Somebody on another site sugested suspension based on a 3rd generation camaro layout.
Anybody on here have experience with this style of suspension?
Printable View
Somebody on another site sugested suspension based on a 3rd generation camaro layout.
Anybody on here have experience with this style of suspension?
Yes, but I don't have any pictures of it.:( The system uses a long torque arm mounted on one side of the drive shaft. It holds the rear end rigidly at the rear and has a shackle type pivot point at or near the front universal joint. Then there is a short bar at each end of the rear end housing that locates the housing longitudinally and keeps it straight (square) under the chassis. Finally, there is either a panhard bar or Watts link to keep the rear end centered under the frame.:whacked: By changing static angle of the short bars by raising or lowering their forward pivot point, rear-steer can be induced into the system. Properly adjusted, it's a great system for making fast runs on twisty roads (road racing, gymkhana, hill climbing):3dSMILE:. However, if this is just a car built for sedentary cruising, the benefits would never be realized. Ordinary hairpins or a four-bar would be easier to set up...:rolleyes:
We have never been easy on anthing we have owned. I don't see why we would be nice to something that looks like a racecar :LOL:Quote:
Originally Posted by J. Robinson
I am making a valiant effort to build it so that it can be driven fairly hard (jag motor, XK150 trans, 4 wheel disc brakes, hopefully a stiff chassis). I know tires are going to be the limiting factor, but I want to make it as sporty as practical.
Doggone it J., I can't find any schematics or photos of the rear suspension you posted. Now, I'm gonna have to go to a boneyard and crawl under. :eek: It sounds like some sort of single link ladder bar, but I can't be sure.
Flipper - You're a man after my own heart. Being an old stock car racer, I like cars that handle GOOD.:rolleyes: I build my cars to drive and I flog them pretty hard sometimes, too. Back in '06 we drove my coupe on a 2400 mile loop up through the midwest. The curvy roads through the western North Carolina mountains were an absolute blast!:D Even though it's a beam axle, my coupe has torsion bars up front and coils in the rear (fully adjustable on all four corners) with NASCAR style truck arms in the rear. It handles like a dream; I would love to put it through a timed Gymkhana course sometime and see how it stacks up against the Camaros and Mustangs...:HMMM:
Tech - Yes, the center torque arm is like a ladder bar. It transfers the torsional force of the rear end housing to its front mounting point. This becomes the lift point or "moment center" of the rear axle.:whacked: The rear end is located fore & aft by the short outer bars (radius rods) and laterally by the panhard bar. This system can be tough to dial in for drag racing because the front pivot point of the center link is usually too low and too far forward to provide good "bite" off the line. For overall handling, though, it can be a great system...;) I have a picture and a diagram of this system in my file cabinet at school. I will try to remember to get it tomorrow and post it here.
J., I'm assuming moment center means instant center, the pivot point on a ladder bar system. Thank you for elucidating.:)
Since I don't currently have floors to get in the way, raising the torque arm mount is not really an issue.Quote:
Originally Posted by J. Robinson
In a perfect world, what would the best set-up look like?
Also, are the locating arms short to induce steering from body roll?
So, what are the opinions on building a car without a traditional style frame under it?
Too early in the build to pass judgement?
Is this thing just too far out there?
There will be lots more angles installed before the plating begins. Some of the plating will probably be bead rolled for even more strength (and style).
http://i110.photobucket.com/albums/n...8/HPIM0703.jpg
Tech - Yes, I meant "instant center":o. ("Moment center" is the suspension axis around which the body rolls in a turn.) In this type of suspension, the "instant center" is a fixed point determined by the front pivot of the long torque arm.:)
Flipper - Yes, the short arms induce rear-steer with body roll. The length of the arms affect how much rear-steer is input (longer arms input less) and the angle determines whether it is negative or positive steer. I'll post pics later if I can find them.:HMMM:
OK, guys, here are the pics I have. I took the photo and did the drawing about 20 years ago for a catalog I was helping to edit. The company went out of business a long time ago, but I still have the pics & drawings I did. I edited out the company's name and phone info...:rolleyes:
Notice the long center "torque arm" is supposed to reach all the way to the rear u-joint area (transmission crossmember) and has a shackle type mount that is made from a female Heim joint mounted in rubber. The short arms are considerably shorter, but could be any length you desire. As I stated above, the longer they are, the less rear-steer they induce. When viewed from the side, if the short bars run uphill from the rear axle to the frame they will induce positive steer and make the rear of the vehicle "loose" in a turn (good for running on dirt tracks). If they run downhill from the rear axle to the frame, they will induce negative steer and make the rear of the vehicle "tight" in a corner (better for asphalt).:3dSMILE:
That's interesting. I just saw this 1st Gen Camaro torque arm setup in the new Hot Rod.
