Lot's of posts discuss adding the brakes but I wasn't able to find anything that actually discussed putting the suspension under a Fiero. I watch these car buildups on TV and many times Corvette suspension is put under the car. Has anyone thought about this much?

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RickN
White 88GT 5spd
White 85GT Auto

Bubbajoexxx is using Corvette suspension parts in his buildup, but his may be a lot more radical of a change than you had in mind.

https://www.fiero.nl/forum/Forum1/HTML/033676.html

quote Originally posted by Formula88: Bubbajoexxx is using Corvette suspension parts in his buildup, but his may be a lot more radical of a change than you had in mind. https://www.fiero.nl/forum/Forum1/HTML/033676.html

Thanks,

Good link...I was interested in the use of the whole Corvette suspension, from spindles inward thru the control arms to the attachment points on the frame. I could imagine that the front might be more straight forward than the rear.

you might squeeze the front in but the rear I expect is simply too wide to do much; you are pretty much stuck with McPherson struts...
The struts can be eliminated and go to upper and lower control arms but the arm length is STILL very much limited by the 'length' of the engine/trans so the new upper control arms would be very short.

Even with a wide body/kit etc.
...........

quote Originally posted by fiero308: you might squeeze the front in but the rear I expect is simply too wide to do much; you are pretty much stuck with McPherson struts... The struts can be eliminated and go to upper and lower control arms but the arm length is STILL very much limited by the 'length' of the engine/trans so the new upper control arms would be very short. Even with a wide body/kit etc. ...........

Do you think the rear could be used without the corvette differential and spring setup? That way width wouldn't be an issue unless I missunderstand your comment about length. Also I wouldn't be upset if it turned the car into a widebody in the process. Use the control arms with custom springs and dampers then marry a fwd style CV axle to the Corvette hubs?

well
I have a bit of unfinished experience in trying to adapt unequal length control arms to a rebodied fiero rear. You need a mounting point, the mcpherson struts have to go, the frame has (in my case anyway) to be modified (which I was TRYing to avoid without luck) and so on.
on top of all that the new upper control arms are QUITE short from inner pivot point to outer connection to the wheel and that is only acceptable because I am running an extremely stiff (as in VERY limited movement) suspension. I am sure you would be into the same thing and that is all due to the transverse mounted engine - it is very wide and doesn't allow connection of (nice) long control arms.
When it is done we will see if I can live with the resulting ride or not. It is not meant to be a daily driver, in fact, mostly only track days etc but with some limited street driving (that is the plan, anyway....)

A longitudinal mount WITH a longer wheel base would be ideal but that is a whole different ballgame.
Anyway
that is the rear........ I think generally you are stuck with only changing the front.

quote Originally posted by fiero308: it is very wide and doesn't allow connection of (nice) long control arms.

People get all stuck on the long control arm thing and forget that in some ways one can "lengthen" control arms by shortening the upright...

my consolation in not having a very long control arm, and therefore a nice slow change of angle to the wheel/tire (during up/down travel) is in looking at this site........
which I wish I never saw.......LOL sort of.......

http://www.ultimasports.co.uk/gtr/design.html

you'll see in the pic of the control arms that the uppers are quite short and that is about what mine are.
so
maybe hopefully...... but time and the eventual road test will tell.
anyway a bit of info/input for you.

The relative heights of the pivots have much more to do with the behaviour of the suspension and roll center, etc. than the lengths of the control arms.

I don't think you can consider one without the other.

the connection points become very important of course in direct relation with the lengths of the arms. If you look at the F1 cars, the control arms are as long as possible. The length dictates how fast they change the angle of the wheel when it hits a bump or is compressed in cornering. In F1, they are trying to minimize that effect for consistency and predictability of suspension reaction.
A longer arm will change the vertical angle of the wheel during ie a 2" compression a lot less than a very short arm. When a very short arm goes thru the same 2" compression, it might rotate thru 2 or 3 times the angle of the long arm (depending of course on the respective lengths).

Since I am talking about just upper control arms here....
That change of angle will pull the top of the wheel INwards a lot with a short arm but only a little with a long arm.
Obviously the connection points, and thus the intersection of the upper and lower arms; and the location (height) of the C of G is going to dictate more things too. Like roll centre, resultant torque arm length etc etc.

And there are lots of varying opinions on that point. The instantaneous roll centre should be about 2-4" above the ground according to a lot of sources but you will find designs (and successful cars!) that have the roll centre below the ground too! You could read suspension books till you die and not really get a total consensus on what is best.

Just a lot of individual issues and concerns. Like this one LOL.

Anyway; get a sheet of graph paper (if you don't have autocad or a drawing program) and do a scale dwg with your wheel, tire, stock lower control arm, cradle frame, "middle frame", engine face (or trans end if left side), etc etc and then see the result of ie a 5" long upper control arm; it is pretty scary. It will pull the top of the wheel in so fast that it will look like an old VW cranking thru a corner......

