Pics & Review of My Bilstein PSS10 Lowered Red Turbo

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#361

06-30-2013, 05:23 PM

cannga

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Quote:

Originally Posted by cannga

BTW, does anyone ever wonder, and has an answer, as to *why* more negative camber results in better traction during cornering? Hint: it has to do with maintaining max contact patch/traction on the outside wheel during cornering. IOW, when you turn left, you want max traction on the right wheel. But why and how?

Ok, I could feel the anticipation exploding

. Following is what I think is the answer; any expert feel free to correct as needed. Although it is common knowledge that negative camber is beneficial for cornering, my problem is I kept asking why. Why is it so? I looked for this information for a long time and finally found it in this book

Stock Car Driving Techniques, Don Alexander

.

First an important basic concept: when you make say a left turn, the left wheel (inside wheel) lifts and loses traction as this side of car lifts up, and the right wheel (outside wheel) gains traction as this side of car is compressed. This is a result of centripetal force causing left to right weight transfer. Traction of the outside wheel (right wheel in this case) is therefore of paramount importance in a turn. It's the one doing a lot of the steering as it is the one with the best contact patch.

And here is the key to the answer, in most front suspension systems, the wheel gains positive camber as it undergoes compression travel. In other words, as you turn, the outside wheel is compressed AND, because of the positive camber gain, starts to tilt outwards. As it tilts outwards, it is no longer parallel to road surface, and therefore loses contact patch area, and therefore loses traction. To counteract this, you pre-set the wheel with negative camber, so that during a turn, the preset negative camber cancels out the positive camber gain of the outside wheel to keep it parallel to road surface, and maintain full road contact and traction. I hope I am making some sense here LOL.
Of course, as in ALL suspension matters, there is a trade-off. Excessive preset negative camber is bad for straightline traction and braking. So for the track, high negative camber is beneficial, while for straightline racing, such as drag racing and racing for best 60-130 times, less negative camber (and less toe-in or toe-out, you want the wheel *straight*) is desirable.

Last edited by cannga; 07-16-2013 at 11:16 AM.

#362

07-01-2013, 09:26 AM

sanham

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Quote:

Originally Posted by cannga

Hi Tom, sure, I sit a little higher too for comfort and just so I could see, but since I saw his comment, I did lower my seat.
Interesting point from a pro, isn't it?

CANNGA: I read somewhere in this biiiiiig and very interesting thread, that the 997 have a litle "dancing" (or side movement) from the rear when going out from some curves and you said that it could be solved whith the drop links...Am I right?
can I use the front and rear drop links with the original sway bars and It will be solved? or you recomend to change allso the sway bars

thanks for your comments

#363

07-01-2013, 03:11 PM

sanham

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eiback sways...

CAnnga: i wrote to the people at eibach and they said that this are their stifnes rankings VS OEM, just to let you know, because in their web page there´s no info.

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· La barra trasera es 22mm diámetro, 3 puntos ajustables, el porcentaje de dureza contra el original es +24%, +62%, +95%."

So the first is for the front and the second for the rear, I know you like GMG, this is just to compare one VS the other...

#364

07-01-2013, 08:05 PM

cannga

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Quote:

Originally Posted by sanham

CAnnga: i wrote to the people at eibach and they said that this are their stifnes rankings VS OEM, just to let you know, because in their web page there´s no info.

· "La barra delantera es 25mm diámetro, 3 puntos ajustables, el porcentaje de dureza contra el original es +77%,+92%, +117%. (REAR)
· La barra trasera es 22mm diámetro, 3 puntos ajustables, el porcentaje de dureza contra el original es +24%, +62%, +95%." (FRONT)
So the first is for the front and the second for the rear, I know you like GMG, this is just to compare one VS the other...

Wow I love this data - thanks. Very interesting comparison to GMG:

GMG Front Sway: 3 settings: soft, medium, stiff. The front settings are 15%, 25%, and 35% stiffer than stock.
GMG Rear Sway: 3 settings: soft, medium, stiff. The rear settings are 30%, 45%, 60% stiffer than stock.

