate) had problems with the front Bilstein drop link: the front link would pop out of its socket. This was determined to be most likely, if not near certainly, to be due to the drop link being installed on the wrong side of the sway bar. In other words, installation error. Hard to understand this without a picture - I'll post the pic later. Since this correction was implemented, I don't recall seeing problem anymore.
3. Around 2011 (?) Bilstein then released the second version of Bilstein Damptronic, which AFAIK is identical to first one, except the front drop link has curves, instead of a straight bar like the first one. (Both version of Bilstein use the stock link in the rear.)
4. The bushing of the Bilstein drop link, while not as robust as an aftermarket or older unit, is identical to the OEM Porsche link. The reason is that Bilstein makes the OEM suspension also. So if it doesn't wear out on an OEM car, then there is no reason it should wear out on a Bilstein car, **unless** there are other factors involved.

Ok so how do we reconcile 1 to 4? I don't know. If the original link is bad, why are there cars running with them without any problem, for many years now? I suspect (but not sure) that it has to do with **other factors**: what after-market sway bar is used, how much lower the car is dropped. For example, IMHO, if you drop the car too much and use after-market sway, the 3D geometry of the suspension system is altered such that the links no longer point in the direction they are supposed to, and forces are exerted sideway instead of straight on, etc.
That said, I agree that after market drop link with metallic heim joint (as opposed to stock and Bilstein with rubber bushing), such as Tarett's, is an excellent addition. Replacement of rubber bushing with metallic heim joint makes the car feels more planted and less rubbery and the rear end has a lot less vertical and lateral "movement." (I've done A/B comparison of metallic vs. rubber drop links many times; the difference is as clear as night and day.). While many companies make these links, Tarett has been around forever, has impeccable reputation, and its prices are so cheap that it remains my first choice. I would buy the Tarett links and give them to the second shop that you mentioned. Good luck and have fun. http://www.tarett.com/items/996-997-products/996-997-suspension/996-997-swaybars~drop-links/996-986-front-drop-link-set-996fdlnk-detail.htm

 

As promised, picture of correct placement of front drop link - outboard. As mentioned above, if you put the drop link on the wrong side of the sway bar (inboard), it will pop out. Even very experienced techs are known to make this error - so you might want to print this picture and "gently" :-) remind your tuner of the proper installation.

BTW, the picture is not of the original Bilstein drop link with polyurethane bushing, but a Tarett after-market link with metallic heim joint. Nevertheless, the principle is the same: **outboard**. You can find the beautiful Tarett drop llinks and other yummy suspension components here : http://www.tarett.com/items/996-997-products/996-997-suspension/996-997-swaybars~drop-links/list.htm. The link makes the car feel more planted and precise, particularly the rear, which likes to mambo LOL a lot in comparsion to GT3/GT2 and the likes. You will feel the difference.

 

nice

 

FYI regarding droplinks, per Bilstein non Bilstein droplinks voids the warranty. Here's a link with a pic of my car, driver side coilover with the redesigned OEM droplink correctly installed. This picture was sent to Bilstein and correct installation was verified by their technicians.
https://www.6speedonline.com/forums/...-question.html

 

Bilstein schematic
<a href="http://s1120.beta.photobucket.com/user/dk10438/media/doc04118720120104103724.jpg.html" target="_blank"><img src="http://i1120.photobucket.com/albums/l487/dk10438/doc04118720120104103724.jpg" border="0" alt="Photobucket"/></a>

Correct installation

<a href="http://s1120.beta.photobucket.com/user/dk10438/media/IMG_0291_zps9c181385.jpg.html" target="_blank"><img src="http://i1120.photobucket.com/albums/l487/dk10438/IMG_0291_zps9c181385.jpg" border="0" alt="Photobucket"/></a>

 

I recently had a Panamera for a few days and would like to add some comments on this latest generation of PASM. In case you are not familiar with PASM, it's Porsche talk for its electronic damper, in which the overall stiffness of the suspension is altered by a button that controls the damping force. This button opens or closes a valve in the damper (aka shock absorber) electronically: In one position (valve closed) the dampening factor is high (stiff), in another position (valve open) the dampening factor is low (soft). Voila, stiffness is changed not by changing spring (the conventional way), but by changing damping factor, a convenient short-cut.

The first generation of PASM (in 997 C2S, Turbo, and GT2) all share something in common: the Normal position is very soft (particularly in the Turbo, not GT2) causing a lot of leaning and a feeling of ponderous, while the stiff position is extremely stiff and jittery. In other words it goes from 1 to 10, with nothing in between. Porsche was aware of this criticism and 997.2 Turbo suspension system was indeed better. The stiff setting was much less jittery, much more useable. However, it was still a 2 level-change: soft or stiff. I've always wondered about a mid level in between.

With the Panamera, lo and behold: 3 settings of PASM! In addition, they have fine tuned the system *extremely* well. I am not a particular fan of electronic PASM but I have to say that I was very impressed with this latest generation. All 3 very useable, and the change is just right. It's a different car, a different suspension but I think this bodes well for 991 indeed.

 

Nice write up and information.

 

Reserved.