Suspension plans for my G-body

[SSninja]

(Warning, semi-long read with multiple questions)

Part of my winter plans for my Monte is to upgrade the suspension on the car.

I've been doing a ton of research and have a few questions that I'm hoping you guys can help me answer.


First off, here's what I'm starting with for the front and rear suspension:

Current front:

- Bilstein shocks
- Eibach ~1" drop springs
- 12" B-body brake swap with Hotchkis upper control arms
- Stock lower control arm with new rubber bushings
- Stock front sway bar with poly end links
- New tie rods/centerlink
- Jeep solid steering shaft
- Stock steering box

Current rear:
- Bilstein shocks
- Eibach 1" drop springs
- UMI non-adjustable upper and lower control arms with poly bushings (Except for the "ears" of the pumpkin, which are new rubber)
- Stock rear sway bar

Wheels/Tires:
- GTA wheels with 245/55/16 Sumitomo summer tires (Forget the model)



The above is probably a pretty typical G-body setup that makes for a car that, to be frank, doesn't handle very well.


Starting with the rear, here's my high level "budget build" plans for the suspension:

Rear suspension:
- From what I've read, poly bushings in general are nowhere near ideal due to binding, so I'll want to replace the old UMI arms with arms with Rotojoint/Johnny joint/etc ends.
- Install a bigger rear bar that attaches to the lower control arms or the Spohn "Pro touring" bar.

Questions:

- As I don't plan on lowering the rear of the car more than it already is, is there any benefit to going with adjustable upper and/or lower control arms?
- Would spherical joints at both ends of the lower control arms along with at one end of the upper control arm cause any issues, specifically allowing for too much motion of the rear end?
If so, should I look into only having spherical joints at one end of the lower control arm and a delrin bushing at the other end? What about the upper control arm? Would arubber at one end and a spherical joint at the other end be ok?
- Have the fitment issues with the Spohn bar and 8.5" rear axle been addressed, or do modifications still need to be made?

Front suspension:
- First and foremost, get rid of the B-body spindles. While the AFX and similar spindles are out of my price range, a set of tall upper and lower ball joints along with stock spindles looks like it may be a good choice.
- I'll also want a set of tubular upper and lower control arms, preferably with Delrin bushings and that improve the geometry rather than mimicking the stock arms.
- Keep the Eibach springs and Bilstein shocks
- Install the 36mm sway bar that I have sitting in my garage.
- Install the SCandC front triangulating brace.
- Install a Lee or similar rebuilt steering box
- Fit the stock spindle or S10 dual-piston caliper spindle with a brake upgrade of some sort
- Install poly or delrin body bushings at the front of the car and replace the "middle" body bushings with new rubber

Questions for the front suspension:
- Do only specific upper control arms work with tall upper and lower ball joints? I've noticed that the SPC upper arms are a popular option, but they just don't seem sturdy enough (I've had a set in my hands before), especially as the cross-shaft relies on a bolt and nut to attach to each arm. Not having to use shims is nice, but I can live with shims for a nice solidly build arm.

Threads like this don't give me much confidence in them:
http://www.nastyz28.com/forum/showpost.php?p=2344692&postcount=78

- The SPC lower control arms seem nice, and I like the adjustable ride height via spacers. However, are they still made such that you have to weld in stock sized ball joints?
https://www.pro-touring.com/showthread.php?70089-SPC-Tubular-Lowers-SC-amp-C-Stage-2-Woes

I'm not sure if I'm too happy with that. Do the other tubular lower control arms have this same "issue"?

If not, can you guys suggest a good lower control arm that will help improve the geometry? Seems like I have at least a couple of options: Global West, UMI, DSE, etc. Any reason to pick one over the others, and can they all be used successfully with tall lower ball joints?



Well, that's all I have for now; I'm sure I'll have follow-up questions based on everyone's responses.

[olds87]

Speed Tech performance is coming out with a suspension system at the end of November. I plan on getting there rear setup. They are a sponsor on this site. I know there a link here with pictures of there suspension on GN.

