Rear Stay bar 101, Page one (from old site)

[chicane67]

camaroboy69
Registered User
Posts: 1313
(7/6/04 7:17 am)
Reply
Rear and front sway bar 101 (excellent info!)
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I was just curious to what some of you were running for a rear sway bar on your 1st gen camaros or any other cars that didnt come with them.
EDIT: Oh yeah pics would be appreciated too.
Adam
My Website 06-25-04

Edited by: camaroboy69 at: 7/12/04 8:55 am

streetfytr68
Registered User
Posts: 1149
(7/6/04 7:54 am)
Reply Re: What are you running for a rear sway bar?
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Addco 1" mounted to the underside of a 12 bolt.
/Steevo

www.lateral-g.net

carreranova
Registered User
Posts: 44
(7/6/04 8:19 am)
Reply Took it off...
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We had a Hellwig bar on the rear of our road racing 64 Nova but removed it after swapping ends unexpectedly a few times. We ended up with a stiffer rear spring and no bar and it works very well.

chicane67
Registered User
Posts: 114
(7/6/04 11:02 am)
Reply | Edit Re: Took it off...
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Nadda....nothing....ZERO....

If the chassis is sprung correctly, a 'Hotchkis Type' rear live axle does not require a rear stabilizer bar what-so-ever.

**EDIT for speeling

Edited by: chicane67 at: 7/6/04 8:23 pm

67Sally
Registered User
Posts: 547
(7/6/04 7:36 pm)
Reply
Re: Took it off...
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I agree......Rear sway bar requirements depend on both the springs and shocks that will be run with it.
William
Project PonySnake - 67 Mustang Fastback

streetfytr68
Registered User
Posts: 1153
(7/6/04 8:04 pm)
Reply Re: Took it off...
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Quote:
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Nadda....nothing....ZERO....

It the chassis is sprung correctly, a 'Hotchkis Type' rear live axle does not require a rear stabilizer bar what-so-ever.
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Uhh..Tom,
Perhaps you should tell the folks what spring rate you consider correct for a "Hotchkis Type rear live axle". I think most of us are running relativley "soft" leaf springs by comparison. Can't a rear sway bar be beneficial with soft springs?


www.lateral-g.net

nancejd
Registered User
Posts: 249
(7/6/04 8:10 pm)
Reply Re: What are you running for a rear sway bar?
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That was my understanding as well. I thought that spring rate and sway bar rate sort of have an inverse relationship to each other.
James

zbugger
Registered User
Posts: 1546
(7/6/04 8:19 pm)
Reply
Re: What are you running for a rear sway bar?
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While you're at it, can you describe how tire/wheel width has an affect on that too?
- Allen

chicane67
Registered User
Posts: 124
(7/6/04 9:08 pm)
Reply | Edit Re: What are you running for a rear sway bar?
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Quote:
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Perhaps you should tell the folks what spring rate you consider correct for a "Hotchkis Type rear live axle". I think most of us are running relativley "soft" leaf springs by comparison. Can't a rear sway bar be beneficial with soft springs?
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This would depend on the front spring and stay bar rates......to give you an applicable answer.

If you were to use a spring less than 240 lb/in, I might think about one.....depending on how the chassis drives. I might use (an outside might at that) a 1/2" bar but I wont just put one on a car because I think or hear its a good idea. You have to drive the car and tune it before you just slap a 1", or any bar on it and go. Most "of you" running softer spring rates like the "Ford approach".....soft spring big - stay bar. I dont. Spring correctly and compliment with a stay bar and shock valving.

I'll give you the recommended 'general racing' rates for springs and stay bars, for the first gen. This information has been compiled for street and in a racing class chassis for over the last 35+ years, so this isnt just my opinion:

Street use:
Front spring- 550 lb/in
Front bar- 3/4 to 1" (depends if autocrossed)
Rear spring- 220 lb/in
Rear bar- none

General use:
Front spring- 700lb/in
Front bar- 3/4" or 9/16" or a 1"
Rear spring- 300 lb/in
Rear bar- 1/2" to 9/16"



High load:
Front spring- 900 lb/in
Front bar- 7/8" to 15/16"
Rear spring- 390 lb/in
Rear bar- 9/16" to 3/4"

I myself run a 720 / 320 package on my 67 and I find NO reason what-so-ever to install a rear bar. With the shock technology we have today AND the bushing technology we have today.....there is really no use for one in my eyes.

Mind you that these are recommendations for 15" wheel and tire combinations and tires from years ago. Now, combine todays available shocks, suspension bushings, wheel and tire packages.......and the need for a rear bar is nill. Unless you have thrown in a 9" boat anchor for a differential.....

As you see by the "recommended" rates, the size of stay bar goes up with spring rate. Not the inverse. And honestly, a 1/2" bar isnt worth the weight of the material it is comprised of.

