Well this post is most probably going to piss in the beer's of the V-6 boys . But my little 4-Banger has done 113 MPH . On a fresh rebuilt after a 543 mile break in period . Ran along side of my buddys Corvette , this is top end people . This is running without a front air dam , my wife wipped the air dam out about two weeks before we tested my little 4-banger . Plus there was a hell of a cross wind .

My buddy the Corvette owner wouldn't piss on a Fiero if it was on FIRE . So I'm pretty sure the top end speed was what his Corvette was reading .

What I had a problem with was the front end lifted and started to dance a bit . Got my attention .

Flame all you want ! This is what is .

Galen Smith
Red 85 Sport Coupe
Founder of Suncoast Fiero Club
Florida Fiero Council

quote Originally posted by fierogsmith: My buddy the Corvette owner wouldn't piss on a Fiero if it was on FIRE .

I love those guys. Makes them mad as hell when I smoke em

quote Originally posted by Toddster: Well...no actually it isn't. It's a little involved but I'll give it a try. First of all, HP is irrelevant for the purpose of this analysis. The measure of a power source's ability to move an object is called torque. Torque is an effort to turn or twist and is measured by an energy source's ability to lift 1 pound of dead weight 1 foot in the air. Torque is derived from power (horsepower) but because of operating characteristics, a gasoline engine does not attain maximum torque (turning effort) at peak power output. Torque is proportional to the distance from the center of rotation. think of a see-saw. It has a fulcrum and swings one way or the other. If you move the fulcrum closer to you it gets harder to lift the kid sitting on the other end. This is the same principle for an engine crank with different sized gears. Each gear represents a longer or shorter fulcrum. If we put a large gear on the shaft we will get more speed and less power at the wheel. By varying the size and combination of gears on a parallel shaft to the crank we can get any number of combinations of speed and power we want within the limits of the engine's ability to produce power...wind resistance and tire size are VERY small parts of the equation. Now for a less well known fundamental of transmission design. 1st, 2nd, and 3rd gears are almost always found on a parallel shaft to the drive shaft. This means that energy is transferred from one shaft to another and back again. 4th, 5th, and sometimes 6th gears are linked directly to the drive shaft, hence there is one less shaft involved and energy is directed right to the drive shaft. Transaxles are different in that, by design, they have one transfer shaft. But you still have one less shaft in higher gears than with lower gears. Transmission are designed to match the weight and power of the vehicles they are made for. Since the getrag was originally designed for the Pontiac 6000 it is a hearty unit for the lighter and more powerful Fiero. Most 5-speeds have only one overdrive gear but like I said, the Getrag-282 was adapted to the Fiero from another car so it essentially has 2. The concept is that the tranny will be designed such that the final NON-overdrive gear, called the "direct drive or high gear", will be designed with the number of teeth and dimension necessary to maximize the power to torque ratio (1 to 1). Why? Simple, in all lower gears the engine crank is turning faster than the output shaft up to the direct drive gear which turns at the same speed. In the lower gears you get MORE power (torque - to move the car from a dead stop). In 5th, the overdrive gear, your crank is turning slower than your output shaft which means you are getting LESS torque. This is the limiting factor. Your engine is less efficient in overdrive and can not rev as high as it can in underdrive gears. If the fastest your engine can rotate in a 1 to 1 gear (like on the Countach) is 8000 RPM how can it rotate that fast in an overdrive gear!? That is the whole point. It can't. The stock Fiero simply does not have the power to turn the 5th gear faster than 4300 RPM.

An 85 merkur has a 4th gear ratio of 1:1 and a 5th of (I think) .8x
now when i had mine i had NO problems redlining ANY gear. well ok it took a good streach of road to get the revs up in 5th but i could pull right to redline. With your theory stated above your telling me this was impossible.

ive never tried to max out my GT but i can max out 4th no problem, which is technically an overdrive gear... again your theory tells me i shouldnt be able to.

What i do agree with is that id does indeed take exponentially more power to get just that little bit more speed.
and yea noone is gonna be able to redline a 282 getrag with a stock motor, but put a x00hp motor in there and your theory still says it will never reach redline in 5th?

It just seems like flawed logic to me.

