suggestions for suspension set up

[Clancy68]

ive had a question that has been nagging in the back of my mind.
my build up (signature) is going to be more performance oriented than anything else. i want it to corner and handle nicely, but i also am planning some strip time. ride isn't that important to me, and im not really going to use the bed(duffle bags, groceries etc.) my thoughts were along the lines of a 4/6 drop with high quiality adjustable shocks, and good swaybars. i would use one set of rear tires, for corner carving, and then when i hit the drag strip, I have some slicks mounted on some other rims.

so basically what i am looking for is ideas... recomendations... and personal expiriences with all sorts of suspension set ups.

--scott

[68LSS1]

I'd suggest a sway bar (if you don't have one). You can pull the lnks for the strip. How about a coil over kit for the rear. There's a couple bolt on kits out there that are priced pretty good. Definately will need an adjustable panhard rod, especially with the drop. You can get some aftermarket A-arms or complete front end kits. That's about it with out getting into some welding and/or fabrication I for one want mine to handle well also, so rack and pinion steering was a necessity. How far do you want to go with the rear suspension? More importantly, what's (1) your budget, (2) experience level (can you weld, etc.) and (3) do you have the tools/equipment available to you for some of the aftermarket set ups? Be warned, you'll probably get at least ten different opinions on this subject. None of them wrong but I've found out that my idea of "handling good" is a lot different than most. Answer those questions and I'm sure we can give you some good options on what to do.

See my sig for what I decided would be good handling with the ability for the once a month trip to the drag strip. Good luck ]

[ShamrockCustoms]

OK, here's my opinion for you. Set it up for the slicks tire size. Try to maintain your original outside trackwidth and have the slicks extend inward some from there. Set up the frame for this setup. If you use some ladder bars, you can run a bolt-on panhard bar for the street, and remove it and use a bolt-on diagonal link on the ladder bars for the strip. As was said already, go for some good coil-overs and you will be happy.

I should say that if you are not going to do too much strip racing, try to limit the rear tire/wheel width as much as possible. I say this because when you set up the frame and suspension to acccomodate the slicks, it will inevitably narrow the frame. This, in turn, will narrow the distance between the suspension components. This means street driving will be affected because of the forces exerted on the narrowed structure when cornering. The wider the better on the suspension pieces for street performance. Remember that you can always raise the rear using the coil-overs and use even wider wheels/tires as long as the backspacing is good. I hope that this post makes sense. Too many things I want to say at the same time.....Whew!


Merry Christmas!

[Clancy68]

sorry for being really vague, i took a look back at the post and realized it wasn't too helpful. let me try again.
the truck in question is a 1968 shortbed, fleetside, it has the factory coils all the way around.(the rest of it is described in my signature) as far as what i want to accomplish, i want to be able to have a good time on all the windy roads that are in my area, the most demanding thing that i have been "kicking around" is maybe a little autocross 2, for funs sake. and as you put it 68lss1, a once a month trip out to the drag strip. monster slicks were not in my plans, 12'' wide or less. the money factor isn't too much of an issue, i have no problem with spending 2500 on suspension by itself, or more if need be. however i do have a little bit of a hard time justifying one of those prefab hot rod independent front deals that go for more than 2000 by themselfes. expirence( a few motors, of several different varities; a th-400 rebuild etc.) no real fabrication expirience(i made a driveshaft loop....thats about it) but i can get a hand from a couple of different buddies of mine that have far more expirience in the fabrication world... as far as tools and stuff like that goes, i have all the regular tools in a roll away a small mig welder, i can get a plasma cutter, and a bigger welder, i do not have a spring compressor, but i was planning on getting one, when i got to this part of the project.
let me know if i forgot anything

--Scott

[Clancy68]

and a decent undisturbed workshop to do all this in...

--Scott

[68LSS1]

