Maybe this should have been in Tech but I get better response here so...

What is it in the Fiero's suspension that makes the rear end step out and come around so fast and so unpredictably?

I was reading an article in an older R&T that compared what they consider to be the eight best handling production cars available. It included the Boxster (6th place), the Lotus Elise (2nd place), and the Ferrari 360 Modena (1st) as the m/r contenders. None of them exhibited this characteristic. The 911 Turbo (3rd place) seemed closest to the Fiero in handling. Understeers on turn-in, and oversteers with attempted throttle correction.

Of course, I am talking about running the car at 10/10ths, not moderately aggressive street driving. So what is the gremlin???

perk

You'll get many opinions on this, but in my opinion there are two factors that come into play here.

First, is that the Fiero was under-powered, which made it difficult to power out of a back end just starting to get 'loose' so to speak. That problem has been eliminated on mine.

Second, the brake system seems to be too agressive on the rear of a hard braking Fiero, hence in turns when hard braking is applied the rear tires will want to lock up producing the slide. I demonstrated this very nicely at Waterford Hills. A manual control front to rear bias adjuster would cure this problem. If you look at newer hi-performance cars you'll notice the that the rear disc brakes are about 50% smaller than the front for this reason. Nearly 80% of effective braking is done from the front discs.

It's not that it's so unpredictable, you just have to react very quickly to it. Once it starts to come around it gets to a point of no return very rapidly. You can't be sleeping at the switch with the Fiero.

Just my opinion on the '88 WS6.

[This message has been edited by California Kid (edited 07-25-2003).]

quote Originally posted by California Kid: It's not that it's so unpredictable, you just have to react very quickly to it. Once it starts to come around it gets to a point of now return very rapidly. You can't be sleeping at the switch with the Fiero. Just my opinion. [This message has been edited by California Kid (edited 07-24-2003).]

As it was explained to me by my friend, Brian Geyer (he was the tall instructor at Waterford), the Fiero has a "low polar moment" due to the mid engine config. The car is very responsive, but a side effect is that it is "on the edge." The more responsive a vehicle is, the quicker it can get away from you. A Cadillac is not very responsive, but is far more forgiving.

quote Originally posted by fierobear: As it was explained to me by my friend, Brian Geyer (he was the tall instructor at Waterford), the Fiero has a "low polar moment" due to the mid engine config. The car is very responsive, but a side effect is that it is "on the edge." The more responsive a vehicle is, the quicker it can get away from you. A Cadillac is not very responsive, but is far more forgiving.

How forgiving is a Fiero with a Caddy 4.9?

quote Originally posted by Mastermind: How forgiving is a Fiero with a Caddy 4.9?

LOl!

not sure wich Cradle your speeking spcfically one issue is Bumpstear since pre 88 fieros rear suspension was actualy the same as its front it was not engineered to control the rearward motion of the Axles from Squat( transition from brake on to brake off) or teh Shift of wiegth caused when teh travel of teh suspension causes a tire to lift it also increases its toe in so basically it steers the Car of course so to speek atleast is what I ahve been told and read else where

Look at the configuration of the 84-87 rear suspension. The toe links are behind the control arms. When the car is sitting level, the toe link is nearly parallel to the ground. If you enter a turn and start to slide, the natural reaction is to get off the gas and/or stab the brakes. If you do that, it extends the rear suspension. When the rear suspension extends, it shortens the horizontal distance between the steering knuckle and the toe link locating bracket on the frame. This causes the rear wheel to toe out (seems like I read that this can be several degrees). Add that to the fact that the rear is already "light" due to the deceleration of the car, and already wanting to spin due to the forces of inertia.
The redesign of the 88 suspension removed most of this tendancy. In full compression or extension, the toe doesn't change much at all.
One of the specialty suspension vendors (Held or RCC) had a much better explanation. Probably on the same page as their bump-steer kit.
This is the "short" version. As I understand it, anyway. (If anyone sees any glaring errors, please feel free to correct me.)

