Sway bar Question

[ranman5608]

I cant seem to find the specific answer i am looking for so I'm hoping you experts can help out.

I am playing around with adding a sway bar to my car and the only place that will work is as pictured which makes the sway bar its self 50.5" long. this is the second to largest 250 wall 1.25 bar kartek offers next size up is 60". The car currently doesn't necessarily need the sway control but i would imagine once the car gets more power it would be. I don't plan on ever taring this thing down to bare frame again so now is the time to make this decision.

my questions are.
1. how much stress is transferred from the bar and suspension to the chassis
2. would the bar make sense in this location? The sway bar arms will wind up being behind the shocks outside of the body panel.
3. with that long of a bar should i go solid? arms are 24" pivot to wheel centerline 2.5" coil overs 3" bypasses.

 

[lincster]

From my experience, and a few buddies.
Hollow bar.
Buddy with a Sand Limo had a solid bar was tearing stuff up, until he went to a hollow bar. Has not had issues sense.

Solid doesn't flex as much and transfers a ton of load into the chassis.
Lots of stress is transferred to the chassis, not so much the arms.

The mounts to the chassis have to be at the end of the bar.
My buddy had a bar added to a Black Widow and the guy that did it, left about 3" on each end of the bar hanging beyond the frame mounts.
First day out, torn the mounts out of the chassis.
Had them redone to be at the end of the bar, and never had an issue again.

Give Alex Arvizu in Tucson a call.
He is an amazing fabricator and will give good input.

 

[ranman5608]

From my experience, and a few buddies.
Hollow bar.
Buddy with a Sand Limo had a solid bar was tearing stuff up, until he went to a hollow bar. Has not had issues sense.

Solid doesn't flex as much and transfers a ton of load into the chassis.
Lots of stress is transferred to the chassis, not so much the arms.

The mounts to the chassis have to be at the end of the bar.
My buddy had a bar added to a Black Widow and the guy that did it, left about 3" on each end of the bar hanging beyond the frame mounts.
First day out, torn the mounts out of the chassis.
Had them redone to be at the end of the bar, and never had an issue again.

Give Alex Arvizu in Tucson a call.
He is an amazing fabricator and will give good input.

Thank you sir after i played with it some more im not even sure i can make this area work since the arm would be behind the shock its not looking like i have the room. I have one more idea.

 

[JM PRO]

Speedway Engineering

Speedway Engineering

1speedway.com

These are the guys I use for all my sway bar projects. You can custom order the length of the sway bar.

 

[lincster]

Speedway Engineering

Speedway Engineering

1speedway.com

These are the guys I use for all my sway bar projects. You can custom order the length of the sway bar.

Let us know if you can get ahold of them.
They sold, then someone bought them, moved the equipment and supposedly they are up and running.
Kartek on their site says "not sure when more will be available".

 

[Rockwood]

1. A fairly significant amount. It can/will rip apart weak support. See below.
2. Where does a 24" arm land on the arm vertically? Will the arm be able to travel with the trailing arm through the full range of travel? Only thing I'd do differently is rather than have this new tube adding stress to the bars it's welded to is have it ADD support to the bars it will be welded to. If you place it slightly lower to bisect the bend in the arm, you will somewhat support the bend (adding a second tube in red or yellow, with red probably being better, would finish shoring it up). Affixed as pictured will likely crack that bent tube since you're adding some stress at a weak point.
3. Unless the bar is being overstressed (as apparently above for @lincster 's friend), shouldn't matter much. A solid bar is about 10% ish stiffer than an equivalent diameter hollow bar. A thicker bar will not twist as much as a thinner bar. The link @JM PRO listed above is a good/reputable source. If you feel it doesn't need a bar now, thinner would be better. With the Speedway jobs above, you can always order another bar, or adjust it for stiffer/softer with the adjustable arms. Also: the longer the arms, the less twist on the bar for a given amount of travel. It will also make the bar softer.

 

[JM PRO]

Let us know if you can get ahold of them.
They sold, then someone bought them, moved the equipment and supposedly they are up and running.
Kartek on their site says "not sure when more will be available".

Well that sucks. I didn't know the bad news.

Bummer, they were a great source

 

[ranman5608]

1. A fairly significant amount. It can/will rip apart weak support. See below.
2. Where does a 24" arm land on the arm vertically? Will the arm be able to travel with the trailing arm through the full range of travel? Only thing I'd do differently is rather than have this new tube adding stress to the bars it's welded to is have it ADD support to the bars it will be welded to. If you place it slightly lower to bisect the bend in the arm, you will somewhat support the bend (adding a second tube in red or yellow, with red probably being better, would finish shoring it up). Affixed as pictured will likely crack that bent tube since you're adding some stress at a weak point.
3. Unless the bar is being overstressed (as apparently above for @lincster 's friend), shouldn't matter much. A solid bar is about 10% ish stiffer than an equivalent diameter hollow bar. A thicker bar will not twist as much as a thinner bar. The link @JM PRO listed above is a good/reputable source. If you feel it doesn't need a bar now, thinner would be better. With the Speedway jobs above, you can always order another bar, or adjust it for stiffer/softer with the adjustable arms. Also: the longer the arms, the less twist on the bar for a given amount of travel. It will also make the bar softer.

The sway bar arm its self would be roughly 15" the standard straight arm speedway sells.
my trailing arm is 24" long I added this information for reference incase someone had a calculator or had experience adding a sway bar to something with that length of trailing arm.

unfortunately after looking at it some more and mocking the shocks up I do not have the room to cycle a sway bar arm behind the shock so i have one more place i can think of for this thing. unfortunately this is a short wheelbase 4 seat car so i am very limited on space.

in the picture below shown in red is the only other spot that i can see working. this shoots the bar directly over the bell housing. i could support it off of this main down tube in a couple spots and have the arms facing forward hitting roughly the center of the trailing arm. This would also allow me to run a 46" bar so my thought is a 46" 188 wall bar with 15" arms attached at roughly the 12" mark on the trailing arms.

 

[Rockwood]

The sway bar arm its self would be roughly 15" the standard straight arm speedway sells.
my trailing arm is 24" long I added this information for reference incase someone had a calculator or had experience adding a sway bar to something with that length of trailing arm.

unfortunately after looking at it some more and mocking the shocks up I do not have the room to cycle a sway bar arm behind the shock so i have one more place i can think of for this thing. unfortunately this is a short wheelbase 4 seat car so i am very limited on space.

in the picture below shown in red is the only other spot that i can see working. this shoots the bar directly over the bell housing. i could support it off of this main down tube in a couple spots and have the arms facing forward hitting roughly the center of the trailing arm. This would also allow me to run a 46" bar so my thought is a 46" 188 wall bar with 15" arms attached at roughly the 12" mark on the trailing arms.

Would you be able to get a long enough arm in there?

If you put it inline with the trailer arm pivot, you could mount it a lot lower since it will follow about the same arc as the trailing arm. This would give you a much shorter dogbone to connect the sway bar to the trailing arm.

Another tool in the belt are the offset arms.