I love my Fieros. We all do. So it is understandable when people want to believe that they have actually done 150mph in their stock Fieros. Nice dream.

But if we are going to have rational discussions we need to know the facts.

here they are:

A)1984 Fiero 4-cylinder, 4-speed manual from Sept 1983 Road & Track Magazine

0-60 in 11.6 sec with a top speed of 103mph (tested curb weight 2770)

Car and Driver did a similar test and came up 0-60 in 10.9 sec with a top speed of 104mph (testd curb weight 2581 - that's bare bones folks)

B) 1985 Fiero 6-cylinder, 4-speed manual from Nov 1984 Road & Track magazine.

0-60 in 8.4 sec with a top speed of 125mph (tested curb weight 2740)

Car and Driver did a similar test and came up 0-60 in 8.2 sec with a top speed of 119mph (testd curb weight 2910 - that's loaded)

C) 1986 Fiero 6-cylinder (fastback), 4-speed manual from Aug 1986 Road & Track magazine.

0-60 in 7.5 sec with a top speed of 123mph (tested curb weight 2860)

D) 1987 Fiero 6-cylinder, 5-speed manual from Mar 1987 Automobile magazine.

0-60 in 7.7 sec with a top speed of 123mph (tested curb weight 2825)

E) 1988 Fiero 6-cylinder (Formula), 5-speed manual from Oct 1987 Road & Track magazine.

0-60 in 8.0 sec with a top speed of 125mph (tested curb weight 2775)

The bottom line is that the Formula is the Fastest Fiero ever built. It has a top speed of 125 (and I have never done it, my fastest time in a stock Formula is 123.77).

Thanks for your attention.

Another tread bound to go down in flames

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

1988GT T-Tops, 5spd, Loaded

that road and track driver that drove the 85 v6 must have sucked! 0-60 in 8.4, heck, my old tired 87 gt could get better than that with me driving! and it weighed more!

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There will always be variables in testing; was the car loaded or bare, was the driver 140lbs or 225lbs, was the test tract straight and level or hilly, etc.

I personally took a stock Formula from 0-60 in 6.9 seconds. No doubt that driver skill is a large part of many test results.

But the issue of Top Speed is pretty simple...floor it!

BTW, I only quoted magazine articles from magazines that actually TESTED the top speed witha real car on a real test track. I also mentioned my own test results on the race track. These are NOT "estimated" top speeds published by Pontiac or insurance companies.

[This message has been edited by Toddster (edited 11-22-2002).]

Well your believing magazine stats too.. not every car will be the same.

I've been in various cars when people speed and when you pass a grand am thats topped out at 110 like its standing still I find it hard to believe you only have 10, 15 mph.

just to end it not every car will be the same. If you believe magazine articles you'll be hard pressed.

the L88 vette think it was a late 60's model was said to only have roughly 400 HP give or take, but was actually pushing close to 500. Many company's will down play the car for insurance purposes. Yeah the fiero probably wont hit 150, but I wouldn't seriously doubt 135-140. If you drive that fast anyways your nuts.

enough here I know I'm bound to get flamed for saying it.

------------------
-KC

1988 Formula, 3.4 modified 5spd
75 NX (Nitrous) 100% polly
3800 SC coming soon...

[This message has been edited by LoW_KeY (edited 11-22-2002).]

quote Originally posted by LoW_KeY: If you drive that fast anyways your nuts.

Agreed! I've always found the fun to be in hard acceleration and great handling!!

quote Originally posted by LoW_KeY: Yeah the fiero probably wont hit 150, but I wouldn't seriously doubt 135-140.

No disrespect low_key but the Fiero Indy that paced the 500 had a 232 hp super duty engine in it, custom suspension and brakes, and a professional driver on the most well know race track in the world. It maxed out at 136.5 mph.

Are you saying a stock Formula might have out run it if it had, say...a good tailwind?

2 or 3 miles per hour difference IS possible with different variables. No more than that.

The Fiero's top speed is 125

Since you have all the information, look and see which ones were drag limited and which ones were RPM limited.