Another thing, I have most of my suspension from Mark at SC&C. He on the right side also.

Here link to Speed Tech suspension on Lateral g http://www.lateral-g.net/forums/showthread.php4?t=33765&page=4

[SSninja]

Continuing on with my research, it appears that I'll need to stick with an upper control arm meant for a tall spindle swap if I want to use tall upper and lower ball joints...That would make sense. :)

Given that my Hotchkis arms have poly bushings in them, can I replace the bushings with delrin or similar? Maybe the del-a-lum that Global West offers?


::Edit::

After some further research, Sphon offers a set of upper control arms with Delrin bushings for a tall spindle or ball joint application at a good price. That might be my option for the upper control arms.

[SSninja]

Based on my research for upper control arms so far, here's an incomplete list of front upper control arms that will work with tall upper and lower ball joints for the G-body:
- Hotchkis http://www.hotchkis.net/gm_ag_body_tubular_upper_aarm_for_tall_spindle_swa p.html
Pros:
(For me) Already own
Appear to be well-built
Cons:
Only available with poly bushings
If you don't already own them, they're almost $700!
- SPC http://scandc.com/new/node/59 (Also available from Summit, Jegs, etc)
Pros:
Seems to be the most adjustable arm on the market
Available with either rubber or greasable steel bushings
Cons:
No upper arm bump stop for when the suspension is at full droop. This will have to be resolved by a travel limiting strap, custom made-bumpstop, etc.
While welds can fail, I'm not sure if I trust two bolts to hold the arms together. This may be an irrational fear as I've read that Marcus has been using these arms for over 100,000 miles on one of this test cars.
UB Machine: (Info link) http://www.s10planet.com/forum/showthread.php?t=23595
Part numbers: http://www.s10planet.com/forum/showthread.php?t=27129
Pros:
Inexpensive (Under $200 for a set)
Cons:
Only available with steel bushings
Unsure of their durability for street use
Similar to the SPC arms, no bump stops

Spohn: http://www.spohn.net/shop/1978-1987-GM-G-Body/Suspension/Tubular-Front-A-Arms-Accessories/G-Body-Tubular-Upper-A-Arms-Tall-Spindle-Swap.html
Pros:
Inexpensive at $300 or so
Available with Delrin bushings
Appear to have bump stops
Cons:
None that I can think of.
Global West: http://globalwest.net/cnr-88a.html
Pros: Solid looking, come with del-a-lum bushings
Cons: Also expensive at around $500 or so.

UMI (Potentially): http://www.umiperformance.com/catalog/index.php?main_page=product_info&cPath=8_59&products_id=398
I have yet to hear back from them in regards to if these particular arms will work with tall ball joints. They look as if they might, although I do know that they very recently started offering arms for the A-body that specifically are marketed for use with tall ball joints
Pros:
If they do in fact work with tall ball joints, they may rank up there with the Spohn in terms of "bang for the buck"
Available with Delrin bushings
Cons:
None, as long as they in fact work with tall ball joints.



Creating a steering stop similar to this may be an option for the UB machine or SPC control arms:

http://www.spohn.net/shop/Replacement-Parts/Rod-Ends-Spacers-Adjusters-Jam-Nuts-Threaded-Ends-Poly-Bushings-Coil-Over/Clamp-On-Steering-Stops-for-Tubular-Front-Lower-A-Arms-with-125-od-Rear-Tube.html

[SSninja]

Tall ball joints:

Two popular options at the moment seem to be:

Howe: http://www.howeracing.com/p-7924-howe-22302-moog-k5208.aspx

Proforged:
Upper: http://www.proforged.com/parts/Proforged-Tall-Upper-Ball-Joint
Lower: http://www.proforged.com/parts/Proforged-Tall-Lower-Ball-Joint

Proforged, while the "new kid on the block" seems to be very popular with the S10 crowd as it appears to be very similar in quality to Howe for less money.

[UMI Tech]

Hey ssninja and gang.

