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#1
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0 - 60 MPH Calculator
It actually works! Well for about 80% of the cars that I tested.
here is the formula: 0-60 time = (weight of car in kilogrammes)/(maximum bhp of car * 0.9) reference: http://www.cars-cars-cars.org/0-60-Times-Calculator.htm That is just what i found recently surfing the internet. I put some numbers for the SVX, and it turned out to be very close to actual times. That makes me wonder, does having AT tranny really matters? 3580 Lb = 1623.86 kg / (230 bhp * 0.9) = 7.84 s that is only 7% error. from real time of 7.3 s. Ok, this formula looks kind of rigged, so I opened the Car And Driver, and started calculating theoretical 0-60s and practical. It turned out the out of about 10 cars - 8 of them were very close to the specs. The only car that was way out of specs is Forester XT. With calculated 0 - 60 at 7.2 and actual 5.4. So.... my conclusion is... SVX is way too heavy.
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Nikita Petrov (Nik) Red 94 LSi 2013 Honda PCX 150 2011 Subaru Impreza 2009 Subaru Outback Alternative Ways of getting around 2011 Felt Edict 9 SE 2009 Felt FX 35 2006 Cannondale CAAD9 |
#2
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Re: 0 - 60 MPH Calculator
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Way too heavy for what? Remember what the car was designed for.
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. Earl .... ... .... ><SVX(*> Subaru Ambassador [COLOR=”silver”]1992 Tri Color L[/COLOR] ~45K (06/91) #2430 1992 Dark Teal LS-L ~184K (05/91) #0739 1992 Claret LS-L ~196K (05/91) #0831 1992 Pearl LS-L ~103K (06/91) #1680 1992 Pearl LS-L ~151K (06/91) #2229 1992 Dark Teal LS ~150K (07/91) #3098 (parts car) 1992 White LS-L ~139K (08/92) #6913 1993 25th AE ~98K (02/93) #164 1993 25th AE ~58K (02/93) #176 1993 25th AE ~107K (02/93) #215 1993 25th AE ~162K (02/93) #223 1994 Laguna Blue Pearl LSi ~124K (1/94) #2408 1994 Laguna Blue Pearl LSi ~144K (10/93) #1484 1994 Laguna Blue Pearl LSi ~68K (10/93) #1525 1994 Barcelona Red LSi ~46K (02/94) #2624 1994 Pearl LSi ~41K (12/93) #1961 1995 Bordeaux Pearl LSi ~70K (02/95) #855 1996 Polo Green LSi ~95K (03/96) #872 1997 Bordeaux Pearl LSi ~55K (08/96) #097 2003 Brilliant Red LS1 Convertible ~29K (04/03) #8951 1999 Magnetic Red LS1 Coupe ~33K (04/99) #6420 My Email | Old Locker | New Locker | Picture of 15 of the 19 |
#3
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Quote:
Plus, a sports car have to be a sports car. Even if it is a luxury car. I say put another 100 hp. to SVX to 330. Or make it just a bit lighter, but still luxury. Hey, it would be more then perfect. I am not saying it is not perfect now. I actually like it the way it is, but as a teenager.... well grown up one already, I want more..... as always. "No matter how fast you are, there always will be someone who is faster then you." (Me.)
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Nikita Petrov (Nik) Red 94 LSi 2013 Honda PCX 150 2011 Subaru Impreza 2009 Subaru Outback Alternative Ways of getting around 2011 Felt Edict 9 SE 2009 Felt FX 35 2006 Cannondale CAAD9 |
#4
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Anybody study Physics or Applied Maths at School?
This is Newtons Second Law: Acceleration is proportional to Force. More commonly written as Force = Mass x Acceleration.
This can be rewritten as a=F/m. acceleration is change in velocity over time (v-u)/t (v-u)/t = F/m t=m(v-u)/F v-u is constant because we are talking 0-60 time. Then you have to play with some constants to convert from SI units to the everyday american ones and you end up with. time = mass / force * some constant. Which is exactly the formula you gave. Phil. |
#5
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I would adjust that 0.9 factor depending on wich type of tranny and engine I have.
Suppose you have a ECVT tranny, then the acceleration is fairly constant over the whole run, but if you have "gears", the acceleration "changes" depending on what rpm you are. The same goes with an AT, i.e longer "shifttimes" (less acceleration) and so on. The power curve of the engine is also a factor, a NA engine increases it's HP when the rpm increases, but a turbo engine gives "full" power earlier and less depending on the rpm, so a turbo engine should have a diffrent factor than a NA engine. If we try to find a suitable factor for MT versus AT and Turbo versus NA, this "tool" can be useful. /Sonny
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Internal name: "SuperSonic" -92 ebony black with 170k KM *** -Stress is when you wake up screaming & you realize you haven't fallen asleep yet. *** |
#6
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elninoalex took 1 second off his 0-60 times when he installed a 5MT. Probably a combination of less drivetrain loss (no TC) and the 4.11 gearing that his car has.
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Mychailo :: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ :: 1995 Laguna Blue SVX L AWD 5MT (sold) Visit my locker SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads. |
#7
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Re: Anybody study Physics or Applied Maths at School?
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Thanks Phil. You must be an engineer. Larry III (Mech. Eng'r.) |
#8
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Quote:
phil
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~Phil Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog. |
#9
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Quote:
From your formula t = mass / Force * constant. However you never specified what force is applied to the car? I am assuming it is Mass * Gravity? Plus, the (v - u) should not be constant, because it is change in velocity according to your derivation. Thus, it is delta V. Then the formula follows ==» Time = (mass * V)/(mass * acceleration), or if we are taking units as follows: Time = seconds = s Mass = kilograms = kg Distance = meters = m Then s = (kg * m/s) / (kg * m/s^2) = seconds. That is what suppose to happen I believe. However, when you substitute everything, as in mass of the car, gravitational acceleration, and change in velocity, which in this case, 0-60mph or (0-26.6 m/s)/2, then the answer that we get is totally unrelated to anything, because then it won¡¦t depend on the mass of the car at all. So here is my solution to this rather complicated problem: Ok, taking the original formula: time = mass / bhp * constant. Now, using units: s = kg / (((kg * m)/s^2) * m/s) * C, where bhp or hp = (((kg * m)/s^2) * m/s) = N *m/s = J/s = Watt Therefore when simplified: s = s^3/(m^2 * C), which is apparently the formula that has to work, however for it to work, constant C has to have units of (s^2/m^2). And again, if you look at it, mass of the car is being canceled out, which is not suppose to happen. So my guess is, that the constant C has also be some sort of Force of gravity or frictional force for this formula to work properly, because otherwise it just does not make any sense. How else would you divide kilograms/ horsepower * constant to get a time in seconds?
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Nikita Petrov (Nik) Red 94 LSi 2013 Honda PCX 150 2011 Subaru Impreza 2009 Subaru Outback Alternative Ways of getting around 2011 Felt Edict 9 SE 2009 Felt FX 35 2006 Cannondale CAAD9 |
#10
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Zamorush,
I am convinced this is Newton's Second Law. I'm afraid I don't really understand your working. The Force I am referring to is the force produced by the engine to accelerate the car. It's 230bhp multiplied by a constant which determines how much of that bhp actually gets transmitted to the road multiplied by some constant to convert that to Newtons. Gravity neither helps nor hinders the acceleration on a flat road (and in any case is constant). v-u is constant. Acceleration is final speed (v) - initial speed (u) over time (t). Since we are talking 0-60 time, (v-u) is (60 - 0) * a constant to convert that to m/s. If you think about it, it can only be N2L. We are calculating the acceleration of a mass, the only tricky bit is finding the right constant (fudge factor) to convert the bhp produced by the engine to the resultant force in newtons that is actually being applied to accelerate the mass. This constant would have many components, including the frictional forces you mention. But it would be too complex to calculate it. I'll bet they came up with the 0.9 by feeding in the figures from hundreds of different cars and taking an average. Have I convinced you? Phil. |
#11
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dont forget to add the weight of the driver. that puts a stock svx above 8 seconds, and has me at 7.6
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"That which can be asserted without evidence can be dismissed without evidence." '92 Dark Teal SVX LS-L, >146,000m 3 pedals, 5 speeds., restoration underway. 2012 Honda Insight, slow but cute. Last edited by NikFu S.; 02-14-2004 at 01:49 AM. |
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