You're goals are similar to mine. What I did is figured out what the biggest differences were between the suspensions in trucks offered today and what we are working with. A truck can be made to handle, it's not cheap, nor easy but it can be done. And when I mean handle, I mean go toe to toe with a newer sports car. Our two biggest problems are weight and CG. What ever you can do to lighten the truck will help performance in every respect. The CG we're sort of stuck with. You can only go so low before you have clearance problems and as mine will be a daily driver I don't want that hassle.
With the front there's is not a whole lot that can be done. The 4" drop will be good. Get good gas charged shocks designed for the drop and get the biggest (as in diameter) sway bar you can get. I haven't researched sway bars yet so i don't know what options there are. There is a factory bar that can be bought but I'm not sure of the diameter. There has to be something out there that can be modified to fit our trucks though (in a larger diameter than the stock unit). Another thing is look into some aftermarket A-arms. Tubular if possible (to save some weight and they look cool . Make sure that after your drop the lower A-arm is parallel with the ground. A-arm suspension work the best with the lower arm this way. Use poly bushings where ever possible, especially on the sway bar links. The only other thing would be if some one makes some bolt on A-arms that are set up for coil overs. To do anything else to the front suspension will require fab work for mounting custom arms or buying a crossmember kit. As far as the steering a rack and pinion is the only way to go (again in my opinion). I just don't feel that as far as response and feel, that a gearbox can compete with a rack. And most every aftermarket kit you find uses Tbird/Pinto racks including Jim Meyer and Progressive Automotive. (I will discuss these two companies at the end.) I don't think it would be too hard to adapt a rack to a stock crossmember, the hardest part will be finding one with the correct dimensions. Again this shaves some weight also.
As for the rear there is many directions you can go. But here I decided to stick with the trailing arm suspension. In theory this is a very good suspension set up. Both for handling and launching. A lot of aftermarket suspension companies are making truck arm kits for the pro touring guys. I believe it just wasn't engineered to fit our trucks as well as it could have been. You said you were going with a 6" drop here. I know some will disagree with what I'm saying but you MUST get shock relocation kits and a adjustable panhard rod. Shocks are meant to be near vertical and when they are layed over they cannot do their job properly. Some will say you will need a C notch others will say you won't. I can't help you there but you definately don't want the housing hitting the frame so it might be something to check into. CCP makes a bolt in C notch kit and a coil over kit that I think is a bolt in also. If you can do it I would suggest making your own adjustable panhard rod as opposed to buying one. You could easily make a 1 1/2" diameter or so bar. A couple heavy duty Heim joints and your done. Any other option (i.e. 4 link) will of course require some fabrication and/or welding. I went with a HTH kit which comes with a BIG adjustable panhard rod. It also has a cossmember you weld in so that you can adjust the angle of the bar to keep it horizontal (or close to) it which is where you want it. It also has screwjacks so I can adjust the ride height and and preload for the drag strip. I won't go into more here but if you would like more info let me know.
As far as the Jim Meyer frames I like them but I wanted to stay with the trailing arm rear and they come with 4 links. Progressive Automotive makes a nice kit using Vette suspension components but I didn't like the spindle adapter. Probably nothing wrong with it, but it just didn't give me warm fuzzies. I figured I'd go the tried and proven Mustang II route and I'm definately impressed with the Fatman Fab's kits looks. I figure I saved at minimum a 100lbs. Got my rack, nice polished coil overs and tubular A-arms. Plus 5" of drop with out spindles nor compromising ground clearance. I will then mini tub it and that should easily allow me to run around a 14" wide wheel (plus or minus, haven't got the 8.8 under there yet). That's my .02 in a nutshell or two. Good luck.

[neonlarry]

I don't know where this sway bar came from but it looks awesome. I have also used an IROC Camero rear sway bar that really helps out in the handling dept. Check out this site, and this post.
You did not say how you were going to drop the front, I would suggest 2 1/2 spindles and the rest with coils. In the coil dept I would suggest some stiffer rate coils along with some stiffer valved shocks. Probably the biggest improvement in handling can be had with some sticky tires.

[Injected68LS1]

As I started reading this page I was thinking of that same sway bar on the cover of sport truck. Funny how that works. I'm pretty sure that truck is one of the editors of sport truck. He was telling me about it a few months back so I assume this is his. Anyway.

I'm going to investigate setting up one of these on my truck. I was planning on looking into the circle track and stock car performance stores to find one the proper width. Then getting the biggest friggin one(diameter) I can fit.

I would also suggest getting a good rear swaybar. I would call Quickor suspension in Oregon. He made the one that is on my truck and I really like it.

I would also look into very good adjustable shocks. If you get coil-overs, this is usually included. If not, Doetch Tech sells most of their shocks with optional 9-way adjustability. Those are the ones I want to get. Other companies to try to find some that will fit are Bilstien, Tokiko, KYB, and QA1.

Don't forget good wheels and tires. Maybe even have a different set for the autocrossing days.

Of course don't spend all of your money on the suspension. I don't care how good a suspension handles if you can't slow down for the turn. BRAKES. Get some good ones. I'm installing Baer 4 wheel disc as I write this(which means untested) and I'm sure they are going to stop on a dime. I'll let you know how they perform.

ECE sells a good rear shock relocator and super-track bar kit that i'm very happy with. That was a huge improvement over stock. I think the rear suspension will handle just fine too with 6" springs, good shocks, the track bar, the shock relocators, and the rear sway bar. Mine handles great like this.