Bugg~ I can not put together a simple answer to your question at this time. There are way too many variables to give a simple answer.......unless David can throw one in off the top of his head. But it will take me some time to word a 'readable' answer to this question. I'll get back to you on that.



streetfytr68
Registered User
Posts: 1154
(7/7/04 5:50 am)
Reply Re: What are you running for a rear sway bar?
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Well that's a real eye opener. I will yank the rear bar and take it for a spin. Explain why spring rates and sway bar rates inversely proportional. Softer springs are more prone to height changes. So I figured that a bigger bar complements soft springs.

My rear sway bar has been in place through many combinations of springs, shocks, wheels, and tires--almost 20 years. I haven't given it much thought, to be honest.

My springs are softer than your recommendation all around, track width is pushed to the limits, tires are 35 series, shocks are 12 way QA-1's. And the chassis is stiff thanks to a roll cage and subframe connectors. So overall, I see no reason not to yank the rear bar.

I look forward to tuning my combination when I get out your way.
/Steevo

www.lateral-g.net

Norm Peterson
Registered User
Posts: 154
(7/7/04 7:14 am)
Reply Rear springs vs bars
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I thought that spring rate and sway bar rate sort of have an inverse relationship to each other.

That's true, but only after you've established how much of the lateral load transfer (LLT) that you need or want happening out back. In turn, that depends on what you've done to the front in terms of springs and bar. And on the roll center heights too (the Guldstrand mod affects the front RC a bit).

You also don't want the sta-bar to be responsible for too much of the rear LLT (it'll lift the inside rear wheel) or too little (if it's so thin that it would only add another 15 lb/in of wheel rate you might as well just use a little more spring instead).

Actually, the Hotchkis leaf spring arrangement already acts a little bit as a sta-bar, particularly if stiff bushings are used in the front eyes.

Norm

Edited by: Norm Peterson at: 7/7/04 7:19 am

chicane67
Unregistered User
(7/7/04 1:23 pm)
Reply rate vs. rate
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Norm hit it right on the head.....it is more CG and RC height related......than spring rate related.

The relationship that the rear has to the front is where roll couple distribution, roll center migration and the respected distributed weight balance has the largest effect.

My reasoning for no rear stay bar, comes because of my spring design and years of tuning that spring to the overall chassis configuration. The spring design has enough rate to handle the power/torque of the specific chassis, it has anti-squat built into it and it's design also controls the IC. All of which have an effect on roll. The Hotchkis stuff is close and it works well for moderate power applications, but it could be ALOT better.

The front to rear rates that I have noted above yield the best results without the use of extra parts........extra parts adds and creates unnecessary sprung and unsprung weight.......which requires less shock valving and tuning. But in the end, the basic suspension needs to be tuned for it to yield the greatest results ~BEFORE~ any additional parts are considered.

It will save you time and believe it or not.....money.

Mean 69
Registered User
Posts: 56
(7/7/04 2:48 pm)
Reply Nice tech!
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Seems like there is more and more tech on this site, I'm liking it.

Just to add a bit more info, for what it is worth. Tom, is 100%, absolutely correct in his statement that the sta-bars (front and rear) come last in the overall tuning of the suspension. At least, that is the philosophy of the folks/literature I trust follow. Spring the car to keep it from bottoming out over the intended conditions, damp it correctly through shock tuning, and then fine tune the system using the appropriately sized sta-bars. Note, this doesn't mean try and do all of this without any sta-bar installed, it merely means that the tuning of them comes last.

So why do we need a front sta-bar, even if we don't need a rear one? Is it because of all that mass up front? Is it because of the smaller tires? Partially, but not mostly. Sta bars are designed to do one thing, resist roll. They will add a bit of spring rate in most cases, but this is because of friction, an unwanted consequence of using poly bushings (race cars use bearings in this location instead).

The amount the car wants to roll depends upon a couple of things. Obviously, the lateral acceleration will have an impact, it is customary to use 1G for lateral loading in calcuations, etc. All lateral forces are "felt" at the CG, so that is obviously a very important number, and is usually of the order of 18" or so for a typical sedan. The next important thing is the roll center, which is where the car will want to roll due to the suspension. The front of the car will have a different roll center height than the rear, and 99% of the time the front is lower than the rear (the other 1% of the time is due to people doing things that they flat don't understand). Anyway, the vertical distance between the roll center, and the center of gravity is called the roll moment. The longer the roll moment, the more the car will want to roll for a given lateral force.

Back to the front versus rear. The front roll center of a well executed car is usually an inch or so below ground level, to about three or four inches above. So the roll moment is relatively large. On the rear of a leaf sprung car, the roll center is found by intersecting a line through the front and rear leaf spring bushings, where this line intersects the rear axle centerline is where the RRCH is. A guess is that is around 14" or so, which means that the rear roll moment is alot smaller than the front, which means for a given lateral force, it will roll alot less. Yes, there's weight distribution, and alot of other factors to consider, but this is a start (you have to start somewhere). There are well documented steps to calculate the front to rear roll bias, weight transfer, etc in the literature. In addition, the nice full car suspension software packages will perform this for you too.