No such thing as magic limits, more power equals more rpm.
I can skip a round rock on a lake just as many times as my kids can skip a flat rock because I can THROW it a lot harder. Call the round rock fifth gear 'cause it takes a far larger amount of energy, but the limit is on the input, larger input means larger output up to the point where self-destruction take place. My arm joints or the tranny gears, same physics.

quote Originally posted by Toddster: [/i] in other words, sorry Jelly, you didn't have your car in 5th gear and pull 5500 RPM (if your engine is bone stock) because it violate the laws of physics. But nice picture of your dashboard

Believe what you may, I am going to PM you my mailing address. If you are in any doubt and want to prove me wrong, its real simple, just come to my place, and you are welcome to drive my car.

It's that simple.

You can go on about your laws of physics and calculations all you want, I am offering you a chance to prove me wrong in real life.

This is no flame, just a friendly offer.

Stock tach's (in MY experience) can be waaaaaaay off.. Using a factory tach, IMHO, is ~not~ a good measure.. Something like an Autometer tach would be much more acurate.

Before I had an Autometer tach in my old 400ci small blocked Z28, I used to think it made it's peak HP at around 7500rpm.. Once I put the Autometer in, turns out it was actually only at 5500 rpm.. heh, that was a little more realistic.

Anyways, just food for thought.

Cheers!

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

Andrew MacPherson
86 2M6 - Stock
82 Z28 - Mod'd to the nuts
86 Firebrid - Beater

Toddster is sortof right, at least in my limited knowledge. Let me explain. Imagine a free spinning motor with no load. Under full throttle conditions, the engine revs up extremely quickly because the torque required to move through the rpm band is extremely low. Now imagine putting a load on it, it will take longer for the engine to rev to its redline. Maybe its time to explain what a redline is... in the days of old the engine revved to the point where one of the parts would bottleneck the rpm, this is what was referred to as the redline. This usually was caused by the valve train. The problem with this "mechanical" redline was that it put extreme pressure on ALL the motor parts, something would eventually break. Nowadays the ECM won't let ppl rev their engines to the point of stupidity. It cuts the fuel or spark to prevent the engine from revving to breaking point. (It still is possible to find the mechanical redline of an engine, get to about 3000 RPMs in 5th and downshift to 1st you'll get nearly "no-load", destroying your engine and/or transmission in the process) As you put more load on an engine the mechanical redline will lower, so in some engines with overdrive they will never reach their "electronically limited" redline.

quote Originally posted by fierogsmith: Well this post is most probably going to piss in the beer's of the V-6 boys . But my little 4-Banger has done 113 MPH . On a fresh rebuilt after a 543 mile break in period . Ran along side of my buddys Corvette , this is top end people . This is running without a front air dam , my wife wipped the air dam out about two weeks before we tested my little 4-banger . Plus there was a hell of a cross wind . My buddy the Corvette owner wouldn't piss on a Fiero if it was on FIRE . So I'm pretty sure the top end speed was what his Corvette was reading . What I had a problem with was the front end lifted and started to dance a bit . Got my attention . Flame all you want ! This is what is . Galen Smith Red 85 Sport Coupe Founder of Suncoast Fiero Club Florida Fiero Council

I don't doubt it.. my brother had my old 84 fiero wrap around to 0. Also for Jelly's pic I believe it to my friend did it in his stock 87 GT 5spd. Like I said not all cars are the same I did 5500 back in the day when I first got the car, my dad got curious and wanted to see.

I've had my car (admitedly, not stock. Lowered 1.5"/1" f/r, different alignment and rubber, few little things like underdrive pully, etc. untouched internally 2.8 though) to 135 one cold evening as indicated by tach RPM in 5th gear, gear ratio, and static tyre diameter (I'm guessing the 186+ rated Pzeros weren't expanding much )

135mph was all she had, and it took forever to get there.

Now this N* is supposed to make around 460hp at 8500rpm, with a redline of 9grand.

Giving a little internet-racing program my data, I should be able (power, gearing, and drag) to hit about 222mph in 5th, but more importantly, nearly 180mph in *4th gear* (which means I get there very fast.) 2,3, and 4 are going to be some MEAN track gears. Car will get a full areo undercarriage development to correct the horrible stock aerodynamic lift. Goal is zero-lift, with my private goal of ~500lbs of actual peak downforce as close to the CG as I can manage.\

Take all for what it's worth.

Best!
Ben.

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

Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

What is the Cd for a fastback fiero? Has anyone done an undercarriage yet? Also the rear window would need to be put a more optimal angle.

quote Originally posted by Neal: It just seems like flawed logic to me.

You are more right than you know Neal. I'm trying to simplify this so I find it easier to just say "it can't be done".