I floored my 8K(at the time) 87GT this year on a stretch of texas highway with pastures on each side and no access roads or driveways. I got it just over 120(I was guessing 123). It felt strong, but there was no more pedal to go faster. (car is stock).

quote Originally posted by Leper: Since you have all the information, look and see which ones were drag limited and which ones were RPM limited.

The Formula and the Indy were not RPM limited. They simply reached the mechanical limits of their designs.

The other cars tested make no mention of rpm limits so I can not comment.

here is another one:

This 1984 Fiero has a 250hp wild SD engine. Top speed on the Bonneville Salt Flats is 148.68 mph

Story of the L88:

The L88 427 motor was installed in a very limited number of production Corvettes from 1967 through 1969. It is best described as a full-race motor, available to the public for street use, straight from the factory. But its offering on the RPO option list was listed there in disguise. Chevrolet wanted to produce a high-performance Corvette that was second to none. But they also didn’t want the inexperienced horsepower-seeking youth ordering one without realizing the true potential of the L88. Also, it was necessary to have the L88 Corvette conform to various government regulations, insurance companies, as well as Chevrolet’s own horsepower policy. Therefore, the publicized rating for the horsepower of the L88; was manipulated by Chevrolet.

The L88 with 12.5 to 1 compression, hi-lift cam, 850 CFM 4 barrel carb and aluminum heads was under-rated at only 430 HP. L88s actually have been dyno-tested at 560 HP. How could GM do this without it being called false advertisement? Easy -- the publicized rating of the L88 actually was its true horsepower. Chevrolet just neglected to point out that this horsepower rating was at approximately 1000 RPM under the peak performance RPM of the L88. Conversely, engines such as the L71 427 with its 11 to 1 compression, tri-power carburetion and milder cam were rated at their actual peak performance of 5600 RPM. The L71 was listed as 435 HP, which was closer to its true peak performance rating, and 5 horsepower more than the L88’s under-rated 430 HP. It may have caused the average guy to unknowingly check off L71 on the RPO option list, thinking it was the biggest motor to be had in his new Corvette order.

The true intent of the L88 was for all-out performance on the racetrack. For example the L88s were delivered without fan shrouds and were notorious for overheating in traffic. They did not have chokes, and were a bear to keep running until they came up to operating temperature. Additionally there was the Radio and Heater delete that was mandatory on the L88. This didn’t work for the individual that wanted a little comfort in addition to performance.

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

No doubt they are fast stock, may not be crazy but for the price Fieros are crazy little cars. Not to mention think of FieroX and his car, God knows what the top speed is of it.

quote Originally posted by Toddster: my fastest time in a stock Formula is 123.77).

123.77mph? What did you use to measure that speed to the nearest hundreth of a MPH?

quote Originally posted by Formula88: 123.77mph? What did you use to measure that speed to the nearest hundreth of a MPH?

On the track or on the dyno maybe, only guessing, he would have to confirm.

Every car is different.

I have had the Finale to 5,200 rpm on the tach. There may have been a little more left in it, but not much. I'd have needed a lot of straight away to get much more. It shows 3,000 rpm at 70mph.

You do the math.

John Stricker

Hmmm.. the 88 GT I've been working on is not exactly stock, 3.2L V6 and 440T4 - 80MPH is at 2000 RPM. You do the math. Also, approximately 100MPH in second gear

It's all an insurance thing. My well worn 86se will bury the 120 speedo and that is with 133000 miles on it. If thats 123 or 135 who really cares. At that speed I want a helmet and a roll cage and be on a track. I don't need a woman putting on there make up and not see me pull out in front of me or a teeage boy distracted because his girl friend let him put his hand on her knee. You get the idea. 75 or 80 get scary sometimes if you live in a populated area. Stay safe and find a track.

------------------
84 coup 117000 miles
86 Gt Fastback conversion Caddie 4.5 V8 soon
85 Gt

A friend of mine, who is a lot crazier than I, claims his top speed ever in a Fiero is 143mph. He says he calculated the speed based on the tach.

