Rear Sway Bar - Advise - Suspension and Brake Forum

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Rear Sway Bar - Advise
Friday, November 07, 2008 5:13 AM
I have an 04 cavalier ls, with the stock front bar. Car is used as a daily driver, but to give you an idea of the cars I drive on the weekend around town, I enjoy throwing my trans ams and vettes through turns, just cruising around. So obviously I won't be replecating the power, but I would like to add some roll stability to the cavalier, so that it doesn't roll so much in turns, the body stiffness doesn't bother me as much (aka the use of strut tower braces) and would rather not put the time into mocking up a CAD design of the cavalier to figure out the answer to my question, the question being what size rear sway bar is a good complement to the stock 24mm front sway bar? From browsing through the suspension FAQ it seems the ideal ratio between the bars is 1 to 1 which I find hard to believe. My general thought is that a 22mm rear bar is the best complement to the 24mm front bar, but I would appreciate the input of members on this board who have had extensive expereince driving and competeing with these cars. Keep in mind that when my endlinks on the front bar go bad....again..., I will be out of the extended warranty and will be replacing the bushings with poly. Also, I will probably at that same time switch to the billstein sport struts with the stock ls springs, and replace the front strut mounts with the 95-99 strut mounts and since I will replace all the struts at once I will replace the rear strut mounts as well, all being stock GM parts, with regards to springs and strut mounts.

Thanks

Re: Rear Sway Bar - Advise
Friday, November 07, 2008 5:31 AM
the generall consensus on the Jbody chassis is that there is a lot of understeer built in. Adding a larger rear bar (all other things equal) will bring the car to more of a true neutral feeling. I have the addco 1" front and rear bars and I think they compliment the handling nicely.

If you add the addco rear bar (25.4mm i think in metric), you will probably boarder neutral/oversteer balance, but if you're used to pushing a vette, it will probably feel comfortable



Re: Rear Sway Bar - Advise
Friday, November 07, 2008 5:45 AM
I'm do not drive competitively, but my two cents:
- The single biggest improvement in handling, for me, was better (low profile) wheels and tires. This was recently reiterated for me when I put on my winter tires and realized just how wishy-washy the car becomes. Even on stock suspension, this does quite a lot for carving corners.
- I have the "1:1" sway bars as you put it (Addco front and back), and the effect suits me for daily driving. Personal preference has a lot to do with the decision here. I've been quite happy with the car's stability in sudden maneuvers, and I was only able to upset the car (and end up backward) once while screwing around. It's tricky to work out desirable balance when working with an underpowered FWD car.




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Re: Rear Sway Bar - Advise
Friday, November 07, 2008 7:53 AM
addco front and rear sways plus the strut tower bars have helped out my cornering ability a lot.



Re: Rear Sway Bar - Advise
Friday, November 07, 2008 10:02 AM
i run addcos front and rear as well.

i ran just the addco rear for awhile with the stock 02 ls sport front (which if memory serves me corectly is a few mm smaller than your 04 front) and the car would get tail happy if you lifted mid corner or carried too much speed in. with both bars in place, it's a different story. The car feels much more planted and is alot more forgiving.



Re: Rear Sway Bar - Advise
Friday, November 07, 2008 10:17 AM
Quote:

the body stiffness doesn't bother me as much (aka the use of strut tower braces) and would rather not put the time into mocking up a CAD design of the cavalier to figure out the answer to my question

With this in mind, you need to go back to the basics automotive class 101.
Without a good chassis, you're wasting your time with doing all the suspension/ swaybar mods.
All your chassis is going to do is twist with the added stiffness to your springs and struts while the squirm of your chassis is going to hurt your camber/ toe alignments for any handling benefits you've done with your suspension.
Maybe this is why the understeer is so bad with our J-bodies because the chassis is so loose.
I'm a big advocate of chassis tuning as is most racers and top tuners.
Maybe they know something that we dont.



Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Rear Sway Bar - Advise
Friday, November 07, 2008 10:23 AM
I run a progress rear bar, and just have my stock equipped Z24 bar upfront. That plus strut braces, and a lower frame brace keep my 99 Z glued down quite well.

The sig pic is chopped heh. Just in case you wondered.