The truth is that if you take that see-saw example, if the fulcrum is dead center you can push down the see-saw with your pinky, but if the fulcrum is one inch away you will need the weight of an elephant to push it down.

The same applies to the Getrag. Sure, you can move 2760 lbs of weight in a .72 gear at the limits of the engine provided the engine was designed to do that. That would probably be a 1200 hp engine (I'm just guessing, don't want to do the math)

But you get the point. No one is going to put a 1200 hp engine on a getrag anyway so it seems easier to say it can't be done.

Jelly, I got your PM and replied. I'm not trying to dis anyone either. I'm just trying to give a little education on the relationship of torque and HP to speed.

My guess is that your tach filter is bad. The math doesn't lie:

at 5500 RPM in 5th gear, your 140bhp normally aspirated stock Fiero would have been driving:

((5500x60)/2.60)/806.72 = 157.33 miles per hour

The same as a 1979 260bhp twin-turbo Porsche Carrera....157 mph top speed.

it just don't add up.

quote Originally posted by Toddster: Jelly, I got your PM and replied. I'm not trying to dis anyone either. I'm just trying to give a little education on the relationship of torque and HP to speed. My guess is that your tach filter is bad. The math doesn't lie: at 5500 RPM in 5th gear, your 140bhp normally aspirated stock Fiero would have been driving: ((5500x60)/2.60)/806.72 = 157.33 miles per hour The same as a 1979 260bhp twin-turbo Porsche Carrera....157 mph top speed. it just don't add up.

Your right, your math doesn't add up. I myself doubt my car will do 157 mph.

Ok , answer this.

At the 120mph mark the tach shows ~4100 rpm.

At the pin in the speedo the tach shows ~4300 rpm.

From there it still pulls to and past 5000rpm, and I've had it to 5500 RPM several times.

Where are these extra 700 - 1200 rpms going?

You know as well as I do that the clutch won't start to magically slip after a certain speed, especially seeing the motor is comming out of it's power band?

I know you are not dissing anybody, but I fail to see why doubt to believe some cars are faster than what R&T tested a different car at.

I have nothing to prove,I have never stated that my car was xxx fast. If you want to set a test up with proper equipement, you are more than welcome to use my car as a test subject.

No calculation, no math, just real hard data.

[This message has been edited by jelly2m8 (edited 11-25-2002).]

quote Originally posted by jelly2m8: From there it still pulls to and past 5000rpm, and I've had it to 5500 RPM several times. Where are these extra 700 - 1200 rpms going? I know you are not dissing anybody, but I fail to see why doubt to believe some cars are faster than what R&T tested a different car at.

Well, I can't answer the first question. It could be that the tach filter or the ignition module is giving a faulty reading. It could be your computer. If you are the second owner it could be that the previous owner made some modification and never told you. But I would have to diagnose the car to know for sure.

I would take a dwell/tach meter if you have one and check your engine's RPMs right from the distributor and compare the results with your tach to see if it's off in the high RPM range.

As for the second question, I raced Fieros out on the desert years ago so it is not just Road & Track or Car & Driver stats that come into play. Note also that I only quote magazines that do actual ROAD tests. They do not publish number determined just by a calculator alone.

I have ran flat out on Lake Edwards and topped out at 123.77. That was pedal to the floor flat out for 6 miles! And the speed was determined by the SCTA, not my speedo.

Now I have seen stock Formulas run anywhere from the 119 to 128 range. That is a variance of 9 miles per hour! That is HUGE! Some Fieros are definitely gifted with something "extra". Temperature, humidity, wind, tuning, tire selection and pressure, spring rates, etc. will all have an impact on top speed. But 128 is the best I have ever seen in stock class fiero race and I was 1/2 tempted to protest. From one stock Formula to another I bet you can see an average 5 mph variance easily, not more than that.

I haven't raced in a whiles but my time slips and my knowledge of the engineering behind it tell me that 128 is "possible" with one hell of a tailwind or some minor mods (I believe he ported his exhaust manifolds). Anything more than that means that the engine has been modified or the speedo is off, etc.

This does not mean that the Fiero is limited. On the contray, Ben said it best when he pointed out that the aerodynamics are the limiting factor. If you built up the engine or put in a different one you can really tear up the pavement.

BTW, nobody try to test this on the freeway, please. There are plenty of race tracks out there.

In addition to what I posted before, I should also add that we had the Fiero on the dyno before the Finale body kit went on but after all the engine work was done.

I have very accurate rear wheel horsepower charts for the engine because of this and some other data.

