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Limited Slip Diff recommendations for 986 Boxster S?

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I'm contemplating a winter drivetrain upgrade, including new clutch, flywheel, IMS, and while I'm in there, possibly a limited slip diff such as Guard, Quaife, Wavetrac. Car sees a number of DE dates each year, as well as aggressive street driving - just trying to find a way to put down more power in tight turns, etc. Wonder if any of the track rats here have gone this route? Experienced opinions greatly appreciated!

Car is a 2001 986 S, with ROW 030 sport suspension (part of original PPBB group buy back in 2002!), FBO engine mods, etc.

- JohnL
Boston
... if it was a dedicated track car, I'd say go with Guard or Quaife.
But for a street car that sees the track I'd say that you'd be better off by replacing the M030 with a set of PSS9s.
I originally ordered my car with M030 and had it for 150,000 miles.
Then I installed the PSS9s and wow!
My lap times at Sebring dropped like a rock. I was running almost 10 seconds faster with PSS9s than with M030.
No LSD will get you that much time per lap.
Happy Boxstering,
Pedro

Pedro Bonilla 1998 Boxster 986 - 284,000+ miles: http://www.PedrosGarage.com
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna
Re: Hi John...
jlegelis - 7 months ago
10 seconds?? That's crazy talk. What are they like in on the street compared to the 030? If you remember I'm up in Boston area where the roads are pretty poor....

May just have decided on my xmas present! the finger smiley
The beauty of the PSS9s is that the damping is adjustable.
For daily driving you set them on "9" which is the softest.
On a flat, fast track you set them on "1" which is hardest.
When I drive Sebring I set the fronts at 3 and the rears at 8. It's a very bumpy track.
When I drive Homestead I set the fronts and rears at 1. It's a very smooth track.

PSS9s on softest setting feel like M030 suspension.
Happy Boxstering,
Pedro

Pedro Bonilla 1998 Boxster 986 - 284,000+ miles: http://www.PedrosGarage.com
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna
I have M030 as my street setup in my 2004 base. I have PSS9s (with all the rubber) in my track car (2000S). Even on full soft, the PSS9s can be abusive on really, really bad roads. On normal roads they are great. I cruise 535 miles to VIR or 480 to Mid Ohio in complete comfort. But on the elevated, decrepit highways snaking into Hoboken NJ and NYC, i have actually had impacts that caused small parts to fall off the car (heat shielding in the engine compartment).

So its all a matter of degree. i am also very tolerant of a stiff ride; i have coilovers and -2deg camber in my station wagon (and love it).

So the question is: how much track?

G

Grant gee-lenahan-at-vee-eff-email-dot-net
Alright - thx all - looks like I've got some suspension research to do first! Thx!
I'm autocrossing my '03 S and having a hoot. I do it with a couple of the local PCA regions and mostly with nearby SCCA regions. All within an hour of my house. I'm getting better every time out. I work hard and took an instructor with me about 50% of the time the first 10-12 autocrosses. I've gone to 16 autocrosses. I changed from 17" to 18" wheels (8" front, 10" rear) and Bridgestone RE-71R's. In my class are the ND Miata's and the Ford FRS with the sport suspension. I'm catching/passing the middle of the pack Miatas but still a couple seconds behind the front runners. I'm not looking to be a solo national champ I just want those pesky Miatas to know they shouldn't make a lot of mistakes.

I plan on attending one or two EVO driver schools in the spring. I'm also considering suspension upgrades. I'd like to stay in C-Street with SCCA.

Here is my question:
Should I uprade to the M030 suspension and go with a GT3 swaybar (the rules state you can change one swaybar to non-OEM) or can I, within the rules, go to PSS9's or some other suspension?

Here is the rule section for shock absorbers:

The make of shock absorbers, struts, and strut housings may be substituted providing that the number, type (e.g., tube, lever, etc.), system of attachment and attachment points are not altered, except as noted below.
The interchange of gas and hydraulic shocks absorbers is permitted. The following restrictions apply:
1. No more than 2 (two) separate external shock damping adjustment controls are allowed. This permits the use of shocks which originally came with more than two external adjustments, which have been converted to double-adjustables, only if the additional adjustment controls have been permanently disabled (e.g., via welding, epoxying, grinding off).
Gas pressure adjustment is not considered a damping adjustment.
2. Suspension geometry and alignment capability, not including ride height, may not be altered by the substitution of alternate shock absorbers. Aftermarket strut housings are allowed provided that they meet the Street category shock requirements defined herein (i.e., that no suspension geometry changes result). This includes the position of the steering arm attachment point in the case of struts with integrated steering arms.
I did some research, and finalized on the Geiken; primarily because; 1. it has a good rep for reliability/durability and many DO NOT. 2. It has good decel lockup as well, important for stable trail-braking etc.

Its really nice. That said, I agree with Pedro - getting setup and suspension right is #1. At the limit its hard to put down full power anyway!

especially for the street it may be worth looking at a Torsen -derived unit - less clanks, bumps, better durability, less inadvertent lockup on tight turns.

I also like my PSS9s, but getting alignment and setup right is just as/more important.

G

Grant gee-lenahan-at-vee-eff-email-dot-net
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