Rear Suspension for street application

[BlackMetal]

Starting to get interested in modifying the stock suspension. Have a 36mm F-body bar ordered for the front, but I'm more interested in the rear and the type of modifications you can do to improve traction. Wanting to learn about this "instant center" stuff and what you can do to help launch a car.

I ordered UMI tubular LCAs from Full Throttle during the year=end sale and am trying to decide if I'm keeping these or going a different route.

Not really worried about a sway bar at the moment. Might go slightly bigger at some point but I don't need a huge bar that turns your ride into a slotcar, like I said, this is a street car.

I was really in love with the idea and theory behind the Southside Lift Bars but I did a search and saw the issues about the mounting holes getting torn up and how they're noisy and overall not worth the trouble. A part of me still wants to order a set... so somebody really needs to talk me out of it if they're that awful. I would weld them to the frame to avoid the bolt hole issue. Is the "lift bar" from UMI any better, or do they all have the same problems?


You can also buy weld-in LCA relocation brackets. Also supposed to help plant your tires into the ground. Any opinions on this?

So should I keep the LCAs that I ordered and install them? Is the UMI lift bar a better alternative than the Southside product? LCA relocation bracket?

Is this design any better as a lift bar?


Then there's the upper control arms... for a street car? Stock? Aftermarket? Adjustable?

Right now my entire suspension is stock except for air bags.

Appreciate any help!

[toofastforyou]

Scott, the rumors you heard about Southside bars ARE TRUE!...You've given me some good advice in the past about some other questions I had...so I feel it's my turn to help you with this...I did have these Southside's on my GN for a short while and decided to get rid of them rather quickly as they did squeak severely and gave the car a very harsh ride due to the solid bushings in them. I'd say they're good for a race car only...As for lowering the rear mounting points with the bolt-on plates supplied with them, well the idea (that was good to begin with) was to reset the pinion angle but this way of doing it is now "old school". The bolt hole that you have to drill in the housing brackets to mount the plates eventually ends up becoming elongated after a while, creating more problems because they let the whole rear axle twist up and down. A good advice: STAY AWAY FROM THEM!...
I think that the lower bars you bought are ok, if they have urethane bushings in them, not solid....but don't get the "relocation" brackets...get adjustable uppers...read on...
About adjusting the pinion angle to plant the tires better, the CORRECT way to do this is to get adjustable UPPER control arms instead of lowering the mounting point of the lower bars like the old Southside method.
What I did on my GN was exactly this...H&R adjustable control arms, H&R fixed lenght lower bars, ( both uppers and lowers with polyurethane bushings), and to complete the package, I also got the H&R sway bar.
A little later, I added "QA1" "Stocker Star" adjustable shock absorbers and air bags in both springs...

I tell you that it's not the same car since I've done this!...wow!... what a difference!

Hope this helps...

Claude

P.S: e-mail me for a few pictures...it'll be my pleasure!

[BlackMetal]

Hm... you still haven't convinced me!

Sounds like there are two main arguments against the southside bars. 1) elongating the bolt holes and 2) dealing with the solid bushings.

Well... 1) I would weld the brackets to the frame to avoid the stress on the bolt holes and 2) the LCAs I bought are poly bushings, not solid, so if I bought the relocation brackets and used the LCAs that I already ordered, I don't think I'd get as much noise as a solid southside bar.

BUT I do understand what you're saying, adjustable uppers seems to be the "true" way of setting pinion angle instead of messing around with the lowers. Adjustable uppers cost three times as much as a few relocation brackets though.

[toofastforyou]

Scott..believe it or not...I DID have to weld the brackets to the housing because one day, while doing some testing at the track, one of the bolts that fasten these plates to the housing broke while making a run making the car do a sharp 90 deg. turn at the end of the track! The guy who was driving my car almost hit the guardrail, but luckily for me was able to save it! But after a while, I discovered that the holes became elongated, (probably because of the solid bushings) which allowed unwanted front-to-rear movement of the rear axle which explained why the slicks were rubbing the lower front part of the wheel opening mouldings. Traction was better than with a stock suspension though...but like I said, that way of setting the suspension has become outdated by today's standards even though some guys are probably still using that setup. It was the thing to do 15 years ago, but not anymore, now that there are adjustable "uppers"available. I ended up removing the plates, grinding off the welds left on the housing, and buying new lower control arms because the poly bushings (even though better than stock ones) were showing signs of abuse.
As for the UMI lower arms you bought, I'm pretty sure you won't have any noise problem and you should be ok with them. Why don't you just install them without the plates and drive the car that way for a while...You can always add the plates later on if you still want them...! It is always best to do one modification at a time so you can evaluate the effect each of them do...