As for the front....The stock suspension with 3" drop springs works real well. That may not be low enough for you though. I just installed drop spindles and ECE 2" drop springs. I think this will handle well but I haven't got it back on the road yet.

Hope my thoughts help you in your quest.

[68LSS1]

I think for most a disc/drum set up will be good. A disc/disc would be great though, especially for pushing suspension limits. Let us know how the Baer works. I'm going with a Hydratech (hydraboost) and probably Wilwoods all the way around.
One thing I didn't mention is wheels. You'll want the widest tires you can get on all 4 corners without clearance issues. And if you upgrade to larger diameter wheels pay the money for a decent wheel. If you end up with some heavy wheels won't help your performance goals any and will decrease brake performance.

[Injected68LS1]

68LSS1, what is hydratech? Is that a hydraulic assist for the brakes? Replaces the booster?

I'm actually thinking that going to a huge front swaybar will be somewhat counter-productive. Here's why. If you look at the weight distribution of our trucks a lot of the weight is forward. I scaled my truck last week and came up with 58% front and 42% rear. If you take that into account you will find that the large front weight will increase understeer(pushing). When you increase the diameter of the front swaybar it also increases understeer. But if you increase the rear swaybar it decreases understeer.

There are other factors in creating understeer and oversteer but those are the main ones(weight and roll bars). So before you go and buy a huge front swaybar get a base line with common front and rear swaybars. Then go TEST. You will know right away if you need more understeer or more oversteer. Then you will know which swaybar to increase the size of.

Here are some guidelines to INCREASE UNDERSTEER:
Lower front tire pressure
Raise rear tire pressure
Reduce front tire section
Increase rear tire section
More positive front camber
More negative rear camber(hard for us)
Stiffer front springs
Softer rear springs
Stiffer front sway bar
Softer rear sway bar
move weight forward

There you have all the good stuff in one little paraphrase. Remember, to increase oversteer just reverse the choices listed above.

[68LSS1]

Injected68LS1 Yes, Hydratech makes hydraboost units. They are quite popular with some of the pro-touring guys. It does take the place of your booster and uses power steering pump pressure for the assist. Many trucks have used them for years although not always with great success. My '97 Mustang has a hydraboost and if I hadn't seen it I wouldn't of known I had one. Hydratech makes a kit for our trucks. There is different kits using rebuilt or new parts. For us LS1 users it also comes with the means to increase/decrease power steering pump pressure. They will decrease stopping distances without upgrading other stuff and will be wicked on 4 wheel discs. They also have a "reserve" so if the engine was to shut down you still have enough to stop (and has been confirmed from triple digits speed). Hydratech There is a GP going on on Pro-touring.com. When ten people are ready to order we can get 100.00 off.
I agree with you about are trucks having a gross understeer problem, however I disagree about the front swaybar. The stock swaybars are not heavy enough for our trucks to start with. And even by increasing the diameter, because of the swing arm length are not as effective as they could be. If you could design one with shorter swing arms and also be larger diameter then I would say that yes you could increase understeer which we are trying to decrease. I think by buying the biggest bolt on bar you can will not be putting you in the postion to be increasing your understeer problem. (We haven't been reading the same books have we? )
A rear sway bar will definately help a lot but I haven't done that much research there as I probably won't be using one. (I'm using a 8.8 with a Hot Rod To Hell kit= coilovers on all 4 corners)

Clancy68 make sure you check out that link that neonlarry posted. I think Injected68LS1 made some good points. Understeer is our problem. Because of the weight bias is why I recommended the tubular A-arms. Every pound will help. It's one of the reasons I went with the aftermarket crossmember, LS1 and am getting a fiberglass frontend....well that and 1/4 times.

[Injected68LS1]

68LSS1 I know what you are saying about the swaybars but I think I mis-stated myself a little. I suggested that a huge front swaybar can be counter-productive by causing understeer. Here's where I didn't really state myself properly. I think that there is a limit on available rear swaybars. Because of this I think that there is a point where you have the biggest rear swaybar you can bolt on. Now you have tune with the front swaybar diameter to get everything back to neutral steer. THAT is why I think a huge front swaybar may be bad. Only because of the limits of the rear swaybar diameters available. But of course if somebody was keen enough to adapt a huge front swaybar, I'm sure that they could use the same type of stock-car setup for the rear. If that is done ---> The sky is the limit on the front swaybar diameter. I actually think I could design a rear setup but it would take a little bit of work. I have my gas tank back there so it's hard to find room. My current swaybar from quickor has the pivots on the rear axle housings and the arms extend rearward toward the tailgate. The ends of the arms are connected to the frame rails with some links. It would be very easy to shorten up the swaybar arms and create a stiffer anti-roll. I think I'm going to start playing with all of this very soon.