Any rear sway bar is going to be a huge benefit as I'm sure you know, I'd just do that and get some polyurethane front swaybar endlinks and call it good.






Re: Rear Sway Bar - Advise
Friday, November 07, 2008 10:38 AM
KFLO wrote:

Any rear sway bar is going to be a huge benefit as I'm sure you know, I'd just do that and get some polyurethane front swaybar endlinks and call it good.

I had that setup for a long time using the Hellwig rear bar and some good D bushings for the factory Z swaybar with Energy Suspension endlinks. It was a nice combination and the handling was sweet and neutral.
Front and rear strut bars were used along with a subframe brace so the car road fantastic.



Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Rear Sway Bar - Advise
Friday, November 07, 2008 8:28 PM
Misnblu wrote:
Quote:

the body stiffness doesn't bother me as much (aka the use of strut tower braces) and would rather not put the time into mocking up a CAD design of the cavalier to figure out the answer to my question

With this in mind, you need to go back to the basics automotive class 101.
Without a good chassis, you're wasting your time with doing all the suspension/ swaybar mods.
All your chassis is going to do is twist with the added stiffness to your springs and struts while the squirm of your chassis is going to hurt your camber/ toe alignments for any handling benefits you've done with your suspension.
Maybe this is why the understeer is so bad with our J-bodies because the chassis is so loose.
I'm a big advocate of chassis tuning as is most racers and top tuners.
Maybe they know something that we dont.


If I was going to be using this car for autocrossing my outlook on it would be much different I see many people that have responded have gone with strut tower braces and sfcs, which are all things I run on my race car, in addition to alot of other componets (allowing for extra adjustability and added or lessend stiffness depending on track demands), with the cavalier my main intent is to relieve some of the stress on the front sway bar bushings, which these cars seem to have a nasty habit of eating, and to lessen the body roll in turns, so the idea is to go with poly front bushings and to add a rear sway bar with poly bushings of course, which should aid in lessening rolling in turns, while still allowing the body to flex as is in a J-body's nature, haha. Adding strut tower braces and the sfcs will just transfer and amplify that body flex to these bushings and put more wear and tear on the stock suspension, which would then lead down the road of needing to use pillowball strut mounts, appropriate lowering springs, performance struts, so on, and so forth. I guess I should have made my intentions more clear in the original post. And I do find it quite shocking that the "ideal" sway bar size proportion is "1:1" so to speak, that is just weird to me, though thinking about the J-body layout it does make sense.

What is the general opinion on using the 24mm stock front bar with the 25mm addco rear bar, (obviously I could go with a 22mm rear bar which would lessen the body roll, but again would not be as close to the "ideal" as the addco bar, I guess another thing to be considered is if all these bars are made of the same material composition, though it appears addco is the bar of choice in this topic so possibly the construction by the different manufacturers does not play as large a roll) this seems to be the most ideal possibility without replacing the front bar, and I really don't want to spend the time dropping the cradle to install a new front bar, when it is only going to be about 1mm larger than my stock bar?

I do apologize for all the questions, however, I am used to dealing with small block chevy cars, so the companies I usually deal with a Spohn, Moates, TPIS, GM, etc.. I have heard of Addco and Eibach, but other than that alot of the companies mentioned in these forums and the FAQ are new to me, such as rksport, mantapart, etc..

Also another note about the car, there was a comment about the wheels and tires above, I have the stock 16in. alloys wrapped with Yokohoma Avid V4s, so I don't have any problem with grip, which is something I could not say about the Goodyear pieces of crap that came on the car new, I don't think that plays any real role into the current discussion (other than increased load on my sway bar bushings), but possibly it could just be my mind missing something, it is getting late for me, been a looooong day.

Thanks again for all the responses.
Re: Rear Sway Bar - Advise
Friday, November 07, 2008 8:34 PM
ya the rear sway bar is a great mod to do.


good luck




Re: Rear Sway Bar - Advise
Friday, November 07, 2008 9:27 PM
John, the 'ideal' swaybar ratio is not 1:1.
Ideal handling would be considered neutral and not oversteer or understeer.
Having the Addco rear with the stock front would initiate trail braking oversteer which is good for autocrossers but not good for street manners, especially in the rain.
Generally you'd want the front bar to be a few millimeter larger than the rear for this neutral handling.
A good setup was the Hellwig rear swaybar which was 19mm with the Z24's front 22 mm stock bar.
The next aftermarket neutral setup would be the Eibach bars with 25mm front and 22mm in the rear. Very neutral handling and you can tune in a bit more oversteer with more air in the rear tires if you want a bit more trail braking oversteer.