So, back to the original question, what type of sta-bar do you run? Obviously it depends. Does your car push, is it neutral, or is over-steer prevalent? On my car, I run (ran) the full Hotchkis deal, with no rear bar. Worked pretty well, but like Tom, I feel that it is a bit too much on the soft-ish spring, big front sta-bar approach. I am in the process of converting the rear suspension on my car from leafs to a link/coil-over arrangement, with highly adjustable rear roll center height. I expect that even with a similar spring rate to the Hotchkis leafs, due a lower roll center height, that I may need to run a small-ish bar. Time (and tuning!!!) will tell.

Steevo, I'd be interested in hearing how your car feels without the rear bar, if you choose to experiment. Just take slow steps, there may be a big difference in the way the car handles, be careful.

Mark

CarlC
Registered User
Posts: 182
(7/7/04 3:35 pm)
Reply Spring, sprang, sprung...
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OK Tom, you asked for it in the past....

Let's use mine as an example. Track days 2 times/year, agressively driven most other times.

It's no lightweight, but is typical of most PT setup cars:

With driver and full tank of gas:

Left-front 1025#
RF 958
LR 864
RR 861

Total weight 3707#, 53.5/46.5% F/R

700 #/in front springs with Landrum adjusters, Hotchkis hollow bar, Bilstein F4-B46-1104-W000 (Guldstrand slalom), del-a-lum, G-mod.

Guldstrand leaf springs (175 #/in?), del-a-lum, Bilstein AK2074 (737 0493 H002 stamped on shock body, Guldstrand slalom), weld-in connectors.

Engine makes 400+ ft-lb to the rear wheels.

Given this scenaro, what's the best plan of attack to make the car better balanced but still not be a kidney beater?

Also, why do the Mustangs tend to run less rear spring? Seems many of them run max 180#/in. Doug at GW told Torker and I at SEMA that springs over 175#/in on F-bodies are not necessary, even the trick spherical bushing/CAT5 setups. I'm not trying to start an argument, just trying to learn/figure out the right way to take a good car to the next performance level.

Mean 69
Registered User
Posts: 57
(7/7/04 3:40 pm)
Reply What do you want to change?
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Carl, I was under the impression that you were pretty happy with your car. What aspect do you want to change, and what do you mean by making it better balanced?

Mark

CarlC
Registered User
Posts: 184
(7/7/04 5:31 pm)
Reply Ignorance is bliss
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Mark,

I dig the car, but I could easily be overlooking/don't understand how well the overall system could be working.

It's got a lot of neat stuff, but are there subtle changes (spring rate, shock valving, etc) that could be made to make it work together better? Many of us bolt on "trick" stuff, but it's really hard to understand and make it all work to the best of it's ability.

I used mine as a test case since it has a lot of "trick" parts, but how well do they compliment each other? That's what I don't know, and would like to try and figure out without spending another $bazillon.

streetfytr68
Registered User
Posts: 1157
(7/7/04 7:20 pm)
Reply Re: Ignorance is bliss
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Carl,
Post your wheel & tire specs as well. I'm curious how tire sidewall affects spring rate selection.
Mean,
I'll yank the bar and mess around with shock damping. Hopefully on Friday. If not then next week. I'll measure fr and rr roll center height as well.

www.lateral-g.net

CarlC
Registered User
Posts: 186
(7/7/04 8:40 pm)
Reply Tires
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255/50/16 and 245/50/16 BFG Comp T/A ZR.

With -1.8* camber, 6.5* castor, and 3/16" toe out the track tire temps, using Pozzi's temp probe, were reasonably consistant across the tread using 39psi cold front, 38psi cold rear. Even with this much camber there appears to be some excessive outside tire wear, but some of that came from pushing the car too hard.

davidpozzi
Moderator
Posts: 1220
(7/7/04 10:05 pm)
Reply
Re: Tires
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Just disconnect one link on the bar to disable it, no need to completely remove it for a test.
Typical spring rates measured at the front wheels are 100 - 200 lbs/in even with 700 lb coils, tire spring rates are above 1000 lbs, if I remember right. Changing tire pressure changes their spring rate but it's felt most on very stiffly sprung cars running on banked tracks. I've seen guys changing tire pressure by a pound at autocrosses, but for me on my Camaros it just wasn't that sensitive.

