Real Fiero Tech

IF your fiero DOES NOT HAVE a HEAVY ASS END <as in a SBC auto swap or something> then use a front and rear sway bar of THE SAME DIAMETER!!!

STOP SAYING A BIGGER FRONT BAR! THIS IS TOTALLY WRONG!

OK??? OK!!!

For example..... 2.8L manual....front and rear same
350SBC auto you could try front and rear same and run poly bushings out back and rubber up front OR a LARGER bar out BACK
USE THE BUSHINGS TO FINE TUNE.

donk_316 wrote:IF your fiero DOES NOT HAVE a HEAVY ASS END <as in a SBC auto swap or something> then use a front and rear sway bar of THE SAME DIAMETER!!!

STOP SAYING A BIGGER FRONT BAR! THIS IS TOTALLY WRONG!

If that's true, then why does GM have no bar on the rear at all? (88s notwithstanding.)

The stiffer you make the rear, relative to the front, the more likely the car will be to swap ends. GM *wanted* the front to wash out before the rear comes around. Inexperienced drivers (probably 95% of the driving public) can recover the car much more easily.
If you know what you're doing (and I mean *really* know what you're doing), and not driving on wet roads, you might have a chance. Otherwise, I stand by my statement, and my post in that thread.
This also backs up what some of the autocrossers and SCCA racers in my area are saying.
There are a few racers on here. If they tell me I'm wrong, I'll back off.

donk_316 wrote:IF your fiero DOES NOT HAVE a HEAVY ASS END <as in a SBC auto swap or something> then use a front and rear sway bar of THE SAME DIAMETER!!!

What is the stock bar size? I have a Fiero Store rear bar that I got for free, is that the same size as the stock front bar?

I wanna say 23mm but im not 100%

I have heard 23mm before. So lets say that is true. The FS rear bar is 7/8" from what I have been told. 7/8" converts to ~22.2mm. So I should be good with a 23mm up front and a 22.2mm in the back, right?

bar diamter isn't everything - bar arm length and how close it attaches to the wheel make a difference..

for example with wills setup attaching the rear bar to the strut the bar will be much stiffer than if it was attached in the middle of the swing arm.. the farther out on the swing arm the bar is attached the stiffer it will be.

if the front and rear bars are shaped and mounted the same then yes the only way to tweak them is with bar diamter and with mounting bushing materials.

Again, donk, keep it tech. If you want to bitch about the Pffiflers, do it in RFTVTW.

There's a whole lot more to suspension than just bars, too. Fieros need a lot of rear stiffness, but need a lot of rear tire as well. If you stiffen the suspension up but don't widen the rear tires, all you've done is create a snap-oversteering monster with a lift-throttle reaction that will bite your nuts off.

The "bigger bar in front" mistake is just a classic case of having no F-ing clue that a car with a rear weight bias has different tuning requirements than a car with a front or neutral weight bias.

The Dark Side of Will wrote: ...There's a whole lot more to suspension than just bars, too. Fieros need a lot of rear stiffness, but need a lot of rear tire as well. If you stiffen the suspension up but don't widen the rear tires, all you've done is create a snap-oversteering monster with a lift-throttle reaction that will bite your nuts off.

This is exactly what happened to Don. Had the same size tires front/rear, and the same size bars. Found himself looking at the pine trees coming at him in his rearview in a big hurry.
His words: "...before I knew what happened."

The "bigger bar in front" mistake is just a classic case of having no F-ing clue that a car with a rear weight bias has different tuning requirements than a car with a front or neutral weight bias.

Maybe I don't have an "educated" clue, but I can see with my own eyes what doesn't work. (See previous paragraph.)
They say that insanity is doing the same thing over and over, and expecting different results each time.