------------------
Raydar

88 3.4 coupe. 17s, cut springs 'n all.

quote Originally posted by perkidelic: What is it in the Fiero's suspension that makes the rear end step out and come around so fast and so unpredictably? perk

I think you should reword this to say "84-87" Fieros. The 88s don't exhibit the so called "holy sh!t" handling that the earlier chassis do because of the revised rear suspension. As explained, the earlier cars had a toe link in a horrible location (because it was adapted from front wheel drive, basically) that caused toe in/out changes with suspension travel (as you know, called bumpsteer). The 88s have a tri-link rear end that has VERY little bumpsteer, although there is still some as it is unavoidable while making other compromises for good handling.

As you said, the rear engine Porsches exhibit the most similar handling characteristics to the 88 Fiero, it's just more pronounced with more power available. With a lot of power, the Fiero will do the same thing as the 911.

Of course, the simple answer to this is, "Those other M/R cars handle better than the Fiero because they cost 3-10 times more!"

Another thing worth mentioning is that with the right combination of parts and knowledge, you can make your car handle just about any way you want. The moment of inertia is pretty much fixed, but oversteer/understeer, turning behavior, bumpsteer, etc. can all be modified by manipulating suspension links, pivot points, sway bars, etc. Since the Fiero was made for sissies...er...I mean, an average driver...it has lots of built-in understeer. Yet again, this is for the 88s, the 84-87 exhibit a lot of snap throttle oversteer.

Bryce
88 GT

Well this is interesting as I have spent alot of time reading "power Steering" posts today. I recall one had a magzine article about a Fiero (Test Mule) with 4 wheel steering. Imagine how well it handled in the corners.

------------------

Fiero 20th Anniversary Pictures
My Black 88 GT

quote Originally posted by California Kid: Second, the brake system seems to be too agressive on the rear of a hard braking Fiero, hence in turns when hard braking is applied the rear tires will want to lock up producing the slide. I demonstrated this very nicely at Waterford Hills. A manual control front to rear bias adjuster would cure this problem. If you look at newer hi-performance cars you'll notice the that the rear disc brakes are about 50% smaller than the front for this reason. Nearly 80% of effective braking is done from the front discs. [This message has been edited by California Kid (edited 07-25-2003).]

What about doing a grandam brake upgrade to the front only on an 84-87? Would that help or hurt the rear pinch?

trailing throttle over steer
a rear sway bar will help

------------------
84 Fiero Turbo Vortec 4300 Phantom GT
L35 block
Syclone Intake and ECM
T04B H3 Turbo
http://www.cardomain.com/id/vortecfiero

"Any significantly advanced technology is indistinguishable from magic"

My guess would be that having 'two' frames bolted together certainly can't be good for handling.. Sure makes for easier engine swaps though..

(oops.. thought we were talking about bumpsteer.. carry on)

[This message has been edited by JohnnyK (edited 07-25-2003).]

Bumpsteer and trailing throttle oversteer are not the same thing, I thought the issue here was the oversteer. There are lots of issues in the early Fiero suspension, the trailing throttle oversteer is not specific to the Fiero, as has already been mentioned, Porsche 911s, especially older models, have it far worse. There is no total cure (short of redesigning the entire suspension, moving the centre of gravity forward etc..) however solidly mounting the cradle and installing stiffer rear control arm bushings will reduce the problem significantly. The large soft stock bushings effectively allow the control arm to angle forward under acceleration, rearward under braking and push inward during cornering. (remember that this design represents GM North America's first attempt at a transverse FWD powertrain, they used the big soft bushings to isolate the passengers from the vibrations and harshness) This is basically uncontrolled motion and will upset the handling. Since more power will cause more deflection of the bushings you will find that trailing throttle oversteer is more of an issue with cars that have significant power increases.

