global west

[redline88]

:drive2: has anyone used the category 5 leaf springs by global west? i'm thinking about getting the complete setup for my '81 trans am, cost about $869. wondering if any feedback was available before spending that much cash.


thanks.

[Lowend]

Best leafsprings money can buy

[chicane67]

Well... the best shackle kit installed into a leaf spring anyway.

[dgoetz]

They probably are the best leaf sprs set up but they are still just leaf springs. Just sold my complete Cat 5 set up, w/Qa1 adj shocks and DSE offset shackels for $700.00. Less than 1yr old.
The car is used for autocross Solo ll and a little street. Couldn't stop whl hop (clamped sprs) Didn't want to use traction bars because of susp binding. Not good weight trans, lots of over steer. Probably great for drag racing and touring. Axle would shift enough for wheels to hit inside fender wells.
Went to mod tri link from Air Ride Tech lowered 2" more then there stock kit would allow w/ Qa1's instead of air shocks. No comparison to wagon wheel springs!!

[mpozzi]

They probably are the best leaf sprs set up but they are still just leaf springs. Just sold my complete Cat 5 set up, w/Qa1 adj shocks and DSE offset shackels for $700.00. Less than 1yr old.
The car is used for autocross Solo ll and a little street. Couldn't stop whl hop (clamped sprs) Didn't want to use traction bars because of susp binding. Not good weight trans, lots of over steer. Probably great for drag racing and touring. Axle would shift enough for wheels to hit inside fender wells.
Went to mod tri link from Air Ride Tech lowered 2" more then there stock kit would allow w/ Qa1's instead of air shocks. No comparison to wagon wheel springs!!

What car were they used on?? And tell us what the rest of the suspension consisted of, please?? What Solo II class did you compete in? And what size wheels and make tires were you running?

Cheers,
Mary Pozzi

[mpozzi]

:drive2: has anyone used the category 5 leaf springs by global west? i'm thinking about getting the complete setup for my '81 trans am, cost about $869. wondering if any feedback was available before spending that much cash.


thanks.

If I ever get mine shipped to me, I'll install them, drive my car, and tell you . . . :woot:

Cheers,
Mary Pozzi

[redline88]

thanks guys, i'll problably go ahead and get them, i have just have a street car that will see the strip sometimes.

mpozzi, keep me posted and let us know how you like yours.

[Taylor1969]

get them from jegs... they are under $800 shipped

[dgoetz]

What car were they used on?? And tell us what the rest of the suspension consisted of, please?? What Solo II class did you compete in? And what size wheels and make tires were you running?

Cheers,
Mary Pozzi
The Car now runs in C Prepared - Check out Welcome to Our Meesenger Board/New Cars, New Member - dgoetz

[David Pozzi]

dgoetz,
You can legally use a three link in CP????
I thought you had to stick with original suspension type and mounting points.

FYI,
I did a test of Hotchkis leaf springs in torsion. They take 27 ft lbs per degree to twist in the car for one spring. They use a stock front bushing, and Polyurethane Energy Suspension type shackle bushings.
David

[chicane67]

They probably are the best leaf sprs set up but they are still just leaf springs. Just sold my complete Cat 5 set up, w/Qa1 adj shocks and DSE offset shackels for $700.00. Less than 1yr old.
The car is used for autocross Solo ll and a little street. Couldn't stop whl hop (clamped sprs) Didn't want to use traction bars because of susp binding. Not good weight trans, lots of over steer. Probably great for drag racing and touring. Axle would shift enough for wheels to hit inside fender wells.
Went to mod tri link from Air Ride Tech lowered 2" more then there stock kit would allow w/ Qa1's instead of air shocks. No comparison to wagon wheel springs!!

Well... that is why I stated that they are the best bushing and shackle out there.

There are however, much better leaf springs available... and in your case, much better dampers as well. I dont blame you for selling that set-up. The spring has to be designed to address the issues you had with wheel hop and traction. Unfortunately, 99% of the off the shelf leafs available to the mass dont or were not designed to combat these problems.

Leaf springs or not... leafs work if you do them correctly.