Carl, I think your Camaro has a little understeer, it seemed you had more times where the front pushed a little than where the rear swung out. I don't think it's badly out of balance but some experimenting would help point the way. Of course, how you enter the turn can greatly influence how balanced the car acts too, so pay attention to the balance in steady state corners where you are not accelerating or decelerating.
David
67 RS Camaro, 69 Camaro vint racer, 65 Lola T-70 Can-Am vint racer.
ourworld.compuserve.com/homepages/David_Pozzi/

jon
Unregistered User
(7/8/04 6:55 am)
Reply x
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here are my numbers;3200# w/full tank,driver.265/50/16 front 275 40 17 rear.hot pressure target is 39 psi.dse uppers relocated with the dse jig.koni 30 series coil overs with bottom moved to 11.5" from pivot,for a motion ratio of .741(.513 correction factor),with 300# spings(that is about 538# conventional coil,doing the math in my head).hotchkis hollow bar.rear leaf,176#,rubber bushing in front,poly for shackle.pro shocks,set at 5/6.i tend towards understeer,if i let more air under the nose it is pretty good.i need a wing.bottoms slightly in the on ramp at buttonwillow.

camaroboy69
Registered User
Posts: 1328
(7/8/04 10:49 am)
Reply
Re: x
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awesome information guys!!
Adam
My Website 06-25-04

[chicane67]

jon
Unregistered User
(7/8/04 11:07 am)
Reply x
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correction:i tend towards OVERsteer.

chicane67
Registered User
Posts: 133
(7/9/04 6:06 pm)
Reply | Edit Re: x
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FYI, I'm not ignoring this, I have to put some though into it. Moving weight around takes a few brain cells and I am spent from work right now.

Give me time for a Vegas Robaina and an 18 year.......and I'll be prime.

CarlC
Registered User
Posts: 190
(7/9/04 6:21 pm)
Reply
Re: x
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.......and I'll buy a round of said 18 year the next time I'm in LV for work. Likely early August or early Sept.

David, the car definately understeers under steady state cornering.

Looks like we hijacked Adam's post (sorry Adam.) Perhaps it's more appropriate to start a new topic. If so can Ralph move the info into a new thread?
http:www.geocities.com/casanoc

Edited by: CarlC at: 7/9/04 7:07 pm

ddennis68
Registered User
Posts: 225
(7/9/04 6:43 pm)
Reply hijacking
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i cant speak for Adam but I don't hink he minds, the wealth of knowledge especially in the suspension forum is unbelievable-getting off topic is inevidable and almost always worth it. Keep going guys.

davidpozzi
Moderator
Posts: 1224
(7/9/04 8:11 pm)
Reply
Re: What are you running for a rear sway bar?
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Quote:
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While you're at it, can you describe how tire/wheel width has an affect on that too?
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As Tom said, lots of variables here.

Wider wheels and tires add more (relative) cornering traction to that end of the car, and also make the springs and bars less effective if the wider wheels results in more outboard offset. Either way, wider tires with more wheel offset wil add traction to the front, resulting in oversteer if the car was neutral before, if you do the rear, the rear sticks better and the front will understeer.

Go-Karts can can add oversteer by pulling the rear wheels in or moving the fronts out.

If you start out with a full gas tank and the car is neutral, when the fuel burns down to a quarter tank the rear springs and bars are now stiffer in relation to the load they had before, the car will go into oversteer and lose traction coming out of turns, especially slow ones.

I used a rear bar on my 67 for autocross with 10" slicks front and rear. I used a 7/8" front bar with solid aluminum blocks mounting it to the frame. I used Guldstrand springs front and rear. The rear bar was the 70 Camaro type and a pretty small one like half inch dia but it's got short arms compared to a Hotchkis rear bar so it's somewhat stiff for it's size.

When I put on the street tires and wheels it oversteered, but I had fun with it.
David
67 RS Camaro, 69 Camaro vint racer, 65 Lola T-70 Can-Am vint racer.
ourworld.compuserve.com/homepages/David_Pozzi/

Edited by: davidpozzi at: 7/9/04 8:16 pm

Ralph L
Moderator
Posts: 3634
(7/10/04 12:35 am)
Reply
Re: What are you running for a rear sway bar?
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I can try and move this info to another post, possibly tomorrow, if I get a chance, sorry for the delay.
Ralph
Project Fantom Expected Completion - May 2005
My Tahoe - "Black Mamba"
Rendering of Project Fantom

Rick Dorion
Registered User
Posts: 597
(7/10/04 4:04 am)
Reply Carl
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Carl, are you still running the Hotchkis rear bar?

CarlC
Registered User
Posts: 191
(7/10/04 12:47 pm)
Reply
Re: Carl
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I took it off. I questioned the affect this bar has since it mounts so far inboard.

I'm going to keep the bar in case I need it for tuning, but I don't see a need for that right now.

Back-to-back testing is necessary but the Hotchkis bar is not easy to remove from the car.
http:www.geocities.com/casanoc

Mean 69
Registered User
Posts: 60
(7/11/04 10:31 am)
Reply More Tech
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Some more goodies on the sta-bar topic. I saw some good bits of info, thought I'd try to tie some of it together.