Bump steer is more related to the toe links, by the time the cars suspension has gone through enough travel to induce oversteer, the soft bushings have already allowed it to happen. Bump steer, as the name implies, causes small toe changes when the suspension moves vertically, this means that the suspension will toe in or out (relative to the steady state in a corner) enough to feel motion at the rear. This is actually more unsettling to the driver than it is to the car. The soft bushings also agravate this condition. The most important issue here is that if you lower your Fiero suspension you will need to get a wheel alignment to reset the rear toe, and there will be one more issue, since you have changed the angle of the rear components you will have changed the bump steer characteristics of the vehicle. This may be why you hear discussions about bump steer more often from people with lowered suspensions. The RCC kit will reduce bump steer in a small range but may actually increase the problem with greater suspension travel (shorter toe link), the Held kit is more effective but heavy and expensive, the increase in unsprung weight may be an issue for some applications but it will make the car feel more stable.

A rear sway bar (used with the stock front bar) will not eliminate these problems, but it may mask them. By reducing relative (side to side)suspension travel during cornering, the sway bar keeps the suspension nearer its ideal (relative) ride height and the alignment changes will be reduced. However suddenly closing the throttle will shift weight forward and cause the rear to lift and the problem returns since the sway bar cannot control two wheel motion. The other issue is that the rear bar will reduce understeer to the point where the transition from normal cornering to trailing throttle oversteer may be more abrupt and more difficult to catch. If you use equal sway bars front and rear you must use wider rear tires. As you can see it is a trade off.

1) Get the stiffer rear bushings (poly or 8sharks UHMW pieces), the old car probably needs bushings anyway so this is the biggest bang for the handling buck.
2) Solid mounts for the cradle (poly or better, aluminum), may increase NVH slightly but well worth it.
3) Don't lower the car too much ( radically lowered cars are typically not good handlers, they offer lots of lateral grip but transitions usually suffer, great numbers on a skidpad but mediocre in a slalom ). Single purpose cars, such as dedicated autocross racers which are not street driven, can be optimized for handling with very little suspension travel, but these would be torture to both the car and the occupants if driven on the street.
4) If you want to try a rear sway bar then make sure you can test (in a safe environment) how the car will now react to cornering, steering inputs, trailing throttle, braking etc.. A big rear bar on a rear weight bias car requires a more alert driving style so always check it out first.
5) Use wider tires (and even wider wheels)on the rear. This may increase understeer in an unmodified suspension but it will decrease the tendency to trailing throttle oversteer by supplying more grip.
6) Keep the front suspension fairly soft, it does a fairly decent job in stock form so better shocks and stiffer sway bar bushings are the biggest gains at the front. A larger front sway bar with a rear bar will reduce roll to the point where there are fewer problems from the rear suspension.
7) Static alignment - Increased caster in the front suspension, some negative camber front and rear, some toe in at the rear and near zero toe at the front will reduce understeer and increase overall stability. For quicker response a little toe out at the front, for long highway trips go with a little toe in at the front since it helps straight line tracking.

Every solution is a compromise so pick the set of compromises which best fits the way you will use your car, and remember the car that is set up to handle best at 10/10s may be difficult to live with in normal driving.

Ira

BTW cars of the same vintage as the Fiero did not benefit from the level of computer simulation in suspension design that modern cars do. The cars you list all have complex multi link rear suspensions to tame the transitional response, since the Porsche 911 has a greater rear weight bias it is harder to tame.
The Fiero's contemporary cars like the 1st series Toyota MR2 will snap spin much more quickly than a Fiero and be much harder to catch, even the 1st series Mazda RX7 was a spin out car despite having a front engine and live axle.
You cannot compare designs which are separated by over 10 years of development. The Ferrari is an engineering marvel, and is priced like one, the Lotus is so light weight that it can be made super nimble, and it took Porsche about 30 years to get the 911 right (great car in the hands of an expert driver but very tricky to drive at speed for the rest of us)
The Fiero was one of the best handling (stock, out the showroom door) American cars of its day, the C4 Corvette would out corner it but you needed a kidney belt to ride in one with the sport suspension. Camaros and Firebirds hopped around over bad pavement and understeered even more than the Fiero. The interesting point is that the Europeans loved the handling of the 1984 Fiero, calling it the best handling car to come out of the US and, in one case at least, tested it at the Spa grand prix circuit and compared it favourably with a Lotus Esprit. Their only complaint was the lack of power. (they even liked the brakes!!

