I've heard you say that an '88 rear suspension with early front suspension is the way to go. Perhaps you could elaborate a bit more?

I drove my '86 SE with early rear (w/ anti-roll bar) and '88 front suspension for a year (before I smacked it up ) and was very impressed. I was using '87 GT front wheels with 235/60-15 tires (cheap ones).
Anyway, the steering was very light and seemed to me to give very good feedback about what the contact patch was doing and exactly how much traction I had left. I don't feel that I get this level of feedback from my '87 GT, even though the GT has delrin suspension bushings and the SE had the original rubber bushings.
I don't have your level of competitive experience, but perhaps you could shed some light on this conundrum? Have you noticed the same feedback difference? How perceptible is the difference in turn-in you've mentioned? Is the difference more noticeable with the stopwatch than driver perceptions?
Any other thought on the topic appreciated also.

The difference on an autocross course is evident in times. I have competed against '88 Fieros with a setup similar to mine, and driven '88 Fieros on course. So I hope the results of those experiences are what you are looking for.

Remember, the '88 was built for better ride quality (softer springs), and offers less nose dive under braking (but in exchange the '88 offers more nose lift under acceleration). The '88 offers the same handling characteristics (understeer comes to mind) as the early chassis, just tries to buffer it with a more mushy ride.

The '88 offers a poorer road feel, is slower responding to steering input, and seems to be slower turning-in as a result of the "improved ride".

What people feel most when they go from an early chassis to the '88 is the improvement in the rear suspension, and the elimination in bump steer. The heftier brakes are obvious also.

But if they put the '88 cradle under their car, and run a beefed early chassis front end they have the best of both worlds.

Now, that isn't to say the early front suspension was good as is. I am an advocate of a larger swaybar, Koni shocks, either Eibach or Suspension Technique lowering springs, and by all means poly bushings all around. I have never used the lighter/stronger tubular A arms, but they would probably help a little also.

A properly set up early chassis front end will certainly outdrive a similarly setup '88 front end.

The brakes are a concern. I use racing pads on the front with a proportioner, braided lines, and synthetic fluid. Coupled with an aggressive street pad and braided lines on the rear (necessary for the cradle swap anyway) I find that this is a far better setup than the stock early chassis brakes, and about equal to a stock '88. I don't particularly care for the GA conversion if any plans include competing in autocrossing, as the GA brakes are adding about 12 pounds of unsprung weight (6 on each corner). The GA conversion is a good option for the street though.

This is all IMO, based on several years of SCCA racing in Fieros. There are others out there with the same early chassis/88 cradle setup. Greg Duncan of Team Python couldn't believe how much more nimble my 84 Q4 is than his 4.9 powered '88, for example. That is why he bought it from me!!

Hope this helps

G

[This message has been edited by cadero2dmax (edited 12-19-2001).]

have you any preferences when it comes to the non 88 front A arms ?

as in the 84 heavy boxed units versus the later lighter units ?

quote Originally posted by cadero2dmax: ...Now, that isn't to say the early front suspension was good as is. I am an advocate of a larger swaybar, Koni shocks, either Eibach or Suspension Technique lowering springs, and by all means poly bushings all around. I have never used the lighter/stronger tubular A arms, but they would probably help a little also. A properly set up early chassis front end will certainly outdrive a similarly setup '88 front end.

George,

What about the "scrub radius" issues with the earlier front susp.?

The issue I had with my 85 GT (traded it in 88 for a Firebird) was the amount of kickback to the wheel. I drove on a rain-grooved interstate from Atlanta to Savannah and it fought with me the entire way.
Of course, I recognize that tires and wheel offset play a major part in this (mine were the stock Goodyear 215/60-14s), and this was also before I learned about tweaking the caster (NTW didn't know how, either), but still...

Are there any parts that address this? Or is this actually a good thing for competition?

Thanks!

S.

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Raydar

From the Department of Redundancy Department.

[This message has been edited by Raydar (edited 12-19-2001).]

Martin White just sent the URL of his webpage about the rear suspensions, both the early and the '88. It also explains why the '88 is better.
http://www.mindspring.com/~martinwhite/fiero/cradle.html

The grooved pavement problem, or "scrub radius" can be a result of several things, but my guess is that you are right on with the caster of the front end. It also is amplified by your choice in tires, and frankly sounds like your steering damper was faulty (or removed, as some are advocating - - but not advisable IMO).

I think a person can't go wrong with a set of aftermarket tubular front A-arms, I just haven't yet done a car with them. (Maybe the SE?).

Hope this helps.

G

Why don't you think that removing the steering damper is a good idea?

I'm very curious about exactly what geometrical aspects of the front suspension cause the differences in turn-in. Caster? Do you happen to know what the differences are in kingpin inclination between the two setups?

If the '88's had a softer wheel rate, then the nose would lift more under acceleration, but because the front wheels transmit no drive torque, geometry differences have no effect on nose lift.

I'll have to go back and look at my notes, but I seem to recall that the early rear suspension actually has a small amount of pro-squat built into it.

A big problem I have with the early suspension is the high reverse efficiency (aka kickback) caused by the larger scrub radius. It seems to me that while this increases feel for the contours of the pavement, it decreases feel for what the tires are doing. Of course, wheel offset and tire height have a huge impact on these qualities.

I hear what your saying and the voice of experience, but I would like a deeper explanation if possible.

George, I just took my Formula for a 300mile round trip up Highway 1, and Highway 128. Much of it was spent in 3rd and 4th gears from 80-100mph (128 is particlular is a great road). And not for the first time I've wondered what you're talking about...

It's the T-top car, not very heavily modified at all, yet it turns like a banshee and is completely neutural, with over or understeer selectable entirely with the throttle.

'mods' consist of: front stock springs cut one coil. Koni dampners front and rear. Rear springs New Poly all around. Rodney's rack bushing. (this is *critical*)

Alignment specs are only a little off from spec (slightly more camber, and a HINT of front toe-OUT. 0.3degree.)

AGIP DOT 5.1 (this is a synthetic high temp glycol, NOT dot5!) and SS lines, plain 'carbonmet' road carbon/metal blend pads. But those are just on the brakes.

OK, granted, I've never ridden in a car with the early front end and 88 rear, much less your prepared racer. So I'm probally talking out my butt here.

But I just don't see it, guess I'd like to hear more about the 88s you've tracked.

Best!
Ben.

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Ben Cannon
88 Formula, T-top, Metalic Red           "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver                     -Mel Gibson, "Braveheart"

[This message has been edited by artherd (edited 12-20-2001).]