'89 super coupe sway bar vs. '95 sway bar - TCCoA Forums
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post #1 of 45 (permalink) Old 03-03-2007, 02:10 PM Thread Starter
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'89 super coupe sway bar vs. '95 sway bar

At this very moment, I'm swapping out my '95 bird's rear stock .950" sway with one that I pulled from an '89 super coupe.
Although the SC bar is is larger in dia. , it is tubular as opposed to the solid stock bar.
While I have them both out, ya'll have any idea which one I should put back in.
( i know the tech art. says that the '89 is solid, but the one I have is hollow and only meas. 1.04")
Thanks for any ASAP help while my bird is in the air.

'95 LX 4.6L/ '99 mustang front calipers/ '96 t-bird rear calipers/Baumann transmission/BOC chip by Lonnie/ 225.55.16 Yokohama's on Borbet 5 spoke/poly IRS/ Eibach 1.5" drop/ Lincoln pumpkin with 3.55 trac-loc/ Lincoln rear upper and lower control arms/ rebuilding '94 Mark Vlll eng. for swap/ -Edit- Engine rebuild now finished by Panhandle Performance (2-16-07)/ swap on soon - but needing to get P.I. torque converter- MSD window switch for '98 IMRC'S- rebuild current Baumann Trans--etc.
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post #2 of 45 (permalink) Old 03-03-2007, 07:57 PM
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An 89 SC rear bar made a noticeable difference installed on my 95 SC. Handling became much closer to neutral, less understeer. I would suggest using it.


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post #3 of 45 (permalink) Old 03-03-2007, 08:01 PM
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I put on 89 bars on my 94 lx and it made a HUGE difference...especially considering I got both bars shipped (two different people) for less than $100.

Combine those with lowering springs, new shocks, all new bushings, and all new arms...it's like a brand new car.

89 Cougar XR-7...slightly modded, 240 rwhp / 340 rwtq, Best time as of 4/22/12 = 13.11 @ 103.82, 1.78 60'
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post #4 of 45 (permalink) Old 03-03-2007, 08:04 PM
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The 89 bar that I bought was also hollow and measured at 1.08 I think (Jk89cat has it now). I question the acuracy of that article from the fact that it states a larger size in 96/97 for Sport cars which is stated in Ford literature but has been proven otherwise.

-Miller

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post #5 of 45 (permalink) Old 03-03-2007, 08:06 PM
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are the bigger sway bars only 1989? or was it up to 91? i've been looking for those at yards

-Matt
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post #6 of 45 (permalink) Old 03-03-2007, 08:16 PM
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The 89-91 SC front bars were the same size (I actually used a 91 front and 89 rear).

89-91 front = 1.20''
92 front = 1.12"

89 rear = 1.10"
90 rear = 1.04"

I want to say our 94 bars are 1.04'' front and 0.96'' rear

89 Cougar XR-7...slightly modded, 240 rwhp / 340 rwtq, Best time as of 4/22/12 = 13.11 @ 103.82, 1.78 60'

Last edited by conversion02; 03-03-2007 at 08:47 PM.
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post #7 of 45 (permalink) Old 03-03-2007, 08:24 PM
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we're putting a 89 sc front bar on a car that has NO front swaybar, i can't wait to drive a normal car again. Thing handles like a funny car dragster without it.
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post #8 of 45 (permalink) Old 03-03-2007, 08:52 PM Thread Starter
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Ok, I put the rear '89 SC bar on.
Will drive it tomorrow to see if there's any apparent difference.

'95 LX 4.6L/ '99 mustang front calipers/ '96 t-bird rear calipers/Baumann transmission/BOC chip by Lonnie/ 225.55.16 Yokohama's on Borbet 5 spoke/poly IRS/ Eibach 1.5" drop/ Lincoln pumpkin with 3.55 trac-loc/ Lincoln rear upper and lower control arms/ rebuilding '94 Mark Vlll eng. for swap/ -Edit- Engine rebuild now finished by Panhandle Performance (2-16-07)/ swap on soon - but needing to get P.I. torque converter- MSD window switch for '98 IMRC'S- rebuild current Baumann Trans--etc.
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post #9 of 45 (permalink) Old 03-04-2007, 04:21 PM Thread Starter
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After driving a couple of hours on a variety roads and at a great variety of speeds, I have to honestly say I can't feel any difference between the sway bars! Maybe my butt's numb.
At first I thought it was stiffer on bumpy roads, then I thought it was softer, then I thought it was the same, and then I lost feeling in my butt. I'm not used to thinking with my butt to evaluate a sway bar.
Same result with taking some of my favorite curves.
I think I'll keep it installed though, at least it's about 3lbs. lighter.

