Author Topic: Front sway bar bushing upgrade (Read 37619 times)

lil goat · « **on:** August 21, 2009, 12:00:37 PM »

I know nothing about this subject but I do have the correct size polyurethane bushings on my car, and they work and do not bind. If anyone wants any info look it up yourself.

smartin · « **Reply #1 on:** August 21, 2009, 07:42:26 PM »

I ordered them as instructed. Thanks.

smartin · « **Reply #2 on:** August 22, 2009, 04:10:50 PM »

Will do.

snaponbob · « **Reply #3 on:** August 23, 2009, 07:06:08 PM »

I have now settled on GXP/Z0K bars at both ends for racing. After a few events I have reverted BACK to stock bushings. No matter what lube used on the poly sway bushings they eventually started to influence the action of the bars. After some testing with corner scales the poly bushings went in a drawer.

BTW, not meant to set anybody's hair on fire.

LiquidPT · « **Reply #4 on:** August 23, 2009, 07:45:52 PM »

Quote from: snaponbob on August 23, 2009, 07:06:08 PM

I have now settled on GXP/Z0K bars at both ends for racing. After a few events I have reverted BACK to stock bushings. No matter what lube used on the poly sway bushings they eventually started to influence the action of the bars. After some testing with corner scales the poly bushings went in a drawer.

BTW, not meant to set anybody's hair on fire.

Did you try the Energy Suspension lube? Looks like it's teflon based and what's recommended for these bushings. I haven't had a chance to put mine on yet.

snaponbob · « **Reply #5 on:** August 23, 2009, 07:55:22 PM »

Quote from: LiquidPT on August 23, 2009, 07:45:52 PM

Did you try the Energy Suspension lube? Looks like it's teflon based and what's recommended for these bushings. I haven't had a chance to put mine on yet.

Yup. Even spoke with a couple different guys AT E.S. and they basically stated that ANY good petroleum based or synthetic grease will do as the bushing are not sensitive to either type. Just personally, and a surprise to me, I like the feel and the car's reactions with the stock bushings. They seem to be firm enough yet let the bars work as intended.

LatinVenom · « **Reply #6 on:** August 24, 2009, 01:39:30 PM »

Quote from: snaponbob on August 23, 2009, 07:06:08 PM

I have now settled on GXP/Z0K bars at both ends for racing. After a few events I have reverted BACK to stock bushings. No matter what lube used on the poly sway bushings they eventually started to influence the action of the bars. After some testing with corner scales the poly bushings went in a drawer.

BTW, not meant to set anybody's hair on fire.

Bob:
What made change your mind about using both Z0K bars?. As you know I ordered both (Rear sway still on Backorder) but you said at the time not to do it.

snaponbob · « **Reply #7 on:** August 24, 2009, 02:14:25 PM »

Quote from: LatinVenom on August 24, 2009, 01:39:30 PM

Bob:
What made change your mind about using both Z0K bars?. As you know I ordered both (Rear sway still on Backorder) but you said at the time not to do it.

Sort of a long slog through 4 pairs of front springs 3 pairs of rears, three different front bars in conjunction with the FE3 rear bar. Given the (correct) advice to suspension tune (for racing) with springs first, THEN bars, THEN shock settings, once I had the basic package close to where I wanted it (things really changed for the better once I had fully transitioned from 295s to 315s) I knew it was time to get the rear bar. At that point I found the FE3 front a bit soft and my Saner bar too stiff. Soooooooooooooo, GXP/Z0K front bar. Saturday the car was a killer but Sunday it turned out I was a bit dehydrated and could not focus well so drove like crap. I am CONVINCED that as it sits a better driver could be well in the B/SP trophies at the SCCA Nationals. ME? I will have to drive out of my skin JUST once on each day and I might trophy as a "last of the best" instead of "best of the rest". Found the 100 octane Sunoco in Lincoln and already have the 96 and 98 octane tunes from Lyndon. Fresh rubber ready to go on, but talent may be on backorder. We'll see.

Note to self: bring lots of water and Gatorade. Try NOS this week to see how THAT works (on ME, not the car).

LatinVenom · « **Reply #8 on:** August 24, 2009, 02:47:54 PM »

Good luck Bob,
Thanks for the info.