------------------
The Iron Duke Resource Site

Sig design by MinnGreenGT

[This message has been edited by Monza76 (edited 07-25-2003).]

well, the rear does come out quick, but its not unpredictable. generally its nailing it around a corner at a intersection, especially if theres wetness about. not a good car to hot dog around a tight corner. you will end up looking like an fool, pointing the wrong way. not like a camaro, fishing the rear all around the corner, a little wiggle, then off you go.
Theres a difference between taking a corner fast & looking like your taking a corner fast. It looks fast all sideway & tires screaming. It is fast when all tires have traction, while pedal is applied as needed.

------------------
1985 Fiero SE
Plain Red V6 Coupe

I tried to post a big THANKS last night but somehow it got lost in cyberspace, so I said to heck with it and went to bed. Now I'm glad a waited cuz Ira stepped up to the plate and delivered a Grand Slammer!

Actually any of my "regular readers" may remember that I am having all new CAD front and rear suspensions designed for the car. I was curious to see what insight the most knowledgeable group of people on this specific car would provide. Just doing more homework before I start feeding the numbers to the company that is doing the suspension designs.

The car will be radically lowered but the suspension will be designed for that height - much different than altered stock components. It will have SLA suspenders w/coil-overs at all four corners. The front will be a complete bolt-in replacement system (I think with a low-assist fast ratio power rack). I am still deciding whether the rear will be a complete scratch design or a factory cradle-based deal, building off the LCA pickup points. Everything will be solid or poly, no rubber allowed, and the lateral links will be done right to correct the bumpsteer issue.

Oh yeah, I was talking about the 84-87 models.

I know a good 10/10ths car is supposed to be not so good at lesser levels but the Ferrari managed to come in 2nd best (to the 911) in subjective "road" ratings (by the R&T staff), while also taking first in subjective "track" ratings - by Bryan Herta. The only thing that beat it was the Lotus in objective performance data.

Herta said of the Ferrari, " I can make it push or I can make it loose. And I can really feel all the bumps on the track through the chassis and steering. On the track, it feels like a race car. A little bit of understeer and a little bit of oversteer are easy to pick up very early on, and it is easy to make corrections. The suspension gives plenty of feedback and the chassis is quick to respond to driver input. Overall, the Modena exhibits mild understeer handling dynamics on corner entry and exit."

I know it costs money to do it but that is my long-range goal. The Ferrari runs 215/45R-18's up front and 275/40R-18's in back. A trend among the m/r cars and even the 911 was narrower fronts (225 max) and wide (up to 295) rears. The Z06 was the only one that used a wide front (265). Just something I noticed.

I was curious about flaws in the factory setup so I make sure to avoid them.

Thanks again,

perk

Thanks Perk , I just fixed some of my typos, I really need to learn how to type.

Your project sounds pretty ambitious, I would like to see some pictures as each phase is complete.

BTW my Fiero handles like a real pig because I still can't afford to get all the suspension work done, but by next year....

Ira

It's not as unpredictable as you may think.

The main reason the rear will "suddenly" step out is when you suddenly take the weight off the rear tires. How rapidly it happens is in direct proportion to how rapidly you either let off the gas or step on the brakes.

We are conditiond to slow down when we precieve we are going to fast into a turn. In a (typical average everyday everywhere) front engine car the rear will cut loose much sooner and at a lower speed than a fiero.

It has been my expierence that the fiero is VERY predictable and infact gracefull when the rear tires break traction. Unlike a front engine car that tends to fish tail "unpredictably" (because of overcorrection) the fiero will slide out and hang there with little need for correction until you exit the turn.

However, lucifer is watching you like a hawk just begging you to THINK about letting off that gas pedal so he can cast unto the pyres of hell.

Cornering a fiero hard demands a different mind set.

Having first hand knowledge of my (finely crafted) machines strengths and weakness, I can state for the record the fiero is the most well balanced and predictable "out of the box" car this poor man ever had the pleasure of driving into a corner, blatently doubleing the "advised corner speed" without a worry.