JMHO

[MonzaRacer]

dgoetz Had same problem several people I know had when they tried to get some straight line use from them WITH NO ANTI HOP ADD ONS.
With SouthSide Machine bars or Cal Tracs I have see nlimite success. For most people the spring still likes to wrap up but if you use the olde track trick and cut some pipe the same width as the spring and weld a flat plat to it and contour them to springs at rest and make those your spring clamp and do away with stock type spring mounts and add on aset of regular spring cups you will get a slightly stiffer ride, loose some handling and pretty much never wheel hope with a well adjusted double adj shock.
BUT the tiangualted 4 link from ART is awesome. Many will poo poo Air ride but I had a 71 Monte Carlo that would ,on cheap street tires, pull consistent ,down the thousandth, 60 foot times. 4000lb+ car, 3.55 gears,mild 350, TCI Saturday Night Special and Street Fighter trans and pulled 2.085-2.089 60 fts. My buddies first gave me s--t about slow 60s but gee whiz I had maybe 350 hp underhood, full 2 1/5 exhaust on daily driver weighing in at 4000lbs + and it ran low 10s first time out in 8th,corrected to 13's in 1/4 and with little more engine/converter would have had 1.60 60 ft and consistent low 8s/high 7's in 8th mile (friend copied my set up in his Chevelle but with more engine and it has ran best of 6.30s then geared it down more and ran5.90s,,, in a steel car ).
The Air ride springs work MUCH better than leafs, that why i have Air on my truck too!!!
Good luck
Lee Abel

[dgoetz]

dgoetz,
You can legally use a three link in CP????
I thought you had to stick with original suspension type and mounting points.

FYI,
I did a test of Hotchkis leaf springs in torsion. They take 27 ft lbs per degree to twist in the car for one spring. They use a stock front bushing, and Polyurethane Energy Suspension type shackle bushings.
David
First of all our club is pretty low keyed. I was running SM2 until I changed the rear susp. I thought the rules for SM required org mounting locations thats why I went to CP, I'm running against other cars like late model Camaros with similar sspensions. If I ran at a national level I might even have to run Mod class ( aluminum Eng & engine set back). The people I run against wanted me to move to that class to compete against them. In Mod class i would run by myself and what fun is that? It is still supposed to be fun especially at this level.

[DarkoNova]

FYI,
I did a test of Hotchkis leaf springs in torsion. They take 27 ft lbs per degree to twist in the car for one spring. They use a stock front bushing, and Polyurethane Energy Suspension type shackle bushings.
David

Is that good or bad? What's the rate for stock monos/multis and/or aftermarket springs?

Matt

[chicane67]

Is that good or bad? What's the rate for stock monos/multis and/or aftermarket springs?

Matt

That depends on the springs design, its build and its application.

Aftermarket springs can be built to dial in whatever is required by the application. You can build a spring with a traction bar built right into it... its what and how you manipulate the second leaf's configuration. The second leaf is primarily how you control the location of the IC and the back half of the second leaf controls the axle tramp.

[Lowend]

Chicane
Just curious what you consider to be a better leafspring? The L2 has an extra leaf on the front side and is made from much thicker gauge steel than any other leaf I have seen for our cars.
One thing I can't abide by is GW's reccomendation for Koni shocks, they just don't have the right rates. You really need a tune Bilsten (at least) to make things behave properly.

David, you are allowed to run aftermarket rear suspension designs in CP (the ultimate 1st gen has an odd 4-link setup), but I believe there is a small weight penalty. There is a clause in the rule book that says you are allowed to "clearance the chassis for suspension travel" which can be pretty liberally interprepted if I recall

[David Pozzi]

Chicane
Just curious what you consider to be a better leafspring? The L2 has an extra leaf on the front side and is made from much thicker gauge steel than any other leaf I have seen for our cars.
One thing I can't abide by is GW's reccomendation for Koni shocks, they just don't have the right rates. You really need a tune Bilsten (at least) to make things behave properly.

David, you are allowed to run aftermarket rear suspension designs in CP (the ultimate 1st gen has an odd 4-link setup), but I believe there is a small weight penalty. There is a clause in the rule book that says you are allowed to "clearance the chassis for suspension travel" which can be pretty liberally interprepted if I recall

Thanks, I may autocross my 67 some day and was wondering how much I can get away with...:hmm:
The guys around here are not going to cut me much slack on the rules I think...

[David Pozzi]

Is that good or bad? What's the rate for stock monos/multis and/or aftermarket springs?

Matt

Matt,
The rate is lower than I expected, I thought it would be around 50 lbs or more. I got 9 degrees pretty easily so they can twist at least that much without any huge binding problems.
I don't have data for other springs, but mono leaf's would be way lower, perhaps a quarter of that, but I'm guessing. Stock multi-leaf springs may not be much lower than the Hotchkis, but that's another guess. If the spring eye bushings were solid aluminum or the Del-A-Lum non-cat-5, it would be a lot stiffer in roll.

