Rear SUPER Swaybar     

   To better understand what happens when a car launches at the drag strip, let's take a look at what is happening there.  When the front rises or does a "wheelie," most of the time the drivers side is much higher than the passenger side front.  This also means the drivers side rear is much higher than the passenger side rear.  Most people add air bags to the rear and pump the passenger side way up to keep the passenger side rear from coming down as far.  Here is a different way to look at what is really happening there.  Because of the rotation of the engine and the massive amount of torque it is producing, those forces are transmitted through the driveline to the rearend.  What is actually happening back there is that the passenger rear tire is actually trying to LIFT off the ground.  The tire is going up into the car, NOT the car coming down on the tire.  The passenger side air bag applies additional weight (down-force) onto the rearend (tire), attempting to equalize the weight on each rear tire.

   Our new swaybar / Anti-roll system transfers the force from one side to the other, doing a much more efficient job of equalizing the weight to each rear tire.  This in effect almost doubles the traction of a fast car with no air bags, because the passenger tire would have had very little weight on it.  With the added traction and the car being much closer to level, the car can now launch harder and straighter.  This reduces the chance of wandering out of the "groove" and further losing traction, while making it much safer to drive.  Not having to worry about the rear slicks getting cut or damaged from excessive body roll is an added bonus.
   

EARLY PROTOTYPE TEST RESULTS 04-06-03:

  We have made up a couple prototype swaybars from 4130 chromoly steel, and bolted one on a test car this past weekend (04-06-03).  The test car is a '87 Buick Grand National (G-body), with a turbo V-6 capable of mid-upper 11's in the 1/4 mile.  This is also a daily driven car that looks almost stock.  The stock front swaybar is on it & was left on it for testing purposes.  The test car also had 12.5 x 28 E.T. Street tires (basically slicks with 3 grooves) on the rear, and filled with race gas and running well.  The tires were pumped up over the "normal" race pressure to approx. 27 psi.  This greatly reduced the rolling effect generated by the rear tires.  The car also had air bags, but to get the full effect of the swaybars, we let all of the air out of the airbags.
  The goal was to see what differences could be found in body roll, body/frame twist, and general street characteristics.  We did several testing methods, with no swaybar, the stock swaybar, and our new HR swaybar with 1/4" wall 1.25" O.D. 4130 chromoly seamless tubing.  We were VERY pleased with the results so far.  Here are the testing methods & results that we found:

    Test 1.)   Rocking car side-to-side by hand, holding the top edge of the driver and passenger door openings.
  1 A - No swaybar - Car moved very easily with little effort, several inches front and back, appeared very loose.
  1 B - Stock swaybar - Car still moved very easily with a slight bit more effort, several inches front and back, still considered very loose.
  1 C - HR 1/4" wall tubular swaybar - Car moved much less, and required much more effort to get it rocking, appeared much tighter.

    Test 2.)   Jacking the front drivers side under the lower a-arm on the drivers side only.  The car was raised with the front drivers side tire several inches in the air, and until the passenger side front tire was just coming off the ground.  This simulated the car launching and pulling a "wheelie."  The "rear out of level" mentioned below was found by measuring from the floor to the bottom of the wheel openings on each side, and taking the difference.
  2 A - No swaybar - Our jack was one notch from being totally extended, and the car was twisted very badly out of shape.  The passenger rear tire was up inside the wheel opening and would have been cut badly (probably ripped wide open) if that was an actual launch.  The rear out of level was 7".
  2 B - Stock swaybar - Our jack was still one notch from being totally extended, and the car was twisted very badly out of shape.  There was not much change in appearance from the "no swaybar" test, only slightly less body roll noticeable.  The passenger rear tire was also up inside the wheel opening and would have been cut badly as well, slightly less than the "no swaybar" test.  The rear out of level was 6-3/8", less than an inch better than the "no swaybar" test.
  2 C - HR 1/4" wall tubular swaybar - Our jack was several notches away from being totally extended, and the car was twisted MUCH less than test A or B.  There was a considerable change in appearance from the other tests, with MUCH less body roll noticeable.  The passenger rear tire was well away from the wheel opening and would NOT have been cut at all.  Remember, this is all with ZERO air in the air bags.  The rear out of level was only 3-1/4", less than HALF of the "no swaybar" test.  The front was also noticeably more level, with 2-1/2" less difference side-to-side than tests A and B.

    Test 3.)   Test driving the car, short cruise on city streets in town, with several "normal" driving conditions each trip.  The exact same route was taken to ensure consistent testing results, with the same people riding in the same positions each time.
  3 A - No swaybar - Did NOT drive car with no swaybar.  Having no air in the air bags, this would have been impossible to do without destroying the rear tires.  They would rub the wheel lips on both sides, as well as the sides of the frame rails on both sides, with any little movement other than straight ahead under minimum throttle.
  3 B - Stock swaybar - The car was barely drivable, taking every corner EXTREMELY easy and slow.  The rear tires rubbed the frame and outer wheel openings on every corner, making us very nervous.  We did a full throttle blast going straight ahead, and the car "danced" around noticeably but not too excessively.  We couldn't tell if the tires were rubbing due to all the excitement.  After getting it back in the shop, we noticed that the drivers side rear tire was cut badly due to the wheel opening digging into the sidewall.
  3 C - HR 1/4" wall tubular swaybar - The car was MUCH more drivable, and could take corners at faster (more normal) speeds and MUCH more aggressively.  After noticing that the rear tires were NOT rubbing the wheel openings, we started to go faster in the corners and swerving side-to-side trying to get them to rub.  The rear tires never rubbed the outer wheel openings on any corner, and only a couple times on the frame rail on the passenger side only.  The test car has always had less clearance to the frame on that side due to GM tolerances, and could probably use a 1/4" spacer there.  We did a full throttle blast going straight ahead, and the car didn't "dance" around at all, and went very straight.  We probably could have let go of the wheel, no fighting or correcting anything was needed.