I wanted to chime in as we recently joined the pro-touring.com sponsorship community.

For the rear suspension we have a few options. Poly/rubber mix isn't so bad for the street but if you get to corner carving in your Pro-Tour machine an upgrade would certainly help. Rod-ends everywhere but in the top of the diff are the best for location and performance at the expense of a bit of road noise/harshness. There is no negative as far as control goes because it turns the compliant stock arm system into a system that only moves in the direction intended. We routinely mix and match Roto-Joints and poly on lower control arms to add a bit more compliance and comfort. For the top, the best combo is poly in the ears and Roto-Joints (or rod ends) up top. As you move from poly/poly to Roto or rod ends the difference is incredible. We demonstrate this by putting a car up on jack stands and letting the rear suspension hang, then jack up the middle of the diff. Then jackstand one side of the axle. If you have a poly set up tightened too tight the opposite wheel drops a bit then stops. With a rod end or Roto-Joint setup it'll move through the entire rebound travel.

Adjustable uppers allow you to adjust back to factory pinion angle or even put more in for drag racing use. As the pinion "climbs" the ring gear it theoretically plants the tires more.

Adjustable lowers allow you to compensate and make sure your diff is perfectly square or in the case of certain auto-x's or track days allows you to skew the diff to induce some rear steer.

I'm currently working on the caster and camber curve graphs for our A-body uppers with 1/2" taller ball joints. The G-body arms with 1/2" taller ball joints are on my project list. They will probably work fine but we don't like to introduce a product without testing it thoroughly.

Be careful with taller lower ball joints as they tend to introduce a bump steer situation which can do more harm than the camber curve they help improve. We are working on the camber/caster/bump steer curves on a number of different ball joint combos and will be introducing that data over the winter.

Also on my project list is a Pro-Tour style bar for your car to be introduced in a few months. The A-body is on the rack right now (literally, I just came from that part of the shop and have the greasy fingers to prove it) receiving the prototype bar and bracket development. The G-body is next on my list as far as bars go. Both Pro-Tour and Drag sizes, fully adjustable on-car with premium rod end links.

I hope I answered at least a few of your questions. Ask me more and I'll get back to you...

ramey

[exwestracer]

Just out of curiosity, what do you mean by "doesn't handle very well"? Do you have specific complaints and situations where they occur?

Many times throwing parts at a car only cuts overall weight by emptying your wallet...without any real performance gains. Nothing you are thinking about buying is necessarily "wrong", but a little more info about he problem would help.

Looking at what you have currently, I'm going to guess initial understeer on turn in to snap oversteer in the center or on exit. Could be all wet here, it's just a guess....

[UMI Tech]

Hey Ray. I just had a flashback to "initial understeer on turn-in to snap oversteer in center or on exit". Did you ever try to make a 3450 lb '76 Monte Carlo go around a corner? Ugh...

[SSninja]

Looking at what you have currently, I'm going to guess initial understeer on turn in to snap oversteer in the center or on exit. Could be all wet here, it's just a guess....

Hi Ray,

You're pretty much on the money. The car ploughs into turns and then promptly wants to do a 180 if I push it. In general the car also doesn't give the driver much confidence in regards to feedback, especially through the steering wheel. I think that a tighter steering box (Instead of my 24+ year old steering box) will help with that as well.

While I know that the car may never handle as well as modern performance vehicles without many extensive (And expensive) modifications, I'd like to be able to enter a corner and have a good idea of where I'll exit, preferably not into the nearest tree! :)

[exwestracer]

Hey Ray. I just had a flashback to "initial understeer on turn-in to snap oversteer in center or on exit". Did you ever try to make a 3450 lb '76 Monte Carlo go around a corner? Ugh...

77 El Camino...is that close enough? :barf:

[exwestracer]

Hi Ray,

You're pretty much on the money. The car ploughs into turns and then promptly wants to do a 180 if I push it. In general the car also doesn't give the driver much confidence in regards to feedback, especially through the steering wheel. I think that a tighter steering box (Instead of my 24+ year old steering box) will help with that as well.