The downside supposedly is the stock type bushings twist to their limit, at which point the whole assembly get's much stiffer in roll and the car winds up oversteering, usually on corner exit. I really haven't seen that with the Hotchkis springs. We had much more body roll with the softer shocks, now with stiffer shocks and less body roll there isn't any reduction in corner exit oversteer, but we didn't have any exit oversteer in the first place.

It is thought that stock type bushings allow more twist of the leaf but you lose some directional stability compared to more solid types. Stock bushings cushion acceleration shocks a little which may help keep the tires in contact with the pavement, but it's all speculation and theory.

The cat 5 gives you a solid connection front to rear, but allows a very free twist of the leaf assy. The hoped for result is less corner exit oversteer, and better directional control.
David

[Lowend]

Thanks, I may autocross my 67 some day and was wondering how much I can get away with...:hmm:
The guys around here are not going to cut me much slack on the rules I think...

Dave - you haven't been to Nat's in awhile. I have seen guys get protested for having the wrong chin spoiler on their S2000... on a 60MPH course.
Those nit-pickers from the east coast are not gonna cut our car ANY slack at Topeka, its legal.
The 3-link is legal in CP

[Norm Peterson]

The 3-link is legal in CP
Absolutely. While the basic suspension types need to be maintained, there's quite a bit of freedom in the details. You can even play around with lengthening/shortening/relocating the wheelbase up to ±1".

17.8.B only restricts the rear suspension type to the retention of a stick axle. Pickup points and linkage components are pretty much unrestricted (you do have to provide a metal barrier between them and the passenger compartment).

Being limited to original suspension arrangement and mounting points sounds more like Street Prepared or Street Touring.

CP has historically been much more tolerant of slightly gray areas than most other classes.

I can't find anything particular regarding engine relocation other than the 51% maximum rear weight limitation and the restriction against relocating the engine or head(s) into the volume provided by firewall recontouring.

Norm

[Lowend]

You are "allowed to clearance the firewall for exhaust clearance"

[Skip Fix]

At one time any mod for GT-1 was allowed in CP, they didn't use to bump you into mod unless it was a big change. But been a few years since I cut corners with SCCA.

[David Pozzi]

I saw a Corvette driver get protested because his steering wheel was 1/2" smaller diameter than stock. Also wheel offset has bitten a lot of people at nationals.

[Mean 69]

Sorry for the highjack on this, but what is the current hot C-Prep car/setup? Seems like there is usually one type of car that has the stronghold on a particular class, and the owner/drivers are especially passionate about anyone else coming in with something that can, or is percieved by them, to have any advantage at all. Case in point? NASA American Iron, "dominated" by late model (modified) Mustangs. Every year when the rules are looked at and changes to increase the competitive field are suggested, the incumbent Mustang owners SCREAM foul thinking that thier cars won't be competitive anymore. Result? Significantly dwindling numbers of cars in the field, and little (negative, actually) motivation for suppliers to bring in new technology or applications to come and play. I'd guess it's far less of an issue (i.e. number of cars) in SCCA, but...

David/Norm/Tom, do you have an approximation for the roll resistance for a leaf sprung car that is based on the torsional resistance of a particular leaf spring (i.e. the number Dave quoted)? The whole mess gets convolved when you put the springs in a car, they are coupled to the rigid rear housing, etc, it's not so straight forward as I see it? I know the argument for the Cat 5 forward bushing is that it reduces the friction associated with roll, there was a great article from one of the circle track suppliers I read a while back but can't find it now discussing this point.

I'm actually surprised that the "a leaf spring, is a leaf spring, bla-bla-bla" folks haven't interjected on this thread, which is refreshing actually. They aren't all created equal by any means. I can't speak to the Cat 5 stuff in my own personal experience as I have never driven a car with them, but a good friend of mine has. In fact, he won an AIX race out here in his rookie season two years ago in a 70 Camaro, which should be one heck of an endorsement for them, right? Er, except that he was the only car in AIX that finished that race, which is not to take ANYTHING away from the win at all, but rather to point out that there is often more to the story than may meet the eye (I can comfortably assure you that the other link suspension/torque arm cars aren't running out to swap over to leafs as a result of his win). I'll see if I can get some opinions from him, he doesn't post on the internet forums. One thing that I am certain he will tell me, make sure you put locking hardware/locktite on the bolts that hold the forward spring bucket onto the frame, it's kind of an issue when that piece comes loose...