He also said that at 143, the back end gets really squirelly and wants to come of the ground.

quote Originally posted by Formula88: 123.77mph? What did you use to measure that speed to the nearest hundreth of a MPH?

The Southern California Timing Association measured the speed, I didn't. It was at a rally weekend at Lake Edwards. I had my old stock Fiero Formula (before I laid it up for a kit car project) tuned perfectly, tires fully inflated, I was on a dead run on a flat lake bed, no wind, and 123.77 was my BEST time.

The Fiero Speedo is not very accurate. It is typically off by 1 mph at 80mph. So it is useless for real accuracy.

As for fast Fieros, I've seen plenty of them, The Huffacker Race Fiero weighed in at 2160 lbs and turned a top speed of 161mph. But that is DEFINITELY NOT stock!!! And that is what we are talking about.

the Ferraros way far from stock, but it will do the test speeds ez in 3rd gear. In fact in passing on 2 lanes, I always downshift if under 100 mph.

quote Originally posted by fierobear: A friend of mine, who is a lot crazier than I, claims his top speed ever in a Fiero is 143mph. He says he calculated the speed based on the tach.

using the tach is not an accurate way to measure speed. There are too many other variables in play.

But if he was doing 143mph, he was not in a stock car or he just did his math wrong.

quote Originally posted by Toddster: using the tach is not an accurate way to measure speed. There are too many other variables in play. But if he was doing 143mph, he was not in a stock car or he just did his math wrong.

I don't necessarily belive him, I'm just relaying what he said. It was in an 87SE, I'm pretty sure it was a 5 speed.

I don't know how to calculate tach for speed. I suppose you can keep pushing the tach to max, and your speed doesn't increase in direct relation to the higher tach indication.

Addendum:

I just talked to my friend again, and his contention is that if your tires are not spinning, and your clutch isn't slipping, then your tach should be accurate for determining speed.

In other words, if your tach reads 2500rpm at 50 mph, then your tach reads 5000rpm and your tires and clutch aren't slipping, then your speed should be 100mph. If this method doesn't work, tell me why.

Just shows that not all Fieros are created equal. I had an 86 GT auto up to 117mph with what seemed like plenty of breathing room left.

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

I've gotten my 84 4spd to 180km/h I think thats about 103mph? no problem.... but I didn't want to push it any further

------------------
Mandi
84 Fiero SE with 85 GT body

quote Originally posted by fierobear: In other words, if your tach reads 2500rpm at 50 mph, then your tach reads 5000rpm and your tires and clutch aren't slipping, then your speed should be 100mph. If this method doesn't work, tell me why.

It doesnt work this way because then you would assume 25 mph at 1250 rpm and 12.5 mph at 625 rpm, and so on. What would work though, is say you are running 2000 rpm at 40 and 3000 rpm at 60. then assuming no slippage of clutch, tires or torque converter (automatic), then you will see 4000 rpm at 80, 5000 rpm at 100 and 6000 rpm at 120. (btw these figures are for demonstration not actual mph vs rpm)
Id like to try mine out sometime, but I think Ill need some decent tires first.

"X" is right "Bear".

Using the tach can give you a rough idea of speed. But it works like this:

gear ratio of the gear you are in x final drive ratio x RPM x tire circ. give you inches per revolution. Then convert that to miles per hour

for example:

An '88 getrag is geared this way:
1st = 3.50
2nd = 2.05
3rd = 1.38
4th = .94
5th = .72
and if you care, reverse is 3.41.

Now the axel ratio is 3.61 and the overall ratio is 2.60 (2.5992 to be exact)

The formula have a rear tire of 78.54 inches circ. which means that the tire will rotate 806.72 times per mile.

the rest is easy.

if for example you note that your tach is reading 2100 RPM (revolutions per minute) then you multiply that by 60 to get 126,000 RPH (Revolutions Per Hour). Divide this by your overall ratio (2.6) to get 48,461 tire rotations per hour. Divide this by 806.72 (rotations per mile) to get 60.07 miles per hour.