Good luck,

Claude

[SNOWBIRD]

I Went With A Complete H R Rear Suspension And Am Very Happy.i Removed The Front Sway Bar And The Car Still Handles Very Well On The Street...my Pinion Angle Is Set At Neg 4 Degrees For The Strip And I Do Not Have Any Vibration At Highway Speeds

[jdpolzin]

Turbo6Chicago, I have a set of SouthSides if you want them, $20 you pay shipping. Thats about all they are worth anyways. Dont buy a new set. If you want to try them, use these. DONT SPEND THE MONEY ORDERING NEW ONES!!!!!!!!!!!!!!! They are junk. Some people machine out the solid bushings and install Poly bushings but thats the only I would ever use them. They ARE noisy, they DO wobble all the mounting holes, and they ARE JUNK!

The only good thing I could say about them is that they will help the car hook. I personally would sell the tubulars you bought. I had a set and they work well but i dont see how mounting a flat swaybar on a tube control arms is effective. I think Metcos and Hotchkis lowers are the way to go. The bar mounts solid on them and wont clang or twist from lack of mounting surface.


Jeremy

[SNOWBIRD]

Hr Or Spoon Is The Best For The Street And Strip....but A Little Priceeeeee

[toofastforyou]

"jdpolzin", by looking at the picture that Scott ("Turbo6Chicago") posted, they appear square tube to me. I agree with you about mounting a flat bar to a round arm...is not the ideal way...
Hotchkiss, Metco, H&R and Spohn seem among the best to get...UMI also has some square one too...part# 3021 for Buick GN's

Clude

[jdpolzin]

I dont think he bought those UMI bars becuase he was asking about them as being there lift bars? Not too sure. He said he bought the tubulars from FullThrottle.

[toofastforyou]

Oops...you're right...Well, as long as he doesn't need a sway bar, he should be ok with them...but on second thought, maybe the sway bar fits better than we think... I've never seen one installed so I can't really say...

Claude

[BlackMetal]

Yeah I did buy the TUBULAR arms and had never heard any issues about mounting a sway bar to them. Before I purchased anything I did a search at these forums about tubular -vs- boxed and the only thing I really came across was that tubular would be stronger. Didn't see anyone mention anything about mounting the sway bar.



I probably will install them as-is for now, no big deal. I was just getting excited about the idea that you could fool around with the rear suspension and get the body to lift up on launches like the GNX does.

[BlackMetal]

I'm having a hard time understanding why the lift bar setup would be so hard on the mount points and everything. In the case of the UMI lift bars, it's just the boxed LCA that they normally sell, plus the relocation bracket that lets you drop the pivot point 2" or 3" inches. Seems kind of strange that components would be under so much more stress just from simply relocating one end of the LCA.

From what I'm hearing it just seems like the Southside bars were prone to causing these problems because the solid bushing didn't take any abuse and the wear n' tear ended up being transferred to the bolt holes. If I used an LCA with poly bushings as my "lift bar" I wonder if things would get beat up as much.

I don't have a thick skull, I'm hearing you that the adjustable uppers are a better way to do this, but fully adjustable suspension components seem like an expense more fitting for a race/track car.

I just can't wrap my brain around how much more stress the suspension would be under when comparing (A) bolting up my tubular control arms as-is, with poly bushings and new mounting hardware or (B) using the same tubular LCAs/bushings/hardware with a simple bracket installed at the frame-end of the LCA. Seems like if the mounting points are so easily destroyed, even the LCA itself without relocation would mess up the bolt holes.

