Swaybars and spring rates

When adding a rear swaybar (maybe front does this too?) I hear and it seems logical that it has the affect of an increased spring rate all in itself. Is there anywhere that lists how much ft/lbs. or kg/mm different bars have the effect of increasing the suspension setup by? I'm thinking like my ITR rear swaybar has an effect of something like 1kg/mm or something like that?

I don't know if there is a direct way to measure it since it involves fulcrum points, if the bar is hollow or not, if it is steel or aluminum or titanium, what tires you are using etc....

I figured it was probably something pretty technical.

It could never be that easy... lol

DoubleTap

corner weighting the car wouldn't tell you this? say weighing it before and after the sway bar?

i don't claim to be an expert, but if the car flexed a little, wouldn't that take the weight off the corner being weighed?

i just thought about it for like 3 minutes, and it doesn't make sense to me anymore, but sometimes my second guesses are wrong.

corner weighting the car wouldn't tell you this? say weighing it before and after the sway bar?

i don't claim to be an expert, but if the car flexed a little, wouldn't that take the weight off the corner being weighed?

i just thought about it for like 3 minutes, and it doesn't make sense to me anymore, but sometimes my second guesses are wrong.

I see the logic in that, but I don't think it would work. Once you add the bar back in (corner weighting before hand) I think there would be some off balance issues that would make determining the actual kg/mm differance.

Also of note, spring rate refers to how much force is needed to be exerted on the spring before it begins to compress, and I don't think a corner weight maching could tell you this. You'd need something that would measure the compression force of the suspension BEFORE adding the bar, and then again after adding it.

Plus when corner weighing a car you are supposed to disconnect the sway bars anyway :)

Plus when corner weighing a car you are supposed to disconnect the sway bars anyway :)

Whoa, that I didn't know. I might be getting the Civic corner weighted pretty soon here too! Thanks for that heads up. :)

sry to dig it up but how much does corner balancing a car actually help in manueuverability also, does the difference in ride height make the car look lopsided enough to look bad?

sry to dig it up but how much does corner balancing a car actually help in manueuverability also, does the difference in ride height make the car look lopsided enough to look bad?

It depends. I do it myself at my sponsor's shop. I'm guessing around $60-100 for corner weighing. And yes it can help with handling. If your car is not 50/50 then you would turn better one way than the other.

Corner weighting helps greatly in a race car, in a street car it's that big of a deal because your not driving on the edge 100% of the time.

No the car won't look lop sided unless there is one side much heavier than the other, for instance a 500lbs driver. Always balance the car with the weight on the driver simulated in the seat by placing weights.

I havent seen SilverY2k on for a while, then again I'm not on much as I used to be. Spend a couple hrs. here on AF + my work(8-10hrs) playing with cars. I think I'm addicted, shit I knew that when I was 4 thanks to this . . . . .
http://files.automotiveforums.com/gallery/watermark.php?file=503/35564General-Lee---Side-View.jpg

I'm on HAN and HT most of the time :)

I'm here too, just not as much as I used to be. I usually browse the www.sohchonda.com forums mostly these days.

Anyways, about 2 weeks ago I noticed (and HEARD) my ITR rear swaybar tearing itself out of the subframe (http://img.photobucket.com/albums/v231/phixion/Stuffs/subfrm1.jpg). :( And yes, I AM running the Beak's SRK. As soon as I discivered it, I immediately disconnected the endlinks from the LCAs, and all is well for the most part, it could still be tearing, though not anywhere near as much as it would be if the pressure of the ITR swaybar were still on it. I'm furtuneate I caught it in enough time before it did some real serious damage to my car. A homie of mine, his dad is welder, so he's gonna hook that part of repairs for me (thank goodness!) and I was able to obtain an AutoCAD templete of an exact dimension steel plate to weld in place over where the tear will be welded back fixed, so that the tear won't spread or start again, which my friend's dad will also fabricate up for me at his work. Thexe plates and welding don't guarantee it won't happene again, as it WILL eventually start tearing again, though somewhere else on the subframe. My remedy for this will be to get rid of my beloved ITR rear swaybar and Beak's kit, get another Si bar and brackets again, and I'm planning to up my currently 6kg. (336lbs.) rear springs to 10kg (559lbs.), all to make up and compensate for the stiffness I'll be losing from the bar. Already the past 2 weeks my car has felt like crapola in the handling dept. Even adjusting my shock dampening softer at the front and stiffer at the rear didn't help much if any. Understeer is VERY prominent now, and ugh! When all is said and done I'll have spring rates of 8kg up front (going down 2kg from my current 10kg there) and then 10kg springs at the rear along with having my rear Teins revalved to accomidate the much stiffer springs.

This suspension stuff is a b!tch sometimes... :(

This is why I did it right the first time and forked out alittle extra money for the Comptech rear sway bar.

Got ya good SilverY2K, luckily in your case it's repairable. My 91 mounts different than the newer Civic's but the brackets bolt to the frame in a cheezy way so I welded & bolted to the frame. That rear sway is on it's stiffest setting(shortest travel) and I haven't had a problem yet.

I think I'm addicted, shit I knew that when I was 4 thanks to this . . . . .
http://files.automotiveforums.com/gallery/watermark.php?file=503/35564General-Lee---Side-View.jpg

Ahh the general Lee.

This is why I did it right the first time and forked out alittle extra money for the Comptech rear sway bar.

