One lap Camaro or other link susppension systems ..SWAYBAR question

[LowBuckX]

Trying to decide if I should add a swaybar to the rear on my Nova with 3 link.

Has anyone added a swaybar to their rear with a link suspension?

What did you use? got pics?? Thanks.

[Bryce]

I wanna hear some of the responses. I am going with a rear sway bar. But i plan on having a low roll center.

[LowBuckX]

Im diggin bad Pennys may copy..

[Steve1968LS2]

If you have a "tunable" rear sway bar then there's really no downside. It's nice to be able to stiffen up the rear roll for auto-x (more rotation) and then loosen it up for a road course were less oversteer is safer.

And my roll center is pretty darn low. :)

[Steve1968LS2]

We need to get Dave Pozzi in here since he designed the rear sway bars on both Penny and the One Lap Camaro.

[LowBuckX]

We need to get Dave Pozzi in here since he designed the rear sway bars on both Penny and the One Lap Camaro.
This is your mission .

[James OLC]

Dave is somewhere between Salinas and Hollywood right now dragging the OLC to the Optima premiere so I'll pitch in on his behalf until he gets to a computer...

When the OLC was first on the road after it was "done" (through SEMA, Optima, GG Costa Mesa, and GG Del Mar) I had no rear bar and a standard Hotchkis front bar. The car was drivable and was far better than any first gen I had driven before BUT it pushed like a 6 cyl Mustang rental, had a ton of body roll, and (looking back on it now) was really just ugly to drive. After Del Mar we added a solid bar off of a 2nd geb which David modified by cutting the formed ends off and making the bar adjustable. We ran that way for a couple of months but continued to have issues with the car pushing (although it was noticably better). David modified that bar a couple of more times trying to increase the stiffness in the rear but got to the point that the geometry was getting ugly because the bar ends were getting pretty short.

At that point, Dave and the guys from Hellwig entered the fray and built us a hollow front bar and a new adjustable rear bar which we got on the car after running the Silver State.

We ran with the new Hellwig bars at the Lockheed SCC Autocross at Christmas and, out of the box, got the car turning pretty well - it was awesome on corner in and through the first part but would push out a bit from midway through the corner as soon as you got on the gas; the rear end was just not rotating very freely. We adjusted the bar by a couple of more holes and took it out on January 1st on what was a brutal autoX course for cars our size and WOW what a difference. The car is probably 90% there now and has never felt better. It turns out that the new front bar is slightly stiffer than the old one so we're swapping that out with a new hollow bar from Hellwig that should be about 100 pounds lighter (we'll do that after the premiere). We also found that the adjustment on the rear bar is not linear and that until we got further in we were not making really big rate changes (more like 40 lbs at a time).

So - long story short - definately go with a rear bar and if you can an adjustable one.

I'll take a look and see if I can find pics...

[James OLC]

The new Hellwig rear bar...
https://static1.pt-content.com/images/pt/2010/01/IMG_0261JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0262JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0266JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0270JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0279JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0283JPG-1.jpg

yeah... I know the exhaust is leaking... it's coming off soon for a tweak or two

[CarlC]

100lbs weight reduction? That must be a heck of a bar James!

I too am interested to hear from David.

[Steve1968LS2]

See.. I can get away with the 2nd gen bar because my floors are recessed and my bar ends are WAY longer than on the OLC car.

Plus I have less of a "push" issue due to my wider front tires.

[JRouche]

I wanna hear some of the responses. I am going with a rear sway bar. But i plan on having a low roll center.

If you are talking about the rear roll center then thats all the more reason to have a large bar on the rear.

A low rear roll center will allow the body to roll over more and give you a car that pushes through the turns. A stout bar is needed to control the excess roll that a low rear roll center gives you.

A high rear roll center will keep the body tight, not as much roll. But it pushes the rear end out in the turn. Gives you over steer.

So then why the heck do we hear that a low rear roll center is good?

