Before I go in for my alignment, I had wanted to run some figures through my simulator to see if I can't make some improvements here or there. Please, feel free to respond if you have the answers to any of the following:

Weight split front-to-rear.

Centre of gravity in the y-axis (Height).

Toe spread at 100KM/H (Or if not, stock toe figure).

Stock spring rate.

Stock ride height.

Thanks in advance!

Weight distribution I think is 43/57.
Not sure about CG, but you could approximate it by taking a height near the middle of the car but down a bit.
There are a couple different springs you may have and I don't know your car well enough... but even if you knew what it was from the factory the springs will probably be softer from the age.

I'm not too sure how much a simulator would help. Even if you found the perfect numbers, the adjustments you can make are pretty limited and you likely won't get there without modifying your car.

Here's the stock alignment specs for 84-87:

Front camber +0.5 deg
Front caster +5.0 deg
Front toe +0.15 deg

Rear camber -1.0 deg
Rear toe +0.15 deg

Dawg wrote: Moog makes an adjustable upper ball joint for chamber.

Don't confuse the boy. That would be "camber".

Found a site http://www.d26.net/240sx/mirrors/Whiteline_WheelAlignmentTermsAndTheory.htm - Here with some good explanations and diagrams.

When I removed the rear struts on my '84 prior to chopping a couple coils off the springs, I discovered that there was one eccentric camber bolt on just one side. That didn't make any sense to me, so when I reassembled the rear suspension I used all regular strut mounting bolts instead.

Clynt and I then just did a "rough" camber and toe-in adjustment on the suspension (front and rear) when we put the cut springs back in. It's not bad, but I'd like to see if I can get it a bit more precise. I'll probably eventually take it into an alignment shop, but I'm curious to see how well it can be done at home.

For those of us who have lowered our suspension, how necessary is it to use eccentric camber bolts on the rear struts in order to preserve/adjust the correct camber?

The mentions the primary issue with alot of positive caster being overcome by modern cars. It should be noted: It will not be corrected by our cars. The article was written for cars with power steering, something our cars lack. Any increased effort will be the driver's job to fight with our cars.

Caster makes the steering wheel hard to turn for two reasons: One, it directs the weight ahead of the tire patch, which causes the tires to want to stay straight. This can be demonstrated with, of all things, shopping cart. Push the cart normally; The tire will follow behind the pivot point, where the weight pushes down. Now, try and turn the wheel 180 degrees out and push forward. It will almost immediately spin around and continue to follow the weight instead. This is due to a phenominom called implied weight. The other reason caster makes the car harder to turn, is because you're essentially turning one tire "into the ground" and "lifting" the other tire. This can only really be thought of if one thinks in the extreme. Using the diagrams from the site, one can see that at zero degrees, the steering ONLY turns the tires. At forty-five degrees half the effort is to turn, the other half is applied to "turning the tire over" (Altering camber). At ninety degrees, the wheels wouldn't turn left or right, but only lean back and forth while still pointing forward.

It is that final "problem" which is also the most beneficial in terms of performance. By causing the tires to lean, this adds in negative camber, which helps correct for tire roll-over (The tires will try and lean opposite the direction the car turns) by adding negative camber to the outside tires, and adding positive camber to the inside tire, helping to flatten both out.

I believe the use of eccentric camber bolts does offer more adjustment. However, they may or may not actually be required on lowered Fieros. (Probably depends on the amount of lowering that's been done.)

Colby, did you bother with them (even for just the added ease of adjustment)?

Alrighty, well, based upon word-of-mouth estimates on what the Fiero GT's spring rate is, I've plugged in the ride height, weight balance, roll-characteristics and tire type, and run through the simulation, and from the speeds at autocross (And highway) the best camber angle would be -0.9 degrees on the front and -1.7, which brings it to about .15 degrees front and -0.05 degrees rear under acceleration at 60MPH, 0 front and rear without acceleration or deceleration, -0.4 degrees front 0.1 degrees rear under deceleration.

The only thing that concerns me is running -1.7 degrees on a daily driven car... Begging for tire wear.

No, the first figures are the static set rates, the last three are what will actually be translated at the bottom of the tire under the circumstances listed, due to caster, tire roll over and body roll.

And you don't find it wears quicker with the -1.6?