Take some measurements of the vette stuff you are looking at and try to figure out where it would go......???

I have a very short upper arm but it is located exactly for the best performance at ride height and the little bit of compression that I allow it; and the whole reason is the (very) high rate of change of the angle of the arm even with a small compression. So the shock I am using will only allow about 5-6" total wheel travel (top to bottom) so that there will not be much geometric change. I believe that I will pick up a nice camber change under extreme cornering (and some body roll) to nicely cancel out the body roll. The tire should stay almost vertical as a result. We will see. Maybe it will simply be a brick. Time will only tell..

Thanks for all the replies, great info!

Could we just be able to use corvette struts and shocks, instead of the entire suspension?

quote Originally posted by goatnipples2002: Could we just be able to use corvette struts and shocks, instead of the entire suspension?

NO.
Why?
Have you seen the C4 C5/C6 set up?

[This message has been edited by Rickady88GT (edited 08-01-2005).]

quote Originally posted by fiero308: Since I am talking about just upper control arms here.... That change of angle will pull the top of the wheel INwards a lot with a short arm but only a little with a long arm. Obviously the connection points, and thus the intersection of the upper and lower arms; and the location (height) of the C of G is going to dictate more things too. Like roll centre, resultant torque arm length etc etc.

You tend to get very bad roll center behaviour when the lengths of the arms are significantly different. Take another look at F1 cars... upper and lower arms are almost the same length.
Changing the height of the UCA inner pivot changes the angle of the UCA at static ride height, which has a much bigger effect on roll center behaviour and camber characteristics than changing the lateral location of the pivot (length of the control arm) and equivalent amount.
Been through all this with SLA configuration for '88 rear suspension.

yup
agreed, great and all that.

I was just trying to tell some things to RickN to watch out for like not having much room for rear suspension components with a transverse mounted motor taking up a lot of space in a car that is narrower than a vette. that's it.
I can't/won't even attempt to be any kind of authority on suspension; it is pretty complex.

From the pics and spec of the new Kappa (Solstice/Sky) platform it looks like it has a perfect suspension to swap into a Fiero If I see a Solstice in an auction I may nab it for a few of it's parts That car turns a .9G on the skid pad, and that is outstanding.

Are there ANY other cars that we could use stuts/shocks from? I mean any performance oriented cars? Camaros, Solstice, Malibu, Chevelle, Nova?

For a bonus point, does anybody know what a stock Fiero runs on the skid pad?

According to Witzenburg's book "Fiero"...

'88GT did .84

'88 Formula did .83

'86GT did .81

'85GT did .82

'84SE did .81 (6 entries ranging from .77 to .81 and a 7th at .84, I don't believe the 7th, must have been tethered to a pole)

quote Originally posted by goatnipples2002: Are there ANY other cars that we could use stuts/shocks from? I mean any performance oriented cars? Camaros, Solstice, Malibu, Chevelle, Nova?

I doubt it.
What wrong with using Konis?

quote Originally posted by 88gtNewb: I doubt it. What wrong with using Konis?

I had koni reds (specials) on my civic and they were pretty tough but they weren't all that COMPARED to the koni yellows (sports). Not knocking the reds but even the techs at Koni will tell you the reds ain't spit compared to the yellows. I am trying to find a car that the fiero shocks will interchange with so I can maybe put koni yellows on my fiero OR find some shocks from a sportier or heavier car that will interchange. I have heard the X-11/citation shocks will fit and they are a little shorter, which helps with the drop. It was somewhere on the forum. Have you guys heard about this?

A-bodies (and presumably X-bodies as well) use struts with a perch about 1/2" lower than the Fiero perch.
Just go to coil overs.

I'd be interested in the availability of double adjustable yellow struts.

Just call Koni. They'll do pretty much whatever you want if you pay them enough. They quoted me $150 each (I think) to convert rear struts to double adjustable and $250 each for front shocks. They can do whatever custom valving you want.

[This message has been edited by Will (edited 08-02-2005).]

quote Originally posted by Will: A-bodies (and presumably X-bodies as well) use struts with a perch about 1/2" lower than the Fiero perch. Just go to coil overs. I'd be interested in the availability of double adjustable yellow struts. Just call Koni. They'll do pretty much whatever you want if you pay them enough. They quoted me $150 each (I think) to convert rear struts to double adjustable and $250 each for front shocks. They can do whatever custom valving you want.

Expensive but i bet you could get over 1G with the yellows and a drop. Damn I want the koni yellows real bad. So would the 1/2 inch hurt the geometry of the fiero. Is it the same strut as the fiero with just a lower perch? Is the valving different?

