DaveM993

Its Sunday morning and I have been thinking about this way too much. I have been debating what type of sway bar to put on my car with my PSS9's. (BTW DE only...). I got a great deal on some H&R sways (26/24) and a number of people who have them on their 993's with PSS9's love them. However, in my investigations...it is clear that there is a very learned group who feel you should only use the minimum sway necessary for your spring rate. Unfortunately, I will not get to try these puppies out until next spring...so I have the winter to wonder...will I see gobs of OS?...can I dial it out...etc.

Then, I am perusing the Sept/06 Pano and the article on the Mantis Sport Caymen build that is tearing up the Club Racing circuit and I read the following:

...two different philosophies in the basic set-up of race suspensions: stiff springs and weak sway bars vs. softer springs and strong sway bars. The latter is more common in North America to help absorb the bumps (softer springs) and still reduce body roll (stronger sway bars). We had installed a 27mm sway bar in the rear...

I did not realize there was a debate..or it was a philosophy???

So...is a 26 mm front and 24 mm rear with PSS9s too much...or just another way to approach suspension tuning? They are adjustable, BUT only two spots front and back.

Thoughts?

(I hope this isn't a popcorn smilie topic?!)

Larry Herman

Suspensions are a system, and everything has to function together to get a system that works. No one item can be evaluated in a vacuum. Basically, the springs control the pitch of the car, and everything else works off of that. The stickier your tires, the stiffer the suspension must be to control the body motions of the car. Also, the faster you go, the stiffer that suspension must be to keep the tires from bouncing off of the track with every bump. Too stiff though, and you may end up with a car that chatters over every bump and actually looses grip rather than maintains grip.

To answer your question in my way of thinking, you should run the stiffer sway bars because the PSS9 setup (we have one on my son's 993) is barely able to control the body roll of the car. Keep in mind that what you are putting together is far from an optimal track setup.

Oh, and as far as running minimal sway bars, that is only for those running high spring rates; 1000 lbs/in plus. At those rates, you have plenty of roll stiffness. With respect to the balance, if you are maintaining the same ratio F/R (you can base it on a cross-section ratio of the bars) with the new bars, then it should not change.

DaveM993

Thanks Larry!!! What a great explanation! I know it is not optimal..but I am still 25-50 track days away from being able to outdrive my PSS9's. But at least it is a step in the right direction. I was using stock US sways (BLAH...)...so I will spend next season getting to know the new ones.

Bull

I ran those H&R sways on my 993 with a JIC suspension. The springs were 600/800lbs and it was a great set-up. I had the front bar soft and the rear stiff, which felt neutral to slight OS for me.. The guy who owns it now in CA is winning TTs with the same set-up.

SundayDriver

You have two ways to set your car up:
1) The right way
2) The practical way (because most of us do not have time/resources to do it 'right')

Right way is take your car to open track sessions and tinker with spring rates (no sway bars), shocks and alignment until you have optimized that part of setup for the track. Then add sway bars, if needed, and as needed. After a bunch of days and lots of money, you will have a great handling car. I have neither the time nor resources to do that and I suspect you don't either.

Practical way - talk to others running the same car and find out what they use and what their driving style is. Copy what seems to match with your style and tweak from there.

Most people prefer very firm shocks because it is easier to feel the edge, even though the car may be slower. Same is true of stiff springs, to a point - it is easier to feel the car. If it is a street car, you will want the springs to stay reasonably soft for comfort and will have to be pretty aggressive with the bars.

DaveM993

Thanks Mark. I am taking the practical approach. Have two other relatively experienced drivers with the same set...both like it. My car is still a street car...will never be a race car....but I will spend next DE season messing around with a pyrometer, tire pressure gauge, my a$$, and various PSS9 settings and sway bar settings.

The reason for my post was the term "Don't over bar your springs"...which I had heard in a few corners...but I did not understand what that meant as a practical matter. But I am neither ready $$ wise or driver wise for a set of Motons...when I am I will get a prepped race car...

Of the open wheel variety...!!

TheOtherEric

I do believe that 26/24 is too much bar for PSS9's. That said, yes, I do have the TRG sways, which IIRC are the same. IMHO, the front bar is way too stiff.

And yes, this is a "philosophy." E.g. Lotus Elises don't even HAVE rear sway bars. Their approach is stiff springs, minimal sways. Makes them awful on rough streets, but a blast to drive because you can use the sway of the car as a useful input.

You'll find that you lose a lot of feel with the 26/24mm sways because the car isn't rolling at all. That probably makes it faster, but IMHO it's not as fun. And without body roll the car can seem a bit more unpredictable /unstable.