In fact, after a take the 476 off ramp near my house (posted at 35mph) I like to mention to my passengers that we were doing 60 and they don't believe me.

NOTE
I "practice" with my fiero when I can. I'll go find a secluded parking lot and tear the joint up! Weather it's dry, wet, icey or snowing. I can even feel when one of my tires is a few pounds low (particularly the rear) and needs a shot.

BTW
Having power and stopping ability is good but my stock 90 horse power 88 2.5 L4 does the job well enough for me. Unlike ALL other "go fast in a straight line" american made cars available today. Sure I could get a hidiously overpriced european "exotic" to do a tad better than my 250 dollar fiero can do.

Pontiac got it right on the money. For us average everyday driving enthusiast family types, the fiero is but a rapidly fading dream.

[This message has been edited by 84Bill (edited 07-25-2003).]

There are as many opinons on the handling of cars as there are drivers!

quote Having first hand knowledge of my (finely crafted) machines strengths and weakness, I can state for the record the fiero is the most well balanced and predictable car this poor man ever had the pleasure of driving into a corner, blatently doubleing the "advised corner speed" without a worry.

I agree totally!!

I do not consider the handling characteristics of my Fiero to be 'unpredictable' or 'bad'. They are consistant. I am the driver. It is my job to know the characteristics of my car and it is also my job to use my skills to match the car and the road.

If I want a car that will usher itself smoothly down the highway with little imput or attention from me ... well ... what do they make Cadillacs for? Or Chauffered limosines?

My opinion. Not worth much, but I'll share.

84Bill and Tryxalon I agree with you both (I hope I made that clear at the end of my long post). A Fiero in good mechanical order has true sports car handling.

If you charge into a turn it will understeer, if you then jump off the gas it will oversteer, that is why drivers like Jackie Stewart do so well, they brake in a straight line and then accelerate (carefully) around the turn (in slow, out fast). Once he helped Car and Driver do a writeup of a Taurus SHO (I believe, it was definitely a Taurus), he talked about always braking in a straight line and never trail braking into turns. They asked why, after all Bob Bondurant taught his students to trail brake in order to set up the car for the turn. Stewart's answer was a classic, "And how many world championships has Bob Bondurant won?" end of argument.

If you drive your Fiero like that it will reward you. In their first test of a Fiero Motorweek said to drive it like a sports car should be driven, always heavy on the gas or heavy on the brake.

quote Originally posted by RacinRob: What about doing a grandam brake upgrade to the front only on an 84-87? Would that help or hurt the rear pinch?

Basically larger brakes up front aren't going to hurt the Fiero, but to get the most out of them they need the correct proportioning valve, or an adjustable proportioning valve to set the correct front to rear pressure bias. As far as the 'rear pinch', brakes are just one of the elements that sets that up.

Earlier than '88 Fiero's would benefit from a a brake upgrade, just switching to the '88 parts makes a very noticable difference. That's the main reason GM changed the system design for '88. Should you go bigger diameter than the '88??? You don't have to as it performs very well, but if you do make sure you read everything you can about setting up a proper system, and dial it in to get the most out of it (without creating more trouble for yourself with this upgrade). Brakes aren't as simple as the seem, and considerable testing is done to achieve the proper system design for that vehicle.

I was plesantly surprised by the performance of my standard diameter vented/cross drilled rotors with 'Carbomet' pads at the Waterford Hills Racetrack. They didn't feel over-worked, no fade noticed, and no excessive pressure required. Could larger brakes on my car adverted my 'spin-out' in turn one due to my ballistic approach??? Highly doubtful, as I braked way too late in order to get past the second car.

Perk is close, but everybody here is barking up the wrong tree. Perk, you "noticed" that all the M/R cars in the magazine have big front/rear tire width splits. That is no coincidence. That is EXACTLY the reason that they are controlable at the limit.

The Fiero's aggressive lift-off reaction is a result of differences in contact patch loading front to rear.

