Pics & Review of My Bilstein PSS10 Lowered Red Turbo by cannga

4 minute(s) of a 612 minute read

2-16-2009

Mike, would you please check the unit of your toe settting? It could be in degree, minute, or distance -- which itself could be in inches or mm. For example my front toe out setting is minus 0.02 degree, or 1.2 minute, which would make it exactly like what you are writing here. My rear toe-in is positive 0.14 degree, or 8.4 minutes (this is same as stock).

BTW, the following is a conversion formula and a table for a car with 25.5" wheel, which just happens to be about the same as our Turbo's wheels: http://www.ground-control.com/toe-out.htm

Toe-Out Data For One Tire With A Diameter of 25.5 Inches 

THIS IS "PER SIDE", multiply by "2" for TOTAL TOE 

Fraction Inches Minutes Degrees mm 

1/32 0.03125 4.21292 0.070215 0.8 

1/16 0.06250 8.42586 0.140431 1.5 

3/32 0.09375 12.6388 0.210647 2.4 

1/8 0.12500 16.8518 0.280863 3.1 

5/32 0.15625 21.0647 0.351079 3.9 

3/16 0.18750 25.2778 0.421296 4.7 

7/32 0.21875 29.4908 0.491514 5.5 

1/4 0.25000 33.7039 0.561732 6.4

(I once again must remind fellow sports car fans that with stiffer coilover and alignment changes of front neg camber and slight toe-out, the Turbo is transformed into something much closer to GT2's behavior. Night and day more fun and aggressive. My next experiment: cup tires! Review to come when it stops raining here in Southern Cal.)

BTW, minor correction to above: 1 degree = 60 minutes (not second). 1 minute of course = 60 seconds. 

Also, btw the table I have above has some mislabeling itself, minute is one apostrophe, not 2, that's second. If I don't make any sense at all, I understand.   I posted the conversion table/formula because sometimes toe setting is given in inches/mm, and you need that to convert angle to distance.

3-9-2009

Updating pictures, now with TechArt front spoiler.

All you need to know about springs -- just kidding, only some basic amateur level info here; any expert feel free to correct or add as needed. 

First the picture: left is Bilstein coilover, right is the TechArt spring. Both are for the rear and come from eclou's excellent thread on Bilstein installation. BTW, this thread was (is?) for a long time the first thing that comes up when you google something like "Porsche Bilstein PSS10". 

Note that the TechArt spring is progressive: You could tell by the variable distances between the coils. A progressive spring has two rates, an initial one which is soft, and a final one which is stiffer. This allows a soft and more comfortable rate at first and then a change to a second rate that is stiffer. 

I don't want to make this too complicated so I'll stop here but actually there is a further differentiation into step linear spring versus progressive spring. If interested you could read about it here: http://www.tuninglinx.com/html/suspension-springs.html

The Bilstein has 2 stacked springs, a main spring and a second, smaller one. The main spring is linear -- one rate only. The main spring of the Bilstein is of "standard" size and therefore allows you to switch and experiment with different springs and rates easily; replacement springs don't have to be Bilstein. It's a controversial topic, but linear springs are more likely to be found in track applications; google "linear progressive spring" to find out more.

The second spring of the Bisltein is called the Helper Spring. It is fully compressed once installed and therefore does not contribute to the spring rate. The spring rate of the 2 stacked springs is in effect that of the main linear spring.

So if the Helper Spring is fully compressed, why do we need it at all? It's there to hold the main spring in place (its seat) during full extension of the coilover -- think airborne as an extreme example. This prevents the spring from making noise when you're having fun (er yes I think airborne = having fun ).

What does this all mean in real life terms? If you were to compare the responses of progressive TechArt to linear Bilstein, it's very possible that the TechArt will take street obstacles a little softer/better. The disadvantage of the TechArt is that it would lean/squat/dive more than the Bilstein for the same reason, and that its response is non-linear, which could be good or bad depending on whom you are talking to.