86 2M4 2.5L w/ auto. Almost stock, 101 mph. Speedo past 85, tach read 4600 rpm.
Tip: Scan tool will provide a digital readout when speedo is maxxed. Set it up for a scan and press the "Enter" button when you've don't want to or can't go any faster. Read the captured data after you've parked the car.
[This message has been edited by 30+mpg (edited 01-02-2006).]
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08:29 PM
PFF
System Bot
Capt Fiero Member
Posts: 7657 From: British Columbia, Canada Registered: Feb 2000
140 mph rather quickly with a 4.9 and Isuszu 5spd. She had more in her, I chose to be on the sain side and shut it down. I had my V6 in the 140-150mph range but that was with a long stretch and help from some nitrous.
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08:47 PM
AutoTech Member
Posts: 2385 From: St. Charles, Illinois Registered: Aug 2004
I had my 2.5 duke five speed up to a bit over 90 once.. (I used my GPS unit to determine the speed).. I think I could have gone a bit faster, but I was running out of road
------------------ 1988 Fiero Coupe 2.5L 1990 Trans Am GTA 5.7L
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08:57 PM
ryan.hess Member
Posts: 20784 From: Orlando, FL Registered: Dec 2002
That's what I calculated with gear ratio formula. That would be in 4th gear in my 86 SE 2.8L V6 pegged at 6000 rpms with no wind resistance....
Realistically? I calculated 134 mph as the speed at 5200 rpms, which is where I think it'd stop pulling. The Fiero just takes too long to reach that speed though, so I haven't tested it out. The longer you're way over the speed limit like that the better chance you'll run into a cop. And besides, the car has a 80 mph speedo and I have no scan tool so I wouldn't know what speed I'm travelling .
In my '88 GT I've personally gone up to about 110 mph, that was when I was driving it back from Chicago right after I bought it . As I remember it was still pulling but not very much, I think it was right around 4600 rpms. Back when Sonic50 still had his '88 GT I raced him and at 100 mph I was at like 4500 rpm, my car doesn't seem to be performing as well?
In something other than a Fiero, the fastest I've gone is 140 mph in my Z28. It'll get up there VERY quick, even with the 4-speed automatic, and it had a lot left in it, but I'm too scared to go all the way to the speed limiter at 155 on public roads.
Northstar w/after market Cams, springs, and race computer(set to 9000rpm). 4 Speed trans with 275/40R18s. The calc says 241.54 but it get way to light at about 130 140.
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11:23 PM
Jan 3rd, 2006
TaurusThug Member
Posts: 4271 From: Simpsonville, SC Registered: Aug 2003
Nearly stock 88GT 5-speed hits about 110 and won't go any further. Goddamn 7,000ft altitude, taking all my power...
As for the highest speed reached while I drove, 178 on a GSXR1000, and 165ish in a Porsche 996 turbo. Both had more in them, I pussed out on the Gixxer and had to stop becuase of traffic in the 996.
As for all you doing calculators with gear ratios, please stop. It is rediculous. Theoretically my LT1 Camaro is capable of over 260mph. BIG DEAL. Doesn't mean it can even go 150. The gear ratio method means nothing unless you have the power to max out your top gear, and I guarantee a 4.9 can't do it (Stock of course), a 2.8 can't do it, a 2.5 can't do it, etc. It takes A LOT of horsepower to overcome 150mph worth of wind resistance.
------------------ "all pushrod motor are better than the dohc because it has less rotational mass" -rick17, MyMonte member, owner of a 3100 Monte Carlo LS
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12:35 AM
fiero_silva Member
Posts: 1493 From: Winnipeg, Manitoba, Canada Registered: Jun 2003
this in reference to maxing out the engine in top gear.
I have had my 84 2.5 engine at about 5400 rpm in 4th gear so i would have to use gear ratio calculations to give me an approximate speed. which with my smaller 215/40/17 in tires would be about, 115 mph oh yeah "theoretically" The point is that there was enough power to max out the engine in my top gear.
Oh btw the only mods to the engine are a fiero store header, 2.5 in custom exhaust, free flow cat, straight thru muffler, and a custom air intake with a K&N cone filter. The car is also lowered 3.5 inches.
[This message has been edited by lodown1 (edited 01-03-2006).]
As for all you doing calculators with gear ratios, please stop. It is rediculous. Theoretically my LT1 Camaro is capable of over 260mph. BIG DEAL. Doesn't mean it can even go 150. The gear ratio method means nothing unless you have the power to max out your top gear, and I guarantee a 4.9 can't do it (Stock of course), a 2.8 can't do it, a 2.5 can't do it, etc. It takes A LOT of horsepower to overcome 150mph worth of wind resistance.
As I said before, with no wind resistance and pulling to 6000 rpm my '86 SE would hit about 154 mph. I think it would stop pulling at around 5200 rpm so the top speed, without factoring wind resistance, is 134 mph. With wind resistance its probably a bit less than that, but I can't give a concrete answer.