Mark

[Norm Peterson]

Sorry for the highjack on this, but what is the current hot C-Prep car/setup? Seems like there is usually one type of car that has the stronghold on a particular class, and the owner/drivers are especially passionate about anyone else coming in with something that can, or is percieved by them, to have any advantage at all. Case in point? NASA American Iron, "dominated" by late model (modified) Mustangs. Every year when the rules are looked at and changes to increase the competitive field are suggested, the incumbent Mustang owners SCREAM foul thinking that thier cars won't be competitive anymore. Result? Significantly dwindling numbers of cars in the field, and little (negative, actually) motivation for suppliers to bring in new technology or applications to come and play. I'd guess it's far less of an issue (i.e. number of cars) in SCCA, but...At least for the Mustang entries,


I know Padberg was running struts and Meier used to run shortened struts. I don't know what Meier ran this year but Padberg whooped all of us. Most of the fast cars are running a three link setup except Padberg who is using a torque arm. Not too many foxes anymore but the rules allow the same mods for everyone as far as suspension type. I like the idea of SLA on a fox but it was proven that it wasn't necessary last year.I also know of one Satchell link car, but not whether it went to Nationals.




David/Norm/Tom, do you have an approximation for the roll resistance for a leaf sprung car that is based on the torsional resistance of a particular leaf spring (i.e. the number Dave quoted)? The whole mess gets convolved when you put the springs in a car, they are coupled to the rigid rear housing, etc, it's not so straight forward as I see it? I know the argument for the Cat 5 forward bushing is that it reduces the friction associated with roll, there was a great article from one of the circle track suppliers I read a while back but can't find it now discussing this point.

You actually have three components of roll resistance.

One is the roll resistance that's due to the vertical spring rate and the lateral separation between the springs (just like with coils; it's a K*t² thing).

Torsion along the leaves is a T*L/(G*R) computation, where the value of torsional resistance R can vary (either step-wise as in multi-leaf designs or gradually if either the width or depth varies gradually - read the latter as requiring an integration of R over L). Most of this comes from the front portion, but the rear also contributes.

The third is due to the fixity of the leaves at the axle, and the general approach that you'd use to write your own formula for sta-bar stiffness would work (i.e. keeping the properties of the arms in terms of the leaf dimensions and the torsional section in terms of axle tube dimensions instead of lumping them both in terms of bar OD and ID). Once again, you have to consider the front and rear portions of the spring as well as leaf property variation over their length.

Note that bushing and shackle stiffnesses will reduce the roll resistance actually seen by the sprung mass, and that the bushing effects are nonlinear (progressive). It's a "springs-in-series" deal, where 1/Ktotal = 1/K1 + 1/K2 + . . . + 1/Kn.

The presence of sliders instead of shackles changes the boundary conditions such that there would be rather little torsional resistance developed by the spring end so supported (as soon as the maximum + loading of the + to - unit loading due to the torsion exceeds the - unit loading due to vertical load, one side of the spring will "lift" and no more torsion can be developed . . . over maybe a 2.5" leaf width that won't take much and the rate becomes zero at this point, so you can use zero and ignore Item #2 for a slider ended leaf portion).


Dave - those sort of weenie protests have to be taken from Stock Category classes. That's also one of the reasons I'll probably never run Stock unless I'm temporarily at a jobsite, found an event, and entered with the rental car.


Norm

[chicane67]

Chicane
Just curious what you consider to be a better leafspring? The L2 has an extra leaf on the front side and is made from much thicker gauge steel than any other leaf I have seen for our cars.

One thing I can't abide by is GW's reccomendation for Koni shocks, they just don't have the right rates. You really need a tune Bilsten (at least) to make things behave properly.

Uhm, my FIA road race spring for one. It can be tuned from a 125lb build, up to whatever. The highest rate I have built is a 390lb. Spring steel type and where its from, spring steel thickness and how you stack it... individual leaf length, the type of spring clamps and where they are loacted... are all part just of the equation. There is WAY more to a leaf spring design that just adding a forward leaf to the spring pack. I dont discount Doug's spring... it has its place. But, there is much more to leafs than most know.

I dont like the off the shelf KONI's for various reasons, but Bilsteins are a piece of cake. You give me corner weights, spring rates and its intended use... and I can come up with valving numbers. I might just have a little experience with Bilstein and changing rear rates... :bananna2:

[Lowend]

I'm assuming the FIA spring is your creation? Is this a setup where you are swapping leafs in an out and moving clamps around to tune? Sounds like something I may want in the future.

[chicane67]

Actaully the original design was from Guldstrand, for Penske, and I implimented all the late model technology and thought... not to mention the time invested into multiple sets of springs and doing the swaps finding the balance for my rates.