First off, the DYNO showed me running 44.36 rpm per mph. That means that at 5200 rpm, I'd be doing 117.22 mph. It should be noted that the rpm comes from the dyno's inductive pickup and the speed comes from the dyno roller. These numbers have nothing to do with the factory tach and speedo. (This is with an automatic, BTW) They also correspond within a few percent of what I've observed on the gauges in the car.

Second, when I used the spreadsheet that was linked earlier in this thread, I plugged in some numbers that I thought was accurate. I used 20 sq ft for the area of the Finale, a number I calculated with a tape measure and some math. It is a bit less than a stock Fiero (but not much) because it's lowered. I also used a Cd of .31 because I think the Finale is a bit cleaner than a Fiero due to the shaved door handles and the hatch back, amongst other things.

Now, when plugging this into the spreadsheet, at 100 mph, if you change the Cd from .34 (about what it is for a Corvette) to .31, the power required only goes up by about 4 hp. Of course, the faster you go, the more this makes a difference.

I know within a few mph what the Finale will do so I adjusted the Cd accordingly. I also think it's pretty close to what a stock Fiero will be required to have in order to go a certain speed.

Now I plugged all this information, some known, some guessed at, into the spreadsheet and used the gears posted earlier for the Getrag. It appears that it's potentially faster than I thought it would be and substantially faster than my Finale with the automatic.

The power required curves and power available cross at 131 mph at 4500 rpm (using the numbers for our 3.4). That's in 5th gear. In 4th gear, it almost mimics our Finale with a top speed of about 121 mph. If we adjust the Cd up to about 3.4, then our top speed becomes about 128 or so. The power required is more, but the horsepower is a little more down lower as well. To make maximum top speed, the car should be geared to about a 3:54 or so and would up the speed to about 134 or so.

It is possible that a really good running V6 (not a 3800SC or TDC, but a semi-stock pushrod motor) with the Getrag could push 135 mph and be aerodynamically limited. But not much more than that. That's still pretty respectable though, and nothing to be sneezed at.

John Stricker

[QUOTE]Originally posted by Toddster:

Well, I can't answer the first question. It could be that the tach filter or the ignition module is giving a faulty reading. It could be your computer. If you are the second owner it could be that the previous owner made some modification and never told you. But I would have to diagnose the car to know for sure.

I would take a dwell/tach meter if you have one and check your engine's RPMs right from the distributor and compare the results with your tach to see if it's off in the high RPM range.

As for the second question, I raced Fieros out on the desert years ago so it is not just Road & Track or Car & Driver stats that come into play. Note also that I only quote magazines that do actual ROAD tests. They do not publish number determined just by a calculator alone.

I have ran flat out on Lake Edwards and topped out at 123.77. That was pedal to the floor flat out for 6 miles! And the speed was determined by the SCTA, not my speedo.

Now I have seen stock Formulas run anywhere from the 119 to 128 range. That is a variance of 9 miles per hour! That is HUGE! Some Fieros are definitely gifted with something "extra". Temperature, humidity, wind, tuning, tire selection and pressure, spring rates, etc. will all have an impact on top speed. But 128 is the best I have ever seen in stock class fiero race and I was 1/2 tempted to protest. From one stock Formula to another I bet you can see an average 5 mph variance easily, not more than that.

I haven't raced in a whiles but my time slips and my knowledge of the engineering behind it tell me that 128 is "possible" with one hell of a tailwind or some minor mods (I believe he ported his exhaust manifolds). Anything more than that means that the engine has been modified or the speedo is off, etc.

This does not mean that the Fiero is limited. On the contray, Ben said it best when he pointed out that the aerodynamics are the limiting factor. If you built up the engine or put in a different one you can really tear up the pavement.

BTW, nobody try to test this on the freeway, please. There are plenty of race tracks out there.

I red on here some time ago that a kid was doing 130 or so in his fiero, got airborn, and crashed and died. Is this true? Cause that would break my heart if I crashed my car testing the limits.

Can tell you the little car below has been cruising with along side a Viper GTS at 165mph, and still had pedal left!!! It was very stabile at that speed, Viper guy freaked out, looked it over real good when we made a pit stop.

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

Click to Listen!

My wife followed me in the 97 WS6 Trans-am, down I-15, she put the needle at 140 she says, my 87 GT was right next to her in the lane to the right. only after she began to push the needle past that did she start to pull away. Only thing i have done to my 2.8 in that 87GT it port the headers.