I like the hydraboost idea. I'm sure it would work very well. To bad I just bought a brand-new 7" dual-diaphram booster. I got the booster and aluminum master for around $300. Maybe I'll upgrade to the hydraboost later. I'm sure I'll have PLENTY of stopping power anyway.

What's your truck weigh 68LSS1? Mine came in at 3480 with 10 gallons in the tank. Did I mention I have a 50-50 crossweight? I was surprised.

[Clancy68]

i will check those links out when i get more time, sorry ive been down with the flu anyway im learning alot from you guys here
thanks

--Scott

[doughby82]

dont know if this helps,but my 85 blazer had a hydroboost brake set up that was stock.i belive all the deisels had them

[57sailplane]

hey i see you guys were wondering were to get a stiff rear sway bar. chassiworks and a number of drag racing companies make them look in summit. this i not the convetional type of bar. it is a heavy straight piece of forged bar with forgings pressed onto end of it or machined not sure.. but this thing is used in drag racing a lot. keeps body from twisting. i also admired one on of the same style on a 40' boom 1 ton pickup.. it has heavier springs but without down riggers the boom can be extended all the way out and lowed to the side(to the side i mean strait out in front of on coming trafic) to the ground, to the grond or a foot above without tipping. as a matter of fact boss jumped up and down in the bucket and tires stayed on the ground. now thats a sway bar.. i don't think there is a front sway bar that can keep up with that. and if it is to stiff use softer bushings. later

[jiggs]

One place to find really big rear sway bars is to look under motorhomes chassis'. The ones that use Chev van cabs and the "home"added to the back. I think they are 1 ton frames. They are used with leaf springs, but could be adapted to the trailing arm suspensions. I have seen ones up to 1 1/2" in diameter. Cut the bar to the length needed, get a machinist to spline the ends and have arms splined as well. Any van type delivery vehicle with a cube box will also have a big bar in the back.

One adition to the suspension ideas. Eibach springs have been the top dog in springs for years. They would be a good investment for springs instead of using the aftermarket lowering springs. They are lowering springs as well, but are rising rate and have control in mind besides the height change.

From reading the Pro-touring forums, the talk is to not use poly bushings on the rear trailing arms. If used, the poly will create bind when the axle and arms twist when cornering. Also, don't weld up the seams on the rear trailing arms. They are riveted for a reason. So they can twist while cornering. If those arms were solid, imagine the stress the bushings would take.

Things to avoid. Ladder bars are great for the straight line. They are terrible for any kind of cornering. always have a bushing at any point where the movable meets the non moving. Heim joints are for the drag racing crowd. Four link rear kits are for draggers. Four bar kits are for the street.(there is a difference)

Keep in mind that the panhard bar is what keeps the axle in the center of the vehicle (side to side) and there is extreme pressure on it while hard cornering. Brace the frame around the pickup points. Don't scimp on the size or thickness of the bar or brackets within the system. The stock location is very bad for cornering. It is out of square both looking from the top and the back. Change this so it is both when finished. It should also be lower. Looking from the back it should rest slightly lower than the center line of the axle. This means a large frame mount.

I am incorperating these tips into my truck. They were hard lessons to learn on my '67 Lemans Pro-touring car.

[tubbedII]

I don't think you are going to go this far, but I heard that boxing in your frame helps stiffen it up. It doesn't seem too hard, but lots of work if you don't already have the body off...just my .02

[68LSS1]

This is a post from the past. jiggs, I think most (not all) lowering springs these days are progressive rate springs. If they aren't, I wouldn't buy them. As for welding up the seams on the trailing arms I agree with you to a point. I am going to stich weld the seams to strengthen them a little while trying not to make them too solid. Something like a 2 inch weld with a 4 inch gap in between welds. I also, spend time on the Pro-touring forum and if your interested in all around perfromance I know you know of Hotrods to Hell and there truck arm improvement kit. Mine should be welded up within the next months or so. It has a monster panhard bar that is adjustable both for length and height. It has screwjacks to adjust wedge/ride height. There was a recent write up about somene installing the truck arm kit on a Nova or Chevelle, and they were really pleased with the kit.
tubbedII, I think boxing the frame is a good idea but I'm watching the weight. I am going to box about three feet along the engine using 1/8" and probably about the same length on the rear.

[neonlarry]

Someone posted where those awesome looking sway bars come from here is a link.
I didn't see any prices, I guess if you have to ask.......