Thanks, I didn't weld it, Tom Dragoun @ 7sOnlyRacing built it. He got a new 220volt welder and that made a big difference. You can copy my design, that's fine. No patent The car is not at my house anymore but I will be seeing it later this month. I'll bring my camera. It's a tight space and tough to get a closeup shot that's in focus...

 

I'm digging up an old one, but I wanted to mention that I have heim jointed lower links on my car. I'd honestly say it was the best bang for the buck nod I have done so far. The only problem is that w/o the bushing the rar ed is a lot more solid and jaring if you know what I mean. I live in Seattle where we have relitivly good roads and it's a rough ride, but worth it in my oppinion.

 

Well, that's pretty much it, actually. Pinion angle and U-joint alignment can be considered one and the same.

I'm not convinced (anymore) that anti-squat is the best thing for given types of racing, so I built mine to have parallel, equal length arms.



The body hackery was nontrivial, given that I'm retaining the Watts linkage and the third link had to clear it under every possible circumstance, but no big deal. The link's been replaced with something beefier and the mounting bracket has been made 3 dimensional, this pic was from the earlier stages of putting it together.

Indeed! I figured, well heck, I'll just leave the existing 4-link intact to keep things situated correctly while I made up the stuff.

Wrong! My pinion angle was waaay off... like 2 degrees down when it should have been 3 or 4 degrees up. Demolished the rear U-joint in no time flat.

 

I will have to disagree with that statement.

It feels like an entirely different car, now. The rear end works so well now that it's highlighted deficiencies in the front suspension. And *predictable*, too, boy howdy is it predictable!

 

The panhard bar cannot be mounted just anywhere you want. The height of the panhard bar determines the height of the roll center of the rear suspension. Get the wrong height, and your car does not handle so good. Spend the $75 for Susko's book, it is well worth it, plus the purchase cost includes rights to free consultations for his expert advice. I am a very satisfied customer of his, and my lap times prove his stuff works.

 

that's a big hole you have there peejay!

so you fix the short angled upper arm issue but keep the screwed up watts link with high roll center and unequal length arms? why? That puppy really needs a good panhard.

 

The Watts is stronger than a Panhard that could reasonably fit between the rear axle and the fuel tank, IMO. At least, it's stronger than one that would move the roll center low enough to justify the trouble. I've already managed to bend the passenger side Watts body mount with one relatively mild slide into a rut (didn't even get the car up on two wheels), I bet I'd demolish a Panhard mount that wasn't heavily reinforced. Not much room in there for all of that hardware and the exhaust system.

I "fixed" the roll center height issue with increased ride height. Kills two birds with one stone, since it now bottoms out almost never. But the 200lb springs are a wee bit stiff for best grip accelerating out of corners, next season I'm experimenting with softer springs and something around 10" of travel instead of the 7 or 8 inches afforded now... and then the softer springs will further highlight the understeer, so the crossmember will get modified for as much negative camber as I can get while I'm reinforcing it...

It never ends!



If I was going to make a pavement cone-squisher or track ****, then yes the Watts would be gone in a heartbeat. Other issues prevailed.

 

Ah, rallycross. Since the watts body mounts are bending are you going to redo the whole mounting structure? Or at least gusset or box in the stock Watts mounting? I bet the watts links themselves are next for the bender. How do you like rallycross, looks like tons of fun.

The watts is still not centrally located.............. but it's all tradeoffs I guess.

 

so ive started to make my 3rd link,, just got some advise on welding the mount to the axle housing,, ive decided to go with a curved bar that wraps undernieth the car, ill see how that goes,, any other suggestions or tips are welcome,, next comes the panhard, if anyone has made thier own one of those,,, haha, i think that one should be generally easy to do.

thanks again for the help guys,, the pics and advise were great help. i will keep you updated once i get photos of progress.

 

i started welding and bending today,, so far i have the mount tacked on top of the axle housing. and the 3rd link half made. its slightly different than conventional as it has the mount perfectly centered on top of the axle housing, (not off to the side like most) and it will still wrap undernieth the tranny tunnel. so far there have been no clearance issues.

thursday im picking up my hiem joints. and i will post pics of progress and possibly plans later on down the road so people can make thier own aswell..

thanks for the help so far guys..