BMR Fabrication
http://www.bmrfabrication.com/f1/images/ta.jpg
Very cool J., thanks a lot. :D
That's a really cool bolt-in conversion.:cool: It uses a telescoping joint at the front instead of a shackle arrangement. Notice it has multiple holes in the bracket for the short arms so that rear-steer input can be fine-tuned. Nice!:3dSMILE:Quote:
Originally Posted by 39Deluxe
Quote:
Originally Posted by J. Robinson
That one has all three links mounting at roughly floorpan level.
Is that ideal? or a comprimise for a stock floor Camaro? Is it better if you went above the driveshaft with the front mount?
I'm not sure, Flipper... Very good question. I would guess that it's a compromise for the stock floor and mounting hardware. If you look under a 3rd generation Camaro, the long arm runs beside the driveshaft, not under it. I'm not sure it would make a huge difference, though, unless you moved the front pivot point up and back a lot which would affect weight transfer under acceleration/deceleration.:HMMM:
When you move the instant center up and back, it improves traction for launch/acceleration (suspension loads), but, if ya go too far, can cause wheel-hop on deceleration (suspension unloads). I think I would follow the Camaro's example and mount the center link beside the front u-joint.:3dSMILE:
Note also, on a 3rd gen Camaro at stock height, the short arms run slightly downhill from the rear axle to the subframe mounting points. That gives the stock Camaro a slight negative input from the rear-steer. I've never talked to any GM designers, but I would guess they designed it that way because the 3rd gen Camaros are slightly nose heavy and need the negatve input to control oversteer (loose condition). For your application, I think I would keep the short arms as level as possible and lengthen them to about 2/3rd the length of the long arm. That way the rear-steer input would be minimal and controllable. My reasoning here is that your car is a lot lighter than a stock Camaro and your weight distribution will be about 50-50; you therefore don't need a lot of rear-steer input under normal driving conditions. If you can somehow incorporate it into your design, it would be nice to have multiple mounting holes so that you could adjust the angle of the short arms. That way, if you ever want to run it through a Gymkhana or flog in on a dirt track at one of the vintage meets, you could dial in the rear suspension to your liking.:D:D
How about multiple mounting holes for the torque arm also?
There is no reason you couldn't have multiple mounting holes for the torque arm. If you raise or lower the front of the torque arm, though, you would have to adjust the rear heims to maintain pinion angle. If you are suggesting holes to move the pivot fore or aft, the arm would have to be made adjustable lengthwise...:HMMM:
No, up and down on the torque arm with LH/RH threaded heims on the rear bars. Maybe LH in the front heim and RH in the rear heim. Weld a nut on the bar itself to fit a wrench to turn the bar after loosening the heim lock nuts.
Quote:
Originally Posted by techinspector1
That torque arm "bar" is a piece of 2x3 tubing that is secuerly attached to the rear end in at least 4 places. I don't think it would easily adjust.
Jim I'm enjoying the build keep them coming!
Referring to post 51. The torque arm is attached at the housing with what looks like heims, so you could raise or lower the torque arm at the front of the arm and adjust the heims in or out to keep the housing at the point you want it for correct pinion angle. The two outboard bars also have heims at each end. Those are the ones I was referring to with the LH and RH heims. If you have a RH heim on one end of the bar and a LH heim on the other end of the bar with a large nut drilled out and slipped onto the bar and welded to the bar, you could just loosen the heim jam nuts and turn the welded-on nut to lengthen or shorten the outer bars.Quote:
Originally Posted by Flipper_1938
If I'm looking at this wrong, tell me and I'll shut up.
Quote:
Originally Posted by techinspector1
Sorry, I was referring to the one posted in #53. It is built like a tank.
Damn, I've exceeded my monthly bandwidth allowance for my free photobucket account.
That is the first time it has happened.
I guess I have to wait 12 more days to do an update.
Pictures are back. I upgraded my photobucket account.
You don't have to use Photobucket unless you just want to. All you have to do is click on the button "Go Advanced". Scroll down to "Manage Attachments" and load your pics directly to this site & thread.:D It helps a lot if you resize your pics first to 640 x 480.:HMMM:
I've been thinking about what I am going to do to it this weekend....
I think I made it too big. I may narrow and shorten the cowl. It looks really big in some of those pics.
I think I am also going to play with the size of the passenger compartment opening. I think the dash may need to come back...or move the seat up just a little.
Oh, and I think I am going three link on the rear suspension.
I decided to try and see how the stock jag rear suspension fit. It fits better than I thought it would. I don't think the springs would have cleared the last set of verticle pieces.
