If so how did you set up camber, stock specs or did you add a degree of negative camber over stock.
Im planning on adding the sway bars when they come in but will be going in for an alignment soon so if any changes are worth while now is my time to do them..
On my car for circuit/trackdays: Front -2.0° to -2.5° camber. Rear -1.5° to - 2.0° camber. Having a fair amount of -ve on the front helps to steer in on the corners. But stabilty at high speeds is compromised. (White knuckle driving!)
For drag racing: Front 0.0° to -0.25° camber. Rear -0.5° to -1.0° camber. Don't want a high speed wobble to start! But do need to keep the rear contact patch as wide (and flat) as possible.
And yes, my '87 has anti-roll bars front and rear.
Edit: I don't like any toe in on the rear. The front I keep pretty stock setting.
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
[This message has been edited by Frenchrafe (edited 06-27-2024).]
Yes, -1° over stock is probably good? You will have to see how the car feels for you? That's all. If it is "jittery" in handling, then go back to stock settings.
These specs were NOT meant by Pontiac to make a Fiero handle at its prime in corners. Rather, it is a compromise between handling and ride. These specs are meant to make the Fiero work for student drivers, old men hunched over the steering wheel with a death grip on it, hot-rod teens, and cruising cross country in a straight line with cruise control set. The stock settings are used for both the stickiest tires and the cheapo’s with a sidewall so flexible you can move the tire side to side by hand. GM and Pontiac have one setting for all types and styles of driving - not what you should want in your Fiero!
For an excellent performing daily driven street Fiero, I would suggest the following (again, as a starting point). These specs will apply to both the early chassis and the ’88.
Caster - 4.50 degrees +/- 0.50 Camber (All Around) - 0.50 degrees +/- .050 Toe (Front) 0.00 (neutral) to 1/16” toe-OUT Toe (rear) 1/16” to 1/8” toe-IN
For a point of reference, I have my dual-purpose 85SE (daily driven and race driven at autocrosses and track days) with an ’88 cradle/suspension set up as follows:
Caster -3.50 degrees (I like the quick turn-in this provides) Camber -1.00 degrees all around Toe (Front) 1/16” toe-OUT Toe (Rear) 1/8” toe-IN
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
Yes, -1° over stock is probably good? You will have to see how the car feels for you? That's all. If it is "jittery" in handling, then go back to stock settings.
These specs were NOT meant by Pontiac to make a Fiero handle at its prime in corners. Rather, it is a compromise between handling and ride. These specs are meant to make the Fiero work for student drivers, old men hunched over the steering wheel with a death grip on it, hot-rod teens, and cruising cross country in a straight line with cruise control set. The stock settings are used for both the stickiest tires and the cheapo’s with a sidewall so flexible you can move the tire side to side by hand. GM and Pontiac have one setting for all types and styles of driving - not what you should want in your Fiero!
For an excellent performing daily driven street Fiero, I would suggest the following (again, as a starting point). These specs will apply to both the early chassis and the ’88.
Caster - 4.50 degrees +/- 0.50 Camber (All Around) - 0.50 degrees +/- .050 Toe (Front) 0.00 (neutral) to 1/16” toe-OUT Toe (rear) 1/16” to 1/8” toe-IN
For a point of reference, I have my dual-purpose 85SE (daily driven and race driven at autocrosses and track days) with an ’88 cradle/suspension set up as follows:
Caster -3.50 degrees (I like the quick turn-in this provides) Camber -1.00 degrees all around Toe (Front) 1/16” toe-OUT Toe (Rear) 1/8” toe-IN
Your using stock rubber bushings and camber has noting to do with sway bars. Go stock specs and use stock size tires. Stock tire diameter and offset is also an important design spec.
A fresh suspension and the addition of sway bars is going to help keep the car flat when cornering, the result is going to push the tires harder , No ?
I am going with stock specs btw,
[This message has been edited by hunter29 (edited 06-29-2024).]
A fresh suspension and the addition of sway bars is going to help keep the car flat when cornering, the result is going to push the tires harder , No ?