Takes sticky tires to pull 1G, not just shocks.

quote Originally posted by Will: Takes sticky tires to pull 1G, not just shocks.

mmmm the smell of R compound int he morning

well, I would start by asking what you like about the Corvette suspension?
other than the name, of course. its is made for a front engine car, ya know. with a longer wheel base.
particular year Corvette?
for the most part, this is all BS. just like when someone puts a 350 SBC in a car, and says its a 'Vette motor.
I think its just to be able to say "its 'Vette suspension", like it means something. IT DOESNT. its the call of the stupid. suspension geometry is pretty damn simple. just control arms. with the space available, make them as long as you can, so you cut down on the deflection angle. then you decide if you want to use a-arms or h-arms, upper & lower or just lower. again, space is the deciding factor is almost ALL suspension.

now, the actual science of suspension is in the materials. strong & lightweight materials. so, whats that leave? lightweight knuckles & control arms. there ya go - alum knuckles & tubular control arms.

anyways, this is all moot anyways. just get a decent set of tires. suspension is only 10% of handling - tires is the rest. get a set of "Corvette" tires...lol

and the front is already 'vette.....Chevette.....lol

and, how many years of 'vettes are better than a Fiero on the skidpad anyways?

here is your light weight (vette) knuckles and tube a-arms

https://www.fiero.nl/forum/Forum1/HTML/048610-7.html

quote Originally posted by Pyrthian: suspension geometry is pretty damn simple. just control arms. with the space available, make them as long as you can, so you cut down on the deflection angle. then you decide if you want to use a-arms or h-arms, upper & lower or just lower. again, space is the deciding factor is almost ALL suspension.

Yeah, just throw it together and old way and it will roll down the road. Brutally simple.

quote anyways, this is all moot anyways. just get a decent set of tires. suspension is only 10% of handling - tires is the rest. get a set of "Corvette" tires...lol

Driver confidence is a HUGE part of handling... that stems from the suspension a LOT more than the tires.

quote Originally posted by Will: Yeah, just throw it together and old way and it will roll down the road. Brutally simple. Driver confidence is a HUGE part of handling... that stems from the suspension a LOT more than the tires.

yes, it really is that simple. just swing arms. if it looks right, it probably is. spring rates & dampening rates are kinda tough tho. gonna use 'vette springs & shocks? lol noooo.

driver confidence? wtf is that supposed to mean? it really is TIRES. slap some meaty steamrollers on, and you can do anything.

This is really good, one person saying that you can have the worst suspension in the world and throw on wide tires and it will be the best, NOT! At least Will is closer to the mark, if the driver is not confident in the suspension he is running he will not drive as he should. What I know is that to get good traction and cornering you have to balance the tires, suspension and weight transfer. You can have the widest tires ever made and if they do not grip the road, because the weight transfer is wrong they will slide. The suspension needs to be designed so you get full tire connact with the road and that is not simple. By no means is the Corvette suspension the best in all applications, but it is close and steers you in the right direction, so to speak. Most car guys will use the Corvette suspension in many applications, because it is easily available and can be easily moded to fit most applications. Being independent suspension, front and back, the Corvette suspension can be easily tuned to give you the right weight transfer so the tires will grip the road. It the Corvette suspension the best, of course not.

quote Originally posted by techman2: This is really good, one person saying that you can have the worst suspension in the world and throw on wide tires and it will be the best, NOT!

yes, I am oversimplifying it. what I am trying to say is the swing arm is not a big deal. simple thing. when someone says they put "Corvette suspension" on, they are just using the swing arms. they probably are not using corvette sway bars, shocks, springs, etc, which is what really makes it work for the corvette. they are going to use components that go with the weight & size of their vehicle. anyone who has ever watched suspension go thru its range of motion can tell you right off the bat if its good or not. like our Fiero suspension - you can easily see the bumpsteer with the how & why it happens, and why its not an easy fix with the existing layout - which is probably where the original question is coming from - fixing the bumpsteer.

There's a lot more than bump steer to designing a suspension. Using modded Corvette parts doesn't gurantee proper geometry. Just the height of pivot points can make or break the functionality.

Case in point - the Guldstrand mod. For 1st gen Camaros and Firebirds, you lower the attachment points of the upper control arms. This produces a negative camber curve so the wheel doesn't roll with the body in a turn. You also move the attachment points back for more positive caster and tip the arm to the back a bit more for anti-dive. Gee, it looked "right" to begin with. But there's a night and day difference in the way the car drives.

GL

[This message has been edited by Tugboat (edited 08-04-2005).]

quote Originally posted by Pyrthian: yes, it really is that simple. just swing arms. if it looks right, it probably is. spring rates & dampening rates are kinda tough tho. gonna use 'vette springs & shocks? lol noooo. driver confidence? wtf is that supposed to mean? it really is TIRES. slap some meaty steamrollers on, and you can do anything.

Instant center, roll center, roll moment, kingpin inclination, caster, camber, toe, caster induced camber gain, pro-dive, pro-squat, roll axis, centroid axis, wedge, reverse wedge, torsional stiffness... I could go on, but it wouldn't do any good 'cause I'm pretty sure I already lost you.
Dude, don't try to bullsh1t me about suspension.. you'll just come off sounding silly.

Go and try putting 4 of the widest stickiest tires you can find on a stock Fiero. It will still crash tail first and drive like a piece of junk.

[This message has been edited by Will (edited 08-04-2005).]

quote Originally posted by Will: Instant center, roll center, roll moment, kingpin inclination, caster, camber, toe, caster induced camber gain, pro-dive, pro-squat, roll axis, centroid axis, wedge, reverse wedge, torsional stiffness... I could go on, but it wouldn't do any good 'cause I'm pretty sure I already lost you. Dude, don't try to bullsh1t me about suspension.. you'll just come off sounding silly. Go and try putting 4 of the widest stickiest tires you can find on a stock Fiero. It will still crash tail first and drive like a piece of junk.

yes, I know. I already said - I am oversimplifying. take your "corvette suspension", put it on some random chassis. does it now handle like a corvette? are all your fancy variables now the same as a corvette? no. they are not. because, like you already know, it doesnt work like that - they are just swing arms....

and tires really is where it is at. anyone who's raced knows that. I'm not saying suspension isnt important. suspension is the only thing you can "tune" for handling. with tires, you just switch them for others. go to an auto-x. the guy who gets the best times, is the guy who got the right tires.

or maybe, its cuz the tires made him so confident....

Ahh.... now you clarify "widest tires" by saying "right tires". I can work with that. The RIGHT tires for a Fiero are NOT the widest tires. Go as wide as possible in back, but then match the front tires to the car's weight distribution. People have put 245's on the front of the car, but they shouldn't be running a front tire that wide unless they're running 305's in back. In fact, 255's are really wide to most people, 255 rear tires would match best with a 205 front tire which most enthusiasts would consider narrow.

I'd say that the guy at any given AutoX who got the best times is the best driver, but does not necessarily have the bet car or the best tires or the best anything else. Now if, as in the Fiero, the suspension of the car is sufficiently #@%ed up, then the widest tires in the world won't keep the car settled over rough pavement mid corner, won't recover from trail-braking oversteer and won't prevent suspension bushing deflection and bump steer from conspiring to create vicious snap oversteer stemming from a trail-braking condition...

Now, Corvette suspension does have its high points... Forged aluminum control arms, aluminum knuckles, bolt on 13" brakes, wheel bearings that can take a hell of a lot more beating than the Fiero bearings... etc.
Now in order to install in a Fiero, one would have to fabricate a new front crossmember, and in so doing one could locate the pivots such that the roll center behaviour would be correct for the Fiero. Note that while this is not an intact transplant direct from Corvette to Fiero, neither is it just "throwing it together" and is not "brutally simple".

Designing the suspension for a car that will handle well is not necessarily a matter of doing everything perfectly right... it's a matter of not getting anything grossly wrong... which is where "just throwing it together" doesn't work.

[This message has been edited by Will (edited 08-05-2005).]

quote Originally posted by Will: Ahh.... now you clarify "widest tires" by saying "right tires"..... Designing the suspension for a car that will handle well is not necessarily a matter of doing everything perfectly right... it's a matter of not getting anything grossly wrong... which is where "just throwing it together" doesn't work.

yes, I am not very clear on what I am trying to say most of the time....very aggrevating to others, espcially if I throw attitude in with it....

and after going over some of my suspensions (for R/C cars... ) I have to admit, I have made a few bad ones.

but, I gotta stick to the "they're just swing arms" when it comes to putting "corvette suspension" on anything.

so, at least we got the answer for the original question.....

quote Originally posted by Will: Now in order to install in a Fiero, one would have to fabricate a new front crossmember, and in so doing one could locate the pivots such that the roll center behaviour would be correct for the Fiero.

along with adding framework to the cradle to make mounts for the upper control arms. certainly dont want to mount the upper to the body & the lower to the cradle....

[This message has been edited by Pyrthian (edited 08-05-2005).]

quote Originally posted by Pyrthian: along with adding framework to the cradle to make mounts for the upper control arms. certainly dont want to mount the upper to the body & the lower to the cradle....

No reason not to. Nobody's going to do this and stay with rubber cradle bushings.
I'm sure the mounting points are sufficiently different that it would require fabbing a tubular cradle for the rear anyway.

Vette rear suspension probably isn't such a feasible changeover as the front suspension, owing to the width of the rear frame rails necessitated by the transverse powertrain.