CivicSiRacer, Extra money is just extra money in the end, with the standard EJ/EM frame, there is no right way the first time unless you weld in an ITR subframe from the get-go or just stick with the 13mm Si swaybar at the rear. The subframe is just too thin and too fragile. The Comptech bar combo isn't any better than my ITR bar since it's almost the same design (as far as the bar is concerned) and the same diameter, and having the integrated tiebar doesn't help it out much more from preventing subframe tearout. Here's a quote from a member that replied to a thread I started on the sohchonda.com forums about my tearout issue...

My roommate works for Honda R&D, in the suspension department, and we had an interesting conversation about rear subframe tearout.

The Honda R&D Showroom Stock C racers use 99-00 Civic Si's with the Comptech rear combo bar/tie bar. Seems they tear them often, and need to replace rear subframes at least once, sometimes twice a year.
And they use the stock 26mm front bar, and factory springs. It's simply the sheetmetal isnt up to par with the loads placed on them, whether it's through the LCA bolts or not.

Also, I asked about the Type R, and he said things might change for the worse when the factory ride height is altered. Which I will tie into the fact that your car is pretty low. Angles are different, acting forces are working against you, and thus a subframe tearout. Had the ride height been higher, it might not have happen.

My roomie has a 96 that had the Progerss set-up, and his tore.
Survived 4 years of autocrossing, then decided it was time to let go.
He added, it's just a matter of time.

Here's a better explanation of what I'm refering to above the quote, this is a reply to an email I shot over to Beak's about my tearout when asking what exactly causes it...

Matt,

I am sorry to hear about your problem with the subframe. The cause is no mystery--it's because the sheet metal is too thin to resist the shear load placed on it. The SRK is design to spread the load over a larger area to reduce the shear stress, thus minimizing the chance of a tear out such as what you experienced. But in a perfect world, the sheet metal would be thicker like how the ITR subframe is.

I have heard more failures of the EK subframe than on EG or DC2's. I suspect part of the reason is the possibility that Honda uses thinner guage metal on the EK subframes. Another has to do with the subframe shape. Both subframes have a recess in the area where the LCA and swaybar bracket bolt to. The recess is stamped into shape. The process "cold-works" the metal, which strengthens the metal at a molecular level but also makes it more brittle. The EK subframe recess appears more arupt than the EG's, where the radius of the transition is smaller. This tighter turn on the metal makes the cold-working effect even more drastic and the material is more brittle where it's being bent. All in all, the areas formed to shape in this manner is weaker and is where it will fail first on the whole subframe structure.

Going with higher coil spring rate helps to reduce vehicle roll and take some of the work (twisting) out of the swaybar, which translate to less stress placed on the subframe mounting area. If you are going to have the damage fixed, weld on a steel plate up to 1/8" thick to the flat area of the subframe (not to the recessed area). This plate will be big, but that's what you want to spread the load. If the welding is done properly (sufficient cleaning, consistent weld beads, etc.), you can probably do without the SRK. In a near perfect world, all ITR swaybar conversion will have welded reinforcements instead of bolt-on plates like the SRK, but few people whats to go that route.

Let me know if I can help with your problem in any way.

-Wil

That reply makes things perfectly clear on the issue! Seems Honda short changed the 6th gens, but fitting since Civics are still econo cars, can't expect much more. The plate I'm getting welded on this coming week is "1/8th think like Wil recommends. Luckily I live about 15 miles from where Beak's is located, so if I need to take it to them for any reason, I can. A plate will NOT completely tear-proof the subframe, just stop the tear in it's tracks, but also allow it to tear in another location in the future.

CivicSiRacer, Extra money is just extra money in the end, with the standard EJ/EM frame, there is no right way the first time unless you weld in an ITR subframe from the get-go or just stick with the 13mm Si swaybar at the rear. The subframe is just too thin and too fragile. The Comptech bar combo isn't any better than my ITR bar since it's almost the same design (as far as the bar is concerned) and the same diameter, and having the integrated tiebar doesn't help it out much more from preventing subframe tearout. Here's a quote from a member that replied to a thread I started on the sohchonda.com forums about my tearout issue...



Here's a better explanation of what I'm refering to above the quote, this is a reply to an email I shot over to Beak's about my tearout when asking what exactly causes it...



That reply makes things perfectly clear on the issue! Seems Honda short changed the 6th gens, but fitting since Civics are still econo cars, can't expect much more. The plate I'm getting welded on this coming week is "1/8th think like Wil recommends. Luckily I live about 15 miles from where Beak's is located, so if I need to take it to them for any reason, I can. A plate will NOT completely tear-proof the subframe, just stop the tear in it's tracks, but also allow it to tear in another location in the future.
Were you using a front sway bar? I think you said before you weren't using one at all.

Were you using a front sway bar? I think you said before you weren't using one at all.

If I remember correctly he wasn't using any front sway bar at all.

You're both right, no front sway. :) I just have the Megan Racing H-brace, actually does help out quite a bit. It cut down on my oversteer i had without adding in much if any understeer. My future setup will be 10kg rears, 8kg fronts and the ability to swap the front springs to the back and vice-versa if the rear ends up being too stiff with the 10kg springs. I'm going to have them revalved to a base of 8kg, so I can go up to 10 on them and as low as 6kg since I have a pair of 4kg, 6kg, 8kg and 10kg springs.