...Dont believe everything you read in a magazine /shrug

------------------
Monkey
"No matter where I go...There's my car"

*Just arrived...84 Indy 4-spd
87 T-Top GT 2.8/5-spd
87 Hardtop GT 2.8/5-spd
97 Trans-AM WS6 6-spd
91 V8 Monster Miata 5spd
69 Mustang Coupe 302 4spd

Added 2 short movies
members.cox.net/lothe/

So Toddster what would be the top speed of an automatic 87GT.

well, just wanted to throw this is - ALL speedos are inaccurate. the faster you go - the more inaccurate they are. the error muliplies as you go faster. GPS or Doppler Radar are MUCH more accurate way to know how fast you are going. or timing mile markers, but thats a pain, and takes at least 5-10 miles of being floored to get a good result (as much fun as that would be - aint many stretches around here for that). your individual top speeds are a function of your engines power & your gearing (including tires - where most speedos lose their accuaracy) if your motor is strong enough, you can redline at top gear. this just means you need another gear - you can go faster then! I know mine will hit 5200 in top gear (3-spd auto) which I think is pretty good. hitting 5000 took some time, and the last 200 was slow creep. I dont know what the works out to, probably better I dont. also, you are gonna have a tough time finding any two cars that have the same top speed.

I don't really care what any of you believe or not..My fiero tops out at Warp Factor 3 It may be able to go faster but I run out of space.

quote Originally posted by FieroMonkey: My wife followed me in the 97 WS6 Trans-am, down I-15, she put the needle at 140 she says, my 87 GT was right next to her in the lane to the right....

And my wife tells me that I have the biggest D*** she has ever seen.

Porting your exhaust manifolds is good for exactly 9hp. I'll buy 130, no more.

quote Originally posted by Ambush: I don't really care what any of you believe or not..My fiero tops out at Warp Factor 3 It may be able to go faster but I run out of space.

And my car can do the Kessel Run in less than 12 parsecs.

Toddster,
sorry, but im not selling 130, or 140 for that matter. 140 is what my wife told me my 87 GT was going when she pulled away. And since she is not in to testoterone fueled matches about top speeds, i was fully inclined to believe her. just thought that someone might find the info interesting.

Im not out to impress anyone with my lil 2.8. if want to make people **** their pants with respect, i drive my 347 stroked V8 Miata with kenny-belle SC and GT40 ported aluminum heads pushing 453 HP to the rear wheels. I also, take off my shirt and oil my chest and buldging byceps (drives the girlys wild)...oh ya, and my Rayban Glasses, that completes the whole experience....anyways no 130 or 140, but everything you see in this last paragraph is for sale, and since you are a PFF'er, ill go easier on the price

------------------
Monkey
"No matter where I go...There's my car"

*Just arrived...84 Indy 4-spd
87 T-Top GT 2.8/5-spd
87 Hardtop GT 2.8/5-spd
97 Trans-AM WS6 6-spd
91 V8 Monster Miata 5spd
69 Mustang Coupe 302 4spd

Added 2 short movies
members.cox.net/lothe/

Monkey,

Fair enough. But tell your wife no more triple digit runs down I-15; don't need to see her obit in the paper because someone in a Winnabego changed lanes without looking in his rear view mirror first.

Toddster,
I am flattered with your concern about my wife. That was her first, and last time playing with speeds over 100. She had never driven that fast, and felt she had to get it out of her system. I told her not any faster than my Fiero, since i was driving next to her. the speedo in the firebird doesnt go over 120 or so my Gtech-pro was running on the dash. when i topped out my fiero she got fiesty and kept the pedal down =/
Before we did this i want you to know that there were fresh tires and brakes on the car, and we did this early in the morning on the Commuter lanes between rancho bernardo and tierra santa. That particular commuter lane has 2 foot cement walls on either side, is one way, and the freshest pavement on any highway in San Diego, and no cars were around.
I realize now how recklace i sounded telling that story, so i wanted to clarify the circumstances. i was very nervous about her doing it, even though she is the best female driver i have ever known *looks out for flames*. And suffice it to say, she assures me that it is completely out of her system, and that she has no need to ever go that fast again =).
Sorry for legnth, peace,

------------------
Monkey
"No matter where I go...There's my car"

*Just arrived...84 Indy 4-spd
87 T-Top GT 2.8/5-spd
87 Hardtop GT 2.8/5-spd
97 Trans-AM WS6 6-spd
91 V8 Monster Miata 5spd
69 Mustang Coupe 302 4spd

Added 2 short movies
members.cox.net/lothe/