Oversteer is when you crash tail first.
Understeer is when you crash nose first.

personally I'd rather crash tail first - you don't get whiplash or seatbelt bruises

parts of the 88's "better" handling is actually that they finally put wider tires ont he rear than the front..
same deal as having a sway only in the front ont he early fieros - they were set up all wrong from the start..
people think they handle well stock - try giving it a proper mid engine tire and sway bar (and spring/shock)

donk_316 wrote:IF your fiero DOES NOT HAVE a HEAVY ASS END <as in a SBC auto swap or something> then use a front and rear sway bar of THE SAME DIAMETER!!!

STOP SAYING A BIGGER FRONT BAR! THIS IS TOTALLY WRONG!

Somebody else making a generic statement that a bigger front bar is necessary is no more incorrect than your assertion that front and rear bars should be the same size.

As has been pointed out, suspension tuning is much more complicated than just bar diameter. You're completely ignoring about seven other things that are equally as important as sway bar diameter.

Kohburn wrote:parts of the 88's "better" handling is actually that they finally put wider tires ont he rear than the front..

The '86 - '88 GT all wore 205/60-15 front and 215/60-15 rear. What you're probably thinking of is that the '86 and '87 had 7" wheels all the way around and the '88s had 6" wheels in the front.

The Dark Side of Will wrote:The "bigger bar in front" mistake is just a classic case of having no F-ing clue that a car with a rear weight bias has different tuning requirements than a car with a front or neutral weight bias.

Bah. Every car on the planet has different tuning requirements. So what.

Doug Chase wrote:

The Dark Side of Will wrote:The "bigger bar in front" mistake is just a classic case of having no F-ing clue that a car with a rear weight bias has different tuning requirements than a car with a front or neutral weight bias.

Bah. Every car on the planet has different tuning requirements. So what.

I was mostly bustin' on people who think that the Fiero needs a bigger front bar than rear because their old Camaro and their daddy's Vette both had great big front bars and smaller rear bars....

Doug Chase wrote:

Kohburn wrote:parts of the 88's "better" handling is actually that they finally put wider tires ont he rear than the front..

The '86 - '88 GT all wore 205/60-15 front and 215/60-15 rear. What you're probably thinking of is that the '86 and '87 had 7" wheels all the way around and the '88s had 6" wheels in the front.

or the fact that I've only ever bought 1 GT - all my others were SE's and they all came witht he same size front and rear - I usually changed them to 235-245's in the rear and 215-225's up front

there is no set size. you use what works for YOUR particular car. there are many other things in picking a sway bar than just "whats my front sway bar size?" if you have no rear sway bar, there is NO WAY you can know what size will be right for you, and theres is nothing wrong with just grabbing a stock front, putting it in back, and see what it does. this gives you a referance point for what you really need.

88GT's and Formula's front bar is larger diameter than the rear bar from the factory.

Pyrthian wrote:there is no set size. you use what works for YOUR particular car.

True, BUT all Fieros are going to take something similar. No Fiero is going to like a Camaro suspension setup (except maybe Boomtastic's).

88GTneverfinsihed wrote:88GT's and Formula's front bar is larger diameter than the rear bar from the factory.

Yeah, but stock just don't cut it.

The reason you typically want a larger sway bar up front is that's usually the best way to make sure you don't get into a sever over-steering setup. The larger front swaybar as compared to the rear will tend more towards understeer than equal front and back, or even a larger rear. And we all know that GM believes that understeer is safer and easier to control for the vast majority of drivers. Unless you're an experienced racer, it's probably safest to stick with that formula and adjust from there.

A larger bar out back will increase the tendancy for oversteer. That's not what I'd recommend when you're also adding weight in the rear. Use stiffer springs and shock valving to deal with the extra weight and tune the bars based on body roll and balance.

I see a lot of talk here.

Lets start with basics.

Who knows why cars use anti-roll bars?

Ooo Oo me me!!

To reduce body roll..

for the purpose of... preventing severe camber changes?

....aaaannnd they do it with roll bars instead of stiffer springs so it only applies during cornering so the ride is still soft going over bumps that don't unequally compress suspension.
Did I get it??