Ride height

[truegearhead]

Is the spec Boxster ride height considered the lowest desirable ride height or are some of you running lower setups?

[itsnotanova]

From what I understand, the 986 doesn't handle better the lower you go. 1-2 inches is max I believe

[steved0x]

From what I've seen from Brad Roberts and others, the fastest spec Boxsters don't run at the minimum allowed heights. Search for threads by insite, lap1doug, thstone, and some others about suspension geometry, control.arm angles, etc... To [poorly] summarize, when you get too low, the angle of the lca passes horizontal and makes for really bad camber curves and bad strut geometry. [I said poorly summarized ]

Edit: What he said below

[The Radium King]

here's an image of boxster suspension:



here is the same shot from the side:



ignore the drop links and sway bars, toe arms, and the torsion arms. for camber, the important thing is the lower control arms and the strut. the boxster likes lots of negative camber (negative camber gets you more contact patch when you roll onto the outside side of the car in a turn) and this is achieved in three ways: shortening the strut will draw the top of the wheel carrier inboard and increase negative camber, moving the top of the strut inboard will achieve the same thing. making the lower control arm longer will push the bottom of the wheel carrier out and increase negative camber. hence the products on the market to make it easier to get negative camber - strut top mounts, adjustable lower control arms.

so, you set your alignment in a static environment, but realise that driving is dynamic. when you turn, your car rolls onto the outside wheels and compresses the outside suspension. this shortens the strut which increases negative camber and gets you even more tire in contact with the ground when you need it. HOWEVER, realise that when the strut compresses that the lower control arm moves also. it is fixed at it's inboard hardpoint so must travel through an arc when the suspension compresses. if the lower control arm is horizontal to the ground prior to the turn, when the strut compresses the lower control arm will rotate upwards and will actually pull the bottom of the wheel carrier inboard and reduce camber. so, you want your lower control arm not quite at horizontal so that when the strut compresses it moves to horizontal and not past, increasing rather than decreasing your negative camber.

of course, lower control arm orientation is determined by ride height, hence why racers don't slam their cars. the ones that are super low have reocated suspension hardpoints. i've had my car at stock, super slammed, and am now at m030 which is where it will stay. the actual m030 heights are in the shop manuals, and steve has posted them on the site before. sometimes refered to as clubsport height depending on the reference.

[steved0x]

Here are the specs for ride height:

Originally Posted by steved0x

[thstone]

My Spec Boxster is not set at the lowest ride height allowed by the rules. At the lowest height, the shocks will occasionally hit the bump stops and there is a lack of suspension travel which reduced grip. I also run a bit of rake (front slightly lower than rear).

Yes, there is a cost to the higher ride height in terms of increased aero and weight transfer but these costs are less than the benefit from greater suspension grip.

For others who might read this, remember that Spec Boxster's have PSS9 coil-over shocks so the ride height is fully adjustable (which is not true of the stock suspension).

Here is the Spec Boxster rule on ride height:

Section 4.H
Ride height minimum 90 mm front and rear as measured at front cross of aluminum cross member and front-to-rear braces near rear sway bar.

Here is what my car looks like from the side (low but not slammed):

[maytag]

Steve, House, TRK, NewArt, AZ986, and any others who are frequent trackers:

So I assume RoW sport is M030 spec?

That's like 40mm from 90mm minimum (spb allowed).

I want low.... 'cuz it looks cool.... but not so low i start giving up performance at the track.

I'll be running 18's on the street, 17's at the track. MOST of its time is spent at the track, and I tend to orient my mods in that direction.

What're your recommendations?

'03 S, gt3 bars front and rear, adjustable LCA's, camber plates, ohlins R&T coilovers (track package, so a little stiffer spring and valving) , running NT01'S, with lots of neg camber.

Edit: I should also note that I'm running the LN deep sump, with sump guard plate. It IS the lowest thing under the car now..... which concerns me just a bit. Especially as much as I like using the curbs.

Edit again: I'm currently at 113mm in ther front and 138 in the rear. The rear actually seems about right, but could maybe come down 10mm. But before I do anything to the rear; the front is too low. The tops of the tires are hiding in the arches, and I can't get a jack under the nose. I think I'll probably bring it up about 17mm, to 130mm.

[maytag]

I'm tentatively planning to set it at 125mm front, 130mm rear.

Any input is greatly appreciated.

Sent from my SM-G970U using Tapatalk

[NewArt]

So that's about 10mm lower than the RoW sport settings that Steve posted. I'm looking forward to see where this discussion goes!

[AZ986S]

I have PSS9 coilover with camber plates and stock arms in front. About -2.8 deg camber front -2.5 rear. I set my height to what I had when I was running with stock struts and my HnR lowering Springs. I haven't measured using this method only using ground to fender arch. But running 17in wheels on the track my car looks very similar to THSTONE. I have 4-5 mm rake front to back.

So Maytag your numbers seem good. But I suspect I am sitting lower than your numbers.

[ianacole]

With the pss9's, do you know the measurement from the bottom of the strut to the bottom of the lower spring perch? I'd like to set this prior to installing so I don't have to go back and forth to get the ride height set.