While I know that the car may never handle as well as modern performance vehicles without many extensive (And expensive) modifications, I'd like to be able to enter a corner and have a good idea of where I'll exit, preferably not into the nearest tree! :)

I wasn't really guessing...at least your suspension is working the way it should...

I had a long explanation typed out and the power went out at I was getting ready to hit the submit button.:pat:

Don't feel like starting over now. If you're interested in discussing the reasons, PM me.

[charlief1]

Be careful with taller lower ball joints as they tend to introduce a bump steer situation which can do more harm than the camber curve they help improve. We are working on the camber/caster/bump steer curves on a number of different ball joint combos and will be introducing that data over the winter.ramey

Could you give a little more info on the bump steer and camber curve issues please. I'm a little new to the forum but would like some explination of what this is and how it efects handling on a chasis. Thanks.:)

[exwestracer]

Could you give a little more info on the bump steer and camber curve issues please. I'm a little new to the forum but would like some explination of what this is and how it efects handling on a chasis. Thanks.:)

The lower ball joint height affects the relative angle of the lower control arm and tie rod. These 2 components should be parallel (...oversimplification...) for minimal bump steer. I'm sure Ramey can elaborate at some point, as they are researching the actual changes.

[exwestracer]

SSninja, where are you at on all of this? Is it making more sense?

[UMI Tech]

Thanks Ray, yes we are indeed plotting bumpsteer curves for the A-body and G-body but they'll probably be awhile due to some new product introductions we're working on.

I have the G-body camber curve (stock vs UMI w 1/2" taller) in-process and hope to have it published by the end of the week.

For charlief1, Ray's bumpsteer explanation was right on as is usual for whatever he writes. A bumpsteer corrected car has better predictability because the tires go where the driver steers them instead of where a pothole or something influences them. The best example I have is from my asphalt Street Stock which was built from a '76 Monte Carlo front clip. I spent all week fixing bumpsteer and went out on the track. The car was so stable it was almost freaky. I came in the pits in a bit of a panic because I thought all my work was for nothing. My crew had their jaws dropped at the speed increase.

If you install a tall lower ball joint and don't adjust the tie rod height, the angles are now dissimilar and can induce bumpsteer.

Another way to look at bumpsteer is a drag car dropping the front back down to earth. If the front tires land and then toe-out 1/4" due to bumpsteer, it's like putting the brakes on. It might only be two hundredths but we spend a lot more money on other things to gain two hundredths.

Camber gain as we discuss in these forums can best be described as preventing the top of the tire from rolling outward during body roll. We want the suspension to pull the top of the tire in with a predictable motion per degree of body roll/inch of suspension travel.

Stick around here and we'll get you helped out...

ramey

[charlief1]

Thanks Ray, yes we are indeed plotting bumpsteer curves for the A-body and G-body but they'll probably be awhile due to some new product introductions we're working on.

I have the G-body camber curve (stock vs UMI w 1/2" taller) in-process and hope to have it published by the end of the week.

For charlief1, Ray's bumpsteer explanation was right on as is usual for whatever he writes. A bumpsteer corrected car has better predictability because the tires go where the driver steers them instead of where a pothole or something influences them. The best example I have is from my asphalt Street Stock which was built from a '76 Monte Carlo front clip. I spent all week fixing bumpsteer and went out on the track. The car was so stable it was almost freaky. I came in the pits in a bit of a panic because I thought all my work was for nothing. My crew had their jaws dropped at the speed increase.

If you install a tall lower ball joint and don't adjust the tie rod height, the angles are now dissimilar and can induce bumpsteer.

Another way to look at bumpsteer is a drag car dropping the front back down to earth. If the front tires land and then toe-out 1/4" due to bumpsteer, it's like putting the brakes on. It might only be two hundredths but we spend a lot more money on other things to gain two hundredths.