Cheese wrote: Romeo wrote: No, the first figures are the static set rates, the last three are what will actually be translated at the bottom of the tire under the circumstances listed, due to caster, tire roll over and body roll. How can the camber be 0 deg under a constant velocity but -.9 and -1.7 deg when stationary? Is there really enough drag (and anything else I'm forgetting) at 60mph to cause the front end to lower and the rear end to get higher, and enough to cause that much change? Or is there something else happening? Romeo wrote: And you don't find it wears quicker with the -1.6? Not sure, I've only had it there for a couple weeks and less than 400km. I guess I'll find out eventually.

And alright. Will wear slower than the way I have it now anyways. lol

Some trivial and useless facts for anyone who has nothing better to read:

As the Fiero is not in that racing simulator, I had to find another car with similar attributes. Some will find it comical that the closest analogue I could find was the Ferrari GTO. Same weight balance, same weight, same suspension height and a 2.9L V6 (Although given that it's a turbo six, it devellops over 300HP. Could put restrictors on it in-game, but it's just as easy to hold the gas at 70% throttle). I had to alter it's tires to match my Fiero's mind you.

The suspension set up still causes drastic oversteer if the rear stiffness exceeds the front. The can be slightly corrected by matching up the sway bars, or by increasing the stiffness of the front struts.

My idea of 275 back, 245 front will cause the car to have a neutral characteristics, unless the brakes are touched, in which case snap-oversteer is the result.

Peak lateral G's on my current tire set-up with that alignment will cause a peak lateral G of 1.04 at 60MPH, but it causes positive camber beyond that which means by 120MPH peak lateral G has diminished to .92

I trekked out to Colby's place yesterday and we spent several hours setting up the alignment on my lowered '84. Gotta get ready to spank some Vettes on the 25^th!

We spent a heck of a lot of time setting up the rear camber... Measure camber, jack car up, remove wheel, loosen two large strut mounting bolts, tweak camber, tighten two large strut mounting bolts, replace wheels, lower car, bounce car to settle springs, measure camber, rinse and repeat and repeat and repeat until the camber is where it’s supposed to be.

Next time we’ll try using these. I think it’ll make setting the rear camber a whole lot easier.

We didn't do any camber adjustment on the front because neither one of us was really sure which way the factory upper ball joints were supposed to be flipped around to tilt the tops of the wheels in a little more. Anyone know? (I believe one side on the ball joints has a "flat" edge that's either supposed to face in or out.) The front upper ball joints are probably already flipped around the "correct" way, but it would be nice to know for sure.

Anyway, the car feels really good after Colby's fine job as the rear camber was way off previously and the toe-in/out front and back is set up properly now.

Cheese wrote: Romeo wrote: ...which means by 120MPH peak lateral G has diminished to .92 30MPH is closer to the speed you'd be going in a turn for autox...

Colby Colby Colby... Tristan fully intends to be rocketing through the autocross course at 120MPH after his engine mods.

Cheese wrote: Romeo wrote: Some trivial and useless facts for anyone who has nothing better to read: As the Fiero is not in that racing simulator, I had to find another car with similar attributes. Some will find it comical that the closest analogue I could find was the Ferrari GTO. Same weight balance, same weight, same suspension height and a 2.9L V6 (Although given that it's a turbo six, it devellops over 300HP. Could put restrictors on it in-game, but it's just as easy to hold the gas at 70% throttle). I had to alter it's tires to match my Fiero's mind you. The suspension set up still causes drastic oversteer if the rear stiffness exceeds the front. The can be slightly corrected by matching up the sway bars, or by increasing the stiffness of the front struts. My idea of 275 back, 245 front will cause the car to have a neutral characteristics, unless the brakes are touched, in which case snap-oversteer is the result. Peak lateral G's on my current tire set-up with that alignment will cause a peak lateral G of 1.04 at 60MPH, but it causes positive camber beyond that which means by 120MPH peak lateral G has diminished to .92 Which racing simulator is this? How many G's do you figure you'll be able to reach at 30MPH? 30MPH is closer to the speed you'd be going in a turn for autox anyway. And what kind tire are you using for this simulator? Obviously the easiest way of increasing your max lateral acceleration is by getting soft, grippy tires.

I can check that tomorrow night, didn't really grab that. 60MPH was the highest I managed to get last time, so I set that as my "worry up to this level" point.

I'm only using my street tires. I could put in really nice, grippy semi-slicks, but that's beyond my budget. Far, far beyond it.

And you know it will Patty.

Well, I've noticed that Koni Reds are only adjustable on the rear... This is problematic, as the only place with the now discontinued Koni yellows are Westcoastfiero, who want $499 for the front axle alone.

