what rpm equals what speed.
10-31-2006, 01:48 PM
#21
5th Gear Member
Join Date: Jul 2006
Location: Alton, New Hampshire
Posts: 2,518
RE: what rpm equals what speed.
ORIGINAL: goathead75
If you're doing 60 in 5th gear what's the rpm say? Maybe get a baseline first. 4000rpm in 5th with stock gears, I'm thinking the tach would have to be way off. Is your clutch slipping at all?
If you're doing 60 in 5th gear what's the rpm say? Maybe get a baseline first. 4000rpm in 5th with stock gears, I'm thinking the tach would have to be way off. Is your clutch slipping at all?
10-31-2006, 01:54 PM
#22
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Join Date: Jun 2005
Location: Michigan
Posts: 3,986
RE: what rpm equals what speed.
86GT isnt wrong, that calculator is THEORETICAL SPEED. You forgot one thing though 86GT it also doesnt take rolling resistance (drag) into the equation. When I punch my stuff in it says something different everytime, anyway the range has always been from 186.xx to 204.xx.
Adder, the '85's and 86's are actually MORE aerodynamic than the 87-93's, you have to look at them from the profile, the 85/86 has a pointed nose where the 87+ is almost literally flat. So which is more aerodynamic? Also, you needed nitrous to get to 150????ARE YOU FUKIN KIDDIN ME! Dude my 94 probe GT with 207K on it will do every bit of 140/145, I test drove a new Saturn Ion redline got it goin 150 NO PROBLEM. And those cars only have 200hp, hell the probe probably only has 190. So if your cobra needs nitrous to get to 150 you got some serious problems.
Also, keep in mind that elevation plays a big role, Im @ roughly 300 ft, and we get lots of cool air from the great lakes, makes muscle cars happy.
-P.
Adder, the '85's and 86's are actually MORE aerodynamic than the 87-93's, you have to look at them from the profile, the 85/86 has a pointed nose where the 87+ is almost literally flat. So which is more aerodynamic? Also, you needed nitrous to get to 150????ARE YOU FUKIN KIDDIN ME! Dude my 94 probe GT with 207K on it will do every bit of 140/145, I test drove a new Saturn Ion redline got it goin 150 NO PROBLEM. And those cars only have 200hp, hell the probe probably only has 190. So if your cobra needs nitrous to get to 150 you got some serious problems.
Also, keep in mind that elevation plays a big role, Im @ roughly 300 ft, and we get lots of cool air from the great lakes, makes muscle cars happy.
-P.
10-31-2006, 01:55 PM
#23
3rd Gear Member
Join Date: Sep 2006
Location: CT
Posts: 621
RE: what rpm equals what speed.
130mph would probably be about right for a top speed, it's just the 4000rpm that's odd. I definitely don't doubt what you're saying, but the numbers just don't add up. Is it the stock tranny in the car too? Has it been rebuilt?
10-31-2006, 02:00 PM
#25
3rd Gear Member
Join Date: Sep 2006
Location: CT
Posts: 621
RE: what rpm equals what speed.
ORIGINAL: P Zero
86GT isnt wrong, that calculator is THEORETICAL SPEED. You forgot one thing though 86GT it also doesnt take rolling resistance (drag) into the equation. When I punch my stuff in it says something different everytime, anyway the range has always been from 186.xx to 204.xx.
Adder, the '85's and 86's are actually MORE aerodynamic than the 87-93's, you have to look at them from the profile, the 85/86 has a pointed nose where the 87+ is almost literally flat. So which is more aerodynamic? Also, you needed nitrous to get to 150????ARE YOU FUKIN KIDDIN ME! Dude my 94 probe GT with 207K on it will do every bit of 140/145, I test drove a new Saturn Ion redline got it goin 150 NO PROBLEM. And those cars only have 200hp, hell the probe probably only has 190. So if your cobra needs nitrous to get to 150 you got some serious problems.
Also, keep in mind that elevation plays a big role, Im @ roughly 300 ft, and we get lots of cool air from the great lakes, makes muscle cars happy.
