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FB Rear Suspension Geometry Problems/Options/Solutions

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Old 07-04-10, 09:41 PM
  #101
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Scott can we get pics of where the upper links in the 4 link mount on the axle?
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Old 07-20-10, 01:42 PM
  #102
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*cough*
Recently did the PB&J mod to my suspension again. It works well, but it's clickity clank annoys me considering my car sees on average 100 miles a day...
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Old 07-20-10, 03:05 PM
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Originally Posted by Hyper4mance2k View Post
Scott can we get pics of where the upper links in the 4 link mount on the axle?
oops! Sorry - not been paying attention

They are using the stock upper control arm mounts that are on the axle.
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Old 08-10-10, 11:24 AM
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my friend bought an AE86 that had had a bunch of things done to it

basically the AE86 is a 4 link with panhard, looks a lot like a 1st gen

anyways the people who built it moved the brackets for the upper control links, so that it now runs stock lower links in all 4 spots.

the other mod is pretty standard in that crowd, the traction bracket, they move the lower link attachment on the axle down
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Old 08-10-10, 06:01 PM
  #105
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Torque Arm Suspension

It was mentioned earlier that there were some successful torque arm suspension setups used in road racing.

Any more details on those setups?

Has anybody used a Granny's SpeedShop setup on a track with turns?
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Old 09-20-10, 12:35 PM
  #106
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i was looking at the GTU SA at seven stock, and those bar/channels behind the drivers seat are NOT chassis reinforcement like i had thought, they are actually relocated upper control arm pivot points.

it looks like they tried a couple different things, as both of those had been used.

the current one as of 9/2010 was (and you can see it) on the diagonal channel
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Old 11-01-10, 01:58 PM
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Has anyone considered a "Lotus Link" for the 1st gen?
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Old 11-02-10, 12:43 AM
  #108
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A what?
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Old 11-02-10, 04:38 AM
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Originally Posted by BFGRX7 View Post
Has anyone considered a "Lotus Link" for the 1st gen?
Yes I have seen them. I know there was one member on here who posted pics of his setup. Can't remember who it was. It usually doesn't happen as with most rearend setups it bumps us into "anything goes" go cart classes.
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Old 11-02-10, 11:49 AM
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Originally Posted by Hyper4mance2k View Post
Yes I have seen them. I know there was one member on here who posted pics of his setup. Can't remember who it was. It usually doesn't happen as with most rearend setups it bumps us into "anything goes" go cart classes.
I see. I had considered a lotus link setup when I was deciding on going FB, or FC for a track car. the design is so clean and lightweight, lowers CofG the most out of all designs, and seems relatively easy to fabricate.

Sorry BlackWorks-I cannot find any pics of the design...

~M
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Old 11-07-10, 07:42 PM
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lotus in a FB
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FB Rear Suspension Geometry Problems/Options/Solutions-murphy1.jpg   FB Rear Suspension Geometry Problems/Options/Solutions-murphy4.jpg   FB Rear Suspension Geometry Problems/Options/Solutions-murphy5.jpg   FB Rear Suspension Geometry Problems/Options/Solutions-murphy6.jpg   FB Rear Suspension Geometry Problems/Options/Solutions-murphy7.jpg  

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Old 11-08-10, 12:17 AM
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Is there an actual term for it? I can always look it up. Lotus link brings up a lot of weird things in google.
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Old 11-08-10, 03:04 PM
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Hyper, thanks for the pictures! I was looking for those exact pictures but couldn't seem to find them. Blackwork, the only pics I know of are the ones supplied by Hyper and I only know of the suspension design as a Lotus Link.
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Old 11-08-10, 04:36 PM
  #114
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Originally Posted by RXDad View Post
I fabed and tacked the center control arm with the 4 link upper control arms in place and the weight of the car on the rear. I then pulled the control arm out and sent it out to be professionally welded (control arm is 4130 chrome molly for strength and has to be carefully tig welded).

RXDad
The upper bar to bushing looks MIG welded. And you can MIG 4130 with no issues.

