pewter82

I have access to the Hunter machine at my place of business. I was wanting to know what the correct settings are for the 996TT.
I have RuF Pss9 with 19" wheels. I think the car feels "unsettled" at higher speeds, and the outer edge of my front tires are wearing faster than the centers.
I don't track the car, and don't have many places to run over 100mph.
Also what pressures should be ran with this set up?

TIA
Jason

MechanicalEng

I would use the X73 or GT2 settings...

pewter82

Thanks, the car sits very low, so it does look like the X73 and GT2 compensate for that.
But it looks like the GT2 settings are somewhat different than the lower X73, how would I know which is correct for my set up?

pewter82

I have read that the GT2 setting differ due to RWD and other hardware. So is the X73 setup the way to properly set up a car with pss9's ?

MechanicalEng

I would try the X73 setup, the only difference is that the X73 gets a bit more camber.

Land Jet

If you are only driving on the street, your tires will last longer with the least amount of camber and toe.

pewter82

One guy says more camber , one guy says less camber... LOL what to do ?

Joe Weinstein

There is not one correct alignment. It depends on what you want to maximize for your car.
It could be braking, acceleration, cornering, or tire wear. (all I can think of at the
moment)

From what you say about yourself and your symptoms, I would suggest a little more negative
camber than whatever you're running now, and maybe something else too...

The first step is to find out what you're running now. If you're at the turbo USA spec except
for too much toe-out, then we should suggest fixing that. If you're nowhere near any of the
recommended ranges, we should suggest something else.

And you should get your corner weights taken with you in the car and your sway bars
disconnected at one end and your tire pressures correct. We don't yet know if your
instability problem at speed is due to the aftermarket suspension being not optimally
set up, letting too much weight be carried by one of the two cross-pairs of wheels...

pewter82

Corner weights? I'm going to a Ford dealership that has the Hunter system...so I doubt the tech will know about corner weights and taking apart the suspension.

But I will check to see what the setting is now and go from there. Next option is to take it to STL or KC to find a tech that does these cars.

Joe Weinstein

The tech should be fired if s/he doesn't know about corner weights, thought they *may* not
have scales, but I can't imagine a Hunter system wouldn't include scales... The tech also
should be fired if they can't disconnect one end of the sway bars.
Just ask them if they can take corner weights with you (or the equivalent of your weight) in
the seat. And depending on your spring preload adjusters, a competent alignment tech
can do a small adjustment to one or two springs to get an unbalanced corner weight right.

If your corner weights are off you will be unstable when you should be smoothly cruising.
Your wheels will be like you sitting on a 4-legged bar stool with one slightly shorter leg.
You'll have a slight teeter back and forth as you rock back and forth onto and off of that
shorter leg and the one opposite it.

pewter82

I see. I have not talked to the alignment tech as of yet. I bet your right on the weights being off. I feel unstable at speed or at least not as stable as I would think these cars should be.
My 993 is very stable and the 928's have been rock solid as well.

Mikelly

I align my own 996TT almost monthly...

Less negative camber will aid in keeping tire wear down to a minimum. Right now, this week, my car sits at the following numbers:

Front Camber -1.0
Front Caster +7.1
Front Toe 1/16 out

Rear camber -1.3
Rear Toe 1/32 in

I normally run less rear camber if I'm driving on the street for months on end. But I do a fair amount of spirited back road driving, so I wanted to keep a little aggressive on the setup.

If you don't drive it "HARD" on the street (ie canyon races) then I'd go with what ever the least amount of camber the tech can get out of the car... here's another tip and he won't know this if he isn't a porsche tech... The eccentrics are all you have in the rear, but the upper strut towers are slotted up front, and he can dial camber from both top and bottom for the front.

Mike

PorscheDoc

Jason,

I do have corner balance scales if you want to corner balance the car before you take it for alignment.

If you want the name of a good alignment guy here in KC, I can give you his name (though he doesn't do corner balancing, that is a separate process, and I usually do that before I take him the car). He does all my customer's alignments. Also, toe is your major cause of tire wear, not camber.

pewter82

Yeah I need a Porsche tech to do this. My shop says the car is sitting too low to get it on the alignment machine. I wanted them to adjust the rear shocks on the Pss9 and they can't see where to get to them through the top from inside...all I'm getting is a wheel balance.
My faithful Porsche mechanic I have used for years on older 911's and 928's says this car's suspension is set up for racing and not much can be done to make it better for daily driving on my roads...
I doubt that is the case and I think a trip to KC is in order. Can you tell I'm pissed???

pewter82

Well, balancing the wheels and putting the correct pressure in the tires has made a big improvement. The car feels much better, but I still would think a alignment check would be a good idea, the car doesn't pull either way, I just think the angle of the wheels could be adjusted.