-P.
86GT isnt wrong, that calculator is THEORETICAL SPEED. You forgot one thing though 86GT it also doesnt take rolling resistance (drag) into the equation. When I punch my stuff in it says something different everytime, anyway the range has always been from 186.xx to 204.xx.
Adder, the '85's and 86's are actually MORE aerodynamic than the 87-93's, you have to look at them from the profile, the 85/86 has a pointed nose where the 87+ is almost literally flat. So which is more aerodynamic? Also, you needed nitrous to get to 150????ARE YOU FUKIN KIDDIN ME! Dude my 94 probe GT with 207K on it will do every bit of 140/145, I test drove a new Saturn Ion redline got it goin 150 NO PROBLEM. And those cars only have 200hp, hell the probe probably only has 190. So if your cobra needs nitrous to get to 150 you got some serious problems.
Also, keep in mind that elevation plays a big role, Im @ roughly 300 ft, and we get lots of cool air from the great lakes, makes muscle cars happy.
-P.
10-31-2006, 02:01 PM
#26
2nd Gear Member
Join Date: Oct 2006
Location:
Posts: 267
RE: what rpm equals what speed.
[quote]
ORIGINAL: frdmstng1986GT
i dont trust those speed calculators. i had my car up to 4000rpm orso in 5th and with 2.73's it said i was doing like 175mph or so in my basicly stock 86 gt.lol.. i dont think so. it doesnt calculate in for wind resistence.. or tire resistence
i dont trust those speed calculators. i had my car up to 4000rpm orso in 5th and with 2.73's it said i was doing like 175mph or so in my basicly stock 86 gt.lol.. i dont think so. it doesnt calculate in for wind resistence.. or tire resistence
the calculator is pretty close
10-31-2006, 02:17 PM
#27
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Thread Starter
Join Date: Jul 2006
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Posts: 77
RE: what rpm equals what speed.
well technically air resistance and tire resistance is irrelevant because the computer uses how many times the tire makes a rotation to determine speed of the vehicle, say your tach is accurate and its reading 4000 rpm in 5th gear, and you know you rear end gears and transmission 5th gear, and your clutch isnt slipping, i know mines not spec stage 2 1 month old, than the engine has a mechanical connection to the ground and the tires are spinning at a constant ratio to the engine than the calc would be correct, unless your spinning tires at 130mph+ than it should be correct.
10-31-2006, 02:20 PM
#28
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Join Date: Jun 2005
Location: Michigan
Posts: 3,986
RE: what rpm equals what speed.
OK, if yall wanna get technical here goes, in 1986 the 5spd gt's came with a 2.73 rear end, automatics came with 3.08's. Power output was rated at 205 hp. The 85/86's were also lighter than the 87+ cars, not to mention more aerodynamic. Also, if he lowered the car at all that helps aerodynamics as well (wind under car = bad). And like I said before what elevation hes at also plays a key role in this. Not to mention, you have no idea how long he was @ WOT to achieve that speed, 1 mile, 2, 5? Like I said before if I can get a 2.5L or a S/C 2.0 to go 150 im sure a 5.0 should easily be able to hit 160. Especially since you can wind out 4th to 150 with a 2.73 rear gear. And a stock stang can wind out 4th gear no prob. And another thing with his cold air intake the faster he goes the cooler the air gets making his intake charge more dense the faster he goes.
-P.
-P.
10-31-2006, 02:22 PM
#29
6th Gear Member
Join Date: Jun 2006
Location: Maine
Posts: 5,693
RE: what rpm equals what speed.
ORIGINAL: P Zero
When I punch my stuff in it says something different everytime...
When I punch my stuff in it says something different everytime...
10-31-2006, 02:26 PM
#30
3rd Gear Member
Join Date: Feb 2006
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Posts: 664
RE: what rpm equals what speed.
the way i see it, wind resustance plays no factor in this. Wind would only slow you down by not alowing your engine to turn more rpms(because of load) If its windy, your not spinning your tires at 90mph. rpms are rpms nom matter what the circumstances are