From previous postings, I believe most GMG users use the 15% and 25% for front, and the 45% or 60% for rear (in other words, soft front/medium rear AND medium front/stiff rear). In theory, this would make Eibach bar quite a bit stiffer; in reality, I have no idea how it compares since not many people have used it and give a detailred report on it.
I'll respond to your other question later regarding which component decreases the rear shake the most, it is an interesting choice to make.

Last edited by cannga; 07-01-2013 at 08:14 PM.

#365

07-01-2013, 09:08 PM

TT Surgeon

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Those eilbach numbers can't be right, that's stiffer than a cup car.

#366

07-02-2013, 11:11 AM

cannga

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^^^Chris, yes it does seem high but I hesitated to comment because I am not sure who is right as far as the numbers, or if they use same standard of measurement. A few years ago Vivid Racing also released the spec from their rear one on a discussion here (not on their web site), and I remember that it was also something in the 100 plus % also, similar to those Eibach number IIRC.

The only way to find out is to test them on our car back to back, and unfortunately that is not going to happen anytime soon.

#367

07-02-2013, 11:15 AM

cannga

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Suspension Mods Overview:
Suspension mod is easier to understand if you categorize the modifications. Then all of sudden, things will seem so simple ;-) and not so intimidating. I will arbitrarily create 4 categories:
1. Stiffer springs: this is the single most important mod in the Turbo and will transform the car. It is accomplished by using lowering springs (I prefer coilover but lowering springs are simpler, less costly, and also work well) or using coilover (springs + shock absorber) such as those made by Bilstein or KW/JRZ/Moton/etc. Positives: Stiffer and lower are almost always better in a sports car: less weight transfer (lower), less body roll (sitffer), less dive and squat, more precise response. Negatives: Ride versus handling trade-off is forever present - the law of physics. As handling improves, ride will suffer. For street driving, don't use Moton or JRZ because they are too stiff, KW is also on stiff side.
2. Alignment: involves toe, caster, camber. For all practical purposes, all you need to worry about in the Turbo is to increase front negative camber. Stock is -.8 or whatever, you want to increase this to minus 1.2 or so (the max possible). Positives: Negative camber increases cornering force/traction of the tire (allows you to corner faster), decreases understeer which is an inherent problem with AWD 997.1 Turbo (complicated, pls just trust me this is the case). Negatives: Excessive & uneven tire wear and straight-line traction/acceleration could be affected adversely if over-done.
3. Stiffer "other" components: This would fall into 2 categories:
A. Sway bar: used to fine tune the system, in particular the understeer/oversteer behavior. After market sway bars are not only stiffer, they have adjustable stiffness. In the AWD Turbo with inherent understeer trait, the recommended setting is soft front, stiff rear, to decrease understeer. Note that sway bar on stiff setting could have major effect on the comfort of your ride (very un-comfortable). Positives: Decrease body roll, adjust understeer/oversteer, stiffer front sway bar makes steering firmer and feel more precise. Negatives: Decreases ride comfort.
B. After market suspension links that use solid metallic bushing/joint, in place of stock rubber/neoprene bushing/joint. The links include rear upper links (dog bones), toe control link, thrust arm bushing, front camber plate, drop links, etc. Positives: Solid links increase precision and make cars feel more "planted"/precise. Negatives: Increase noise, vibration, harshness, some more than others. Also, these are wear-and-tear items and need to be checked periodically and replaced when the joints become loose (metallic joints/links don't last as long as rubber/neoprene joints/links).
4. Tires: Don't under-estimate this major component of suspension system, and never race another car that has superior tires! This means: R compound tires such as Michelin Cup or Pirelli Corsa. Positives: have inherent advantages: stickier rubber, stiffer wall. Negatives: Dangerous on wet roads (no traction, aqua-plane), takes time to warm up, noisy & stiff especially when old.