'95 LX 4.6L/ '99 mustang front calipers/ '96 t-bird rear calipers/Baumann transmission/BOC chip by Lonnie/ 225.55.16 Yokohama's on Borbet 5 spoke/poly IRS/ Eibach 1.5" drop/ Lincoln pumpkin with 3.55 trac-loc/ Lincoln rear upper and lower control arms/ rebuilding '94 Mark Vlll eng. for swap/ -Edit- Engine rebuild now finished by Panhandle Performance (2-16-07)/ swap on soon - but needing to get P.I. torque converter- MSD window switch for '98 IMRC'S- rebuild current Baumann Trans--etc.

Last edited by Thundernerd; 03-04-2007 at 08:22 PM. Reason: left out the word "it"
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post #10 of 45 (permalink) Old 03-04-2007, 04:26 PM
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well when i put the bar on the 92 i got frommiller i noticed a differance, its much better handling, but it could of been partially due to the NON sagged springs i also got from miller

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post #11 of 45 (permalink) Old 03-04-2007, 08:30 PM
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Quote:
Originally Posted by Thundernerd View Post
After driving a couple of hours on a variety roads and at a great variety of speeds, I have to honestly say I can't feel any difference between the sway bars! Maybe my butt's numb.
At first I thought it was stiffer on bumpy roads, then I thought it was softer, then I thought it was the same, and then I lost feeling in my butt. I'm not used to thinking with my butt to evaluate a sway bar.
Same result with taking some of my favorite curves.
I think I'll keep it installed though, at least it's about 3lbs. lighter.
I would check some bushings when I put my rear 89 SC bar in it made the car have way less body roll. check you IRS bushings. and did you install new end links and sway bushings?

93 LX: 89 SC rear sway, Tokico drop kit, JBA headers,ported and polished Edle Brock intake,ported e7's, E303 cam, Cold air intake,75mm TB,03 Lmaf, TwEECed T4M0, smog pump & ac delete, under drive pulleys, msd 6a, 1.7 ratio roller rockers, electric fan, 3.27 trac lok, 5spd, aluminum drive shaft, digital cluster converted to analog and it works!
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post #12 of 45 (permalink) Old 03-04-2007, 09:01 PM Thread Starter
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Thank's for the suggestion dwinthrup, but I just switched all the IRS bushings to poly in January of last year. I take that back, I haven't replaced those big pad bushing things that fasten the whole IRS unit to the chassis.
Can you get those in poly?-- or would that be too stiff?

'95 LX 4.6L/ '99 mustang front calipers/ '96 t-bird rear calipers/Baumann transmission/BOC chip by Lonnie/ 225.55.16 Yokohama's on Borbet 5 spoke/poly IRS/ Eibach 1.5" drop/ Lincoln pumpkin with 3.55 trac-loc/ Lincoln rear upper and lower control arms/ rebuilding '94 Mark Vlll eng. for swap/ -Edit- Engine rebuild now finished by Panhandle Performance (2-16-07)/ swap on soon - but needing to get P.I. torque converter- MSD window switch for '98 IMRC'S- rebuild current Baumann Trans--etc.
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post #13 of 45 (permalink) Old 03-04-2007, 09:33 PM
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just need to slap on the 1.25 addco rear bar, went from a boat to a go-kart in 30 min! That is if you want to spend another $150.. , but hey I was unknowingly driving with a cracked rear bar for quite a long time, so I'm not sure what stock felt like lol

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post #14 of 45 (permalink) Old 03-04-2007, 10:11 PM Thread Starter
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just need to slap on the 1.25 addco rear bar, went from a boat to a go-kart in 30 min! That is if you want to spend another $150.. , but hey I was unknowingly driving with a cracked rear bar for quite a long time, so I'm not sure what stock felt like lol
That's what I plan to do in the future mike884_2 since I did'nt see any difference between bars. But the sway bar was an unforseen distraction from my prime directive- which is getting that new DOHC out of my laundry room and connecting it to my gas pedal.
What happened was that a friend of mine has three super coupes that he wants to sell and/or part out. I wasn't interested, so I suggested that he post on TCCOA under the parts for sell area. Well, he got booted 'cause he's not a member and stuff. Then I got to thinking, Super Coupes have pretty groovey front seats, I better grab 'em before some of those fanatics at TCCOA do.( I didn't know he got the boot at the time.) Then I remembered that SC's had trac-loc 8.8's and bigger bars, and then I forgot about my prime directive and then I bought the seats and the bar and the diff.
Sooo- since my wallet was back on empty, I thought I throw that bar in-- then confusion set in, then I --- I better shut up now or I'll end up talking about my girl friend and stuff.

