FB Rear Suspension Geometry Problems/Options/Solutions
08-10-10, 11:24 AM
#104
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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
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
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
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
11-02-10, 11:49 AM
#110
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Sorry BlackWorks-I cannot find any pics of the design...
~M
11-08-10, 03:04 PM
#113
Well, DAMN!
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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.
11-08-10, 04:36 PM
#114
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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
RXDad
GD
11-27-10, 04:40 AM
#118
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.
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.
11-27-10, 01:08 PM
#120
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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.
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.
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!
11-27-10, 05:30 PM
#121
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.
11-27-10, 07:17 PM
#123
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.
Since noone else has ever put up Gforce engineering panhard pix installed I thought I might.
11-28-10, 01:02 PM
#125
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.
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.