Oh well, still planning on picking them up, need to try and balance out finances and figure something out... Don't want anything less.

Cheese wrote: You can even buy a pair of them there for $258.

And a quick google search shows them to be had for http://www.horsepowerfreaks.com/cart///13655 - $105 apiece , probably less elsewhere.

Bare in mind that friction is dominated by normal force, which itself is generated by how much the car is "pushing" on a tire. While it's true over-stiffening can aversely affect a car's handling, a softer suspension is bad in three ways:

Driver confidence will naturally go down as body lean is increased. This unto itself is probably a soft shocks single greatest sin.

The second reason is transverse balance. In a car that's leaning, there's too much weight to handle on the outside tire, and not enough weight to get friction on the inside tire.

Third reason being momentum. As the car leans over, it wants to continue moving to the outside. Off-setting this is key to cornering quicker.

Remember, the fastest cornering vehicles on the planet - Formula One vehicles - Are also one of the stiffest, with a suspension capable of deflecting only 1/2" at 5 g's.

Cheese wrote: Some good reading relating to this topic http://www.fiero.nl/forum/Archives/Archive-000001/HTML/20031110-2-039385.html - here (specifically, shark93726 and Monza76's posts have good info).

That is a very informative thread.

After reading it I suspect the lowered (and very stiff) suspension on my '84 now actually contributes to perhaps worse handling than stock, but you know what Johnny Boy says...

"It doesn't have to perform, it just has to look good." 

Colby, I've lost track now of all the links that have been presented, but I imagine you've seen http://ironduke7.tripod.com/Handling.htm - This page (by Ira Crummey) and all the other pages it links to?

Romeo wrote: ...repeatative bumps

Are those anything like repetitive bumps?

It's a common misconception that rally cars have soft suspension. Rally cars have soft shocks, and a tall suspension, but it isn't soft by any stretch of the imagination. And rally sort of follows it's own special guidelines, as the tires will spin before body roll becomes an issue. Like I said, the best approximation is the unpaved air-strip section of Sebring, or the two straights after the main straight of Monza. They're rough as sin, but during those races crew chiefs do not scale back stiffness.

I understand that point on a daily driven vehicle, as when dealing with bumps it's nice if the car soaks up some of the shock, rather than your vertibrae, but performance almost always favours a suspension that is supple enough to let the tires bite down, but stiff enough to fight the car from leaning over too much. And looking at the simulator results, I have a long way to go before that becomes problematic. Hell, even the Koni yellows look like they'd have a tough time being that bad.

And yes Patrick, I think I was caught between wanting to type repeating and repetitive and ended up with both.

Romeo wrote: And yes Patrick, I think I was caught between wanting to type repeating and repetitive and ended up with both.

That's okay, you just invented a new word!

Yeah, I'm pretty gnarley like that. 

Cheese wrote: Romeo wrote: Like I said, the best approximation is the unpaved air-strip section of Sebring, or the two straights after the main straight of Monza. They're rough as sin, but during those races crew chiefs do not scale back stiffness. I'm not familiar with those tracks or even very familiar with Formula 1 in general, but if it's the straights that are rough then they wouldn't care about increasing cornering power for those sections. Even if they're not straights, would you sacrifice traction on every other part of the track just so you can go faster around just a couple of the corners? I wouldn't. Romeo wrote: ... but performance almost always favours a suspension that is supple enough to let the tires bite down, but stiff enough to fight the car from leaning over too much. That's more or less what I've been saying all along. A stock Fiero doesn't seem to have too much lean, so making the front softer rather than making the rear stiffer should result in a car that has more traction while cornering. I made the mistake of not doing enough research before I bought some of my suspension parts and so I've taken potential traction away from both ends of my car.

Mine does (If you saw at autocross). Although an anti-sway bar may help, it will not totally alleviate the issue. Whatever the weak link in the Fiero's traction is, I'm going to try and concentrate on that until everything is flat as a board around the corners (If I have to Delrin - I will).

Cheese wrote: A stock Fiero doesn't seem to have too much lean...

While I was watching Tristan slipping and sliding around the track during his final run at the last autocross , I overheard a fella who was also watching talking to his buddy. What he said was something like this...

"Those Fieros go pretty good, but the problem with them is that they lean over so much in the corners."

Seriously, that's what the guy was saying!

Cheese wrote: In other words, make your suspension as soft as you're able to...

