

04122005, 12:12 AM

#1

CF Newbie
Join Date: Mar 2005
Posts: 61

formula for how fast a car can go?
is there a certin formula to figure out how fast a car can go, like to compare two cars, where you could plug in specs of a car?



04122005, 12:46 AM

#2

Dodger65's weirdo
Join Date: Jan 2005
Location: Down Below
Posts: 2,081

Quote:
Originally Posted by c90acm
is there a certin formula to figure out how fast a car can go, like to compare two cars, where you could plug in specs of a car?

No, it depends on many variables, such as:
engine power / torque specs
gearbox and other transmission ratios
car mass
wheel diameter
tyres
aerodynamics
efficiency of transmission
etc etc etc ....



04122005, 12:50 AM

#3

CF's Anal Orifice
Join Date: Feb 2003
Location: Redneck Hell
Posts: 8,630

Quote:
Originally Posted by windsonian
No, it depends on many variables, such as:
engine power / torque specs
gearbox and other transmission ratios
car mass
wheel diameter
tyres
aerodynamics
efficiency of transmission
etc etc etc ....

You mean not all cars are the same? WTF was I thinking.
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04122005, 12:53 AM

#4

CF Freak
Join Date: Mar 2005
Location: new york
Posts: 582

to calculate horsepower
most of the people i hear from take the actual horsepower of their car (as listed on a manufacturers website) multiply it by 2, then add about 20 horse power for whatever mod they put on (whether it be an air cleaner, spoiler, or k and n oil filter).
so my ford escort would be (105 * 2 + nothing) = 210 horsepower.



04122005, 01:42 AM

#5

Dodger65's weirdo
Join Date: Jan 2005
Location: Down Below
Posts: 2,081

Quote:
Originally Posted by vwhobo
You mean not all cars are the same? WTF was I thinking.

Ssssh!!! Don't tell him that all cars are the same or the secret will be out



04122005, 04:55 AM

#6

BMW 3rd Year Apprentice
Join Date: Aug 2004
Location: Vancouver, BC
Posts: 2,053

Quote:
Originally Posted by carls47807
most of the people i hear from take the actual horsepower of their car (as listed on a manufacturers website) multiply it by 2, then add about 20 horse power for whatever mod they put on (whether it be an air cleaner, spoiler, or k and n oil filter).
so my ford escort would be (105 * 2 + nothing) = 210 horsepower.

Sweet, my mazda 323:
82 HP * 2 + tinted windows + skull shifter + cd player = 224 HP



04132005, 03:25 AM

#7

El del Supra
Join Date: May 2004
Location: Puerto Rico
Posts: 1,863

oh my god...... no wonder those Hondas down at the pizza parlor go so damn fast.
lets see.... the typer sticker.... nos sticker.... sir sticker..... typeABCDEFGHIJKLMNOPQRSTUVWXYZ sticker..... plus the 10 cans used to paint for the stocker rims......
holy krap, thats a lof extra horsepower!!!
so if i cut out a pepsi can and add it to my twin exhaust muffler..... i get 40hp?!?!?!!?
we could build our very own 1000hp civic in our backyards by just drinking pepsi cans and buying everything we see at pep boys!!!
PS: i had a bad day..... i just had to do it with the oneliners.....
__________________
Supra: To surpass or go beyond.



05012005, 03:41 PM

#8

Banned
Join Date: May 2005
Posts: 21

Converting torque to Hp
Have you ever looked at the specs of an engine in a magazine and seen something like "this engine makes 300 poundfeet of torque at 4,000 RPM," and wondered how much power that was? How much horsepower are we talking about here? You can calculate how many footpounds of horsepower this engine produces using a common equation:
(Torque x Engine speed) / 5,252 = Horsepower
The engine that makes 300 poundfeet of torque at 4,000 RPM produces [(300 x 4,000) / 5,252] 228 horsepower at 4,000 RPM. But where does the number 5,252 come from?
To get from poundfeet of torque to horsepower, you need to go through a few conversions. The number 5,252 is the result of lumping several different conversion factors together into one number.
First, 1 horsepower is defined as 550 footpounds per second. The units of torque are poundfeet. So to get from torque to horsepower, you need the "per second" term. You get that by multiplying the torque by the engine speed.
But engine speed is normally referred to in revolutions per minute (RPM). Since we want a "per second," we need to convert RPMs to "something per second." The seconds are easy  we just divide by 60 to get from minutes to seconds. Now what we need is a dimensionless unit for revolutions: a radian. A radian is actually a ratio of the length of an arc divided by the length of a radius, so the units of length cancel out and you're left with a dimensionless measure.
You can think of a revolution as a measurement of an angle. One revolution is 360 degrees of a circle. Since the circumference of a circle is (2 x pi x radius), there are 2pi radians in a revolution. To convert revolutions per minute to radians per second, you multiply RPM by (2pi/60), which equals 0.10472 radians per second. This gives us the "per second" we need to calculate horsepower.
Let's put this all together. We need to get to horsepower, which is 550 footpounds per second, using torque (poundfeet) and engine speed (RPM). If we divide the 550 footpounds by the 0.10472 radians per second (engine speed), we get 550/0.10472, which equals 5,252.
So if you multiply torque (in poundfeet) by engine speed (in RPM) and divide the product by 5,252, RPM is converted to "radians per second" and you can get from torque to horsepower  from "poundfeet" to "footpounds per second."
Hope this helps