Uranium-238 · « **Reply #9 on:** August 24, 2009, 03:25:04 PM »

I swear by Monster and Gatorade. Monster wakes you up, the gatorade keeps the energy drink from making you dehydrated. Last A/X meet I drank at least 2 gallons of gatorade over the course of the day. That stuff is a must.

snaponbob · « **Reply #10 on:** August 24, 2009, 04:31:16 PM »

Monster dries you out???? THAT sucks.

Uranium-238 · « **Reply #11 on:** August 24, 2009, 04:32:39 PM »

Anything with caffeine will do it. Coke or Pepsi aren't as bad, it's noticeable with Mountain Dew, it can get bad with energy drinks.

snaponbob · « **Reply #12 on:** August 24, 2009, 07:11:35 PM »

I knew about caffeine. So, back to what I know works !!!!!!!!!!!!!!!! Drink water until my eyes start floating !!!!!!!!!!!

Uranium-238 · « **Reply #13 on:** August 24, 2009, 07:13:16 PM »

Well, at least switch to Gatorade.

smartin · « **Reply #14 on:** August 25, 2009, 05:57:33 PM »

The rear ones arrived today. I still need to order the front ones.

kennysabarese · « **Reply #15 on:** August 28, 2009, 12:06:05 PM »

Let us know how it goes. Hopefully I will be putting on bars soon.

I guess really I should just try the combinations myself...

LatinVenom · « **Reply #16 on:** August 30, 2009, 11:25:07 PM »

When I order the Z0K bars I also order the Z0K hardware. I also order the grease fitting ones for comparison.
Once I get rear bar, will do some testing to see which ones I like better.

Uranium-238 · « **Reply #17 on:** September 03, 2009, 05:29:06 PM »

Since I have access to a decent caliper, Goat asked me to measure the front stock anti-sway bar...turns out it's 1.319 inches, or 33.5 mm.

kennysabarese · « **Reply #18 on:** September 03, 2009, 07:17:30 PM »

i got both front and back bars today

the orange stickers say 25919110, and 25919109 bushings are 25855623

snaponbob · « **Reply #19 on:** September 03, 2009, 08:35:56 PM »

Quote from: kennysabarese on September 03, 2009, 07:17:30 PM

i got both front and back bars today

the orange stickers say 25919110, and 25919109 bushings are 25855623

JACKPOT. You'll like the results.

kennysabarese · « **Reply #20 on:** September 03, 2009, 09:09:22 PM »

i'm gunna try the rear first, drive around, then the front. then maybe play with urethane bushings

snaponbob · « **Reply #21 on:** September 04, 2009, 10:34:46 AM »

Quote from: lil goat on September 04, 2009, 07:02:19 AM

OK I am showing my age hear but if I remember right the rear bar effects the front and the front effects the rear at least to some degree. I have noticed two things with the new front bushings, the front seems to require a little less input to turn and the rear seems a bit looser. I have not played with damping yet. I feel like I need to soften the rear a bit, they are pretty stiff now. The fronts feel about right. with 0 being stiffest I am at at +14 in front and +17 in the rear. Before I put on the stiffer front bushings I was going to increase damping in the rear. I am going to try the 34mm bushings up front.

The sway bar is actually a preloaded lever, when you change the front bushings not only does it change the bushing to a stiffer bushing it changes the preload as it is so much thinner. It moves the bar about 3/4 of an inch closer to the frame. Bob can probably explain this better than I can but I am sure it has an effect. If I understand it correctly this will make the bar stiffer. I think even more stiffness could be achieved by changing the end links to shorter ones. They are also very cheap I may try this at some point. I think ours are 2 7/8 " now. I like the cheap easy stuff, if it doesn't work just change it back.

I'm sort of confused as to what bushings you have on which bars.
if I remember right the rear bar effects the front and the front effects the rear at least to some degree
The bar affects the end that it is attached to. BUT, the way THAT end now works makes the other end feel better or worse.
the front seems to require a little less input to turn and the rear seems a bit looser
Not knowing what rate springs you have it's sort of hard to nail down what is happening. But if the shocks are set wrong (relatively speaking) or the front springs are too soft, the firmer action of the front bar may be doing this.
The sway bar is actually a preloaded lever, when you change the front bushings not only does it change the bushing to a stiffer bushing it changes the preload as it is so much thinner
Now I AM confused.