You have to be careful when comparing one sta-bar to another, due to a couple of issues with the design approach. One, the link length from the center of the bar, to where it connects to the frame, or wherever, has a huge impact on the torsional rigidity of the overall system. Think about it in side view, not the vertical portion that links the arm, but rather the "longitudinal" length. The longer this length, the softer the bar will be. It is pretty sensitive too, and is a very common way to fine adjust the torsional aspect of a given bar, you just move the link attachement fore and aft.

Another very important aspect is the effective length of the bar, as viewed fro the top/rear, etc. The longer the length of the bar, the softer it will be for a given cross section.

As far as tuning for understeer/oversteer, pretty much all drivers will favor a bit of understeer relative to oversteer. With understeer, the driver will feel like he has more control, you can just try to turn the wheel more, for instance. It is a lot harder for a driver to deal with oversteer, once the booty end of the car comes around there isn't a whole lot that you can do to correct for it. I had a couple late model Mustangs, which are notorious for snap oversteer, caused by bind in the rear suspension setup, they were scary to drive until I got things sorted out and learned where the limits were.

And by the way, though I love the movie, the "loose is fast" comment from Days of Thunder doesn't imply that a loose car will make it around the track faster. There is a saying that slow in, fast out will virtually always win races. This is particularly true for front engine sedans, which are nose heavy, and where you can only fit a limited amount of tire on the car. By braking earlier for the turn, and then getting in the throttle through the turn, you transfer weight from the front of the car to the rear due to forward acceleration. This take a bit of the load off of the front tire, and makes available more opportunity for lateral grip. Driving technique has so much to do with the performance of the car-driver system. Most of us want to put as much meat on the back as possible, and you can take advantage of this by setting the car up correctly, and unloading the front through turns by using the throttle.

Mark

davidpozzi
Moderator
Posts: 1227
(7/11/04 11:48 am)
Reply
Re: More Tech
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Mean 69, some good comments as allways.

To add some tips, you can tune the sway bars by swapping out polly end link bushings for stock rubber bushings, this will soften the bar and allow you to change the handling. You can change only one, two, three, or four bushings per side to achieve the softening you want. An understeering car would benefit from this approach on the front bar links. You could also change the frame mounts to rubber but that would probably make too much of a change. The softer you go, the more the car will roll in the turns but usually the amount of softening is not great enough to be noticeable, you just want a fiew pounds less front bar rate to get the balance you need.

If the car is understeering a lot, a rear bar or stiffer rear spring is going to be required.

If you need more front bar and the end links and bushings are all polly allready, you might try mounting the bar to frame in aluminum blocks.
David
67 RS Camaro, 69 Camaro vint racer, 65 Lola T-70 Can-Am vint racer.
ourworld.compuserve.com/homepages/David_Pozzi/

Edited by: davidpozzi at: 7/11/04 5:10 pm

chicane67
Registered User
Posts: 135
(7/11/04 2:15 pm)
Reply | Edit Re: Carl
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Alright, lets start out with what has already been stated. You say the chassis has an understeer even with the amount of toe-out you have dialed in. As David briefly pointed out, this condition can be handled with rate changes either spring, bar or both.

With understeer, it can be corrected by either a rate increase in the rear spring (and/or) the addition of (and/or) an increase in rear stay bar, or on the other end of a chassis, a reduction of front spring (and/or) a reduction in front stay bar.

Your stated tire temps with the amount of toe and noted understeer tells me that you don't have enough rear roll stiffness and is pointing toward an increase in rear spring. Not to mention that you will also have better IC location from the rate increase/spring build/spring design which is a major contributor to "off corner" acceleration and exit stability.

The weight issue. The chassis needs to go on a 500 pound diet (yea, I know)........the driver, a 25 pound diet (the wifie would love that huh?)......you need to remove 44 pounds from the left front and distribute that 44 pounds across the rear, something to the tune of 18 to the LR and 26 RR. Rescale the chassis. What the object to do here is get the L/R split even and worry less about the F/R split. Cross weight and F/R split is all about weight management and its placement, but the L/R split is all about transition and that is what we need to concentrate from the beginning.

IMO, a 240 ish rear spring rate without a rear stay bar would be an easier place to start. Keep everything else the same and only tune one aspect at a time.

Spring.....shock/valving.....stay bar.

jon
Unregistered User
(7/11/04 5:29 pm)
Reply x
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has anyone tried afco leafs?they are about $110 each and have springs in some of the rates discussed.not sure of the fit,they are listed for 70-81 camaro,does anyone know if that will fit a first gen?i'm adding a 1.25 dia. tubular bar right now.it will have arms adjustable to 8.5 or 9".i'm going to start with a .125" wall bar and also ordered a .188" bar also.the bar is 40.5 long.any opinions?

streetfytr68
Registered User
Posts: 1169
(7/11/04 5:47 pm)
Reply The Magic Question
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And now: For the magic question:

Where does one get the right 240lb spring?