'95 LX 4.6L/ '99 mustang front calipers/ '96 t-bird rear calipers/Baumann transmission/BOC chip by Lonnie/ 225.55.16 Yokohama's on Borbet 5 spoke/poly IRS/ Eibach 1.5" drop/ Lincoln pumpkin with 3.55 trac-loc/ Lincoln rear upper and lower control arms/ rebuilding '94 Mark Vlll eng. for swap/ -Edit- Engine rebuild now finished by Panhandle Performance (2-16-07)/ swap on soon - but needing to get P.I. torque converter- MSD window switch for '98 IMRC'S- rebuild current Baumann Trans--etc.

Last edited by Thundernerd; 03-04-2007 at 10:48 PM.
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post #15 of 45 (permalink) Old 03-04-2007, 10:38 PM
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hmmmm, 3 lbs less...that right there is enough for me to go find one.

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post #16 of 45 (permalink) Old 03-07-2007, 04:57 PM
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I have seen this too...some 89 SC's either on purpose or by mistake got tubular rear bars. I've gotten them out of 2 parts cars that way, and both were obviously original.

They belong in the dumpster.

John

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post #17 of 45 (permalink) Old 03-07-2007, 05:05 PM
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Quote:
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I have seen this too...some 89 SC's either on purpose or by mistake got tubular rear bars. I've gotten them out of 2 parts cars that way, and both were obviously original.

They belong in the dumpster.

John
Why do they belong in a dumpster? Do you know anything the mechanics of a beam? The OD has more to do with the rigidity of the bar then if it is solid or not. It's all about the area moment of inertia of the beam's cross section, otherwise known as I in beam mechanics.

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post #18 of 45 (permalink) Old 03-07-2007, 09:08 PM
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Why do they belong in a dumpster? Do you know anything the mechanics of a beam? The OD has more to do with the rigidity of the bar then if it is solid or not. It's all about the area moment of inertia of the beam's cross section, otherwise known as I in beam mechanics.

-Miller
Ha ha ha...oh but I do. Here's what I know. Let's assume that the wall thickness of this sway bar is .120. That would be fairly typical, and it pretty close to what I measured on one of the bars I cut up. That would mean that the effective rate of that hollow bar would be roughly 63% of that of the solid bar. In other terms, it has a rate equal to that of a .94" diameter solid bar, and thus why it belongs in the dumpster.

These calculations assume these bars are made from the same materials, and have the same shape.

Have a nice day.

John

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post #19 of 45 (permalink) Old 03-07-2007, 09:26 PM
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Quote:
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Ha ha ha...oh but I do. Here's what I know. Let's assume that the wall thickness of this sway bar is .120. That would be fairly typical, and it pretty close to what I measured on one of the bars I cut up. That would mean that the effective rate of that hollow bar would be roughly 63% of that of the solid bar. In other terms, it has a rate equal to that of a .94" diameter solid bar, and thus why it belongs in the dumpster.

These calculations assume these bars are made from the same materials, and have the same shape.

Have a nice day.

John
Wrong.

For .94 solid bar:

I = (Pi)*R^4*.25 = 3.14*(.47)^4*.25 = .0384

For 1.08 hollow bar using .125 wall thickness (t):

I= (Pi)*R^3*t = 3.14*(.54)^3*.125 = .0616


.0616/.0384 = 1.60

Hollow bar is 60% stiffer. Thank you and have a nice day.

-Miller

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post #20 of 45 (permalink) Old 03-07-2007, 10:15 PM
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Ummm...you realize that sway bars work mainly on the principal of torsion right?

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post #21 of 45 (permalink) Old 03-07-2007, 10:18 PM
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Yes I do unfortunately I misplaced my mechnics 2 book but have found that the torque capacity of the hollow bar is about 5 times that of the solid.

-Miller

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post #22 of 45 (permalink) Old 03-07-2007, 10:24 PM
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Ok found it, I was wrong it is based on J which still comes out to being .077 for solid bar and .123 for hollow bar. This is still a 60% increase with all other variable remaining the same in the spring rate equation.

-Miller

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post #23 of 45 (permalink) Old 03-07-2007, 10:29 PM
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hey glad to see at that schooling came in handy bryan

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post #24 of 45 (permalink) Old 03-07-2007, 10:30 PM
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Ok...here...my numbers match perfectly with these...

http://www.1speedway.com/swaybar32.htm

You are comparing D^3 for a solid bar to (D^4 - d^4)/D for the hollow bar. Go ahead and check the numbers in that chart using those equations.

I don't know what kind of math your school is teaching you, but maybe you should try that class again.

John

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post #25 of 45 (permalink) Old 03-08-2007, 07:28 AM
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Your link clearly shows that a larger hollow bar has a higher spring rate than a smaller solid bar so I am not sure what you trying to make a point with. All of my calculations are from equations found in my machine design text book. Have you looked at the cross-sectional area of the two? The areas are with 2% of each other. Can you tell me a why a smaller bar would have a larger spring rate when the areas are nearly the same? No, you can't because you are wrong. Even though I was incorrectly using I initially, it is closely related to J which is why the numbers are nearly identical. I ran the calculations for the SC bar before selling it to Justin and if I felt it was crap I would not have sold it to him. I worked in suspension systems for four years, I have a good idea of how they work.

