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| Is the Ackerman angle on the 88 really bad? It looks it. (Page 1/5) |
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ricreatr
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JUN 26, 04:57 PM
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Dumb question i know, but was playing around with solstice knuckles last night. (for better bearings). I know it has been done before, but is was fun to mock it up. Roughing it in looked like there was going to be a little additional negaitve camber. good.
also the ackerman (mind you i am just eyeballing it) looked like it was not quite enough, but then i eyballed the factory knuckle, and the factory ackerman looked all backwards (steering arms angled way in). supposed to be the other way around on a front steer car right.
the solstice knuckle was pretty much straight, so averaging between the upper and lower knuckles it appeared to be outboard of the upper and lower ball joint centers.
I could not find any discussion about the factory ackerman angles on the 88.
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jelly2m8
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JUN 26, 11:45 PM
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Car and Driver numbers for what ever they are worth
07 Sosltice GXP Skidpad 0.85
88 Formula 0.83
The Fiero was tested on 30 or more year old tire technology, The Solstice on something quite a bit newer.
Ya the Fiero is terrible, should look for a different platform.
Don't compare the Fiero's SLA design to the Solstices modified Double Wishbone design, might look similar but are 2 different designs with different geometry.
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Frenchrafe
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JUN 27, 04:31 AM
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Yeah... Stick some semi-slick tyres on a Fiero and the handling can be a bit better, but it's never going to be a modern car.
I get hammered on the corners by the Lotus and other more modern cars. It's just that I'm very powerfull and that I can keep up!
I've tried lowering the roll center etc..., but it doesn't feel any better? And I can see how the other cars handle, and mine doesn't do that!
The Fiero is not a race car, but you can have fun with it!------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
https://youtu.be/hUzOAeyWLfM
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fieroguru
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JUN 27, 07:09 AM
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The 88 ackerman angle isn't great, but also isn't a constant (varies by cornering loads, tire deflection, as well as front toe adjustment), and there are contradictory theories on what the "best" ackerman should be.
I run almost zero toe in the front and have 235/40/17 front tires and can feel some tire scrubbing in parking lot turns.
The placement (up/down & side to side) is all function of the front suspension design. You can't change it without also changing other parameters (like bump steer). So if you change the location of the steering arms, you likely will be changing the location and/or length of the steering rack to bring bump steer back into something tolerable.
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82-T/A [At Work]
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JUN 27, 07:43 AM
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I'm so not a race-car driver, and I barely did SCCA and it was like 30 years ago now and I only did the stuff with the cones in a parking lot in Homestead (I think it was SOLO-1 or something... had to borrow someone's helmet, it was nasty).
But I owned a Solstice back from (late) 2005 to 2009. I modified it so it was honestly pretty quick... header, high-flow cat, better exhaust, intake, etc. The handling was "different." I'd say that the Solstice felt more stable in the rear to the point that, if I started to lose control a little bit in the rear, it was easier to regain control (don't ask why I know this, since this was on public streets when I was more immature). But the Fiero seemed more stable over-all. There was a handling threshold (if you will) that I realized that once I reached that, there was no going back. But in every other category, the Fiero felt more stable, and more... how can I say... the handling was more predictable across all driving situations.
The Solstice... maybe because I was older and a little bit less immature, so I never really pushed it as much... it felt solid, but it never felt as predictable. It drove fantastic, don't get me wrong... it had an excellent balance between great handling and a comfortable ride. It just didn't feel as competent as my 87 Fiero. There were times that at triple digits (again, don't judge me, I was an idiot)... I'd have all four wheels squealing in a turn with my Fiero, and I was right on the edge / pushing that envelope, and as long as I didn't push it too much further, I could really control the car's skid / slide as I made it around that turn.
The Solstice had a more stable back-end, but after 3 years of driving it... at some point the rear end got completely squirrelly. I don't know how to explain it, but the entire back end felt loose. It was still under warranty so I never bothered with it, and my daughter had just been born, so I traded it in for an SUV and I've been driving the speed limit ever since.