    EXTRA NOTES:  The test car had a 40 minute drive back home after all this, with about half of that highway miles.  The air bags were left empty because it seemed there was no need to add air to them at this time.  The car felt much stiffer and under control, and needed much less "correction" over bumps and around corners.  The stiffer and more effective HR tubular swaybar does create additional over-steer that is quickly noticeable.  It takes a few miles to get used to it, toning down the corrections that you would normally do to keep the car going straight.  It basically gives you the feeling that it is on rails, like a slot car or road racer, taking corners with ease.  This was expected, but we did want to make sure that it was not a potential problem or undesirable feeling.  It definitely eliminates any sloppy or lazy feeling it may have had before.

RESULTS FROM DRAG STRIP TESTING 04-13-03:

  We had the chance to test 2 different vehicles this weekend (04-13-03) at a local track.  The available traction was marginal, but we got some great information and results!  Weather was decent, with temps in the 60's to low 70's.

  First car was Doug Conway's street/strip '69 Chevelle with a built 502 cu. in. BB Chevy, and 29 x 10.5W x 15 Hoosier slicks.  It is actually a pump gas motor, but you couldn't tell from the huge roller cam and it's performance.  It weighs in at 4100 Lbs. with driver, which puts a lot more stress on things than most cars out there.  We also felt a 3400 Lb. car would have to run in the 9's to put this much stress on the rear suspension.  The Chevelle runs consistent 10.70's to 10.80's with NO power adders, mid-low 1.4 "60 foot" times, and pulls the wheels every launch off a transbrake.  Below is a before and after picture with the only change being the addition of our new tubular swaybar.

        
  The pictures really tell the story here (click on them for larger view).  The "before" picture actually has 40+ psi in the passenger side airbag in an attempt to keep it from rolling over too far.  This made the car sit extremely out of level, making many people think there was a problem with it.  The "after" picture is with our new swaybar installed and only 5 psi in both airbags (NO preload).  This made the car sit level, improving the stance 1000%, and also allowed the drivers door to be opened on the trailer where it wouldn't clear the trailer fender before.  Doug (the owner of the Chevelle) was EXTREMELY happy with the results and couldn't believe the improvement!  He was smiling so much, we wondered if he was going to be able to get his helmet off!  Instead of gripping the wheel with white knuckles wondering where it was going to go, he could have just about let go of the wheel and let it go straight down the track.  Another bonus we found by eliminating the high preload in the passenger side airbag is that the tires will NOT wear "funny" on the street.  The best part of it all is that he now can run the nitrous that he couldn't use before.  With the "old" suspension setup, the NOS would just overpower the car and make for a violent wild ride off the line.  Now that it leaves the line level with equal traction to both wheels, it should handle the added power with ease.  Next will be a 572 on the bottle, making it more fun than ever before.

  The second test vehicle was a street/strip '86 Buick Grand National (GN) with basic bolt-on's owned by Jim Pliss.  The GN has a TE-60 turbo, 3000 stall converter, and other items setup for mid-upper 11's on 116 race gas.  On such short notice, he could only get 110 octane, which limited the boost levels to 22 psi max.  He also didn't get his Moser axles that I ordered for him in time, so he kept the launches on the mild side so he could still drive it back home.  We followed him to the track, which is where we noticed the first big improvement.  With M/T 12.5 x 28 x 15 E.T. Streets on the rear and 10 psi in each airbag, the car had NO problem tracking a straight line.  He actually swerved back and forth duplicating quick lane changes on the expressway at 65 mph, and had NO tire rubbing issues, and had very minimal body roll.  It truly looked like an indy car with total control and super reactive steering.  Our new tubular swaybar eliminated any and all "sloppy" feelings the car had before installing it.  Jim (the owner of the GN) was EXTREMELY pleased with the results BEFORE we ever got it to the track!
  At the track, there was absolutely NO body roll present at the launch.  The car launched straight and level, and was totally in control the entire pass.  This GN had previously run a best of 12.6's on drag radials.  Even launching mildly with approx. 5 psi boost, he ran a best of 11.92 and 11.93.  It used to have a mild "floating" feeling when accelerating, which was eliminated with our new tubular swaybar.  He mentioned the same feeling that it would have went straight on it's own.  Once he gets the new axles installed, gets some 116 octane race gas, and swaps the rear cargo springs out for some stock replacement springs, mid 11's will be easily attainable.

This was Dave Bamford at the 2003 GS Nationals with our lower CA's and the new swaybar. The car was under MUCH more control each pass, and stayed right in the groove. The "before" setup on a superb track (Norwalk OH) netted some mid-upper 1.5x 60 ft's which were quite a bit off for a low 10 second car. The "after" setup with HRpartsNstuff lower control arms and new swaybar/anti-roll system netted some upper 1.4x 60 ft's, and has a lot more to go. Dave expects some 1.3x 60 ft times with the new Swaybar, once he sorts out some coil spring/shock setting/converter stall issues.