I guess what I'm trying to say is, I could understand the lift bars causing problems if they relocated the control arms and had them mounted somewhere different than their original mounting points or something like that, maybe then I could understand things getting torn up. But it's using the same mounting points as a regular LCA would, I would think these moint points should be fairly strong and can't imagine one little bracket creating such a drastic change in forces that the mount points can't handle it. Not to say I don't believe all the stories about guys tearing up the bolt holes, I believe it, just don't understand it.

[buickbert]

Originally Posted by Turbo6Chicago

Yeah I did buy the TUBULAR arms and had never heard any issues about mounting a sway bar to them. Before I purchased anything I did a search at these forums about tubular -vs- boxed and the only thing I really came across was that tubular would be stronger. Didn't see anyone mention anything about mounting the sway bar.



I probably will install them as-is for now, no big deal. I was just getting excited about the idea that you could fool around with the rear suspension and get the body to lift up on launches like the GNX does.

i have a set of the umi tubular upper and lowers on my gn (havent driven it yet, still re-assembling it) and i just put a set on my big block skylark a little over a week ago. there is a noticable difference from the stock stamped/ rubber bushing stock arms to the tubular/ poly umi ones. the car feels like it is hooking up a little better and it feels a like a little more firm ride. although the stock rubber bushings were completely worn out on the stockers so im not sure how much of my feelings on how the car seems to ride/ launch better comes from there actually being a bushing in the arms i would recommend them as they are not very expensive and they are east to install.

as for getting the car to lift up, my big block car also has the edelbrock anti-hop/ uca relocation bars on it also and the rear of the car "perks" up while power braking it as the bars are forcing the rear down therefore lifting the car up. but if i had to do it over again i would spend the extra money and get the adjustable uppers from umi and not put the edelbrock bars in.

just my opinion

buickbert

[toofastforyou]

Scott, don't worry, I don't think you have a thick skull...it never crossed my mind! Now, let's be serious...I must admit that the elongated holes problem on my car was more than likely to come from the Southside bars with solid bushings rather than the bars with poly bushings. Speaking of poly bushings, they should be good for several years of abuse, but will eventually need to be replaced one day as they do deteriorate like everything that is submitted to a lot of stress. I'm pretty sure that you can buy replacement bushings from the manufacturer.
Like I suggested before, begin by installing them as is and drive the car like that without the plates. You'll see if you're happy with the improvement and it will always be possible to add the plates later if you decide to do so....That's the best advice I can give you...

Claude

[BlackMetal]

Thanks for the replies everyone. I'm just stubborn about things once I have my mind set on doing it.

I will try the LCAs on their own for now and see how I like it. I'll get an angle gauge and see what my pinion angle is in the first place.

I was reading more about the tubular arms and it mentions the sway bar mount holes are reinforced with extra plating and welded so hopefully there won't be any issues. I understand what you guys were saying that it seems like the sway bar would have a better surface to mount to on a boxed control arm rather than tubular, but I don't really anticipate any problems.

[SRGN]

The relocation brackets aren't for changing the pinion angle, they're for changing the instant center. I had no problem hitting 1.5 60' times off the footbrake with an easy launch with UMI fixed length upper and lowers. Ran an old ATR bar too. Do some research on instant center and suspension theory, you'll find that the IC with factory stuff on a g-body is actually behind the car...not too good for launching at the strip or on the street.

[jdpolzin]

Yes, very true. the relocation brackets only change the instant center. The pinion angle is the angle of the driveshaft and without rotating the rear end, you will not change the pinion angle. Although, depending on your length of lower control arms and size of relocation brackets, you could change your pinion angle with these. It is better accomplished with adjustable uppers. As far as the UMI tubulars and swaybar issues, the tubular arms only allow the swaybar the mount to a small surface on the bar. It will work fine but you will more than likely have issues with "popping" noises while entering a driveway or in some cases, while turning hard. As far as the bushings in these arms, polly bushing are not choice bushings. They will also snap, crackle and pop. They are inexpensive and will work, just make sure you use Poly grease. Beleive it or not, regular high temp grease will deteriorate the bushing. You can get polly grease from the parts store. Make sure the apply a generous amount on the sides of the bushing as well as the in the hole before you install them. Keep them greased well and you probably wont have any problems.