Last edited by cannga; 07-16-2013 at 11:35 AM.

#368

07-02-2013, 11:27 AM

cannga

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Quote:

Originally Posted by sanham

CANNGA: I read somewhere in this biiiiiig and very interesting thread, that the 997 have a litle "dancing" (or side movement) from the rear when going out from some curves and you said that it could be solved whith the drop links...Am I right?
can I use the front and rear drop links with the original sway bars and It will be solved? or you recomend to change allso the sway bars

thanks for your comments

sanham, the key to this thread is page 1 with the summary and index; I went into rambling monologue mode

somewhere along the line but everything that is important is on page 1, for example the suspension overview I repost above (posted here because it's relevant to my answer below).

Ok back to your question,
1. Please remember my observation of drop link reducing extraneous rear motion of Turbo was made with a car with Bilstein and GMG sway bars on board (in other words a stiffer car than your stock), whether the same thing applies to your stock car I don't know. Yes it will stiffen the stock bar, but I don't know how much it will affect the extra motion.
2. The drop link increases the effectiveness of the sway bar, and will make stock sway feels stiffer, but it's not a replacement for a proper set of sway bar. So the answer is yes I would recommend stiffer sway bars as well.
3. Besides the drop link, other after-market components that use heim joint instead of plastic/rubber bushings will control the rear motion of the Turbo, such as rear toe link (which I don't have but is very highly recommended by tuners).
4. That said, if you are looking for a transformation of the driving experience, and cost is an issue, then my vote for the first component to be changed is actually for stiffer springs (whether lowering springs such as GMG or Techart, or coilover such as Bilstein), second, sway bar, and last drop link. IMHO, the springs (and tires) are the heart and soul of the suspension system; they control weight transfer (body roll), a key parameter of suspension tuning. Subjectively this is what makes a sports car feels like a sports car; objectively the reduction in weight transfer makes you faster in a corner. So change springs first, then fine tune with sway bar, then other components (drop link, rear toe link, etc.) are used primarily to further control unwanted motion of the car, and yet more components to increase camber (lower control arm and camber plate). All at the cost of some degree of comfort of course.

Last edited by cannga; 07-02-2013 at 01:09 PM.

#369

07-02-2013, 03:06 PM

E55AMG

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Can, have you ever taken all of this knowledge you've gained, and put your car on the track?

I seem to remember you saying you don't track. Putting in on the track will give you a much deeper appreciation of what your car can and can't do, and will give you an even better understanding of all things suspension.

So what do you say, why don't you go out and REALLY push that car!?

#370

07-02-2013, 07:32 PM

cannga

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Latest shot of my baby :-), background is Southern Cal coast line:

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#371

07-11-2013, 05:41 AM

WaltB

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Cannga,

Lots of great information here. You helped me formulate my next modification. Damtronics and H&R sways. Should get them on in the next few weeks. Looking forward to the improved handling.

Thanks for all you advise!

Walt

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#372

07-12-2013, 10:14 AM

cannga

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Quote:

Originally Posted by WaltB

Cannga,
Lots of great information here. You helped me formulate my next modification. Damtronics and H&R sways. Should get them on in the next few weeks. Looking forward to the improved handling.
Thanks for all you advise!
Walt

First, wow! I love those wheels and very nice picture. Gunmetal + gorgeous wheel + yellow brake + black car = stupendous. I even like the red accent of the center lock. What OZ wheels are these? Among my most favorites, and very light too right?

Yes it is a guarantee that Bilstein + sway bar will be a total transformation from the stock handling and will allow you to compete with those #@!!~@# GT3 in the curves a lot better :-). This combination is a known entity so there will be no surprise.

You got the Bilstein from an authorized dealer right? And installer is a seasoned veteran, not a first timer in training or anything like that? Good luck and have fun!

Last edited by cannga; 07-12-2013 at 10:20 AM.

