Dampers

 I have a favorite bumpy road that I enjoy "loping" over.  Due to it's gentle undulations and pretty uneven pavement, it's is a great place to evaluate a car's suspension.

A long time ago, I was obsessed with making the 911 more capable on the track.  I spent many a track day at Blackhawk Farms, particularly enjoying coming out of Turn 3, a third-gear "carousel corner" that leads into a hard braking zone and a quick second-gear right-left combination. Going into Turn 4, I got feedback from other track day participants that my inside front wheel was off the ground.  The stock suspension was surprisingly soft, and when compressed with the throttle on in second gear, the inside tire would float.

That didn't seem like a good idea to me, so I made a couple of modifications to the car in pursuit of more traction.  The stock 16" wheels were 6 inches wide at the front and 8 inches wide at the back, with 205 and 225 series tires, respectively.  I replaced them with 17" Fikse  FM5s, 8 inches wide in front and 9.5 inches wide at the back, wearing 225 and 255 series tires.  The increased contact patch definitely helped with turn in!

The other thing I did was replace the stock springs with sport springs from H&R.  These are the somewhat well-known "green springs," which you can see here:

The combination of the wider wheels, stiffer springs, and track tires solved the "cornering on three wheels" phenomenon.

Anyway, that's more words than necessary to say that the suspension on the 911 isn't stock.  It's certainly stiffer than stock, and the springs lowered the car and got rid of what I thought to be excessive wheel gap.  I don't find it punishing, but it is stiffer.

My "take the kids to school" route includes my favorite bumpy road section.  Moving briskly, the 911 moves about a bit on the bumps.  While it never feels dangerous, the car feels very lively beneath me.  In the spirit of evaluating suspension compliance, I decided to drive the Boxster over the same road.

The difference is immediately noticeable.  The Boxster feels planted and secure, despite riding on 19" wheels to the 911's 17" setup.  You hear the bumps, but the car doesn't move around in the same way the 911 does.  Beyond the stock suspension, perhaps the longer wheelbase helps?

I then took the GLI over the same stretch of road.  On its stock 18" wheels, the car just soaks up the bumps, similar to the Boxster.  

I'm looking forward to doing a couple of passes on that road in my brother's Spyder RS, first in normal, then in sport, to see how it deals with this stretch of road.

It kind of reminds me of when I first adjusted the suspension on the FJR.  Stock, it hammered me on rough roads.  Adjusting the suspension per the recommendations in Sport Rider magazine transformed the motorcycle, soaking up bumpy roads while remaining stable in corners.

I continue to be impressed by passive suspension systems that smooth out the bumps while providing good body control in the twisties.