Not really sure how the springs are supposed to be mounted. Dad pulled the rear suspension out of the jag. At the time, I had no plans to use anything except the axle. Anybody got any good ideas?
http://i110.photobucket.com/albums/n...8/HPIM0719.jpg
http://i110.photobucket.com/albums/n...8/HPIM0720.jpg
http://i110.photobucket.com/albums/n...8/HPIM0727.jpg
http://i110.photobucket.com/albums/n...8/HPIM0728.jpg
So, does anybody have any guesses as to how to hold a spring tight enough in the middle so that it acts like a quarter eliptic, but loose enough that the other quarter of the spring still works?
I think the cernter pad fit into a pocket onthe bottom of th chassy and the front would be bolted in. the shackle movement if you could call it that is the rear axle and the upper mount. different setup
I looked at your pics and envisioned a 4 link, using both axle mounts on a staggered mount on the frame and a angled forward coilover like on a older dirtbike.
If memory serves me, I believe that older Jag setup was called "cantilevered leaf springs".:rolleyes::confused: Anyway, the center spring perch is mounted on a pivot and the front of the spring is trapped in a bracket on the frame that allows the end to move fore and aft slightly without binding, but not up & down. Everything is mounted in rubber to ensure against squeaks. It works a lot like a quarter-elliptic spring, but the ride is softer and rebound is less "choppy".:HMMM:
Why not just cut the forward part of the springs off, solidly mount the center part to the frame and use them as quarter elliptics. You probably don't want the soft ride that cantilevered leafs would provide in this type of build anyway, and the "choppy" rebound can be controlled with a good set of shocks. Even those upper control arms could be lengthened to give you, essentially, a four link suspension.
Finally figured out how the stock jag suspension worked....I think.
It pivoted on the lower half of the spring pin. The upper half was mounted in rubber such that the pin couldn't catch anything. as the spring cycled, the top portion of the spring pack could move front to back.
Here is my attempt to immitate the function.
http://i110.photobucket.com/albums/n...8/HPIM0731.jpg
more almost free material was used for my spring boxes. ....cop car roll bars that dad bought at an auction. I used the 1/8" panel at the bottom.
http://i110.photobucket.com/albums/n...8/HPIM0730.jpg
http://i110.photobucket.com/albums/n...8/HPIM0733.jpg
I overlapped the tops so I'd have double thickness on top.
http://i110.photobucket.com/albums/n...8/HPIM0734.jpg
The insert captures the spring pin. It is secured by four 3/8" bolts and really beefs up the spring box when it is all bolted tight.
Here's how the box fits into the overall car. The box I just made made will be behind the seat. The front bucket (upside down box) will be under the seat.
http://i110.photobucket.com/albums/n...8/HPIM0738.jpg
http://i110.photobucket.com/albums/n...8/HPIM0740.jpg
http://i110.photobucket.com/albums/n...8/HPIM0741.jpg
Here is a view that shows the eurothane bushing inside the box. It sits over the spring pin.
http://i110.photobucket.com/albums/n...8/HPIM0739.jpg
Still have a lot of figuring out to do. the nuts will be welded to the side of the box to make it easier to re-assemble in a finished car. Need to remeber to keep the bolts accesible when I build more of the rear bulkhead.
Quote:
Originally Posted by RestoRod
I think the longer leaf will make it easier to distribute the spring loads onto the unibody chassis. Without a "real" frame, it would be hard to build a mount that could handle the torque of a quarter eliptic spring.
I guess it would depend on the frame structure and how it is integrated into the unibody. The Austin Healey Sprite/MG Midget used a quarter elliptic rear suspension albeit with much lower HP than you are using.Quote:
Originally Posted by Flipper_1938
If you haven't figured out, these boxes are going to be tied into the frame/sides/floor and heavily supported.
These boxes to way longer to figure out than I would have ever guessed.
Somebody on metalmeet posted a pic of the sprite style mounts. It is a lot simpler than I thought it would have been.Quote:
Originally Posted by RestoRod
http://i110.photobucket.com/albums/n...pringmount.jpg
Due to the automotive slowdown while chrysler re-organizes (I work for a supplier), my job has said we are going to a 4 day workweek. That means I have a months worth of 3 day weekends to work on my car. :)
I always like the positive spins that come of negative situations. Hope to see some more progress. This is a great thread from an educational stand point for me. Keep on posting.
yeah, lucky you.. summer weekends even! WOOT... my six months of unemployment landed me sitting in the house, with too cold/rainy outside to work. now I have a job again.. *sigh* Planning to take some time off before my next job ( I re-enlisted, will deploy on July 13 ) but then it might be too HOT to work much.. but then, there is always evenings / late night.