I am a big fan of the 88 rear suspension setup because it had dedicated links to handle the lateral loads and acceleration/braking loads independently. What I do not like about it is that in stock form there is little to no negative camber gain under compression. Since it is a strut based suspension, the only way to get negative camber under compression is for the bottom of the wheel to kick out under compression. This is done by positioning the lateral links at a downward angle between the cradle and the wheel.

The stock ride height has the bottom of the 88 cradle about 6 1/4", but for the following mockup purposes I used 6 1/2" because it was easy (and 28" to the top of the rear wheel well).



As you can see in the pic above, at stock ride height the lateral links are nearly parallel. So with much compression or body roll the wheel that wheel will generate positive camber... exactly the opposite of what is needed.

If you lower the rear of an 88, it makes the camber issue worse because the links are already point upward, which will accelerate the positive camber gain under compression and body roll. Here is the stock suspension with the rear lowered about 1.5" (about 26.5" at the wheel well)


The lower you go, the worse it continues to get. Here it is with the rear lowered 3" (25" at the wheel well):


Relocating the lateral links to improve the camber curve and restore the suspension geometry back to near stock levels isn't anything new. The common method is to relocate/raise the lateral link mount locations on the cradle like in this picture:


Raising the lateral links at the cradle works, but you quickly run out of available room on the driver side due to the tripod and transmission clearance.
My lateral link relocation takes a slightly different path and leaves the cradle unmodified while lowering the lateral link mounts at the upright. To test out the concept and make sure there was room for this modification, I made some simple plates to relocate the lateral link 1 1/2" lower and the trailing link (the trailing link needs moved to allow clearance to the lower lateral links).




From this mockup, there was plenty of room for the lateral links inside a 16 x 7 (38mm offset) wheel, but the trailing link mount was getting very close to the wheel lip. This setup will not clear a 16" wheel wider than 7" unless the offset is adjusted accordingly. This modification is best suited for 16" (7" max width and 38mm offset) and larger wheels. Then it was a matter of making some cardboard templates of the right general shape.



The cardboard templates were used to make some 16ga templates, then the 16ga templates were used to make the 1/8" plates:



Then it was time to assemble the final relocation bracket. The only modification to the cradle was grinding down a sharp corner here:


Putting the side pieces together:


Added the sleeves, backing plate and final welding:





Slide it back onto the upright:




Then it was a matter of installing it and taking a picture of the lateral link angle at the various heights:

Stock height with the fieroguru lateral link relocation (lateral links angled down, so there will be positive camber gain under compression... which is what we want):


Lowered 1 1/2" with the fieroguru lateral link relocation (pretty much restores the geometry to the stock configuration)


Lowered 3" with the fieroguru lateral link relocation (about as poor as the stock suspension lowered 1 1/2"):


Granted these lateral link relocation brackets are a lot more work than raising the cradle points, but there is more room for a larger change, and there really isn't anything keeping you from doing both (lowering the connection at the upright and raising the connection at the cradle to even more camber gain.

If you want to see the precise suspension geometry changes between stock and my lowered lateral links, Zac88GT ran the #'s (stock #'s supplied by Bloozberry) and plotted the curves in this thread (along with most the discussion about this modification and many other fiero suspension discussions).

https://www.fiero.nl/forum/F...2/HTML/117227-6.html

[This message has been edited by fieroguru (edited 02-11-2012).]

Cool Thread!

No moss growing on you I see!

Nolan

OK, so my 88 is lowered about 1.75 or so in the back, and looks like your picture with the lateral links going up. What I don't understand about your post is what does it mean when I am driving? Because i don't know what I should be feeling. I do plan on changing out my struts and going with Koni''s over the KYB I have now, but again, what happens when I drive it hard. I assumed any bad handling I was getting was due to an alignment issue, but from reading this, I wonder if its because of the bad Camber.

Are you planing on selling this at some point? If so, I think I need a set.

Rob

Great innovation on this mod Guru. We need more people like you who are willing to share their ideas freely.

Another added benefit of lowering the trailing link at the knuckle is:

a. improved anti-dive geometry if you decide to keep the stock ride height; or

b. restored anti-dive geometry if you decide to lower the car no more than the amount the trailing link was lowered; or

c. less severely impacted anti-dive geometry if you decide to lower the car more than the amount the trailing link was lowered.

I gotta ask......Are you going to to be selling all these new improvementyou are coming up with?

^X2 & It looks the stock length trailing arm would pull the wheel forward slightly with the lowered mounting point, it that the case?

quote Originally posted by qwikgta: OK, so my 88 is lowered about 1.75 or so in the back, and looks like your picture with the lateral links going up. What I don't understand about your post is what does it mean when I am driving? Because i don't know what I should be feeling. I do plan on changing out my struts and going with Koni''s over the KYB I have now, but again, what happens when I drive it hard. I assumed any bad handling I was getting was due to an alignment issue, but from reading this, I wonder if its because of the bad Camber. Rob

As you take sharp corners, the bottom of the loaded wheel will start being tucked in and reduce the tire contact patch to be the outer edge of the tire. This is the exact opposite of what you want with is for the lower portion to kick out to help maintain the full tire patch contact that the tire is deformed. The camber characteristics in the rear is one of the reasons that when the rear end breaks loose around a corner, it is difficult to recover. The harder you corner, the worse this issue is.