The same can be done to calculate top speed. My stock Formula maxed out at 4300 RPM in 5th gear. Remember that it's an overdrive gear so you will NEVER be able to red line it...by design

((4300x60)/2.60)/806.72 = 123 mph top speed

what a surprise.

quote Originally posted by Toddster: gear ratio of the gear you are in x final drive ratio x RPM x tire circ. give you inches per revolution. Then convert that to miles per hour

I should have added "assume the same gear for all the given rmp."

My engine revs to 7K, makes most its power up there, I have an Isuzu 5 speed. (soon)

anyone care to guess?

[This message has been edited by Fierobsessed (edited 11-23-2002).]

quote Originally posted by Toddster: "X" is right "Bear". Using the tach can give you a rough idea of speed. But it works like this: gear ratio of the gear you are in x final drive ratio x RPM x tire circ. give you inches per revolution. Then convert that to miles per hour for example: An '88 getrag is geared this way: 1st = 3.50 2nd = 2.05 3rd = 1.38 4th = .94 5th = .72 and if you care, reverse is 3.41. Now the axel ratio is 3.61 and the overall ratio is 2.60 (2.5992 to be exact) The formula have a rear tire of 78.54 inches circ. which means that the tire will rotate 806.72 times per mile. the rest is easy. if for example you note that your tach is reading 2100 RPM (revolutions per minute) then you multiply that by 60 to get 126,000 RPH (Revolutions Per Hour). Divide this by your overall ratio (2.6) to get 48,461 tire rotations per hour. Divide this by 806.72 (rotations per mile) to get 60.07 miles per hour.

So try this with twice the rpm's.
4200x60=252000
252000/2.60=96923.07
96923.07/806.72=120.14
twice the speed, go figure
Since the only variable that changes is the rpm, 2x the rpm is 2x the speed.

So if 2100rpm is 60.07
5600rpm is 5600/2100ths of 60.07
5600/2100*60.7=161.86

quote The same can be done to calculate top speed. My stock Formula maxed out at 4300 RPM in 5th gear. Remember that it's an overdrive gear so you will NEVER be able to red line it...by design

The reason I brought up rpm limited vs drag limited was because the 84 4.10 4 speed has a top speed of 105 due to redlining and not because the engine couldn't pull any higher. Guess what? it has a .81 overdrive as well.

Maybe youre car will actually pull past 4300 if you give it enough road.

quote ((4300x60)/2.60)/806.72 = 123 mph top speed what a surprise.

A look at this link might help with your calcs. It takes into consideration the drag, frontal area and horsepower required. Fill in the information for your car and let the spread sheet do the math.

Except for a few occasions in Montana (pre 75 mph speed limit) I limit my 100+ mph experience to the track. Everybody there is going the same direction, no cross streets and paying much more attention to what they are doing than most people on the public streets.
http://home.earthlink.net/~jonaa/topspeed.html

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Bill Levin

[This message has been edited by 87GT3800SC5SPD (edited 11-24-2002).]

87GT,
Nice lookin fiero!! Looks kinda familiar!

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quote Originally posted by Toddster: My stock Formula maxed out at 4300 RPM in 5th gear. Remember that it's an overdrive gear so you will NEVER be able to red line it...by design

Mine will go past 4300 np.

We've had it up to 5500 rpm several times in 5th.

Oh btw, Stock 2.8L/Getrag 40k miles on drivetrain.

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

1988GT T-Tops, 5spd, Loaded

Thanks for this link. I just plugged the numbers into the spreadsheet for the Finale and it shows that it should be capable of about 124 mph. I had it to 121 based on the tach and it was almost played out there, but not quite.

Pretty darn close if you ask me.

John Stricker

quote Originally posted by 87GT3800SC5SPD: A look at this link might help with your calcs. It takes into consideration the drag, frontal area and horsepower required. Fill in the information for your car and let the spread sheet do the math. Except for a few occasions in Montana (pre 75 mph speed limit) I limit my 100+ mph experience to the track. Everybody there is going the same direction, no cross streets and paying much more attention to what they are during than on the public streets. http://home.earthlink.net/~jonaa/topspeed.html

quote Originally posted by Leper: 5600rpm is 5600/2100ths of 60.07 5600/2100*60.7=161.86 The reason I brought up rpm limited vs drag limited was because the 84 4.10 4 speed has a top speed of 105 due to redlining and not because the engine couldn't pull any higher. Guess what? it has a .81 overdrive as well. Maybe youre car will actually pull past 4300 if you give it enough road.

