Sway Bar Madness!

[Chunkerz]

I bought some Turbo S sway bars (26.8mm front/16mm rear) for my 88 NA and upon comparing them I noticed that the Turbo S rear sway bar was thinner than the one I pulled from my car! I measured it and it came in at 18mm. I did some reading and it looks like the 18mm rear bar was an option on 87+ cars, so I don't think one of the previous owners added it. While reading I noticed that all 87+ cars (excluding the 968) with the M030 option came with dinky 16mm rear sway bars. Why is that? I'd expect the M030 cars to come with a thicker rear sway bar. Does it have something to do with the M030 struts/springs/socks/torsion bars set up?

[flash968]

sounds like you got a set of stock 968 bars. that's what comes in them

just looked it up. the turbo rear was 16 and 18. the way the manual reads, they went down to 16 from 18 in 89. that would be weird indeed.

front was 26.8 on both

note: 968 M030 bars are 30 and 19

[Chunkerz]

The 26.8/16 bars I bought were from a Turbo S. I measured my old front sway bar and it was 25.5mm, same as what came on NA's with the M030 option according to one article I read. My options code sticker doesn't say M030 on it, so I wonder where that came from. I sure hope that extra 1.3mm is noticeable...

Anyone want a 16mm rear sway bar? I'm planning on keeping the 18mm one that came on my car.

[v2rocket_aka944]

perhaps they changed the rear bar down in size because the M030 turbos had stiffer rear t-bars.

[Chunkerz]

That's what I was thinking, but who knows. Thicker torsion bars+thicker sway bar= more tendency to oversteer, correct? I read that Porsche dialed in some understeer to make the cars "safe" for normal people to drive, so you could be right.

[9FF]

Originally Posted by v2rocket_aka944

perhaps they changed the rear bar down in size because the M030 turbos had stiffer rear t-bars.

Most likely. It's always better to control roll/sway/weight transfer with the springs and torsion bars only. Thing is too stiff a spring or torsion bar to control that weight transfer in a turn will mean a harsher ride in a straight line. So they normally dumb down the springs and fit sway bars to control the weight transfer in a turn instead. It's a compromise. Makes perfect sense that you don't need a larger sway with larger spring rates.

[smokin_944]

From what I recall, the front 25.5mm was the M404 option bar, the 26.8mm was the turbo M030 option bar and the 30mm bar was the 968 M030 option bar. The rear bar from the turbo was originally 18mm, then downsized to 16mm and the 968 M030 was a 19mm bar. I believe v2rocket is right about the reason for the down sizing. I was told at one time the was also a 21mm Turbo Cup rear bar (951 333 701 34) being used on the track.

[v2rocket_aka944]

Originally Posted by Chunkerz

That's what I was thinking, but who knows. Thicker torsion bars+thicker sway bar= more tendency to oversteer, correct? I read that Porsche dialed in some understeer to make the cars "safe" for normal people to drive, so you could be right.

its a balancing act, the front and rear must be stiffened relative to eachother.

currently my car sits level f/r, with 25.5mm/18mm sways, and 200# springs in front and stock t-bars...it understeers like its got a snowplow on the front. when the front was an inch lower it would steer pretty well.

need to get bigger t-bars for me.

Originally Posted by 9FF

Most likely. It's always better to control roll/sway/weight transfer with the springs and torsion bars only. Thing is too stiff a spring or torsion bar to control that weight transfer in a turn will mean a harsher ride in a straight line. So they normally dumb down the springs and fit sway bars to control the weight transfer in a turn instead. It's a compromise. Makes perfect sense that you don't need a larger sway with larger spring rates.

these cars are silly-soft with spring rates, they roll over like an italian cruise-ship on stock hardware if you turn too vigorously...but going stiffer just makes the ride suck, so its a tradeoff.

[Rasta Monsta]

search google for "pasha suspension prep" and you will find a list of most factory components

[guru944]

Recommend checking your wheel alignment. Just did poly bushings up front with mo30 blocks. Poly sway bar bushings. All stock height. Everything lined up like new. Car never handled better. My OEM lower bushings were completely shot with too much control arm play.. initially thought I had a bad ball joint. Worth doing this one big time... later.