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| Weird Alignment Changes? (Page 2/4) |
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pmbrunelle
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JUN 22, 03:40 PM
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pmbrunelle
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JUN 22, 03:46 PM
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| quote | Originally posted by Yellow-88:
Solid control points require at least some machining and fabrication.
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Will produced a set of metallic spherical bearing pivots for the front lower A-arms:
https://www.fiero.nl/forum/Forum4/HTML/080567.html
If you ask (along with other folks), he may consider doing another batch. Custom machining not needed (well, he takes care of it)!
| quote | Originally posted by Yellow-88:
Also be aware that solid control points transmit a lot of road noise, not at all pleasant for normal driving. |
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I have Will's spherical bearings, and I find that the ride of my Fiero is quite smooth and comfortable  When I haven't broken something on it, my Fiero is an everyday-use car...
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Additivewalnut
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JUN 22, 04:19 PM
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| quote | Originally posted by pmbrunelle:
I have Will's spherical bearings, and I find that the ride of my Fiero is quite smooth and comfortable When I haven't broken something on it, my Fiero is an everyday-use car... |
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That looks pretty hardcore as far as the install goes, but also like the perfect solution.... I'll shoot him a pm and see what happens.
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Yellow-88
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JUN 24, 10:21 AM
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| quote | Originally posted by Additivewalnut:
This car hasn't had a warranty since 1989 LOL. My car is on it's way to being trailered to the track anyway since I'm starting to do stuff to get it prepped for road courses. I figure what you had were off the shelf parts since you were saying it's that much better than poly. I don't really have the facilities to be making custom control arm mounts or whatever is involved with it. |
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Yeah ... LOL. What was I thinking. You're off the hook.
Pretty much any bearing is available from several venders. I did consider buying some but they still require some work to make them fit. I ran into, close but not quite, so I made them. If someone has done the work and there still available, by all means buy them.
The pre 88 cars have some seriously compromised suspensions that require a lot more than just better control points for the track. Tell me more about you car.
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Additivewalnut
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JUN 24, 10:46 AM
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| quote | Originally posted by Yellow-88:
The pre 88 cars have some seriously compromised suspensions that require a lot more than just better control points for the track. Tell me more about you car. |
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It's an 86 SE, poly bushings and Hiro Performance coilovers on front and rear. Soon to have a rear sway bar once those get back in stock at the Fierostore. At some point I plan on getting adjustable upper arms in an attempt to get more camber out of it for cornering. 3800sc swapped. fairly standard deal except for the coilovers.
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Yellow-88
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JUN 24, 12:04 PM
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| quote | Originally posted by Additivewalnut:
It's an 86 SE, poly bushings and Hiro Performance coil overs on front and rear. Soon to have a rear sway bar once those get back in stock at the Fierostore. At some point I plan on getting adjustable upper arms in an attempt to get more camber out of it for cornering. 3800sc swapped. fairly standard deal except for the coilovers. |
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Camber is based on roll angle. Ideally the tires are ALWAYS perpendicular to the road. High aspect ratio tires will tend to squash sideways and counteract extra camber, that maybe why people do it. With really stiff, low aspect tires, extra camber may actually hurt your cornering.
It's always best to limit roll angle. Absolutely you need a rear sway bar but it needs to be sized correctly or at least be adjustable. Too stiff will lift the rear inboard tire, thus loosing traction. Front and rear bars must work together. In a nutshell, it's all about keeping as much rubber in contact with the road as is physically possible .... always. A skid pad is essential for tuning sway bars. I can't comment on the Fiero Store bar. Anybody want to jump in?
The early cars have some issues with "bump steer". Try to keep roll angle low so as not to use too much suspension travel. The most successful race cars are easy to drive. The driver should not have to compensate for changing suspension geometry. Most likely, you and many others, are doing that without knowing it.
What class will you be running in?
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olejoedad
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JUN 24, 12:51 PM
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| quote | Originally posted by Yellow-88:
Camber is based on roll angle. Ideally the tires are ALWAYS perpendicular to the road. High aspect ratio tires will tend to squash sideways and counteract extra camber, that maybe why people do it. With really stiff, low aspect tires, extra camber may actually hurt your cornering.
It's always best to limit roll angle. Absolutely you need a rear sway bar but it needs to be sized correctly or at least be adjustable. Too stiff will lift the rear inboard tire, thus loosing traction. Front and rear bars must work together. In a nutshell, it's all about keeping as much rubber in contact with the road as is physically possible .... always. A skid pad is essential for tuning sway bars. I can't comment on the Fiero Store bar. Anybody want to jump in?
The early cars have some issues with "bump steer". Try to keep roll angle low so as not to use too much suspension travel. The most successful race cars are easy to drive. The driver should not have to compensate for changing suspension geometry. Most likely, you and many others, are doing that without knowing it.
What class will you be running in? |
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I had the Fiero Store front and rear anti-roll bars on my 86SE ( as well as Eibach springs and full poly.)
The bars are a set, and balanced for the 84-87 Fiero.