There is nothing wrong with your math Leper, just your assumptions. First of all, I tested my car at Lake Edwards (a dry lake bed in the Southern California Desert). I had plenty of road. Pedal to the floor 4300 RPM max in 5th gear.

The main assumption you are making is that the car's performance is limited only by the engine's Rev limit. Big mistake. There is a law of physics called the Law of Diminishing Returns. You've probably seen curves in math class that rise rapidly then start to flatten out, such that the more energy you put in the less speed you get.

It's a natural assumption to think that speed and HP have a linear relation but they do not. There is an old Hot Rodding saying, "If you want twice the speed, you need 4 times the horsepower".

To make this clearer, have you ever noticed that one of your gears seems to perform better than another? Like for example, do you ever say to yourself, "Man, my 3rd gear is kickin but 1st gear sucks!"

The reason is that the power curve of yuor engine is optimized for a certain gear ratio. Since the 5th gear of the getrag is .72, when mated to a 60* V-6 your engine sinmply does not have enough horsepower to push the limits of it's RPM range.

The Iron Duke is a different engine with different gearing in the tranny and can therefore pull higher in the RPM range. I used to have an Indy and I maxed it out at 105 too. You said it yourself, 4th gear is .81 which is easier to drive than a .72 gear. Hence you can get more RPM.

By definition, you need a 1.00 gear to redline it because any smaller gear requires MORE energy to drive it than the engine can produce.

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

Here is an example using a 1975 Lamborghini Countach, the reason is that it is the only car I know of with a 4th gear that is nearly exactly 1.00 to 1.00:

the Countach tranny is geared this way-
1st 2.256
2nd 1.769
3rd 1.310
4th 0.990
5th 0.755
axle ratio 4.080

The engine has 375bhp, hence the lower starting gears. Redline is 8000rpm and torque is 268 ft/lbs on the stock 2.40 cu in V-12. Factory tires are 215/70R14 in back (I'm estimating circumferance so I might be off by a few RPMs but it will be close enough for par).

Top speed is listed at 175MPH which is only 7247 RPM using the tach formula above.

Top speed in 4th gear (.99)is listed as 149 mph which equates to 8092 RPM (the red line, more or less).

Hope this helps make it a little clearer.

[This message has been edited by Toddster (edited 11-24-2002).]

quote Originally posted by Toddster: By definition, you need a 1.00 gear to redline it because any smaller gear requires MORE energy to drive it than the engine can produce.

Not true. It's multiplied by the final drive ratio and the diameter of the tires anyway.

Whether or not a car will redline in ANY gear depends solely on if it has enough HP approaching and at redline to overcome the resistance (primarily air) at the MPH dictated by it's OVERALL gearing and tire diameter. If you put a low enough final drive and/or small enough tires on a Formula it could redline in 5th gear at 50 MPH.

Another factor that limits some cars is the highest gear drops the car well below it's peak HP. It might be able to sustain a higher top speed IF it could get to it in the first place.