Most guys who road race/autocross the 88's have to dial in quite a bit of positive camber and greatly reduce body roll to counter act this issue.

By modifying the suspension to have positive camber curve under load, you can allow more suspension movement (softer springs, and less stiff of a sway bar) while still having favorable geometry to maximize the tire contact patch on a street drive/focused application. I needed a better solution for the 11" wide rear tires my Fiero will be getting.

quote Originally posted by fieroguru: positive camber

Top of the tire inboard is negative camber.

quote Originally posted by Will: Top of the tire inboard is negative camber.

Good catch. I will update the initial post.

Would you say this is similar to using drop spindles in the front?

Jonathan

quote Originally posted by Boostdreamer: Would you say this is similar to using drop spindles in the front? Jonathan

Not completely, this will not lower your car, it only "corrects" the gemotry for an already lowered car.

well, when you finish the design, and are happy with the product, i'd like to order a set from you.

Rob

quote Originally posted by Boostdreamer: Would you say this is similar to using drop spindles in the front? Jonathan

Similar in that the relative placement of the wheel is shifted upward from the lower attachment point, but since the spring attaches from the top, it doesn't lower the ride height directly... just allows the suspension to be lowered with shorter (and often times stiffer) springs while retaining near stock suspension geometry.

Dropped spindles in front lower the car while keeping the spring rate stock.

I finished the other side and cleaned up with outside surface:




Also, modified the shape of the backing plate - making it flat across the top vs. curved. This gives it more clearance to the wheels and allows the 1 1/2" setup to clear a 16x7 wheel (38mm offset).





Now that this setup will fit 16" (38mm offset) and larger diameter wheels, how many people would be interested in purchasing a set for $350 shipped?

quote Originally posted by fieroguru: This weekend I might be building a 2nd set with the points lowered 2 to 2 1/2". I need to get out the Percys wheel tool and figure out how low I can go within the 18" wheel and build my personal set to that dimension. I am looking for improved camber curve at a 1 1/2 to 2" drop vs. just restoring it to stock.

Need to emphasize that the extreme geometric changes are to correct the geometry of the car when lowered, and may not be a good idea to use with stock height cars. IE, this is a game of optimum rather than maximum.
Using the part that drops the outer pivots 2 1/2" at stock ride height might be moving the roll center too high and making the car unstable... YMMV.

quote Originally posted by Will: Need to emphasize that the extreme geometric changes are to correct the geometry of the car when lowered, and may not be a good idea to use with stock height cars. IE, this is a game of optimum rather than maximum. Using the part that drops the outer pivots 2 1/2" at stock ride height might be moving the roll center too high and making the car unstable... YMMV.

I checked and 2 1/4" is all that will fit within my 18" wheel and this set will be for a car that is lowered 1 1/2"... just looking for some slight improvement to camber gain on a lowered car (vs. merely restoring it to stock, which has little gain built in). I agree putting a 2 1/2" setup on a stock height car would probably not be a good idea.

quote Originally posted by fieroguru: The first fieroguru Lateral Link Relocation Kit is going to its new owner on Monday. If anyone is interested in a set of these, they are $350 shipped and made to order (5-7 day delay for fabrication). I will start a thread in the mall shortly.

yes. ill take a set. not painted, i'll powdercoat them myself.

Looking forward to the mall thread.

rob

quote Originally posted by qwikgta: yes. ill take a set. not painted, i'll powdercoat them myself. Looking forward to the mall thread. rob

Here you go:
https://www.fiero.nl/forum/Forum4/HTML/060635.html

Have you done any skid pad or track testing to see what improvements this mod produces?

quote Originally posted by Rick Vanderpool: Have you done any skid pad or track testing to see what improvements this mod produces?

Nope. Maybe this summer when I get my car running I can do some testing.

The first pass of rough cutting the needed parts is done for the next 3 sets... still a long way to go before these are done.

Great product. I love the idea that the camber changes more as the suspension compresses. I suspect with these I can actually run with less air in my tire. With the camber changing more there is less likelyhood the tire will roll on its' side.

My only concern is this adapter will recieve a lot of stress under extreme conditions (braking, cornering). Do you have any concern the bracket will flex?

quote Originally posted by My1stMidEng: My only concern is this adapter will recieve a lot of stress under extreme conditions (braking, cornering). Do you have any concern the bracket will flex?

With the triangulation and gusseting designed into these brackets, deflection of the brackets under load should be a non-issue.

As the buyer of the first set I will do my best to brake them as springs rolls around and I get to a few more autocrosses. I see nothing wrong although I do not have them in my hands yet. Fieroguru is very competent and knowledgeable and I am confident that if these meet his standards they will certainly meet mine.

I will keep this thread updated with photos when I get them and as I install the 88 cradle.

Finished all the drilling and shaping for the next 3 sets:


Then started welding up 1 set (I still need to add the sleeves and backing plate to this one):