So Colby, do you think Herb would approve of the lowered, rather stiff front suspension on my '84?

Cheese wrote: Does that make sense?

Theory all goes out the window Saturday once we're on the track.

Reflexes and luck will be playing a huge role. A good wheel alignment doesn't hurt either.

All I'm worried about is being able to follow the course. I don't want to get lost out there like I did on my first run at the last autocross.

I was holding back quite a bit last time (being my first autocross and not being familiar with how the car was going to feel while being pushed). I was probably braking too early and starting my turns too late.

I suspect I'll be hitting more than one cone tomorrow.

Cheese wrote:   don't you think?

As much as possible sometimes.  other times not! 
I actually dont have any practical experience in the matter - it's all pretty much theory at this point for me.  I was just trying to make a point that there are many factors to consider and probably many we aren't aware of.

Cheers!

     I don't mean to shoot anyone in the foot here, but you guys do realize when it comes to driving a car, even the biggest best race teams in the world are still only doing a "best guess" when they set a car up, they don't know if it works until the driver comes back and says change this or that, and most of what they "know" works, is from real track trials and errors.  Some of the best drivers in the world simply get in and drive, then tweak the car till it suits them.  Hence why on the same track you may have 100 different variations of the setup of nearly identical cars.    If science could tell us the "best" way to setup a car...................... lets just say life would be a lot less interesting.

Capt Fiero wrote:   I don't mean to shoot anyone in the foot here,

Owwwwwwwwww  don't burst our theoretical bubbles now.
It's all in good fun and learning of course.

Yeah, without the struts to keep them in check, spring stiffness becomes pretty much irrelevent. Still damn fun out there though, despite Gretchin's misaligned feet.

Time to pony up for Koni (RHYME).

Cheese wrote: This means I need to lose a few of the changes I've made to my car, like the cut springs...

There's no way I'd return my '84 to the "bush-buggy" look just to comply with the totally stock class in autocross. I hate the huge wheel-well gaps that all stock Fieros have, especially the 84's which were the worst of the lot. I don't want my Fieros looking, ummm... silly.

I don't know if V6 Fieros are in a different class in autocross than the duke powered ones, or if there's some "penalty" to even things out, but if I was serious about autocross and wanted to be competitive, I wouldn't be driving a duke. There just isn't enough GO power when the gas pedal is pressed to the floor.

Having said that, I have no idea how Colby and I managed to stay competitive with the V6 Fieros (except for Brian of course) at the last autocross. When I watch the videos and see the GTs accelerating at the start and coming out of the corners, I'm not sure why Colby and I with our 4-bangers weren't blown out of the water.  Doesn't mean I didn't have fun though, it was a blast!

Cheese wrote: There was only really a single main straight where there was a significant difference...

Oh, I don't know if I completely agree with that comment Colby, but I know what you're getting at.

I guess I just miss the power and the instant neck-snapping throttle response and the wonderful SOUND  that I had years ago with my various high performance V8 Chevys.

Perhaps I'm going through a mid-life crisis.

427 cubes of fun are waiting for you Patty... Drop it in the back of your Fiero.

LS7 win, baby.

Romeo wrote: By the way, mid-life crisis? You intend to live until you're 196?

"196"...

For a 98 year old geezer, my duke and I didn't do too bad against you and Gretchin at the autocross.

Romeo wrote: Still lost.

Yes, you most certainly appear to be. It's those power drinks you consume. They're over-revving your brain cells and causing temporal oscillations.

Yep, you whipped the old geezer in a 4-banger by 65/100ths of a second!

Yes I did.

Damn, I'm livin' the dream.

Ok you guys - back to your corners

I PLAY FOR KEEPS KEVIN. FOR KEEPS.

Nah, it's ok. Patty loves me just the same.

Romeo wrote: Nah, it's ok. Patty loves me just the same.

As I've said before, Tristan is the little brother I never had.

And I just love scaring the bejesus out of him on the track with my 4-lung duke.

Patrick wrote: Romeo wrote: Nah, it's ok. Patty loves me just the same. As I've said before, Tristan is the little brother I never had. And I just love scaring the bejesus out of him on the track with my 4-lung duke.

Back to topic for half a moment, more related to springs than shocks, but I forgot to mention what a drastic effect spring stiffness has. Doubling the spring rate (Alot, I know) allows one to drop the camber down to -0.5 front -0.8 rear. Huge difference, keeps the tires significantly flatter (More than twice as flat on the rear) during straight line.