Because the front roll center is always low. It makes it easier to set a car up when you can get both roll centers closer to each other. Get the front and the rear of the car rolling on the same plane, or as close to the same plane as possible. It creates a more stable platform when both ends of the car are reacting to roll in a similar manner. Not as "twitchy" of a car. Much more predictable. JR

[James OLC]

100lbs weight reduction? That must be a heck of a bar James!

I too am interested to hear from David.

lol... 100 pound reduction in rate. The big (1.125") hollow bar (at 0.188" wall thickness) is around 900 pounds, the Hotchkis bar (IIRC) is around 850 at 0.156" wall thickness. Our new bar from Hellwig is 1.12" diameter with 0.156" wall and should be around 10% softer than what we've got now.


If you are talking about the rear roll center then thats all the more reason to have a large bar on the rear.

A low rear roll center will allow the body to roll over more and give you a car that pushes through the turns. A stout bar is needed to control the excess roll that a low rear roll center gives you.

A high rear roll center will keep the body tight, not as much roll. But it pushes the rear end out in the turn. Gives you over steer.

So then why the heck do we hear that a low rear roll center is good?

Because the front roll center is always low. It makes it easier to set a car up when you can get both roll centers closer to each other. Get the front and the rear of the car rolling on the same plane, or as close to the same plane as possible. It creates a more stable platform when both ends of the car are reacting to roll in a similar manner. Not as "twitchy" of a car. Much more predictable. JR

We've got the rear roll center very low to try to match the front. One of the great things about the LD 3-link is the ability to change the rear RC easily. We started with it too high and nothing that we did made the car any better. We changed the RC an felt an instant improvement. The front RC is so low that (on paper) it actually goes below ground level upon hard breaking and moves laterally a bit - no doubt contributing to our issues.


We ordered a new set of tires from Jason today and will be moving to 275s on the front and 335s on the back for the One Lap which should help.

[LowBuckX]

James is there a part number for this bar? Or Someone I can talk to to at Hellwig to get one??


The new Hellwig rear bar...
https://static1.pt-content.com/images/pt/2010/01/IMG_0261JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0262JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0266JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0270JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0279JPG-1.jpg

https://static1.pt-content.com/images/pt/2010/01/IMG_0283JPG-1.jpg

yeah... I know the exhaust is leaking... it's coming off soon for a tweak or two

[James OLC]

Give Dave Wheeler at Hellwig a call (559-734-7451) and tell him that we were talking - he'll be able to hook you up!

[David Pozzi]

Hellwig is not in the business of making one-off special rear bars, you can ask them and see but don't be surprised if they won't do one for you.
Try and select a regular bar that will fit and do what you want.
The OLC rear bar is perhaps stiffer at 1" than you would want for most "normal" cars. The Hotchkis 2nd gen Camaro rear bars are a good choice too. Hotchkis 1st gen bars are too narrow.

The bellcrank watts pivot ,or panhard bar height will need to be close to axle center plus likely need a rear bar to get enough rear roll stiffness, perhaps even higher. If you run the pivot point much lower than the axle center line, the axle will move side to side a lot more and the driveshaft can easily contact the transmission tunnel sides. We had that issue with Bad Penny.
David

[LowBuckX]

I was looking at the gen 3 bar from Suspension tech for price reasons because Im not paying $400 to have to mod it anyway. the choice is 7/8 or 1"

[David Pozzi]

The Hellwig rear bar for 1st gen Camaro is 3/4" solid with 3 adj holes. The Hotchkis 2nd gen Camaro bar is 7/8" but hollow. The good thing is, you can usually sell a Camaro rear bar if it doesn't work for you.

[LowBuckX]

dont know if its hollow 7/8 but the 1" bar is (by description) I live 5 minutes from summit racing and they are good about letting you inspect parts before purchace I can go down there with a tape measure and shop till they kick me out or I run out of ideas.

As for contacting the tunnel .. Novas must be very differant Id have to have a major failure for contact to happen and Im at 3" below center right now ( I can adjust to on center to 4"below)

[hotrdblder]

Hellwig is not in the business of making one-off special rear bars, you can ask them and see but don't be surprised if they won't do one for you.
Try and select a regular bar that will fit and do what you want.
The OLC rear bar is perhaps stiffer at 1" than you would want for most "normal" cars. The Hotchkis 2nd gen Camaro rear bars are a good choice too. Hotchkis 1st gen bars are too narrow.