Increasing the downforce on a tire decreases the ratio of lateral force to down force. IOW, with 100lbs on it, a tire may be able to absorb 100 lbs of lateral force (corner at 1 g), but with 200 lbs on it, it may only be able to handle 140 lbs of lateral force corner at 0.71 g). That's just the way tires work. The heavier the car on a given tire, the lower its max lateral acceleration.

So, if you have a car with more weight on the rear, but the same size tires front and rear, the rear contact patch is loaded more heavily than the front and is not capable of as much lateral acceleration before it lets go.

Widening the rear tires (& wheels) to the point that the contact patch loading is equal front to rear (ie, match the f/r tire width to the car's weight distribution) goes a LONG way toward taming the car's lift-off reaction. Wider rear tires do not eliminate it entirely, but do change it from a snarling monster to an amusing plaything.

To get a Fiero to handle well, you basically have to go crazy on the rear: stiff springs, stiff struts, big bar, really wide tires.

Very true Will, but just to remind some on the Forum, when you go to those 'big meats' on the rear, you'd better watch your butt on wet roads!!! For a daily driver tire selection will be very important.

Can someone PM me and explain what this is...I'm fairly new to Mid Engine cars, and I do have a few VERY SHARP corners that I have to take at a pretty fast speed (Stupid Highway Intersection).

I took my car down the road and cruized at about 35mph while jerking the car left and right (NASCAR Move to keep the tires warm) and I loved the way the car handled, I did the same on a dirt road but trying to lose control and it was hard. I did the same on the dirt road with my dad's Prelude Si with Mimicing 4WS and I spun the car around quickly.

------------------

My 85 Fiero On CarDomain.Com
Visit New Mexico Fiero's

Hey Will, give me a break, I may not have made as big a deal about the tire sizes but I did say that if you are using a big rear bar you must use larger rear tires. The more engine performance you have the more important that is because the larger engines also produce more engine braking when you lift off the throttle too fast.

I am not disagreeing with you, you have been experimenting with Fiero handling for quite some time, I am merely saying that driving style is equally important with a Fiero, and it isn't as bad a handling car (in stock form) as many people make it sound. As far back as the 1970s Porsche was using different tire sizes on their first 911 turbo, 185/70X15 front and 215/60X15 rear, pretty radical for back then.

Thanks for checking in.

Ira

BTW Will do you have a web site?

[This message has been edited by Monza76 (edited 07-25-2003).]

Will steps up to the plate. The catchers signals for a fast ball. The wind up... The pitch... CA - RACK!!!

It's outta here folks!!! Another grand slam home run! These PFF Fiero Nuts are really smackin 'em tonight!!!

Yup Ira, there'll be plenty of pics. To date all I have done is strip the base car, and I think most people around here know what's under the pretty skin. Hopefully I'll be starting the engine/trans mockup and start posting pics soon.

2FAST_FIERO did anyone answer your ?'s

perk

[This message has been edited by perkidelic (edited 07-25-2003).]

Ira, you are a vault, a treasure, a fiero friend to the end. The info I absorbed from your site last year started me down a clear path of suspension upgrades that has resulted in a car that handles and corners on par with just about anything out there (within reason).
Your eloquent, knowledgable, enjoyable writings have helped make owning my very modified 87gt 3.4 an incredible joy. Along with Gerold at 8shark, aluminum engine cradle bushings from WCF, Herb Adams sway bars and a few others I have been able to turn a car with some mild shortcomings into a serious track scorcher that won't let go. It all started from your recommendations!
The blend of parts/decisions up to now has created a car few people who get in want to get out of. Unless they are "G" challenged.

In response to the brake question, my barretta/grand am brake upgrade w/stainless lines and porterfield steet/track pads is Grrreat! Stands up to the hardest braking at Willowsprings International Raceway without ANY fade all day long.

Ira, It breaks my heart you can't afford to do what you have helped so many others to achieve. That's not right! I know that will change soon. JD Thanks again!

[This message has been edited by vse1fiero@cox.net (edited 07-26-2003).]