I also posted what I did because the cars I drive daily I still want to handle for situations like having to do evasive maneuvers. WIth a good chassis and suspension, evasive maneuvers are much more controllable than one that is totally stock. It could mean saving your car from that corner you're having to evade or hitting it because of the squirm of your chassis not being able to handle the quick transition.
This is why I advocate such things as I've been in these situations that I know would have never saved my cars were it not for the work to the chassis as well as the suspension.

Good luck though and don't feel bad for asking questions. We don't mind answering the best of our abilities.



Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!






Re: Rear Sway Bar - Advise
Saturday, November 08, 2008 10:49 PM
Quote:

Generally you'd want the front bar to be a few millimeter larger than the rear for this neutral handling.
A good setup was the Hellwig rear swaybar which was 19mm with the Z24's front 22 mm stock bar.
The next aftermarket neutral setup would be the Eibach bars with 25mm front and 22mm in the rear. Very neutral handling and you can tune in a bit more oversteer with more air in the rear tires if you want a bit more trail braking oversteer.


And you're referencing the daily driver.
Which I hope you got the K brace and trailing arm bushings in.
(how was the install on those)

But I thought by nature, physics, or dumb thinking, our fwd cars had narual understeer.
Hence the lager by
Quote:

a few millimeter
bar in the rear was better to get the neutral action.

-M


Remember....syringes go in the RED waste basket.
Re: Rear Sway Bar - Advise
Sunday, November 09, 2008 7:06 AM
Mastin, yeah, most fwd vehicles have inherent understeer programmed into them for safety reasons because most consumers can't drive.
Also, with a front engine car, you'd usually want a larger front bar to offset the weight difference compared to the rear of the car, hence the larger diameter front bar compared to the rear.
This is basic suspension theory as most engineers use this formula for their suspension designs, including race cars.
Cars that are better than our J-bodies have the luxury of having adjustable swaybars with endlinks that can be adjusted via heim joints or holes. These offer more tuning over what we have available.

Oh and I'm tearing down the 'blu this week for the rear axle removal to install the new bushings for the trailing arms. I'll be doing a write up on it and will post it on a couple of forums when I'm done with it.
Since the car is all taken apart, the Neon disc swap will take place too.
I do have the K-brace on the car but was a bit disappointed in the design of the flanges having to be bent to accomodate the subframes non so flat surface.
Here's what it looks like. Oh and it was a bitch to bolt up the two flanges in the back of the K-brace.


/End thread jack


Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Rear Sway Bar - Advise
Monday, November 10, 2008 12:40 PM
^^^ ok, that is a little strange.
Mine sits perfectly flush.
Even with drilling holes with no light at 2 in the morning in 30 degree weather.
And we're both auto.


And the bolts were easy to install once I realized to take the wheels off.
I was replacing the RK brace, so the front holes need tlc.

But the ends should not bend like that.

-M



Remember....syringes go in the RED waste basket.
Re: Rear Sway Bar - Advise
Monday, November 10, 2008 4:02 PM
Mastin wrote:^^^ ok, that is a little strange.
Mine sits perfectly flush.
Even with drilling holes with no light at 2 in the morning in 30 degree weather.
And we're both auto.


And the bolts were easy to install once I realized to take the wheels off.
I was replacing the RK brace, so the front holes need tlc.

But the ends should not bend like that.

-M

Pics would be nice Mastin.
On having to bend the tabs like that, it was the only way to have it attached to the subframe because any other way, they would've just dangled there in the air.
And yeah, I had the wheels off with the car as high as it could go on the jackstands. Where the bolts go for the rear of the K-brace, you have to insert your bolts through the hole where your control arm comes into the subframe and believe me, it wasn't easy. I think I learned a few new curse words while doing this.
I would like to see a picture to make sure I did this right. I'm pretty sure I did but again, would like to do some comparisons of what you did and what I did.
Thanks man.
Oh, just a peek at the trailing arm bushing swap and Neon disc conversion. It'll be a few weeks before it's complete but it's started along with other projects I have going on right now with the 'blu.



Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Rear Sway Bar - Advise
Wednesday, November 12, 2008 6:02 PM
I have the pics stored on the camera, I will get them up.
Been stuck at work upgrading servers kickin my azz.

-M


Remember....syringes go in the RED waste basket.
Re: Rear Sway Bar - Advise
Wednesday, November 12, 2008 7:14 PM
^^^^ uhm yeah... james.. i think you need to change your name to braceboy. you literally have 14 braces (that i can see and remember) throughout your car. dear god man.

i didnt know you had those underside braces either, i like that zig-zag one in the center!! (you better believe your getting a pm about it)

my addco rear did wonders for my car. made it feel so much more 'sporty'. definitely a must if your going to be doing fast corners.



+ + + ++ + +++ + =
Re: Rear Sway Bar - Advise
Thursday, November 13, 2008 3:35 PM
i would say go with the progress bar. thickness between that and the addco is what 3.5mm but bar thickness has nothing to do with the spring rate in the end and the progress does not use end-links that flex and kill some of the spring rate/roll resistance when it comes down to it. and the progress is tucked up better!


see ya!

Re: Rear Sway Bar - Advise
Friday, November 14, 2008 12:41 PM
Pic of my K brace on an automatic:






I was in a rush.
And I went from the RK brace to this one. So the front holes are a little off.

But, I'm not having the major bending issue.
And since I suck ass at drilling, I'm using grade 8 of both 5/16" and the 3/8" bolts.
Basically whatever what easiest to shove up the holes with minimal reistence.

I wonder that's different for you car?

-M


Remember....syringes go in the RED waste basket.
Re: Rear Sway Bar - Advise
Friday, November 14, 2008 2:10 PM
Hmmm, I'd still love to see how the back braces are on the subframe and to see how you got the bolts through the subframe to bolt it down.
I'm also using 3/8's and 5/16th nuts and bolts but am using a grade 5 stainless steel so I'll never have a rust issue of the bolts.
Thanks for the pics though.


Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Rear Sway Bar - Advise
Friday, November 14, 2008 3:36 PM
^^ once the tires are removed its pretty easy.

Even with the sway bar in the way it was no problem.

To actually drill the holes, I have the brace bolted in the front, and just haning for the back parts.
Then drilled up up and away until the hole was made.

-M


Remember....syringes go in the RED waste basket.

Re: Rear Sway Bar - Advise
Friday, November 14, 2008 4:11 PM
Yeah, I did the same with tire removal and mounting the front part of the K-brace and using the holes in the rear section for making my holes.
But my question is, how did you get the bolts through the subframe, through the holes so that you can spin the nut onto it?
I had such a difficult time reaching into where the control arm bushing is to insert the bolt and wrench to tighten it all down. I mean the job got done but I was just wondering for not only my sake but the sake of others doing this if there's an easier way to do that and that there may have been something that I was missing while installing the K-brace.
Thanks.



Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Rear Sway Bar - Advise
Saturday, November 15, 2008 3:17 AM
Umm, there was plenty of space.

Once I had the tire off.
I just sat down near the spacing behind the front rotor.
I was able to reach in and use 2 ratches like normal, one top one underneath, and it worked out fine.
Actually went quicker than the front 4 bolts.

Maybe because you have the larger sway bar you had more difficulty?
Mine is just the factory 22mm.

-M



Remember....syringes go in the RED waste basket.
Re: Rear Sway Bar - Advise
Saturday, November 15, 2008 5:05 PM
Not sure Mastin.
But thanks for the feedback on how you did your install.
As long as I've got the K-brace on the car and it's solid, that's all that matters.



Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Rear Sway Bar - Advise
Sunday, November 16, 2008 10:27 AM
how the hell do you guys have like a half inch of distance between the brace and the tranny pan? ive tried the rk and the control fx bars on my car and the damn things RUB on the pan. no clearance whatsoever.

is it because your ground clearance is less? is it even less?



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