-Miller

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post #26 of 45 (permalink) Old 03-08-2007, 07:35 AM
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just get an adcco bar and be over with it...screw all this math stuff lol....i was happy with a 1.25" bar in the rear
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post #27 of 45 (permalink) Old 03-08-2007, 08:58 AM
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Quote:
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Your link clearly shows that a larger hollow bar has a higher spring rate than a smaller solid bar so I am not sure what you trying to make a point with. All of my calculations are from equations found in my machine design text book. Have you looked at the cross-sectional area of the two? The areas are with 2% of each other. Can you tell me a why a smaller bar would have a larger spring rate when the areas are nearly the same? No, you can't because you are wrong. Even though I was incorrectly using I initially, it is closely related to J which is why the numbers are nearly identical. I ran the calculations for the SC bar before selling it to Justin and if I felt it was crap I would not have sold it to him. I worked in suspension systems for four years, I have a good idea of how they work.

-Miller
Ok Mr. Wizard, since you apparently can't grasp the concept from what I have given you, I will walk you step by step through it. I've given you the two relative portions of the equations for this discussion, D^3 for the solid bar and (D^4-d^4)/D for the hollow bar. Let's apply these to a couple of bars in the link from above to show that the theory is correct. We will look at the 10" long bars in 1.25" diameter. We will compare the solid bar and the .120 wall bar. First, D^3 for the solid bar is 1.953. For the hollow bar, (D^4 - d^4)/D is 1.120. Ok, if we divide 1.120 by 1.953, we get .573, which means that the hollow bar is 57.3% as strong as the solid bar. So lets check now, the listed rate for the solid bar is 664. If we multiply that by .573, we get 381. If we check the chart for the hollow bar, low and behold it lists the rate of 381.

Now, we will apply this principal to the t-bird bars. From the tech articles, it lists the diameter as being 1.10, so we will use that, along with the .120 wall thickness dimension for a hollow bar. In this instance, D^3 equals 1.331, and (D^4 - d^4)/D equals .834. If we divide .834 by 1.331, we get .627, thus the hollow bar has a rate of 62.7% of the solid bar. Now, if we want to find the diameter of solid bar with the equivelant rate of the hollow bar from above, all we have to do is take the cube root of .834, which just so happens to equal .941. Do you think it was a coincidence that a lot of the later model cars got .94" diameter solid rear bars? I don't think it was.

By the way, what suspensions have you worked with? I would like to make sure and steer clear of them.

John

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1992 Thunderbird GT 5.0L
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post #28 of 45 (permalink) Old 03-08-2007, 09:33 AM
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ouch!

Hello

My Brain hurts just reading these posts.

I agree with Dode. There is a big difference between the Solid & Hollow rear sway bars. I have had both on the rear on my Circle track car, Street stock.

I am trying to get my car from pushing coming out of the corners. To no Avail.

I found the best was to support the upper shock towers in the rear. This removed alot of chassis flex. I still have the solid rear sway bar, Unhooked on left side. I left it in for more rear weight. Still only at 48% rear weight.

My new car will have a 1 3/8 Addco front swaybar with custom adjustable end links.
No rear bar(rules)

Paul

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post #29 of 45 (permalink) Old 03-08-2007, 09:51 AM
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I will make one small correction here...in the first part of the discussion, I was comparing torsional moments, so the correct units were used. However, in the last part to get to the equivalent rates, which are in terms of angular deflection, we need to compare D^4 and D^4-d^4. Thus, to find an equivalent solid bar to the hollow 1.10" bar, we need to calculate the 4th root of .917 which yields you a .98" solid bar, which still pretty much sucks.

John

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post #30 of 45 (permalink) Old 03-08-2007, 12:26 PM
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Quote:
Originally Posted by dode View Post
I will make one small correction here...in the first part of the discussion, I was comparing torsional moments, so the correct units were used. However, in the last part to get to the equivalent rates, which are in terms of angular deflection, we need to compare D^4 and D^4-d^4. Thus, to find an equivalent solid bar to the hollow 1.10" bar, we need to calculate the 4th root of .917 which yields you a .98" solid bar, which still pretty much sucks.

John
Well it seems you just agreed with me that the 1.10 hollow bar is better than a .94 solid bar. Let's see here, you say that a .98 solid bar is equivalent to a 1.10 but wait you also say the .94 solid bar is better than a 1.10 hollow. Seems you were wrong which would make me right...

I do a complete run through of all the math when I get home, shouldn't take any more 15 minutes. And oh yeah here are a few of the largest platforms I can remember off the top of my head: GMT900, GMT360, KA/KK, W-car, P221.

-Miller

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