GD
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Old 11-26-10, 08:46 PM
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When this shows up in the mail, you just gotta put it on.
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Old 11-26-10, 10:15 PM
  #116
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lol, I don't know Hyper. Mine's been sitting on the shelf for three years now.
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Old 11-26-10, 10:20 PM
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I'm telling you throw it on. They're life changing.
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Old 11-27-10, 04:40 AM
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Holy christ!! Wow that's amazing! I'm still running the stock uppers and lowers, but I traded the Watts for the old school GForce bolt in Panhard bar. Wow what a difference. I just got back from a quick jaunt around the block. Mind blowing how different it is. I can't wait until I can do the 4 link like posted above.

P.s. I had to remove the rear swaybar. It desktop for with the kit. Oh well. Crazy how well the car drives right now. I was doing 70 MPH slaloms without anytype of slide.
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Old 11-27-10, 11:23 AM
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So the lotus link is just a 4 link ?
How is the axle located laterally ?
Kinda hard to see with the closeup photos.
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Old 11-27-10, 01:08 PM
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Originally Posted by Hyper4mance2k View Post
Holy christ!! Wow that's amazing! I'm still running the stock uppers and lowers, but I traded the Watts for the old school GForce bolt in Panhard bar. Wow what a difference. I just got back from a quick jaunt around the block. Mind blowing how different it is. I can't wait until I can do the 4 link like posted above.

P.s. I had to remove the rear swaybar. It desktop for with the kit. Oh well. Crazy how well the car drives right now. I was doing 70 MPH slaloms without anytype of slide.
Huh, so you're running the panhard without the tri-link? I hadn't considered trying that. I had assumed that they had to be used together.

I didn't quite understand what you were saying about the swaybar, other than the fact that you had to remove it. Just remember that just by removing the bar you would've "stabilized" the rear end (less sliding). How bad is the body roll at the back end now? Any issues with understeer?

Thanks for the update!
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Old 11-27-10, 05:30 PM
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Its actually flatter in the rear now with less roll becasue of the greatly reduced roll center. The mount for the panhard bar bolts to the axle right where the sway bar mounts and makes it near impossible to get the sway bar back on with the mount there. I might try and replace it later. I've driven the car with and wothout the rear bar hundreds of times and with the stock watts and upper links I feel the car is much much faster with a rear bar. I put the panhard on with the watts still attacked and you can actually see how easily the watts in conjunction with the upper links binds and causes the snap oversteer horror we all know. Huge upgrade and I recomend it to anyone. The car now has a slight natural understeer which is easily corrected with the application of throttle. It doesn't even feel like my 7 anymore. so much better... Better improvement than the springs, RB front sway bar. Biggest improvement to my car's handling since I added the roll bar.
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Old 11-27-10, 06:11 PM
  #122
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I have heard they can be noisy. Is it louder ( road noise wise ) or significantly harsher than the watts linkage?

Are you running it on a street driven car?
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Old 11-27-10, 07:17 PM
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Mine has teflon heim joints in it. It's honestly quieter than the stock rear setup with the PB&J mod. Secondly this is not a BMW. If I wanted one I would've bought one. You're not going to make a crazy fast FB that's BMW quiet. Like any built car you sacrifice some noise for performance.



Since noone else has ever put up Gforce engineering panhard pix installed I thought I might.
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Old 11-27-10, 11:17 PM
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this thread rocks.
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Old 11-28-10, 01:02 PM
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This car has a Lotus link rear suspension:



This style of rear suspension was used in Roush Trans AM cars in the 90's. So it has a high HP potential. The beauty of the design is that is has only 4 links, a very low roll center and no roll steer. All of the advantages of a watts link in a much less complex and light weight design plus a roll center height that a watts can't really match.

There are negatives with this design, however. On an RX7 the lower links cut into exhaust clearance. The V8 cars get away with it because they can meet sound with a shorter exhaust. Also, roll center is not easily adjusted because the mount is in the bottom of the rear end housing.

Here is a diagram of a Lotus Link - Classic 3 Link rear suspension. The view is from below.



If you look under a stock FOX or SN95 Mustang (79-04 Non IRS Cobra) you can see an example of Lotus Link turned upside down. The lateral controling links are mounted on top of the rear end and the parallel links are mounted below the axle housing. GM also used this system on a number of mid size RWD cars from the 60's to the 80's. Among other things this design puts the rear roll center higher in the car. Not really very good at all.
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