05012005, 06:49 PM

#9

CF Enthusiast
Join Date: Jan 2005
Posts: 117

Quote:
Originally Posted by TheSpecialist
Have you ever looked at the specs of an engine in a magazine and seen something like "this engine makes 300 poundfeet of torque at 4,000 RPM," and wondered how much power that was? How much horsepower are we talking about here? You can calculate how many footpounds of horsepower this engine produces using a common equation:
(Torque x Engine speed) / 5,252 = Horsepower
The engine that makes 300 poundfeet of torque at 4,000 RPM produces [(300 x 4,000) / 5,252] 228 horsepower at 4,000 RPM. But where does the number 5,252 come from?
To get from poundfeet of torque to horsepower, you need to go through a few conversions. The number 5,252 is the result of lumping several different conversion factors together into one number.
First, 1 horsepower is defined as 550 footpounds per second. The units of torque are poundfeet. So to get from torque to horsepower, you need the "per second" term. You get that by multiplying the torque by the engine speed.
But engine speed is normally referred to in revolutions per minute (RPM). Since we want a "per second," we need to convert RPMs to "something per second." The seconds are easy  we just divide by 60 to get from minutes to seconds. Now what we need is a dimensionless unit for revolutions: a radian. A radian is actually a ratio of the length of an arc divided by the length of a radius, so the units of length cancel out and you're left with a dimensionless measure.
You can think of a revolution as a measurement of an angle. One revolution is 360 degrees of a circle. Since the circumference of a circle is (2 x pi x radius), there are 2pi radians in a revolution. To convert revolutions per minute to radians per second, you multiply RPM by (2pi/60), which equals 0.10472 radians per second. This gives us the "per second" we need to calculate horsepower.
Let's put this all together. We need to get to horsepower, which is 550 footpounds per second, using torque (poundfeet) and engine speed (RPM). If we divide the 550 footpounds by the 0.10472 radians per second (engine speed), we get 550/0.10472, which equals 5,252.
So if you multiply torque (in poundfeet) by engine speed (in RPM) and divide the product by 5,252, RPM is converted to "radians per second" and you can get from torque to horsepower  from "poundfeet" to "footpounds per second."
Hope this helps

i'm sure the original author of what you just typed would appreciate it if you put that into ""
__________________



05012005, 06:56 PM

#10

Banned
Join Date: May 2005
Posts: 21

I would think so.. ..
Quote:
Originally Posted by mirot
i'm sure the original author of what you just typed would appreciate it if you put that into ""

In essence you are right. The only problem is that I do not know which one of my instructors told me that. I have bunch of notes from my racing courses but I've never wrote down the name of the instructor.



05012005, 07:32 PM

#11

UnFedFat in Disguise
Join Date: Dec 2004
Posts: 1,697

Quote:
Originally Posted by TheSpecialist
In essence you are right. The only problem is that I do not know which one of my instructors told me that. I have bunch of notes from my racing courses but I've never wrote down the name of the instructor.

*cough* Bullshit *cough*
http://auto.howstuffworks.com/question622.htm
Come on, man, don't plagarize and lie about it.

I have an equation for theorectical top speed using the gear ratios, tire radius, and redline, but that doesn't involve the power aspect. I don't want to type it up if nobody is going to use it. if anybody wants to see it, just say so.
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I am everything you want to be



05012005, 08:17 PM

#12

CF Enthusiast
Join Date: Jan 2005
Posts: 117

Quote:
Originally Posted by TheSpecialist
In essence you are right. The only problem is that I do not know which one of my instructors told me that. I have bunch of notes from my racing courses but I've never wrote down the name of the instructor.

hahaha... wow... even after you're caught you still lie and act like a freaking idiot
__________________



05012005, 08:19 PM

#13

UnFedFat in Disguise
Join Date: Dec 2004
Posts: 1,697

Quote:
Originally Posted by mirot
hahaha... wow... even after you're caught you still lie and act like a freaking idiot

He's done it twice though. You should've posted the link to the original.
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I am everything you want to be



05022005, 06:08 PM

#14

Banned
Join Date: May 2005
Posts: 21

Stupid people trying to play smart.
Quote:
Originally Posted by Godlaus
*cough* Bullshit *cough*
http://auto.howstuffworks.com/question622.htm
Come on, man, don't plagarize and lie about it.

I have an equation for theorectical top speed using the gear ratios, tire radius, and redline, but that doesn't involve the power aspect. I don't want to type it up if nobody is going to use it. if anybody wants to see it, just say so.

And why exactly would I type information that is aleready there?
The participants to this forum are asking for information not for links you idiots!
The purpose of any forum is to put together information relevant to a certain subject and create a debate among the participants.
First of all you don't know how to spell plagiarize. Second you don't know what "Plagerize" means. You would call "Plagerize" if I woul have claimed it was written or conceived by me, which I never did.
How many times did you pass an information without citing the origin? How many times didn't you tell a joke without mentioning the source? Many times. Why? Because at the time, the information or joke itself was relevant, was more pertinent than the source.
If the question on the forum would be "does any one know any link to... .. ", then yes, you post the link... .. but if someone asks about a specific information in the forum, then you have to bring that info into the forum regardless where and when you got it.
Get it?
Bottom line, if you are such a smart ass, why didn't you post the whatever link or information relevant to the question befor I did?!?
Bottom line... ... quit being a punk, stop busting my balls and start learning how to drive!



05022005, 06:09 PM

#15

Banned
Join Date: May 2005
Posts: 21

Quote:
Originally Posted by mirot
hahaha... wow... even after you're caught you still lie and act like a freaking idiot

Read above! Same goes for you! ( I don't like to type twice)



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