Power to weight ratio calculations
#1
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Power to weight ratio calculations
Where am I going wrong fellas?
Take my car.
1260kg = 1.240 ton
Est. power 300 bhp
300 / 1.24 = 241 bhp per ton
However I pick up copy 011 of EVO (which got my started on this particular conundrum) and take these stats
STi 5
1310kg = 1.29 tonnes
Power 276 bhp
276 / 1.29 = 213 BHP per ton
But evo list it as 192 bhp per ton. What am I doing wrong?
J
Take my car.
1260kg = 1.240 ton
Est. power 300 bhp
300 / 1.24 = 241 bhp per ton
However I pick up copy 011 of EVO (which got my started on this particular conundrum) and take these stats
STi 5
1310kg = 1.29 tonnes
Power 276 bhp
276 / 1.29 = 213 BHP per ton
But evo list it as 192 bhp per ton. What am I doing wrong?
J
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Nothing much, it would appear that Evo have got it wrong..!
Check out hear for accurate conversions http://www.onlineconversion.com/
Check out hear for accurate conversions http://www.onlineconversion.com/
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i think you have the difference between a metric tonne and imperial ton
slighty differing.....but if you just do it all in metric it makes it easier
slighty differing.....but if you just do it all in metric it makes it easier
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1260kg = 1.26 metric ton
Est. power 300 bhp
300 / 1.26 = 238 bhp per ton
STi 5
1310kg = 1.31 metric ton
Power 276 bhp
276 / 1.29 = 210 per ton
But evo list it as 192 bhp per ton. What am I still doing wrong or are Evo's figures wrong?
Est. power 300 bhp
300 / 1.26 = 238 bhp per ton
STi 5
1310kg = 1.31 metric ton
Power 276 bhp
276 / 1.29 = 210 per ton
But evo list it as 192 bhp per ton. What am I still doing wrong or are Evo's figures wrong?
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Originally Posted by 911
Why are they everywhere?
Got a 430 ish bhp one in my class tomorrow....
Graham.
Got a 430 ish bhp one in my class tomorrow....
Graham.
Graham,
Were my revised calcualtion correct?
J
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Originally Posted by SCD Simon
Try THIS
So my calculations were right - I was about to take my old maths teacher to court!
Thanks a lot chaps
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Dont forget that the ptw doesnt mean that a car with slightly more ptw is faster, there are then the additions of gear ratio's, aerodynamics and drag to add to that.
Tony
Tony
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I'm never sure about the differences between manufacturers with "unladen" weight or "kerb" weight. A lot of German stuff includes 68kg driver, 7kg luggage, full fluids and 90% full fuel tank. Could easily be 125kg+ of difference. A/C or bigger wheels that are not original could have a huge effect as well?
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Originally Posted by john banks
I'm never sure about the differences between manufacturers with "unladen" weight or "kerb" weight. A lot of German stuff includes 68kg driver, 7kg luggage, full fluids and 90% full fuel tank. Could easily be 125kg+ of difference. A/C or bigger wheels that are not original could have a huge effect as well?
When calculating my PTW I also intend to include my considerable mass in the equation. This should encourage me to get fit and stop eating pies.
As an example, I'm a about thirteen stone or 82.5 kilograms (with clothes and shoes on).
So true weight is 1342kgs.
300bhp
1342kg
PTW - 227 bhp / ton
So if I lost a stone, weight would be reduced to 1336 giving PTW of 228 bhp/ton. Actually - it barely seems worth it (particularly the fleeting notion of driving naked)
J
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What is the spec/mods of your car for interest since it comes out at 1260kg with full weight without driver? A/C? Wheel upgrade? How much ICE weight? Exhaust/manifold? Intercooler? Presumably a classic saloon?
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Originally Posted by john banks
What is the spec/mods of your car for interest since it comes out at 1260kg with full weight without driver? A/C? Wheel upgrade? How much ICE weight? Exhaust/manifold? Intercooler? Presumably a classic saloon?
Here you go John. Started life as an RA ltd.
http://bbs.scoobynet.co.uk/showthrea...12#post4933512
You'll notice if you look at the rest of the thread I'm in the process building an exhaust system so the cat'll be out. I don't know the weights but will compare the decat with the cat (just out of interest) tomorrow.
I know the CUSCO coilovers are fairly light and will endeavour to find out what specifically their weight is.
J
Last edited by JTaylor; 04 September 2005 at 03:41 PM.
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Originally Posted by john banks
That engine is begging for a huge hit of midrange boost, 1.8 bar on a nice turbo I know I would with that spec
I'd be looking at a complete package. Turbo, injectors, fuel rail, actuator etc. I don't want silly / laggy power but would love 400bhp. Any reccomendations?
This would give me the on paper PTW of 300bhp/per ton - a figure I've dreamed about since I was 17!! I'd really like to acheive this whilst maintaining everday useability and driveability - and I thinks it's within reach.
To be honest mate it's becoming a bit of an obsession - I can't get enough of it
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