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ricreatr
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JUN 27, 07:57 AM
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Jelly, I am not complaining about the way my 88 handles (just not sure what to do about a loose hub)! i put on sticky tires this summer and did a short autocross course. Got within three seconds of some very pricey porches. I am just an ole guy having fun, but it was a blast. my wife has a sky, and i secretly love the handling of that goofy front-engined car.
Slug, you just cost me some time checking out drag videos. wow. that is some amazing work on that car.
Thanks Guru, you are always expert helpful. The design just looked like it was off from what i had learned, looking for a reality check. I would rather just buy a set of Rodneys hubs, except his no racing clause...
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Frenchrafe
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JUN 27, 08:55 AM
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Yeah! I like upsetting pricey Porsches as well👍
Turbo Slug thanks you for the complements by the way.
And yes, I've tried to get the best out of what I have in terms of suspensions, without going totally nuts and custom made arms, etc...
Interesting what Todd said about feeling secure with his Fiero. I feel the same. I know it's limits and I can push it a bit.
My brother in law, who has the pricey Porsches, Corvettes, Jaguars and whatever, was pleasantly supprised when he drove Turbo Slug on a trackday. His only complaint was for the gear shift; but he should remember his old 911's...!? They shifted badly as well.
He pushed my car further than I tend to do and he found it to be quick!
Concerning '88s, I've always thought it was strange to narrow down the wheel width at the front? Is the track significantly narrower as well?
While the back suspensions of an '88 are better (on paper), it would seem that the front design didn't improve anything?
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"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).]
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olejoedad
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JUN 27, 09:12 AM
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| quote | Originally posted by jelly2m8:
Car and Driver numbers for what ever they are worth
07 Sosltice GXP Skidpad 0.85
88 Formula 0.83
The Fiero was tested on 30 or more year old tire technology, The Solstice on something quite a bit newer.
Ya the Fiero is terrible, should look for a different platform.
Don't compare the Fiero's SLA design to the Solstices modified Double Wishbone design, might look similar but are 2 different designs with different geometry.
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The Solstice runs 245 width tires on all 4 corners, vs the 205/215 setup on a Fiero.
I test drove a second year Solstice at a local dealership.
I probably scared the salesman to death.
The test drive was all it took for me to decide to rebuild the suspension in my 86SE.
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cartercarbaficionado
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JUN 27, 10:25 AM
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can speak for the handling of an 88 wish I could upload a video to prove my poin. yellow as much as he prods at my patience is honestly the expert on 88 suspension improvements. I'm more familiar with how he modified his 88 now since I started doing sim software and doing some 3d modeling and mods to the fiero suspension out of boredom and wanting to make use of some newly gained chassis knowledge and found out he's doing extremely well and getting close to the limit of what the control arms and such can hapoint.
tldr. yes it ls bad compared to any modern car that someone didn't penny pinch the engineers on but can be made into a real monster with some work
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cartercarbaficionado
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JUN 27, 10:36 AM
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| quote | Originally posted by cartercarbaficionado:
can speak for the handling of an 88 wish I could upload a video to prove my poin. yellow as much as he prods at my patience is honestly the expert on 88 suspension improvements. I'm more familiar with how he modified his 88 now since I started doing sim software and doing some 3d modeling and mods to the fiero suspension out of boredom and wanting to make use of some newly gained chassis knowledge and found out he's doing extremely well and getting close to the limit of what the control arms and such can hapoint.
tldr. yes, it ls bad compared to any modern car that someone didn't penny pinch the engineers on but can be made into a real monster with some work |
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edit: I decided to share the Google drive link. note the fiero is doing ~80 because it is interstate and dodged quickly and perfectly controlled, and this was with bad front bushings
https://drive.google.com/fi...Tc/view?usp=drivesdk
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