Most of us are building hot rods that handle. The ride height must deliver good looks and clearances as well as good handling. So given a baseline rate and arch and a new target rate, how do you establish a target arch to avoid do-overs?

www.lateral-g.net

chicane67
Registered User
Posts: 140
(7/11/04 5:48 pm)
Reply | Edit Re: x
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I believe they are good enough for a race car, but would need replacement after a season or two maybe even three and the design has definite limitations. I have seen some use the AFCO springs is limited street applications, but can only tell you that the spring steel used is imported and not of the highest quality. Not saying that they are all that bad, cuz all there stuff is real nice, but there is a difference in spring steel and the difference in cost is actually quite staggering.

The build of the leaf is just as important as the rate itself. So, just throwing a leaf spring in a chassis that meets a specific rate will only do so much......the leaf spring has to be built correctly to do more than just hold up the ass end of the car.

I dont have my 'black book' in front of me right now, but the dimensional differences between the 1st and 2nd Gen are similar, but.....do have some slight differences. I believe the differences in the center to center and pin to forward eye dimensions.

As for the bar......I'd have to scribble the math to give any kind of thought to it.



chicane67
Registered User
Posts: 141
(7/11/04 6:00 pm)
Reply | Edit Re: The Magic Question
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Quote:
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And now: For the magic question:
Where does one get the right 240lb spring?

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You sell your house and move your ass to Vegas.....and then I build you a set.

I have two spring builders in the country that can and have built my spring design to 'spec'. However, I myself will only use one of them for my personal builds. This cat is also the very same that builds the famed 'TriCity Competition' springs.....his attention to detail and knowledge is second to none.

The free arch is set to run flat when installed into the chassis and the final ride height is tuned with a 1" lowering block..... but the target arch has already been tested and works as configured. When you get out this way, we'll give you the grand tour with the 320 inchers that are currently in the 67.

streetfytr68
Registered User
Posts: 1171
(7/11/04 6:11 pm)
Reply Re: The Magic Question
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Works for me. But the wifey's gonnna be pissed. "Honey, I dropped the price on the house so'z I could get summa dem 320 lb springs"

www.lateral-g.net

Mean 69
Registered User
Posts: 61
(7/11/04 6:19 pm)
Reply Or....
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You could drop the leafs altogether, cut a little channel in the driveshaft tunnel (not too bad), and convert to a really cool three link!!!! Then, anytime you wanted to change spring rates, it would cost you less than $100, and take you minutes. And adjust the ride height. With plently of room for shock compression. And, on top of everything else, it looks really cool! Want to dial in more anti-squat? You got it. Lower the RRCH? You can do that too.

Packaging is 90% done, now all I need to do is to get Matt from RFR to make me the real brackets.....

Geez, Steevo, are you really moving to Vegas?! Oooh! You can get in trouble out there, with the likes of Tommy in town and all....... I'd give Tom's spring design a shot, the young man is wise beyond his years, no doubt. Just a question though, like Carl, I kind of assumed you were happy with your car, what doesn't it do that you want it to?

M

chicane67
Registered User
Posts: 142
(7/11/04 6:57 pm)
Reply | Edit Re: Or....or what ??
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Hey M.....

You are almost like a 'pusher' on an Oceanside street corner......."Pssssst, hey buddy.....have you ever tried a threee link......do ya wanna ??".....

Your next homie. Go public and then hook up with the Vegas punks. The four of us (Tyler, Steevo, you and myself) need to have a little pow-wow.....what is looming in the near distance may be worth some real consideration. Looks like its time for a round of e-mail.

Is everone coming to SEMA this round ??

Edited by: chicane67 at: 7/11/04 8:18 pm

davidpozzi
Moderator
Posts: 1228
(7/11/04 7:07 pm)
Reply
Re: Or....or what ??
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Tom, I've got a mental picture of you standing on a street corner, wearing an overcoat with leaf springs hanging inside!
David

67 RS Camaro, 69 Camaro vint racer, 65 Lola T-70 Can-Am vint racer.
ourworld.compuserve.com/homepages/David_Pozzi/

Edited by: davidpozzi at: 7/11/04 7:17 pm

Mean 69
Registered User
Posts: 62
(7/11/04 8:09 pm)
Reply Ha!!!!!
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Can you just imagine the picture!!!! Tom, with springies hanging out of his jacket.... Sly look on his face... You'd better start lifting weights, Tommy, those leafs are heavy!

E-mail away, I'm all ears. There are SO many people to delight with really great hardware solutions, and oh-so-many ways to do such.

M

P.S. I've seen some of those O-side folk, but I ain't never seen one with a three link!