With the car EMPTY and setting on level pavement, the bars should be completely unloaded. This is where adjustable endlinks come in to play; with driver weight in the seat set the adjusters to ZERO load at the control arm. (Theoritcally, only ONE adjustable end link is needed per bar.) The poly bushings are reducing the movement of the bar as loads go into the suspension and thus "act" just a bit quicker, but once the twist starts very little is different from rubber bushings. For left and right driving there should (ideally) be ZERO preload at rest. The roundy round guys can use preload to adjust how their cars corner (entry, middle, and exit).
If I understand it correctly this will make the bar stiffer. I think even more stiffness could be achieved by changing the end links to shorter ones
In practical terms, the endlinks are there to keep the bar clear of other pieces and fairly parallel to the ground. The bar is as it is, and can't be "tricked" into being anything different (stiffer or softer) than it is. It is hollow or solid with certain diameters and wall thickness (and even different hardness), X inches left to right (in the center), arms are Y inches long at Z angle, and people that know this stuff can be figure out what "rate" a given bar is. Moving the mount up, down, in, or out fractions of inches really doesn't matter unless there have been REALLY big changes in average ride height. On some cars suspension binding can occur as the pieces "compete" with each other as the suspension moves. I know that mt TR8 can have that problem, but I seriously doubt this is an issue. (After all, the differences in a poorly designed 30 year old British car and a Kappa ARE rather easily appreciated !!!!!!!!!!!!!!! Trust me on THAT one.) The stock end link is the best legnth to stay with, should be at about a right angle to the travel, and its legnth will not effect the rate of the bar. On a given bar only moving the location of the link on the bar will change the bar's rate. I punched a hole (on each end) inboard of the existing hole on my FE3 bar and I could feel the change. Getting back to the bushings, THEY will alter WHEN the effect of the bar takes place - it isn't getting stiffer (that is a constant for a give bar and endlink point) it is just "working" sooner.

Phew. Sorry. Goat touched on a bunch of things in one post.

(Disclaimer; not trying to lecture. I have been screwing with the suspension and alignments since October 06 when I first Solo'ed my RL while in SCCA Solo Stock class for 07 and 08, and this year has been a real thrash for Street Prepared. I have made a ton of changes and nearly as many mistakes. Just trying to shorten other peoples learning curves as it is cheaper NOT to repeat other peoples mistakes.)

Semi off topic, but not too far. Did you know that C4, 5, and 6 Corvettes come with PLASTIC end links!!! Just found that out two days ago.

Critterman · « **Reply #22 on:** September 04, 2009, 10:46:00 AM »

Okay Bob after reading that I now have a question.

Bob said->

Quote

Moving the mount up, down, in, or out fractions of inches really doesn't matter unless there have been REALLY big changes in average ride height.

How much difference are we talking about, say in a Kappa lowered 1 1/2"? That would pre-load the swaybar correct?

Uranium-238 · « **Reply #23 on:** September 04, 2009, 10:50:57 AM »

If both wheels move the same amount, the sway bar has no effect, so no, it doesn't do anything.

Am I right in my understanding of this?

snaponbob · « **Reply #24 on:** September 04, 2009, 01:05:15 PM »

Critter, 238 has it correct. The sway bars only "function" when there is different vertical deflections at the opposing end. Adjusting the ride height seems not to have any problems as it relates to the bars or suspension binding up. I referred to my TR8 as the front sway bar doubles as a locating component for the front struts. Now, that IS screwed up, but there is a fix for that in the form of aluminum blocks that moves the frame locating points for the bar. While this DOES matter on the TR8 it does not matter on the Kappa. COMPLETELY different set up.

As for sway bar "pre-load", that does not happen unless one intentionally alters the length of one of the links. And pre-loading the sway bar is a BAD thing unless one ONLY turns left or right. Yes, there IS a bit of uneven loading of the bars when a person jumps in the car, but a passenger will almost completely offset this. The little bit of uneven load on the bar on our cars is not a big deal, and nobody will really notice it.

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Author Topic: Front sway bar bushing upgrade (Read 37619 times)

lil goat