Calculating with gear ratios is a good first step to determining top speed. Factoring in wind resistance and horsepower/weight can give better results but I don't have those formulas and I don't feel like calculating them.
Theoretically, my LS1 Camaro can go 215 mph. I know it won't get there, but I know it'll pull to at least 155 mph (speed limiter). It had PLENTY of rpms left at 140 mph and plenty of horsepower.
[This message has been edited by Tinton (edited 01-03-2006).]
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01:46 AM
Capt Fiero Member
Posts: 7657 From: British Columbia, Canada Registered: Feb 2000
I think 2.5 with the obvious execption of the 84 2.5 with the 4.10 diff in it, which will rev till it explodes the motor in 4th gear given a long enough stretch of road.
------------------ 85GT 5spd ,93 Eldorado 4.9 Dual O2 Custom Chip, Archie Clutch. Custom Exhaust. MSD Everything 245/50/16's Cant wait for Dyno Time and Track Results. Not Your Average 4.9 Capt Fiero Com --- My Over View Cadero Pics Delta Cam and Allante Intake Soon.
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01:58 AM
AaronZ34 Member
Posts: 2322 From: Colorado Springs, CO Registered: Oct 2004
this in reference to maxing out the engine in top gear.
I have had my 84 2.5 engine at about 5400 rpm in 4th gear so i would have to use gear ratio calculations to give me an approximate speed. which with my smaller 215/40/17 in tires would be about, 115 mph oh yeah "theoretically" The point is that there was enough power to max out the engine in my top gear.
Oh btw the only mods to the engine are a fiero store header, 2.5 in custom exhaust, free flow cat, straight thru muffler, and a custom air intake with a K&N cone filter. The car is also lowered 3.5 inches.
Did you choose to omit me saying STOCK OF COURSE? Of course a modded motor can do it, but I thought the people here would pretty much get that I meant stock or near stock for all the motors listed so I didn't have to type it after each one.
quote
Originally posted by Tinton: As I said before, with no wind resistance and pulling to 6000 rpm my '86 SE would hit about 154 mph. I think it would stop pulling at around 5200 rpm so the top speed, without factoring wind resistance, is 134 mph. With wind resistance its probably a bit less than that, but I can't give a concrete answer.
Calculating with gear ratios is a good first step to determining top speed. Factoring in wind resistance and horsepower/weight can give better results but I don't have those formulas and I don't feel like calculating them.
Theoretically, my LS1 Camaro can go 215 mph. I know it won't get there, but I know it'll pull to at least 155 mph (speed limiter). It had PLENTY of rpms left at 140 mph and plenty of horsepower.
How are you even talking about top speed without factoring wind resistance? It is basically the sole force that makes there be a top speed! Without wind resistance there would be no such thing as a top speed, to do better just change gears. The only limit is friction and gearing. Since gearing is infinite, and the friction between the tires and road surface isn't going to stop a car at WOT, there is no top speed. and without it my aforementioned Z28 would do 260+ mph. You cannot just disregard the most important factor in determining top speed.
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02:43 AM
Steven Snyder Member
Posts: 3326 From: Los Angeles, CA Registered: Mar 2004
Originally posted by lodown1: Oh btw the only mods to the engine are a fiero store header, 2.5 in custom exhaust, free flow cat, straight thru muffler, and a custom air intake with a K&N cone filter. The car is also lowered 3.5 inches.
Then how did you get to 5400 without hitting the 5000 rpm rev limiter?
My top speed with the 3.4 DOHC 5 speed is 110. I won't take it any faster because it just rained. Not to mention my tires arent rated for it :-)
[This message has been edited by Steven Snyder (edited 01-03-2006).]
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05:16 AM
Fastback 86 Member
Posts: 7849 From: Los Angeles, CA Registered: Sep 2003
As I said before, with no wind resistance and pulling to 6000 rpm my '86 SE would hit about 154 mph. I think it would stop pulling at around 5200 rpm so the top speed, without factoring wind resistance, is 134 mph. With wind resistance its probably a bit less than that, but I can't give a concrete answer.
Calculating with gear ratios is a good first step to determining top speed. Factoring in wind resistance and horsepower/weight can give better results but I don't have those formulas and I don't feel like calculating them.
Theoretically, my LS1 Camaro can go 215 mph. I know it won't get there, but I know it'll pull to at least 155 mph (speed limiter). It had PLENTY of rpms left at 140 mph and plenty of horsepower.
A brand new Fiero V6 was limited to 124mph, so your 20 year old V6 isn't going to do more than that. Additionally, it'll stop pulling at about 4200 with the stock intake, not 5200. Sure, it'll spin all the way up to red line in top gear, if you have a long enough straight road, but you're not going to get much more speed out of it. Believe me, I've tried. Took long enough just to peg the damn speedo with my 2.8.