quote Originally posted by Toddster: There is nothing wrong with your math Leper, just your assumptions. First of all, I tested my car at Lake Edwards (a dry lake bed in the Southern California Desert). I had plenty of road. Pedal to the floor 4300 RPM max in 5th gear. The main assumption you are making is that the car's performance is limited only by the engine's Rev limit. Big mistake. There is a law of physics called the Law of Diminishing Returns. You've probably seen curves in math class that rise rapidly then start to flatten out, such that the more energy you put in the less speed you get. It's a natural assumption to think that speed and HP have a linear relation but they do not. There is an old Hot Rodding saying, "If you want twice the speed, you need 4 times the horsepower". To make this clearer, have you ever noticed that one of your gears seems to perform better than another? Like for example, do you ever say to yourself, "Man, my 3rd gear is kickin but 1st gear sucks!" The reason is that the power curve of yuor engine is optimized for a certain gear ratio. Since the 5th gear of the getrag is .72, when mated to a 60* V-6 your engine sinmply does not have enough horsepower to push the limits of it's RPM range. The Iron Duke is a different engine with different gearing in the tranny and can therefore pull higher in the RPM range. I used to have an Indy and I maxed it out at 105 too. You said it yourself, 4th gear is .81 which is easier to drive than a .72 gear. Hence you can get more RPM. By definition, you need a 1.00 gear to redline it because any smaller gear requires MORE energy to drive it than the engine can produce. 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 Here is an example using a 1975 Lamborghini Countach, the reason is that it is the only car I know of with a 4th gear that is nearly exactly 1.00 to 1.00: the Countach tranny is geared this way- 1st 2.256 2nd 1.769 3rd 1.310 4th 0.990 5th 0.755 axle ratio 4.080 The engine has 375bhp, hence the lower starting gears. Redline is 8000rpm and torque is 268 ft/lbs on the stock 2.40 cu in V-12. Factory tires are 215/70R14 in back (I'm estimating circumferance so I might be off by a few RPMs but it will be close enough for par). Top speed is listed at 175MPH which is only 7247 RPM using the tach formula above. Top speed in 4th gear (.99)is listed as 149 mph which equates to 8092 RPM (the red line, more or less). Hope this helps make it a little clearer. [This message has been edited by Toddster (edited 11-24-2002).]

i dont know where you get your numbers for a countach but they are far off

1989 Lamborghini Countach 25th Anniv

General



Make Lamborghini
Model 1989 Countach 25th Anniv
Powertrain Layout Mid Engine / RWD
Base Price $145 000
Dimensions

WheelBase 2500 mm / 98.4 in
Length 4140 mm / 162.9 in
Height 1070 mm / 42.1 in
Width 2000 mm / 78.7 in
Weight 1490 kg / 3285 lbs
Front / Rear Track F 1536 mm / 60.5 in
R 1606 mm / 63.2 in
Engine

Configuration V12
Valvetrain DOHC, 4 valves / cylinder
Displacement 5167 cc / 315.3 cu in
Power 339.3 kw / 455.0 bhp @ 7000 rpm
Torque 501.0 nm / 369.5 ft lbs @ 5200 rpm
Bore 85.5 mm / 3.37 in
Stroke 75.0 mm / 2.95 in
Compression Ratio 9.5:1
BHP / Liter 88.06 bhp
Redline Not Available
Transmission

Type 5-Speed Manual
Final Drive 4.09:1
1st Gear Ratio 2.23:1
2nd Gear Ratio 1.63:1
3rd Gear Ratio 1.09:1
4th Gear Ratio 0.86:1
5th Gear Ratio 0.71:1
6th Gear Ratio Not Available
Chassis & Body

Steering Rack & Pinion
Tire Sizes F 225/50ZR-15
R 345/35ZR-15
Brake Types Vented Discs w/ Hydraulic Assist
Brake Size F 300 mm / 11.8 in
R 284 mm / 11.2 in
Available ABS Not Available
Body Material Aluminum & Composite
Performance

Top Speed 183.3 mph / 295.0 kph

I keep it simple. I just use a friend in police dept on a long stretch of road with a radar gun, take a running start and pass him parked up the road a ways. Im running 4 spd, 225/15/60s, 7500 rpm, turbo, 3.1

Figures/math dont alway match reality. I had 2 identical 460 cu in lincoln Mark IIs. exact same equip, ratios, hp, even color. One would smoke the tires off, other barely chirped. One ran at least 30 mph top end faster. Both were in perfect running order.

[This message has been edited by rogergarrison (edited 11-24-2002).]

quote Originally posted by thekevinator26: i dont know where you get your numbers for a countach but they are far off 1989 Lamborghini Countach 25th Anniv ..blah blah blah

No disrespect Kevinator but you are the one who is mistaken. If you will re-read my post you will see that I quoted the 1975 Lamborghini Countach because it has a near 1 to 1 ratio. See stats below: