Fun with numbers ... P:W edition

TouringBubble

TouringBubble

601
ProjectTuning
I love data and numbers when it comes to cars. When I was building Dori, I had an idea of the power I could get from the engine and a target for the weight of the car with all said and done. But, this was my first experience with a truly light car ... I'm used to heavy cars with lots of power to make up for it, like my Evo.

P:W is a good measurement for determining the acceleration potential of a given car. As Dori is a rally car, acceleration is key. Of course, this basic math doesn't take in to consideration gearing, aero (frontal area, etc) or torque curves ... but it's still fun to compare.

When I did the math to estimate Dori's P:W numbers, I was extremely surprised. Based on WHP numbers and actual weights of several comparison cars, the car is extremely fast on paper, with a P:W value of .1125. Theoretically, this puts a '73 Beetle in the same range of potential acceleration as my 355 whp Evo.

So, I thought it might be fun to list some cars here, along with their P:W values to see a more balanced comparison of cars past peak HP numbers. We'll use BHP (engine) output rather than WHP (chassis) output, so we can work in some factory cars in to the comparison.

If you want to participate, Post this info:

Vehicle Model:
Engine:
BHP (US):
Curb Weight (US):
P:W value:

To calculate P:W, you can use this simple calculator - http://easycalculation.com/physics/fluid-mechanics/power-to-weight-ratio.php. We are using US values for a standard of comparison, as changing the units of measurement also changes the P:W, so you may need to convert units for non US spec cars.

I'll keep a list here so we can compare and discuss the findings. Feel free to post your own car's numbers, or just a car that you find interesting.

THE LIST
higher number = better theoretical acceleration performance
listed as bhp:lb ratio

Top Fuel Dragster - less than/equal to 500cui SC V8, ~10,000hp, 2,320lb - 4.3103
'13 Koenigsegg Agera R - 5.0L V8 - 1124hp - 3160lb - .3556
'12 Bugatti Veyron SS - 8.0l W16 Turbo - 1200 BHP - 4052 lb - .2962
’66 Ford Fairlane Thunderbolt - 427ci SOHC V8 - 656 BHP - 2,916 lb - .2249
'85 Lancia Delta S4 Group-B - 1.7l I4 Turbo - 480 BHP - 2139 lb - .2244
@Bopop4 '07 Kawasaki ZX6R - 599cc I4 - 120hp - 550lbs (with rider) - .2182
'13 Ford Fiesta ST GRC - 2.0l I4 Turbo - 560 BHP - 2600 lb - .2154
’65 Shelby Cobra 427 S/C - 7.0L 427ci V8 - 495 BHP - 2,335 lb - .2119
'86 Tiger 500 R3 - 482cc 2-Stroke - 48 bhp - 280 lb - .1714
C6 ('06-'13) Corvette Z06 - 7.0L V8, 505hp, 3,130lb - .1613
'15 Nissan GT-R Nismo - 3.8l V6 Turbo - 600 BHP - 3793 lb - .1582
’70 Ford Torino Drag Pack - 429ci SCJ V8 - 494 BHP - 3,141 lb - .1572
'14 Porsche GT3 - 3.8l H6 - 475 BHP - 3173 lb - .1507
@TouringBubble '06 Mitsubishi Evo MR - 2.0l Turbo, modified - 465 BHP - 3160 lb - .1472
'70 Chevrolet Camaro SS 454 - 7.4L V8 - 450 bhp - 3,278 lb - .1372
’69 Ford Mustang Mach 1 - 7.0L 428 SCJ V8 - 410 BHP - 3,000 lb - .1366
’85 Honda ATC250R - 246cc 2-Stroke - 38 BHP - 290 lb - .1310
@TouringBubble '73 VW Beetle Rally Car (Dori) - 2109cc H4, modified - 192.5 BHP - 1650 lb - .1167
'69 Dodge Charger - 7.0L V8 - 425 bhp - 3,646 lb - .1165
’72 Ford Ranchero - 460ci V8 - 375 BHP - 3,300 lb - .1136
'03 Ford Focus WRC - 2.0l I4 Turbo - 300 BHP - 2712 lb - .1106
@Hayden '92 Nissan Skyline R32 GTS4 - 2.5L I6 Turbo - 311HP - 2860 lb - .1090
'14 Lotus Elise S CR - 1.8l Supercharged - 217 BHP - 1995 lb - .1088
@Harry6784 ’98 Pontiac Trans-Am - 5.7l V8 - 377 BHP - 3487 lb - .1081
@RenoRanes007 ’05 Audi A8L - 6.0 W12, 450hp, 4398lbs - .1023
’64.5 Ford Mustang - 289ci V8 - 271 BHP - 2,700 - .1003
@Murcie_LP640 ’00 Subaru WRX - 2.0l H4 Turbo, modified - 276 BHP - 2844 lb - .0985
'98 Nissan 240 SX - 2.0l Turbo (SR20), modified - 275 BHP - 2800 lb - .0982
’70 Ford Country Squire Wagon - 460ci V8 - 375 BHP - 4,139 lb - .0906
'92 Acura NSX - 3.0l V6 - 270 BHP - 3010 lb - .0897
@savage388 ’94 Chevrolet Camaro Z28 - 5.7l V8, modified - 300 BHP - 3450 lb - .0870
@Clark BMW 130i - 3.0l I6 - 260bhp - 3,196 lbs - .0819
’00 Subaru WRX - 2.0l H4 Turbo - 224 BHP - 2800 lb - .0800
’93 Ford Mustang GT - 5.0L V8 - 225 BHP - 3,255 lb - .0783
@Badasp5.0 '95 Ford Mustang Cobra - 5.0L V8 - 240 bhp - 3,354 lb - .0720
@Hayden '13 Toyota 86GT - 2.0 H4 - 200HP - 2766 lb - .0720
@huskeR32 ’08 VW R32 - 3.2L VR6 - 250 BHP - 3,521 lbs - .0710
@Doog ’03 BMW 530i - 3.0l I6 - 228 BHP - 3549 lb - .0642
@Slashfan ’83 Honda ATC200X - 192cc SOHC 4-Stroke - 18 BHP - 282 lb - .0638
@Hayden '92 Nissan 300zx Convertible - 3.0L V6 - 222HP - 3500 lb - .0630
@Joey D ’95 Dodge Neon - 2.4l I4, transplant - 150 BHP - 2391 lb - .0627
'87 Pontiac Trans Am - 5.0L V8 - 210 bhp - 3,460 lb - .0606
@Spacegoat ’81 Holden VC Commodore - 5.0l V8 - 169 BHP - 2971 lb - .0569
’90 Pontiac Sunbird - 3.1L V6 - 140 BHP - 2,540 lb - .0551
'77 Chevrolet Monza Spyder - 5.0L V8 - 140 bhp - 2,580 lb - .0542
@Joey D ’12 Ford Focus - 2.0l I4 - 160 BHP - 3076 lb - .0520
@Bopop4 '07 Ford Focus ZX5 - 2.0L I4 - 136 bhp - 2672lb - .0509
’76 Ford Mustang II Cobra II - 5.0L 302ci V8 - 140 BHP - 2,754 lb - .0508
'81 Chevrolet Camaro Z28 LM 1 - 5.7L V8 - 175 bhp - 3,508 lb - .0498
@Slashfan ’85 Ford F-250 4x4 - ’75 351ci Windsor V8, modified - 310 BHP - 6,600 lb - .0469
@Slashfan ’99 Dodge Caravan SE - 3.3L V6 - 158 BHP - 3,500 lb - .0451
@Badasp5.0 '96 Subaru Legacy - 2.2L H4 - 135 bhp - 3,000 lb - .0450
'78 Dodge Little Red Express - 5.9L V8 - 225 bhp - 6,050 lb - .0371
@xXKingJoshXx '89 Lincoln Town Car - 4.9L 302 V8, 150hp, 4100lb - .0365
’77 Ford F-250 4x4 - 7.5L 460 V8 - 225 BHP - 6,512 lb - .0345
'74 VW Super Beetle - 1584cc H4, 60hp, 1900lb - .0315
@AudiMan2011 Vauxhall Corsa - 1.3 diesel - 1248cc I4 - 75hp - 2491lbs - .0301
'03 Ford Model A - 1668cc H2 - 8hp - 1240lb - .0064
'86 Benz Patent-Motorwagen, - 954cc 1 cyl - .75hp - 220lb - .0034
 
Last edited:
'89 Lincoln Town Car - 4.9L 302 V8, 150hp, 4100lb - .0365
'74 VW Super Beetle - 1584cc H4, 60hp, 1900lb - .0315
C6 ('06-'13) Corvette Z06 - 7.0L V8, 505hp, 3,130lb - .1613
Top Fuel Dragster - less than/equal to 500cui SC V8, ~10,000hp, 2,320lb - 4.3103


Edit: Hope the TFD is okay.

Edit2: I should add that the Town Car is mine in case you didn't know. Just realized you're tagging owned cars to their owners.
 
Last edited:
I've got a lot of cars I want to do for this, so sorry if this list gets a bit long. Feel free to exclude the vehicles that aren't strictly cars. I included them to see how they compare in theoretical acceleration to some of the cars on the list, as I thought some of them were neat.

The website settings are in horsepower and pounds. Make sure you check these when you enter them in so you don't have to redo them all like me :/




Vehicle Model: 1977 Ford F-250 4x4
Engine: 7.5L 460 V8
BHP (US): 225
Curb Weight (US): 6,512
P:W value: 0.0345

____________________

Vehicle Model: 1969/1970 Ford Mustang Mach 1
Engine: 7.0L 428 SCJ V8
BHP (US): 335 (Real Crank HP 410)
Curb Weight (US): 3,000
P:W value: 0.1366

____________________

Vehicle Model: 1976 Ford Mustang II Cobra II
Engine: 5.0L 302ci Windsor V8
BHP (US): 140
Curb Weight (US): 2,754
P:W value: 0.0508

__________________

Vehicle Model: 1965 Ford Shelby Cobra 427 S/C
Engine: 7.0L 427ci Side-Oiler V8
BHP (US): 495
Curb Weight (US): 2,335
P:W value: 0.2119

____________________

Vehicle: 1983-1985 Honda ATC200X
Engine: .19L 192cc SOHC Single Cylinder 4-Stroke
BHP (US): 18
Curb Weight: 282
P:W Value: 0.0638

__________________

Vehicle: 1985-1986 Honda ATC250R
Engine: .25L 246cc Single Cylinder 2-Stroke
BHP (US): 38
Curb Weight: 290
P:W Value: 0.1310

__________________

Vehicle: 2013 Ski-Doo MXZ800
Engine: .8L 800cc Rotax V-Twin 2-Stroke
BHP (US): 169
Curb Weight: 500
P:W Value: 0.3380

__________________

Vehicle: 1970 Ford LTD Country Squire Wagon
Engine: 7.5L 460ci V8
BHP (US): 375
Curb Weight: 4,139
P:W Value: 0.0906

____________________

Vehicle: 1964 1/2-1966 Ford Mustang
Engine: 4.7L 289ci K-Code V8
BHP (US): 271
Curb Weight: 2,700
P:W Value: 0.1003

____________________

Vehicle: 1966 Ford Fairlane Thunderbolt
Engine: 7.0L 427ci SOHC "Cammer" V8
BHP (US): 656
Curb Weight: 2,916
P:W Value: 0.2249

__________________

Vehicle: 1970 Ford Torino Drag Pack
Engine: 7.0L 429ci SCJ V8
BHP (US): Rated 375, Produced 494
Curb Weight: 3,141
P:W Value: 0.1572

__________________

Vehicle: 1972 Ford Ranchero
Engine: 7.5L 460ci V8
BHP (US): 375
Curb Weight: 3,300
P:W Value: 0.1136

__________________

Vehicle: 1985 Ford F-250 4x4 (Personal Vehicle)
Engine: 1975 5.8L 351ci Windsor V8 (Modified)
BHP (US): 310 approximately
Curb Weight: 6,600
P:W Value: 0.0469

__________________

Vehicle: 1999 Dodge Caravan SE (Personal Vehicle)
Engine: 3.3L 201ci V6
BHP (US): 158
Curb Weight: 3,500
P:W Value: 0.0451

__________________

Vehicle: 1993 Ford Mustang GT 5.0
Engine: 5.0L 302ci Windsor V8
BHP (US): 225
Curb Weight: 3,255
P:W Value: 0.0783

_________________

Vehicle: 1988.5-1994 Pontiac Sunbird
Engine: 3.1L 189ci LHO V6
BHP (US): 140
Curb Weight: 2,540
P:W Value: 0.0551
 
Last edited:
2012 Ford Focus
160hp 2.0L I4
3076lbs.

0.05202

=====

And for kicks I thought I'd try my racecar.

1995 Dodge Neon
150hp 2.4L I4 from a Dodge Stratus
2,391lbs.

0.06274
 
Just a heads up, these numbers are all going to be off if you don't factor in driver/rider weight.

5% of a car is still 5%, and when you get down to something that only weighs 300lbs, the rider totally changes the p/w value.
 
Bopop4
Just a heads up, these numbers are all going to be off if you don't factor in driver/rider weight.

5% of a car is still 5%, and when you get down to something that only weighs 300lbs, the rider totally changes the p/w value.
Click to expand...

You are correct, but I did state curb weight, which is what most manufacturers use, and does not include the driver. We can't assume driver weight for an objective comparison.

But yes, a lighter car's P:W will shift more with drive weight considered.
 
MY00 Subaru Impreza WRX
EJ205 turbocharged-and-intercooled flat-4
224hp
2800lb
P:W of 0.08.

My car stock, though now it produces something along the lines of a Version VI STi's power (276hp) and weighs a tad more due to stereo equipment (about 1290kg or 2844lb). Estimation of P:W is about 0.0985.
 
11469261143_a48074aa74_h.jpg


2003 BMW 530i.
228 horsepower 3.0 liter I6.
3549 lbs.
0.0642434489.
 
TouringBubble
I did a ton of CTRL+C, CTRL+V ... it slipped through. =)

Just added some Rally cars from Group B, WRC and GRC for comparison ... it's interesting.
Click to expand...

Ill have some more for you when I get home later. This is pretty cool.
 
I'll bite.

It's hard to get numbers though, since I don't know what the bike weighs right now.
Also, I don't know how much power it makes, I would think it to be at about 110whp, but it's not that fast against some other bikes supposedly at that power level.

The bike is getting dyno'd in a little while so I'll get an accurate number then.

(Dyno numbers are so inconsistent that I'm seeing 113whp for an almost stock bike online, even though I know mine would make more power.)

2007 Kawasaki ZX6R
599cc I4, 120hp.
Straight through cat, slip on muffler.
PCIII fuel mapping software with ignition module.
U4.4 Oxygenated race gas.

Race bodywork, probably sitting around 40lbs lighter than stock, so about 370lbs.
I'm going to calculate this with a rider, because otherwise the numbers are way off.
175lbs full gear.
545lbs, let's say 550 with gas.

0.2182


2007 Ford Focus ZX5 SES
2.0L I4 136hp
2672lbs
0.0509
 
'86 Benz Patent-Motorwagen, 954cc 1 cyl, .75hp, 220lb, .0034
'03 Ford Model A, 1668cc H2, 8hp, 1240lb, 0.0064
'13 Koenigsegg Agera R, 5.0L V8, 1124hp, 3160lb, .3556
 
You acknowledge that these numbers are inaccurate so why keep track of them when we have much more accurate data in the form of drag times, 0-60 times, and comparison races?
 
Zenith
You acknowledge that these numbers are inaccurate so why keep track of them when we have much more accurate data in the form of drag times, 0-60 times, and comparison races?
Click to expand...

I didn't say they are inaccurate ... and they aren't. They are quite accurate representations of power:weight. Power:weight simply isn't the end-all-be-all of comparisons ... just like 0-60 or drag times also are not. Also, manufacturers all list power and weight for a car ... not always 0-60 or other acceleration times.

I feel that P:W is a great "general" comparison of the performance of a car, and can easily span across decades where 8-speed automatic transmissions, advanced traction control and others can skew acceleration comparisons.
 
1992 Nissan Skyline R32 GTS4 (personal car)
Engine: RB25DET Neo (2.5L Inline Turbo 6)
Power: 311HP (using 10% conversion )
Weight: 2860IB
P-W Ratio: 0.109

1992 Nissan 300zx Convertible (personal car)
Engine: VG30DE (3L V6)
Power: 222HP
Weight: 3500 (Approx)
P-W Ratio: 0.063

2013 Toyota 86GT (personal car)
Engine: 2.0 Boxer
Power: 200HP
Weight: 2766 IB
P-W Ratio: 0.072

Interesting to see how everything stacks up. Cheers!
 
Vehicle Model: 1987 Pontiac Trans Am
Engine: 5.L RPO L98 350ci V8
BHP (US): 210
Curb Weight (US): 3,460
P:W value: 0.0606

____________________________________

Vehicle Model: 1969 Dodge Charger
Engine: 7.0L 426ci HEMI V8
BHP (US): 425
Curb Weight (US): 3,646
P:W value: 0.1165

____________________________________

Vehicle Model: 1978 Dodge Little Red Express
Engine: 5.9L 360ci V8
BHP (US): 225
Curb Weight (US): 6,050
P:W value: 0.0371
 
Hayden
1992 Nissan Skyline R32 GTS4 (personal car)
Engine: RB25DET Neo (2.5L Inline Turbo 6)
Power: 311HP (using 10% conversion )
Weight: 2860IB
P-W Ratio: 0.109
Click to expand...

Just curious ... did you swap in a R33 engine? I thought the R32 had the RB20DET in the GTS. Also, not familiar with the GTS4 designation ... what's the story on the "4?"
 
That's what I thought, but I've never seen a "4" designation on a Skyline. Might be Aus. specific or something. If it's AWD I'd want to adjust the BHP as AWD has more drivetrain loss than 2WD. I would use a 15% correction.

A lot of people claim 15% on FWD and 25% on AWD, but I think that's just trying to inflate numbers. My Evo was rated at 287 BHP and dyno'd at 255 WHP completely stock. That's only a 13% shift. I think 15% is fair to account for dyno variances and different drivetrain configurations.
 

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