#373

07-12-2013, 04:07 PM

WaltB

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Can,

They are Superforgiata with 325/245 Pirelli Trofeo tires. A very nice combination. With the Sportec tune and with my Turbo S PDK in sport + mode the car is amazingly fast. Not much can touch it in the straights so I thought after reading your thread it was time to improve the corners.

The Damptronics are from AWE and the H&R sways are from ESC tuning. Both had prices I could not turn down. The install will be done by a veteran so no worries there.

Walt

#374

07-14-2013, 10:22 AM

cannga

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Quote:

Originally Posted by WaltB

With the Sportec tune and with my Turbo S PDK in sport + mode the car is amazingly fast. Not much can touch it in the straights so I thought after reading your thread it was time to improve the corners.

The Damptronics are from AWE and the H&R sways are from ESC tuning. Both had prices I could not turn down. The install will be done by a veteran so no worries there.

Walt, tuned Turbo S with PDK, R comp tire, and now Bilstein, you don't plan to take prisoners do you?

I agree that straights or curves, not many will pass this car. Congrats on a great and very fast car and drive safely.
PS I do like very much the refined simplicity of the Superforgiata. The spokes are so elegantly thin.

Not for Walt of course, but for those new to this: the tire is a part of the suspension system, in fact a critical part. it is a great equalizer and if you ever want to race a GT3, especially in a road course with tight corners, don't ever use street tire! A switch to R comp is a must.

There is this concept of tire matching spring stiffness. In other words, if you put R comp (a tire with very stiff sidewall) on a soft suspension like stock Turbo, it's not ideal because the system is only as strong as the weakest link. Because the R comp has so much more traction, you will carry more speed through a corner. Problem is the soft spring will then have too much compression travel (as a result of the higher cornering speed) and causes body roll. Stiff tire likes stiff springs.
Conversely, changing to a stiff spring system such as JRZ while keeping street tire is not good either. Here, the tire will cause the body roll as sidewall rolls on its shoulder in a high speed corner. Stiff spring likes stiff tire.

In other words, in Walt's car, the stiffer Bilstein is a better match for the stiffer Trofeo R comp tire, than the soft stock suspension. Walter Rorhl talked about this concept during the prep of the GT3 he was going to race.

Last edited by cannga; 07-20-2013 at 09:21 PM.

#375

07-16-2013, 09:25 AM

cannga

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I was asked in PM about famous Mulholland Drive for a leisure Porsche drive in Southern Cal and thought I should share my ideas here in case others are interested.

Fabled Mulholland Drive is actually not my favorite as it is frequently relatively crowded with other drivers. There are many officers eager to hand out tickets, especially on weekends. You are almost guaranteed to get a ticket for speeding here on weekends. Because it is mostly mountain and canyon roads, one has to be careful of blind spots and of other drivers.
The only good things about Mulholland Dr is the scenery is absolutely spectacular (you look down on Malibu and the Pacific Ocean at times), and of course, the name. You like to drive through just so to see the setting for those storied Mulholland road races in the 60's. There were 911's made specifically to race Mulholland back then (stiff as helll, low, wide track, etc.).

My favorite road course in Southern Cal is actually the Lake Hughes area. On a weekday it is deserted; even on weekend it is mostly empty once you are out there around the Antelope Valley California Poppy Reserve (worth a visit in blooming season!!) area. This type of road course, combination mountain/canyon/desert, is what makes California fantastic for Porsche owners.

The drive below is from a PCA drive that we organized in the past. I love this course because it is a combination of twisty canyon roads (careful, canyon roads mean blind corners) and wide open desert roads with great vision ahead. On a weekday particularly the northern 2/3 end of the loop, you are going to be all by yourself for miles around. If I get out from work early and would like to enjoy the scenery, this is where I drive, by myself mostly (don't like convoy) and always safely and within the legal limits of course. Anyone else has any favorite road, you are welcome to post your map here.

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Last edited by cannga; 07-16-2013 at 11:27 AM.