Well, I was really bored at work today and started thinking about cars. My random thought of today was on how HP/PS/KW/(Power in general) is the most common measurement of a car's performance, but yet how unsatisfactory such a measurement is for really comparing the performance of two cars. Everyone knows that Power to Weight is a more accurate measure by which to compare two cars' performance, yet this measure seems to be mostly sidelined in favour of raw HP/PS numbers.
So I then started thinking about how I could convert/represent weight savings (in terms of kg) into equivalent HP figures. That is, how much HP a carbon fibre bonnet could "gain" for your car.
Here's the algorithm I came up with, I am wondering as to its logical correctness:
1) First we need to start up with some base stats, from which to base our gains. Everything is relative after all. Your current car's weight and power would be good numbers to use here:
Benchmark Weight (kg): 1260kg
Benchmark Power (rwhp): 245ps
Benchmark P/W ratio: 0.1945 ps/kg
2) Now, let's get some exemplery weight savings. I got these from jekyl&hyde's website.
Forged Wheels: 36.36kg
CF Doors: 18.18kg
CF Bonnet: 18.18kg
3) Now the algorithm. First, let's assume we got a new set of forged Wheels which saves us 36.36kg.
New weight: 1260 - 36.36 = 1223.64 kg
New power: 245 (unchanged)
New P/W ratio: 245 / 1223.64 = 0.200222
Comparison of New P/W ratio with Benchmark P/W ratio:
New P/W - Benchmark P/W = Increase in P/W
0.200222 - 0.194444 = 0.00577929 ps/kg
4) Representation of this increase in P/W ratio as PS/HP:
Power / Weight = 0.00577929
Power = 0.00577929 * Weight
Assuming weight is the same (i.e. you did a power mod instead of a weight saving mod), the corresponding increase in power is 1260 * 0.00577929 = 7.28 ps
5) Conclusion:
Installing a set of forged wheels, saving you 36.36kg in weight, is equivalent to getting a 7.28 ps increase in power.
Put differently, one could state the following in an advertisement and not get sued: "Volks Forged Wheels for sale. These wheels are guaranteed to increase your cars performance by 7hp!!"
Is this a valid conclusion?
So I then started thinking about how I could convert/represent weight savings (in terms of kg) into equivalent HP figures. That is, how much HP a carbon fibre bonnet could "gain" for your car.
Here's the algorithm I came up with, I am wondering as to its logical correctness:
1) First we need to start up with some base stats, from which to base our gains. Everything is relative after all. Your current car's weight and power would be good numbers to use here:
Benchmark Weight (kg): 1260kg
Benchmark Power (rwhp): 245ps
Benchmark P/W ratio: 0.1945 ps/kg
2) Now, let's get some exemplery weight savings. I got these from jekyl&hyde's website.
Forged Wheels: 36.36kg
CF Doors: 18.18kg
CF Bonnet: 18.18kg
3) Now the algorithm. First, let's assume we got a new set of forged Wheels which saves us 36.36kg.
New weight: 1260 - 36.36 = 1223.64 kg
New power: 245 (unchanged)
New P/W ratio: 245 / 1223.64 = 0.200222
Comparison of New P/W ratio with Benchmark P/W ratio:
New P/W - Benchmark P/W = Increase in P/W
0.200222 - 0.194444 = 0.00577929 ps/kg
4) Representation of this increase in P/W ratio as PS/HP:
Power / Weight = 0.00577929
Power = 0.00577929 * Weight
Assuming weight is the same (i.e. you did a power mod instead of a weight saving mod), the corresponding increase in power is 1260 * 0.00577929 = 7.28 ps
5) Conclusion:
Installing a set of forged wheels, saving you 36.36kg in weight, is equivalent to getting a 7.28 ps increase in power.
Put differently, one could state the following in an advertisement and not get sued: "Volks Forged Wheels for sale. These wheels are guaranteed to increase your cars performance by 7hp!!"
Is this a valid conclusion?