With street tires on 15" lace wheels (215/60/15 - 225/60/15), the car ran autocross times mid pack with race-prepped Corvettes.
They are the best suspension upgrades one can make on a pre-88 Fiero.
Edit to add....
I see Fieros at shows the have way too much rubber on the road, and the front/rear width stagger is all wrong; too much rubber on one end or the other.
More rubber on a Fiero does not necessarily equate to better handling or faster lap times.[This message has been edited by olejoedad (edited 06-24-2024).]
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Additivewalnut
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JUN 24, 01:45 PM
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| quote | Originally posted by Yellow-88:
Camber is based on roll angle. Ideally the tires are ALWAYS perpendicular to the road. High aspect ratio tires will tend to squash sideways and counteract extra camber, that maybe why people do it. With really stiff, low aspect tires, extra camber may actually hurt your cornering.
What class will you be running in? |
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As someone who works in a shop that specializes in race tires and alignments, I have to disagree. The way our cars are set up, in a turn we gain a ton of positive camber. You have to put in -1 or -2 degrees of camber so that your tire is truely perpendicular to the track mid corner. You wouldn't really be racing on a tire with a 55 sidewall anyway as it would have way way too much flex so those people are simply doing it for show and are just destroying their tires.
As olejoedad said, more rubber doesn't inherently mean more gooder as far as cornering performance goes. I got the same times with 205 front tires that I do with my current 235 because I spend the entire race fighting the car on my tow out changing and understeer from lack of swaybar. Adding a sway bar and camber alone should help a TON as this chassis really enjoys understeering for reasons that I'm still not really 100% on. Lack of weight up front? Shitty suspension design? Both?
I'm running SSM in SCCA classes, so I'm in a pretty loose on the rules class. I'm running with a guy in an LS swapped miata with 315 hoosiers.
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Yellow-88
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JUN 24, 05:48 PM
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| quote | Originally posted by Additivewalnut:
As someone who works in a shop that specializes in race tires and alignments, I have to disagree. The way our cars are set up, in a turn we gain a ton of positive camber. You have to put in -1 or -2 degrees of camber so that your tire is truely perpendicular to the track mid corner. You wouldn't really be racing on a tire with a 55 sidewall anyway as it would have way way too much flex so those people are simply doing it for show and are just destroying their tires.
As olejoedad said, more rubber doesn't inherently mean more gooder as far as cornering performance goes. I got the same times with 205 front tires that I do with my current 235 because I spend the entire race fighting the car on my tow out changing and understeer from lack of swaybar. Adding a sway bar and camber alone should help a TON as this chassis really enjoys understeering for reasons that I'm still not really 100% on. Lack of weight up front? Shitty suspension design? Both?
I'm running SSM in SCCA classes, so I'm in a pretty loose on the rules class. I'm running with a guy in an LS swapped miata with 315 hoosiers. |
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Back when 70 series was wicked wide you could almost squash the tires off the 5 1/2" rims. On a hard corner you were running on the outside edge of the tire. It didn't really matter how much camber you started with. Am I dating my self?
Yes, you need to keep maximum rubber on the road but, if some of it is fighting you, because your steering more than you have to, extra rubber costs power and eats up your lap time. 235's with "dynamic" geometry is exactly that. What you gain in rubber you loose in friction. I think perfectly controlled bike tires, could run equally with fat, poorly controlled ones. (Not really but an Interesting test.)
What you're seeing is the compromised geometry of the pre 88 Fiero. As long as you don't move the control arms up or down, it's fine. That's why I say to limit the roll angle as much as possible. Make it into a giant go kart.
Weight distribution is actually pretty good. It's good to know that there's a bolt-on roll bar that is correct for the pre-88 cars.
Detroit must build cars for normal folk, so understeer is the choice. Even the 88 naturally understeers. The 88 does that with unequal length lateral links in the rear. I modified Yellow with equal length links so it's now dead neutral. And .... all 4 tires point where there supposed to.
You have your hands full with your choice, but that just adds to the challenge. Surprise everybody.
I've been away from the sports car racing scene for a long time. SSM looks like a lot of fun.
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Yellow-88
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JUN 24, 11:00 PM
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I must correct my statement to be; Camber setting is based on roll angle accepted.
Roll will cause the inboard control arms to drop and the out board ones to rise. If the Fiero geometry show's positive camber as the arms move just a little toward full bump .... that's really bad geometry for serious driving. I've never measured pre-88 in detail. Is it common to see that in other suspension's? I always thought that unequal length control arms cause negative camber on bump or they should. Of course the 88 does ... I know ..... but that is a really nice front end.
You could do a full analysis of a pre-88 chassis by putting it on the rack with no springs and 4 jacks. That way you could run it through a simulation of every thing it can do. Simulating maximum roll before it gently unweights it's inside tires would need data from the skid pad. What are the toes and cambers in that condition? What happens when you turn in from zero roll? And of course, what's the rear end doing? Now that would be interesting data to see.
Another thing to watch out for is scrub radius. The idea is to pivot around the center of the tire's contact patch. That's based on tire diameter and wheel offset. Big scrub radius costs wasted rubber.
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