The bellcrank watts pivot ,or panhard bar height will need to be close to axle center plus likely need a rear bar to get enough rear roll stiffness, perhaps even higher. If you run the pivot point much lower than the axle center line, the axle will move side to side a lot more and the driveshaft can easily contact the transmission tunnel sides. We had that issue with Bad Penny.
David
david, the driveshaft would hit the tunnel because the rear was moving laterally so much? was the rear built with the pinion offset, ot centered in tunnel? did you ever measure lateral movement, with bellcrank at a/c ? and then below? would it have worked better if the axle side watts link mounts had adjustability to keep arms level,thus controlling rear better?so the roll center is around 12-13 inches?
I usually build my rears so they put the pinion center in the center of the camaro, which the tunnel is 3/4 inch off center in camaros towards the pass side, so i run 1 inch offset on my rear to put pinion in center of tunnel.

[Dave@Hellwig]

If you're looking at a Gen 3 Camaro bar for your Nova, we have an adjustable 7/8" bar avaialble for that application. It will take some fabrication to make it fit right. We can upsize our adjustable rear bar for the Nova as well. Its 3/4" dia and designed for leaf spring applicaitons but we can run it up to about 1" dia if needed. For a custom diameter of a currently tooled sway bar you are looking at about $375.

[JRouche]

If you run the pivot point much lower than the axle center line, the axle will move side to side a lot more and the driveshaft can easily contact the transmission tunnel sides. We had that issue with Bad Penny.
David

Are you using a PH bar? On my watts link I dont have more than about an 1/8" movement side to side on the rear end with the pivot about two inches below the axle CL. That is while traveling the suspension through five inches of travel. And the drive line is gonna shift even less than the rear end.

When I had the PH bar in there I saw a greater amount of side to side movement. Thats why I changed it.

Maybe it depends on how the watts link is mounted also. When I change the pivot height I also change the axle mounting points so they keep the links within a decent angle, less travel. If I move the center pivot down I rotate the axle clamps and rotate them down so the links are still within a desirable angle. I dont need to change the axle to link length (the bar from the axle to the end link), it only pulls them in slightly. But there are enough threads on the rearward tubes and mounting bolts that I could push the links out some (about one inch) if they were getting pulled in too much with the rotation..

I gotta say. After putting the watts link in there is basically no side to side movement of the axle. JR

[LowBuckX]

I found that a 68 Charger Addco bar is nearly the same specs as the Nova rear bar but the arms are straighter and the dip runs behind the pumpkin instead of under like many Ive seen... This may be the bar I get friday.. Still will mod it for rod ends and make it adjustable..

[David Pozzi]

david, the driveshaft would hit the tunnel because the rear was moving laterally so much? was the rear built with the pinion offset, ot centered in tunnel? did you ever measure lateral movement, with bellcrank at a/c ? and then below? would it have worked better if the axle side watts link mounts had adjustability to keep arms level,thus controlling rear better?so the roll center is around 12-13 inches?
I usually build my rears so they put the pinion center in the center of the camaro, which the tunnel is 3/4 inch off center in camaros towards the pass side, so i run 1 inch offset on my rear to put pinion in center of tunnel.

Jake, Penny was pretty well centered, but just very slightly to the left at the driveshaft. The Lateral Dynamics 3 link requires a rect tube crossmember that is welded into the floor, it intrudes perhaps 1/4" into the tunnel around 8" - 10" forward of the yoke. When the watts pivot is low, the rear moves much more side to side during chassis roll, when it's in the upper holes it's fine. The links are length adjustable side to side, but not vertically. The way it's set up, I had to have a little more room between tire and fender lip on the LH side to get the driveshaft evenly centered.

JRouche, Penny is very low, this puts the watts pivot near the bottom of the diff housing when on the bottom hole. The drive shaft moves side to side when the chassis rolls, perhaps I didn't explain very well how I was testing it. When just raising and lowering, there is no problem.