P.S.S. Michael Shuie and team Red are just nuts, unreal domination. Just watch how calm his hands are with the steering wheel, it's just not right!!! Watching the BGP, halfway through the replay...

[chicane67]

streetfytr68
Registered User
Posts: 1172
(7/12/04 6:29 am)
Reply Viva LV
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Yeah. I'm headin west. I'm tired of watching the west coast have all the fun. I'm takin it one step at a time. House is on the market. As soon as I have a buyer, I'll hop a plane and buy sommething in LV or Boulder City.

I'm real happy with my car. My situation is very diiferent than Carl's though. My chassis is tied together with a cage/SFC's and my car is light due to the ARDF front clip, hollow doors, fuel cell no back seat and forged wheels. It handles awesome. Slight understeer to neutral) If I had any driving skills, I'd probably get myself in a lot of trouble.

But I'm never happy. Up front I have 10" 450lb springs in coil-overs designed for 12" springs. (The coil-over mounts are in the wrong place, IMO. So the springs are cranked all the way up (near the top of the threads) which puts the spring close to coil bind. I really need an 11" spring--probably a 550 or 600 since I'm at 51.3% front. Or I can move the upper mount down and go back to 10" body coil-overs. But I'd rather have the 11" spings and keep the travel.

As far as the leaf springs go--I'm mostly just curious. The DSE 3" springs work very well on the streets of NY. I will test them in anger at Pocono in August. But when I get out west, I will have numerous track days and Silver State to look forward to (as well as smooth roads). So custom springs are probably in my future.

I suspect that Tom is chompin' at the bit to tweak my ride.
/Steevo

p.s. Don't worry. I think I can keep up with Tom and Tyler.

www.lateral-g.net

jon
Unregistered User
(7/12/04 8:11 am)
Reply x
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not having long life would not be a problem.if i'm going to try a few rates most of those springs would get used for a day and never again.i would put them on,try to guess a matching front spring,turn some laps,and try other front springs.but in a day some rates would be clearly wrong.this is the problem with tuning-you give up whole track days with a car that is clearly wrong after the first lap,and you run out of time and energy to make many changes.so then it's back to the shop and try again next month.and what are these smooth roads you speak of,stranger?i read your words but they make no sense.nevada?man you are but one border from perfection.it will be about 72 today in the bay area,vegas will be,i dunno,197?anyone who wants to be further confused about leafs should read the tech section of both the landrum and afco sites.those are 2 big names in leafs,and they have very contradictory info.

camaroboy69
Registered User
Posts: 1336
(7/12/04 8:52 am)
Reply
Re: x
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Quote:
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Looks like we hijacked Adam's post (sorry Adam.) Perhaps it's more appropriate to start a new topic
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ABSOLUTELY NOT!! You didnt hyjack the thread at all. I am loving all this information and I know many more are also. I am going to rename the thread so more will read this!!!
Adam
My Website 06-25-04

Mean 69
Registered User
Posts: 64
(7/12/04 1:03 pm)
Reply Lookin' forward
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I am certain we will cross paths here sometime in the near future, Steve. I should get my motor back from the machine shop in a few weeks, and complete the rear suspension around the same time, so I hope to get some track event experience later this year to start the process of sorting out the new design. Some great folks out this way, I met Carl last year at Super Chevy, Tom has been over to the house, and I look forward to meeting more motorheads at the track very soon.

Great hobby!

Oh, and as far as SEMA goes, I vow to never miss another show after having attended my first last year, and I will stay for more than two nights next time too! Darned fun time, to say the least!

M

CarlC
Registered User
Posts: 199
(7/12/04 9:34 pm)
Reply Springs
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Tom,

Much gras. I'll talk to ya more about spring builders.

I'll be at SEMA but likely not in the Camaro.

streetfytr68
Registered User
Posts: 1174
(7/13/04 7:30 am)
Reply Re: Lookin' forward
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Mark,
I wasn't aware that you are in LV as well. Actually I'm still not sure. But that's how I'm reading your post. Either way--I get around, so yeah our paths will cross.


www.lateral-g.net

baz67
Registered User
Posts: 165
(7/13/04 3:27 pm)
Reply Get out here.
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Steve better jump on it. Houses are getting stupid out here.

streetfytr68
Registered User
Posts: 1186
(7/14/04 9:39 am)
Reply Re: Get out here.
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Brian,
Can you email me. I need some ballpark numbers.

www.lateral-g.net

camaroboy69
Registered User
Posts: 1465
(7/28/04 10:00 am)
Reply Test
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I was surprised to see that even with my car as low as it is, the front sway bar is completely worthless. I just simply turned the wheel back and forth at about 40mph and was surprised with the body roll. I mean its not even close to as bad as it used to be but its still not anywhere I would consider acceptable. Even with all new rear bushings in the car. The most shocking thing I saw was that my daily driver 96 Saturn has a larger front sway bar than my 69 Camaro.