I just wanted to chime in again because I like sharing my delight in the way my fiero feels when cranking around a curve.

In addition to the outstanding information above about the mechanical parts of the fiero and the basics of how the rubber meets the road. There is another aspect to the fiero (and other cars) that one must have a basic understanding in order to appriciate a cars ability through chance or design.

The physics involved in getting a car to turn a corner are as complex as a shuttle launch and setting a car up to do it well can cost as much in research and development. At the center of this canundrum is what I will describe as "energy management and dynamics". In short it is the way energy (weight)is transfered around the car and ultimatly to the ground.

To start with, the fieros balance point is very close to the drivers head (inner ear)when seated with the seat all the way back and slightly reclined. To further enhance this sense of balance is put both hands on the wheel, snug the seatbelt up and sit squarely and firmly in the seat.
A typical front engine cars balance point is typicaly somewhere between your knees and kiester and if you never noticed, every seat is reclined slightly putting your head even further from the fulcrium. NASCAR drivers sit very close to the steering wheel for this reason, it also reduces arm fatigue on those gruleing 500 milers but as any driver will attest, having a good "feel" for the car is crutial and putting ones inner ear as close to the CG is all the better.

Having a feel of how much and how fast energy is disapated when cornering is important. Particularly with a fieros propensity to sling it's rear end out when the tires get unloaded due to a forward weight shift as (speed) energy gets scrubbed off.

Having more power does help in a fiero but only to a point. Compared to a corvette in the same condition requires a bit more finess in order to get weight to the rear without agrivating the situation by overpowering the rear wheels even more. Yes, one can easily get both cars in a heap quick but basicly a corvette requires a totaly different energy management strategy.

If you can get a fiero to stay door handle to door handle with a corvette in a straight line, you will smoke him off the track in the corners. Having weight on the rear has it's pluses and minuses but the pluses are far more in number.

Is a fiero "dangerous" in a corner going fast? Absafrigginlootly yes if you are an unweary novice but then again any car is dangerous if you do not know what it will do and how it will react.

A fiero will not fishtail agressively like a front engine car can If anything a fieros rear will come back without any steering correction at all and do it slow and steady as long as you dont let off the gas and upset the front/rear balance. To me that is a major plus, I like keeping my foot on the gas.

84Bill, interesting point about the CG (longtitudinal, horizontal) being near the drivers head, I hadn't realized why cornering in the Fiero felt so different. As you pointed out, stay on the gas as you corner (Brake before you turn), Brakes and cornering do not mix in any car, even the most forgiving. Here is a picture that may help illustrate the complexity of handling, this just represents the basic cornering forces and does not get into anything about alignment, steering ratio, CG, polar moment of inertia, slip angles, weight bias.......

vse1fiero@cox.net, wow, glad I could be of some assistance, but I can't really take much credit, most of what I learned was in the 1970s, family obligations have kept me from exploring farther. Over the next few years I am hoping to finally put together the car that I want, and it will be a Fiero, either this one or, dare I say it, the next one. Thanks for the kind words.

Ira

BTW in response to what Will and California Kid said about tires. The important thing for balance is tire size spread, I believe it was Will who once posted that the percentage difference in tire width must be at least that of the percentage difference in weight, so 10% to 15% larger rear tires. Now if you drive your car daily in all sorts of wet weather try a 185 front and a 205 or 215 rear, not all that wide so not the ultimate in dry grip, but the right balance. For most driving it is balance that matters most, a well balanced car can be driven hard because, as someone stated in an earlier post, it is consistent.

[This message has been edited by Monza76 (edited 07-26-2003).]

quote Originally posted by Monza76: Hey Will, give me a break, I may not have made as big a deal about the tire sizes but I did say that if you are using a big rear bar you must use larger rear tires. The more engine performance you have the more important that is because the larger engines also produce more engine braking when you lift off the throttle too fast.