Paul

 

Be careful of the driveshaft clearance, thats why they are off to the side. Make sure it doesn't hit when the rear end is up against the bumpstops.

 

Very cool. Plans would be greatly appreciated! Best of luck and certainly keep us updated.

 

im doing all my fitting with the bumpstops at max hieght, there is enough room if done properly,,

, my plan of using a eurothane bushing is working out great ! but i am still using 1 heim joint in the 3rd link, for adjustment, and swivel purposes.. 1 should be enough especially with stiffer springrates in the rear, my next step is make a mount on the body for the third link, i will have it as close as possible to center without interfering with the driveshaft in any way,, but i can tell it will need to be slightly offset, possibly with a low clearance hex headed bolt to mount it..

thanks

pics later tonight,

 

some pics of the progress..

the parts are just tac welded onto the axle housing by me,, but im gonna have my brother (ticketed welder) to weld the parts fully.
you can see how i have the link located almost perfectly centered,, (there is still about an half an inch of clearance at full drop!

http://photobucket.com/albums/b345/a...t=DSC01275.jpg

http://photobucket.com/albums/b345/a...t=DSC01274.jpg

(yes i am using a shop rag as a temporary bushing, (just for visual lining up purposes)

http://photobucket.com/albums/b345/a...t=DSC01273.jpg




and just a pic of my cage for anyone who likes chromoly 6 pt cages in fb's, I know i do

http://photobucket.com/albums/b345/a...t=DSC01271.jpg

comments welcome

Paul

 

very nice

 

Please box in that bracket so it won't flex or bend. Please use fat washers on the bolt so it'll spread the load over a wider area of the bracket.

Good Start!

 

I concur, it looks pretty light as is, definately beef it up. ^^^^

 

you bet, im just starting out... and it will be boxed in, i will probably make plans for pple if they want when im done... we will see...

thanks for the tips... more pics will come with progress..

Paul

 

So.... the third link doesn't make contact with the drive shaft or housing or body at full spring/shock compression? How did you come to that conclusion or test it?

 

by using a jack and raising and lowering my axle many times, no so far at max extension it hasnt hit the driveshaft or the body i will have to see because the pinion angle still has to be adjusted so it will be pretty close but im not worried. where it bolts to the body is really low clearance (as close as i could mount it)
will post pics later... i still have lots of work to do and im painting my engine bay at the same time so i dont have allot of time just yet...

thanks for the interest guys i will definately keep you all filled in how it goes...

 

Thanks for sharing your project with us.
I'm also in the process of eliminating the watts linkage and upper control arms. Will share pics soon.

Bruce

 

That's kind of what I figured.

You do realize that's not nearly full extension, right? That's pretty much normal ride height. A good dip, hard corner, anything that puts a lot of G's straight down compresses the springs a lot more than the weight of the car can.

You might want to find a couple fat guys to stand in the trunk and double check that before you weld it in place. Unless you've got A LOT of clearance, there's probably not enough, unless you're running 1000# springs...

 

actually no. thats with no springs... it will fit.. i have plenty of clearance with the axle sitting on the bumpstops.. theres only another inch or so that it can possible move up before the wheels will bottom out in the wheelwells.. so your ride hight would be much higher than this so that you didnt rub on every corner... trust me the car will be "slammed" and i will still maintain clearance..

Paul

 

Oh, ok, that's different then.

Wouldn't be the first time I knew somebody weld something solid then find out the clearance wasn't there.

 

I spent the winter eliminating the Watts link and upper control arms on my 82 Rx-7 I use for autocross. I used Suskos setup manual and pictures of other rear suspensions to fabricate it myself.
I am happy to report after the first autocross this year that the car is so much better. Now the rear end is well planted through long fast bumpy sweepers, and a pleasure to drive in the slaloms. Where as before I would be focused on keeping the back end under control now I can focus on putting the car where I want it and keeping the speed up. In truth the car is quicker than me right now.

This is the best thing I've done to improve the handling.
Just wanted to let you know
Bruce