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05:44 AM
Steven Snyder Member
Posts: 3326 From: Los Angeles, CA Registered: Mar 2004
Tinton:154 mph..... That's what I calculated with gear ratio formula. That would be in 4th gear in my 86 SE 2.8L V6 pegged at 6000 rpms with no wind resistance....
Those 154 mile per hour tailwinds are great for top speed runs, but when you have them as a headwind, it kills your gas mileage. I just hate that.
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08:10 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
between 120-130. my inaccuarte speedo runs out at 85.... but, based on gearing, 2000 rpm = 40+, 3000 rpm = 60+, 4000 rpm = 80+ I estimate at 6000 that'll be 120+ I havent actually seen how far past 6000 I can go in 4th, but I can go to 7000 in 1st 2nd & 3rd easy
------------------ 1985 Fiero SE - Plain Red V6 Coupe 3.1 Crane272 MSD 4.10-4spd DarthChip Borla D.A.M.M. - Drunks Against Mad Mothers
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08:51 AM
badger Member
Posts: 420 From: Leawood, KS, USA Registered: Feb 2004
Tip: Use a handheld GPS to get your true speed. I have verified that Fiero spedometers quickly lose accuracy above 70.
Disclaimer: My motor is stock. Well, technically it's a new 2.8 so it didn't come with the car, but it's an exact replacement. It's my transmission that is decidedly not stock. It's a 4T60.
The car's top speed? Since the tach shows 2,000 rpm at 70mph when the TCC's locked up, that makes redline a whopping
***** 210 mph! *****
In the real world (where pass-thru muffers and drilled and slotted rotors do NOTHING) the top end is about 135, where the wind starts to do really scary things. "There's a demon that lives out there just past mach .3" Maybe with some lead in the trunk and bonnett, and a Katrina tail-wind...
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10:37 AM
badger Member
Posts: 420 From: Leawood, KS, USA Registered: Feb 2004
Originally posted by Fastback 86: ... Sure, it'll spin all the way up to red line in top gear... but you're not going to get much more speed out of it.
No it won't. Unless your transmission is slipping you won't get any more increase in RPM without a corresponding increase in speed. Therefore if wind resistance is limiting your speed it will also limit your RPM.
Never got any Fiero over 100 MPH even though I had plenty of power left.
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11:43 AM
DOHC_SWAPPER Member
Posts: 365 From: Igloo, Toque, Canada Registered: Nov 2005
my best 1/4 mile is a 15.5 @ 87mph with a 2.1 60ft. my best topspeed is around 140mph in my practically stock 86gt 2.8L with 4spd. i got scared when it started plowing through a long swooping turn up I-5
------------------
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11:53 AM
FastIndyFiero Member
Posts: 2546 From: Wichita, KS Registered: Aug 2002
------------------ My Web page | The Turbo Super Duty Build. You know that little voice that says it can't be done? I duct-taped mine's mouth shut and pushed it down a flight of stairs.
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12:58 PM
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
Those 154 mile per hour tailwinds are great for top speed runs, but when you have them as a headwind, it kills your gas mileage. I just hate that.
If you saw, I was kidding around . I'm thinking that you are too though . Of course I know wind resistance does some mean things to keep me from attaining 154 mph in my stock 2.8, lol.
Fastback 86, it will pull to somewhere around 5000 rpms. 4200 rpms would only be about 100 mph or so in 4th gear. In 4th gear it would pull up to about 5000 rpms at 120-130 mph. If I was driving in a VACUUM (impossible to do, but anyways....) I would top out 4th gear at around 150.
Aaron, top speed is also limited by gearing. Unless you have a VERY tall final gear in a Fiero you'll be held back. Without wind resistance my '86 Fiero 4-speed would still be limited by gearing, it wouldn't be able to go beyond redline in 4th gear, which is at 154 mph. However, in my Camaro because of the last gear being so tall compared to the 4th gear in the Fiero, it'd stop at around 215. But, yes, you are somewhat correct because with no wind resistance you could put the tallest gearing you could to fit the engine and it'd hit 300+ mph. But what I'm saying is that on slower cars like the Fiero, calculating gear ratios can give a ballpark figure for top speed. 134 mph isn't that far off from 125 mph, which is what some people have hit. On faster cars like the Camaro, because of the increase of air resistance at higher speeds, it can't really be used because it gives a figure not even close to realistic top speed. In my 4-speed Camaro with no wind resistance my top speed (5400 rpms'ish) is around 190 mph. That's not even close to the real top speed of around 160-170 mph without the speed limiter. So, the only real way to get your top speed is to test it in the real world, and I know I don't want to lose my license for doing 155 mph (speed limiter) on the interstate.
.
. As I remember it was still pulling but not very much, I think it was right around 4600 rpms. Back when Sonic50 still had his '88 GT I raced him and at 100 mph I was at like 4500 rpm, my car doesn't seem to be performing as well?
. I'm thinking that you are too though 