I am going with stock specs btw,
Push the tires harder? meaning that sway bars let you push harder? Yes, but adding extra camber doesn't compensate for that. The idea is to keep the largest possible tire contact patch for all 4 tires, always. Camber other than zero puts more load on the edge of the contact patch, making it a bit smaller. Suspension is designed to compensate for the fact that the chassis "rolls" in a corner. At maximum roll, camber should be zero.
Suspension geometry gets pretty involved pretty quickly. That's my favorite part of car stuff, and I try to get into some of it in the varies threads that I'm in. You'll find my input in any thread about suspension.
In a nutshell, if you running a stock car on real roads, trust the designers. Running with unnecessary camber just eats tires. Yes, sway bars should have been included in the design.
Push the tires harder? meaning that sway bars let you push harder? Yes, but adding extra camber doesn't compensate for that. The idea is to keep the largest possible tire contact patch for all 4 tires, always. Camber other than zero puts more load on the edge of the contact patch, making it a bit smaller. Suspension is designed to compensate for the fact that the chassis "rolls" in a corner. At maximum roll, camber should be zero.
Suspension geometry gets pretty involved pretty quickly. That's my favorite part of car stuff, and I try to get into some of it in the varies threads that I'm in. You'll find my input in any thread about suspension.
In a nutshell, if you running a stock car on real roads, trust the designers. Running with unnecessary camber just eats tires. Yes, sway bars should have been included in the design.
Ok I understand, I was giving bad advice, I was told a bit more camber would keep the tire patch flat. Thanks for your input.
[This message has been edited by hunter29 (edited 06-29-2024).]
I want to step in here with a question (86 2.8 Ferrari F 40 replica); my car is about a foot wider than stock, although suspension looks relatively stock( ( poly bushings in the front) tires are 245/ 16 front, and 295/16 in the rear. No spacers. Would this alter my suspension settings? I am going to do a self alignment this summer ( no shop here has equipment for this car) car lately is wandering on the highway.
Ok I understand, I was giving bad advice, I was told a bit more camber would keep the tire patch flat. Thanks for your input.
Your running a stock Fiero. I have a lot of suspension stuff going in a thread on this forum called: Is the akerrman angle on the 88 really bad? it looks it. Do jump in.
Being a certified Hunter and John Bean Tech, I had my share, your share and everyone else's share of alignment rack time. I tried this, I tried that. Unless you are looking for the most performance for one specific goal, close to or at OEM specifications is where you want to be. Much as it pains me, the Fiero dudes knew what they had and knew how to get the most out of it.
I want to step in here with a question (86 2.8 Ferrari F 40 replica); my car is about a foot wider than stock, although suspension looks relatively stock( ( poly bushings in the front) tires are 245/ 16 front, and 295/16 in the rear. No spacers. Would this alter my suspension settings? I am going to do a self alignment this summer ( no shop here has equipment for this car) car lately is wandering on the highway.
Your transmission is not relevant, why the fuk would you think the trans is relevant? I will suggest the over weight body and modified from stock suspension for sure. in your case, it's an expensive time consuming trial and error of what works best overall.
[This message has been edited by jelly2m8 (edited 06-30-2024).]
Being a certified Hunter and John Bean Tech, I had my share, your share and everyone else's share of alignment rack time. I tried this, I tried that. Unless you are looking for the most performance for one specific goal, close to or at OEM specifications is where you want to be. Much as it pains me, the Fiero dudes knew what they had and knew how to get the most out of it.
Yes .... The designers knew just how compromised the earlier cars were. The settings they chose are for a reason. For a stock pre-88 Fiero running on real roads, trust the designers. And that includes tire diameter and wheel offset.
A lot of what you hear here, is typical "hot rod" stuff. Fiero's lend themselves to modification by enthusiastic car guys. I see you as more of a "classic car" restorer. We do need some of that in the Fiero community.
I want to step in here with a question (86 2.8 Ferrari F 40 replica); my car is about a foot wider than stock, although suspension looks relatively stock( ( poly bushings in the front) tires are 245/ 16 front, and 295/16 in the rear. No spacers. Would this alter my suspension settings? I am going to do a self alignment this summer ( no shop here has equipment for this car) car lately is wandering on the highway.
The only TRANS that I see in this post is a body TRANSplant.......
[This message has been edited by olejoedad (edited 06-30-2024).]
I want to step in here with a question (86 2.8 Ferrari F 40 replica); my car is about a foot wider than stock, although suspension looks relatively stock( ( poly bushings in the front) tires are 245/ 16 front, and 295/16 in the rear. No spacers. Would this alter my suspension settings? I am going to do a self alignment this summer ( no shop here has equipment for this car) car lately is wandering on the highway.
Especially with an 86, witch is seriously compromised already, screwing with the scrub radius will absolutely alter your suspension "geometry". Tire diameter and wheel offset determine scrub radius. The Chevette had pretty tiny tires. The reason that stock size tires and wheels look too small on an earlier Fiero, is because the geometry of the Chevette called call for a fairly small tire. The designers didn't want to make it worse than it already was.
The correct front tire diameter to keep scrub radius within design is about 24 1/12". Giant tires on a car designed for small ones just doesn't work. What wheels are you using with those monsters? What is the offset? What is the aspect ratio of the tires?
Originally posted by Yellow-88: The correct front tire diameter to keep scrub radius within design is about 24 1/12". Giant tires on a car designed for small ones just doesn't work. What wheels are you using with those monsters? What is the offset? What is the aspect ratio of the tires?
Bigger diameter front tires reduce scrub radius, which to me seems like a good modification for the 84-87 Fiero.
Bigger diameter front tires reduce scrub radius, which to me seems like a good modification for the 84-87 Fiero.
How do you know that? Do we know what it is with stock size tires and wheels? I haven't seen an actual published number. Bigger diameter than what? For an 88 Fiero front end, the stock tire size is 24.7" diameter with a wheel offset of 37mm.
Scrub radius is wicked hard to measure accurately in real life. Really easy with a 2D drawing of the suspension geometry.
One thought I had was to sprinkle some chalk chips a smooth surface and roll a front tire onto it. Turn the steering wheel. Zero scrub radius would create circles with a distinct dot in the center of the contact patch. A 3D Cad Model would be really nice. Does anyone out there have a scanner and CAD capabilities?
Originally posted by Yellow-88: How do you know that?
As long as the scrub radius is positive (which for all years of Fieros it is), then larger diameter wheels will raise the spindle and move the intersect point from the kingpin angle closer to the center of the wheel, which will reduce the scrub radius.
We have Bloozberry to thank for the countless hours he put into detailing the 88 Front and Rear suspension. Here is just 1 of his many 88 Fiero suspension drawings.
The 88 front was supposed to have 30% smaller scrub radius vs. the 84-87 (among other changes).
There are several of us who have done our own Fiero suspension modeling in CAD and have a pretty good understanding of the impact of common modifications (like lowering) as well as the fundamental limits of the Fiero suspension.
[This message has been edited by fieroguru (edited 07-05-2024).]
Here is a diagram to show how a bigger-diameter tire will change the scrub-radius...I have wheels that are 38 mm offset (8 mm inset from stock) + 1" larger diameter front tires- almost no kick-back thru the steering wheel.
[This message has been edited by cvxjet (edited 07-05-2024).]
Thank you. Where did you find that drawing !? I have the one of the rear but have never seen the front. Clearly increased tire diameter over stock, will reduce scrub radius. I understand also. thank you for sharing.
Fieroguru and all; do you have 3D CAD capabilities? I was a pioneer and now a dinosaur in 3D CAD. Some of the modeling I see today is truly astonishing. And 3D scanners ... were science fiction in the late 80s. I think it would be cool to see a modern animated model of the 88 front end.
Originally posted by Yellow-88: Fieroguru and all; do you have 3D CAD capabilities? I was a pioneer and now a dinosaur in 3D CAD. Some of the modeling I see today is truly astonishing. And 3D scanners ... were science fiction in the late 80s. I think it would be cool to see a modern animated model of the 88 front end.
I have used AutoCAD for 30+ years, and have played around a little with Fusion 360. Since I picked up a CNC mill last year, I do need to learn more on the 3D side.