Oops. Sorry about that. You did mention it, so not everyone was barking up the wrong tree

Tire size is just that important, though. It's worth saying it twice.

quote Originally posted by Monza76:...Now if you drive your car daily in all sorts of wet weather try a 185 front and a 205 or 215 rear, not all that wide so not the ultimate in dry grip, but the right balance. For most driving it is balance that matters most, a well balanced car can be driven hard because, as someone stated in an earlier post, it is consistent.

The Lotus, which doesn't seem to be a bad comparison to a relatively stock Fiero, had 175/55R-16's and 225/45R-17's - not too far off of Dr. Ira's recommendations eh. It has a 122hp/124lb-ft inline 4, 44/56% weight distribution, but it a good bit lighter than a Fiero at 1900lbs. It has an even shorter 90.6" wheelbase.

Interesting note on the issue of brakes: Three of the eight cars (1st, 2nd, & 3rd place winners) had the exact same size rotors front and rear. Two had one-tenth of an inch LARGER rotors in back. Three carried the traditional larger front/smaller rear rotor setup.

I bought this stack of six R&T mags from the local library for a buck! They have a lot of good stuff in 'em too.

Great stuff guys!

perk

My turboed v6, grips like a panther in turns, any rear end slide is very predictable. My V8 car on the other hand is quite a bit more twitchy. I suggest before you do anything, just get a 4 wheel alighnment and check your tires for pressures and sizes. As far as being unpredictable, try driving a Porsche 911 or 996 at speed around curves They will snap loose and come around before you can blink.

------------------

3.1 Turbo 4 spd/ L-98/ carbed LT1

Hey Will and Cali - what size "meats" are you guys running (f&r)???

I know the Kid has a TPI SBC, Will don't you have a N*??

quote Originally posted by perkidelic: Hey Will and Cali - what size "meats" are you guys running (f&r)??? I know the Kid has a TPI SBC, Will don't you have a N*??

215X50X16 Frt, 245X50X16 Rr. BFG Radial T/A

Could very well be why Monza, I have driven a multitude of cars and the fiero is by far the best "feeling" car of them all. Granted I have not driven another mid or rear engined car other than a fiero but I have driven many different "performance" cars. It is hard to describe what I mean by "feel" because they all feel responsive in steering with minimal roll but after whipping around a few turns in my old mans jetta then have a go in a fiero I am always left with the thought "wow! that was different and I like it" even on the same road. If I tried to compare it to my 79 camero there would be no comparison, the camero feels like a tank, its heavy on the turns but has loads of power. Even newer cameros (I drove a new 96 back in 96) feels heavy though not as sloppy as the 79.

I feel a fiero is pound for pound and dollar for dollar the best car GM has built and no other american built or rebadge comes close right out of the box.

quote Originally posted by perkidelic: Hey Will and Cali - what size "meats" are you guys running (f&r)??? I know the Kid has a TPI SBC, Will don't you have a N*??

Currently: 215/55-16 front and 255/50-16 rear. I'm running 16x6 front wheels and 16x8 rear wheels. Yes, I have a Northstar.

I will probably end up doing something similar, but not as radical, to what Will has done. Wider rear tires, stiffer rear bushings and some rear sway bar, smaller than the front if I can find one that fits since I like a little more understeer than some people do. The (expensive) alternative would be to take the Herb Adams route, and the simplest would be a simple Gerald Storvik wheel alignment. Either way the car will have to be inexpensive, since I have very little to spend, and better "feel" is more important than ultimate grip.

84Bill, the Fiero, even in stock form, certainly does feel more alive than the typical understeering FWD. Although I do like early FWD VWs (first generation Rabbit and Jetta).

Ira

quote Originally posted by perkidelic: 2FAST_FIERO did anyone answer your ?'s

Nobody!

quote Originally posted by 2Fast_Fiero: Nobody!

It's called pushing the outside of that envelope and reeling it back it. It doesn't take skill to find the outside, but it takes skill to manage it. Finding the incredible limits of the Fiero is exciting as it changes the whole way you drive the car, as well as giving your car a 'true' race car feel. But keep in mind that if you aren't mentally wired up to know everything that's going on around you when you're pushing it hard (and I mean absolutely everything), this will happen!!!