Racecar Project - Front Sway Bar
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
Racecar Project - Front Sway Bar
I was able to recently pick up a GT2 Evo front in cockpit adjustable blade style sway bar. It needs some reconditioning and replacement of parts, but they are minor and easily fabricated or purchased new from PMNA. This bar has more adjustability that the stock 24mm RSR sway bar I'm running now. One blad is fixed and sets the overall range of stiffness. The other blade is connected to a cable located in the cockpit and allows for 5 positions of adjustability and will adjust more detail than the overall range set on the other side. Hopefully I can get this together and tested this year.
Both this bar and the original RSR bar are for wide body front suspension mounting positions.
Both this bar and the original RSR bar are for wide body front suspension mounting positions.
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
Here is an update on repair of the cockpit adjustable bar. Most of the movable parts of the end link assembly was worn so I machined new pieces. The end links themselves were bent/broken and extremely expensive and not in stock from PMNA. I took a standard RS end link, cut it off, machined it down and threaded it with left hand threads. This required me to make a die holder to center the die and ensure a straight cut.
In addition, I didn't like the factory cockpit adjuster, the leverage is wrong and it is difficult to move when the car is loaded. I purchased a Genesis Technology adjuster and converted it to a metric rod end. The throw is different between the two, so I'll have to further modify it, but I won't know until I have fully assembled it.
Left to right: Bent factory endlink, hub side of the RS end link, bar side of the RS end link partially threaded (now the hub side), and the fully threaded end link. At the top is the custom die holder that centers itself.
Top to bottom: Factory adjuster, Genesis Technology adjuster.
In addition, I didn't like the factory cockpit adjuster, the leverage is wrong and it is difficult to move when the car is loaded. I purchased a Genesis Technology adjuster and converted it to a metric rod end. The throw is different between the two, so I'll have to further modify it, but I won't know until I have fully assembled it.
Left to right: Bent factory endlink, hub side of the RS end link, bar side of the RS end link partially threaded (now the hub side), and the fully threaded end link. At the top is the custom die holder that centers itself.
Top to bottom: Factory adjuster, Genesis Technology adjuster.
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Michael S. Palmer
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Joined: Jul 2003
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From: Peachtree City, Ga
How does the slide cable linked to the right side of the bar adjust the tension or stiffness of the swaybar -
In the first picture I can see the cable links to a lever on the front side of the bar which must turn the attachment arm - but what does this accomplish ? Doesn't the arm need to be shortened or lengthened to vary the stiffness of the swaybar. It appears to only turn - how is the increase / decrease changed -
Looks like the Genesis lever is going to need an additional bellcrank (to reduce change) as the intervals of movement are much greater than the stock intervals .
In the first picture I can see the cable links to a lever on the front side of the bar which must turn the attachment arm - but what does this accomplish ? Doesn't the arm need to be shortened or lengthened to vary the stiffness of the swaybar. It appears to only turn - how is the increase / decrease changed -
Looks like the Genesis lever is going to need an additional bellcrank (to reduce change) as the intervals of movement are much greater than the stock intervals .
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
A swaybar can be made stiffer using several different methods. The one most common is to lengthen or shorten the sway bar arm, which either allows more bending (lengthen) or resists bending more (shortening). A blade adjustable bar (either cockpit adjustable or not) uses a blade and when the blade is in the vertical position it resists bending the most and when it is rotated horizontal it allows more bending of the bar. In the case of this bar, both ends rotate, so the end not attached to the cable sets the overall bar rate, and the cable attached end fine tunes the bar stiffness, and in this case is adjustable from the cockpit while driving. This allows the driver to compensate for things like a lighter fuel load at the end of a session.
On the Genesis piece, I think I am going to end up making a new lever on the bar which is longer, and machining the Genesis part to raise the rod end attachment point. This will shorten the throw required to rotate the bar from vertical to horizontal (90 degrees rotation)
On the Genesis piece, I think I am going to end up making a new lever on the bar which is longer, and machining the Genesis part to raise the rod end attachment point. This will shorten the throw required to rotate the bar from vertical to horizontal (90 degrees rotation)
Rennlist Member
Joined: Jul 2003
Posts: 1,964
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From: Peachtree City, Ga
So the right side of the sway bar (or both sides ) have a blade or flat piece of steel. The blade on the right side is connected to a circular or piston shaped piece housed inside the end of main cross bar. By pushing or pulling on the lever/cable it rotates the blade or bar from vertical to horizontal ( stiffest to softest ). Understand the cockpit adjustment and advantage - just could not figure out how the changes were made - Had an adjustable on an old Elva that move the rods in or out on the sway bar arms to make it stiffer or not -
Drifting
Joined: Aug 2002
Posts: 2,215
Likes: 72
From: Stockholm, Sweden
"On the Genesis piece, I think I am going to end up making a new lever on the bar which is longer, and machining the Genesis part to raise the rod end attachment point. This will shorten the throw required to rotate the bar from vertical to horizontal (90 degrees rotation)"
yes please, and then you can start to sell this swaybar as a kit in two versions, wide/narrow body! :-)
yes please, and then you can start to sell this swaybar as a kit in two versions, wide/narrow body! :-)
(centering die tool.)
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
Without pistons and cylinders for my engine I am a little stuck right now so I've turned my focus back to the sway bar. I removed the old widebody RSR bar and installed the new bar which has very little clearance in several places. I may need to machine some new steering stops to keep the brake lines from hitting the swaybar end link. I believe the 993RSR came with 5-10mm thicker steering stops in part for this reason as well as to keep from ruining the brake cooling ducts.
I installed the new controller on the center tunnel and made a cable bracket and then drilled a hole through to the center tunnel. It really turned out well with no real issues and I can't wait to try it. Here is the finished installation.
I installed the new controller on the center tunnel and made a cable bracket and then drilled a hole through to the center tunnel. It really turned out well with no real issues and I can't wait to try it. Here is the finished installation.