68Protouring454
Registered User
Posts: 329
(7/28/04 11:07 am)
Reply Re: Test
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adam, yeah the stock sway bars are junk, you should up to a 1 1/8 solid or 1 inch hollow, it will make a nice difference, along with poly bushings for the sway bar
jake

yody
Registered User
Posts: 331
(8/1/04 1:32 pm)
Reply How about this?
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ON a first or second gen when using del a lums in the rear shackle, my question would be, does the rear sway bar create bind? is that basically how it creates antiroll? i ask because i am using del a lums in the front spring eye pocket as well, which will create a certain amount of bind, which is why i am not using a rear sway bar, this is on my 71 bird. i am using all hothckis up front. Would a rubber bushing with a bar in the rear control the roll better?
firebird website

ddennis68
Registered User
Posts: 307
(8/1/04 3:08 pm)
Reply Re: How about this?
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A properly set-up suspension should need little to no stabar in the rear at all. I concentrate on learning the coil sprung suspensions so I won't be of much help in getting you started on a leaf car-where are the suspension guru's?
Dennis-

check out progress of Bondobucket

davidpozzi
Moderator
Posts: 1258
(8/1/04 11:11 pm)
Reply
Re: How about this?
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Yody,
The delrin front bushings help to create a bind in roll.
The rear delrin bushings also don't allow the spring to twist, so they would all combine to stiffen the rear in roll, the leaf spring then acts like a sway bar, if you don't allow it to twist in the bushings, the spring itself has to twist in roll.

A rear bar is a spring that is twisted only in roll, it isn't creating a bind by my definition of bind, because a bind implies an uncontrolled stiffening of movement that is not just progressive, it's severely progressive.
David
67 RS Camaro, 69 Camaro vint racer, 65 Lola T-70 Can-Am vint racer.
ourworld.compuserve.com/homepages/David_Pozzi/

Edited by: davidpozzi at: 8/1/04 11:17 pm

yody
Registered User
Posts: 333
(8/1/04 11:53 pm)
Reply Re: How about this?
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can you further explain the "twist effect" when using the delrin bushings how does the leaf spring actually twist? it seems with the delrin bushings the spring will only move up and down, and the body roll is now produced by the lean of the car making one spring more compressed than the other? in what way can the springs twist? or am i interpeting incorrectly? and does that translate very bad for the spring to actually twist rather than the bushing, sounds pretty harsh! I think i understand about the rear sway bar the more roll the more twist or resistance in the bar and it will get progressively more; not bind, but with the front spring eye being solid it does not create any bind in the actual bushing/front spring eye, but the bind comes from the no lateral movement in the entire spring?
firebird website

Norm Peterson
Registered User
Posts: 168
(8/2/04 6:14 am)
Reply Re: How about this?
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Think rear view only. When you corner, the chassis rolls by some amount relative to the axle. Sure, there's vertical motions involved at the springs, just don't forget about that angle. Something has to give in order to accommodate this angular difference. In the usual case of leaf springs, the bushings *squish* a bit (rotationally as seen from the rear) and the springs twist along their length. So when you stiffen up the bushings for better axle location you're forcing the springs to deform a bit more at any given roll angle, and you end up with greater resisting force.

There's nothing inherently wrong with twisting a flat leaf, though if you were intentionally designing a spring to be primarily loaded in torsion you wouldn't normally start out with a wide/thin rectangular cross-section.

As far as 'bind' is concerned, there seem to be a number of narrow definitions. What they all have in common is some induced amount of wheel rate that's due to something affecting the free movement of the suspension. It's the difference between a real suspension with real components and that which you expect when you look at individual sketches during the design stage. This can be a negligibly small amount (the effect of OE bushings falls in this category) or quite large (such as when the arcs of one or more suspension links act in opposition to the arcs of other links) and abrupt (e.g. a rod end runs out of angular travel).

(Edited for spelling)

Norm
'79 Malibu (too unstock for Street Mod)

Edited by: Norm Peterson at: 8/4/04 3:37 am

68ssconvt
Unregistered User
(8/3/04 6:58 pm)
Reply Landrum Parabolic springs
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Great reading!

On the subject of leaf springs, does anyone have any knowledge or thoughts on the use of Landrum's parabolic leaf springs? Has anyone tried these? They supposedly provide more forward bite, similar to Tom's spring design.

Per Landrum's website: "It’s unique design promotes more forward bite, less pinion angle loss, and better weight transfer during acceleration than the O.E. (original equipment) leaf springs."
www.landrumspring.com/rac...l#che_mono

Thoughts?

Ray

jon
Unregistered User
(8/4/04 7:34 am)
Reply x
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if you feel like a real head spinner,check out afco's website,rpmnet.com,and read the tech section on leafs there,then compare with landrum's tech.2 of the big names in leafs,completely contriditory information.