Camber gain as we discuss in these forums can best be described as preventing the top of the tire from rolling outward during body roll. We want the suspension to pull the top of the tire in with a predictable motion per degree of body roll/inch of suspension travel.

Stick around here and we'll get you helped out...

ramey

Thank you Ramey. That explanes a lot of issues. Now for the next dumb question.

I understand the relation of the tire rolling outward in a curve so what would be the optomum (sp) height to increase the ball joints to help the car handle curves? I've seen .5" top and bottom and up to a difference of 1.5" thrown around but what would be the best height increase to help with the camber curve and reduce the bump steer issues?

[SSninja]

SSninja, where are you at on all of this? Is it making more sense?

Yup, all of the suggestions in this thread have pointed me in the right direction.

I picked up Herb Adam's Chassis Engineering book the other day and started reading it last night. I also finished the book from Marcus at SCandC which gave me a good primer on the issues that the G-body and early A-body need corrected.


One of the things I definitely need to research more is effective spindle height and how that effects the front geometry.

I think the ATS spindles are definitely out of my price range for now considering everything else that I want to purchase, but using tall ball joints may be a good budget solution.

That said, I need to figure out if I want to use both tall upper and lower ball joints, just uppers, etc.

[exwestracer]

Thank you Ramey. That explanes a lot of issues. Now for the next dumb question.

I understand the relation of the tire rolling outward in a curve so what would be the optomum (sp) height to increase the ball joints to help the car handle curves? I've seen .5" top and bottom and up to a difference of 1.5" thrown around but what would be the best height increase to help with the camber curve and reduce the bump steer issues?

Charlie, there is a very long answer to that very short question... The first thing you have to know is what tire and wheel size you are planning for. How much camber gain you need depends almost entirely on what tire you use and how much travel you are expecting.

High travel, short sidewall would need the least camber gain. (Less ball joint spacing)

Low travel, tall sidewall would need the most camber gain. (More ball joint spacing)

Throw in the fact that most GM muscle cars have reverse camber gain stock and things get even more complicated. You should check what your car does stock and go from there.

[UMI Tech]

Hey Charlie, Dave, Ray and gang.

I'd add to this the idea that suspension is highly variable with regards to what you're doing with the car. As Ray mentions, knowing the tire/wheel combo is critical and for most of us with limited budgets is usually locked in once we buy the first set.

For camber gain and how much you need whether it be from tall spindle, tall ball joints, pickup point relocation or some combination of everything, we need to look at the application. UMI has customers who replace their a-arms and the improved bushings and caster is all they require and are perfectly happy (daily driver, drag race). Some customers run tall spindles with our arms and hit the autocross course or Pro-Tour event. We have our upper arms with 1/2" taller ball joints on A-body cars starting to elicit positive customer feedback. Those customers range from daily drivers to a few autocross/Pro-Tour style test cars. Half inch ball joints are pretty cool because they improve the CC in general without requiring a bunch of fab work to be effective.


more soon

ramey

[UMI Tech]

Hey Charlie, Dave, Ray and gang.

I'd add to this the idea that suspension is highly variable with regards to what you're doing with the car. As Ray mentions, knowing the tire/wheel combo is critical and for most of us with limited budgets is usually locked in once we buy the first set.

For camber gain and how much you need whether it be from tall spindle, tall ball joints, pickup point relocation or some combination of everything, we need to look at the application. UMI has customers who replace their a-arms and the improved bushings and caster is all they require and are perfectly happy (daily driver, drag race). Some customers run tall spindles with our arms and hit the autocross course or Pro-Tour event. We have our upper arms with 1/2" taller ball joints on A-body cars starting to elicit positive customer feedback. Those customers range from daily drivers to a few autocross/Pro-Tour style test cars. Half inch ball joints are pretty cool because they improve the CC in general without requiring a bunch of fab work to be effective.


more soon

ramey

[charlief1]

It may be a while before I get back on but thanks for the info Ramey. We're changing providers so chacking email ect may be an issue for a few days. Looking foward to what you post on the info Ramey.