Cleggy the Spyder Man Posted January 2, 2009 Posted January 2, 2009 Ayup all ...just trying to work out my BHP per ton ... a little unsure of the weight of my vehicle, it's a 2000 sport - anyone know what it would weigh? It is standard as far as I know ! I believe you divide the bhp by the kg ... i.e. 205bhp divided by .600 kg = 341bhp per ton Should this weight include tank of fuel and one/two occupants or is it done without driver Quote
samcooke Posted January 2, 2009 Posted January 2, 2009 QUOTE Should this weight include tank of fuel and one/two occupants or is it done without driver Do it with an empty tank and washer bottle and without the driver - that way it sounds better. Seriously, though - there's no real standard way of doing it, the most meaningful way is how it's usually run - prolly one occupant and half a tank of petrol. 600kg without driver prolly isn't far off for yours, but they say that 200bhp is optimistic for the duratec. Quote
MVS Posted January 2, 2009 Posted January 2, 2009 QUOTE but they say that 200bhp is optimistic for the duratec. If it's a factory supplied one, it'll be about 180bhp, that's what mine did on a RR after about 2k miles of 'running in' sadly Quote
Cleggy the Spyder Man Posted January 2, 2009 Author Posted January 2, 2009 How come Westfield claim 205bhp? from memory their is a disclaimer in the literature Ok gotta get that spare wheel off plus lose a few stone plus get it rolling road tested and tuned Quote
perksy Posted January 2, 2009 Posted January 2, 2009 Your Local Council probably has a public weighbridge that you could use (They charge £6 in our area) 180 brake is probably not far away (Depends which Rollers you take it to ) PERFORMANCE CALCULATOR Not sure how accurate it is though Quote
Cleggy the Spyder Man Posted January 2, 2009 Author Posted January 2, 2009 Thanks all .. I had just stumbled across that performance calculator Quote
nikpro Posted January 2, 2009 Posted January 2, 2009 Why does it matter? Make the car lighter and it will be faster If the power is a guestimate and the weight is a guestimate then the figure you get is worthless anyway. If you know the exact weight and the exact power the figure is still useless! Quote
Cleggy the Spyder Man Posted January 2, 2009 Author Posted January 2, 2009 curiosity my man ... maybe something to do with that campervan R500 thingy Quote
pistonbroke Posted January 2, 2009 Posted January 2, 2009 power to weight is meaningless on its own , what matters is how and when it puts the power on the road , so you need to consider power and torque along with throttle responce , grip , handling and etc . a whole can of worms . A very peaky 205 bhp engine would be harder to drive around a twisty track compared to say 180 bhp with a nice wide power band and big flat torque curve . Quote
Norman Verona Posted January 2, 2009 Posted January 2, 2009 I weigh mine with all fluid and 1/2 tank fuel. I also take the bhp at the flywheel. However as the modern RR can be manipulated I agree with Nikpro, the figures are useless. Just remember that the stop watch doesn't lie Quote
nikpro Posted January 3, 2009 Posted January 3, 2009 curiosity my man ... maybe something to do with that campervan R500 thingy I guestimate you are around 240-270 bhp/tonne. Any good to you? Quote
lippydave Posted January 3, 2009 Posted January 3, 2009 Why does it matter?Make the car lighter and it will be faster If the power is a guestimate and the weight is a guestimate then the figure you get is worthless anyway. If you know the exact weight and the exact power the figure is still useless! Agreed ... The law of diminishing returns means however, that the lighter the car the bigger the effect (on power/weight figures) the driver will have .... ie Stick an 80kg driver in say a Nissan GTR and the figure is less affected than sticking the same driver in a 2000S/R500/any Seven/clone you care to mention.... Quote
juansolo Posted January 3, 2009 Posted January 3, 2009 Gives me another excuse to post a link to the Power to Weight table that I did eons ago. I haven't updated it in a long while but if anyone wants adding I just need the wet weight of your car and bhp. Preferably weighed and dyno'd rather than guestimates. Quote
fatbaldbloke Posted January 3, 2009 Posted January 3, 2009 Now, just looking at this a bit laterally. My car's about 175 bhp, probably around 610kg, but throw in my 90kg and you have 175/0.700, i.e. 250bhp/ton. Now, suppose I wanted to push that up by 10 to 260bhp/ton. I could increase the power to 182 bhp, but that's going to need cams and possibly headwork to retain some driveability, so there would be small change from £1500 by the time it's finished. I could lighten the car by 27kg, but that would mean extensive use of composites, even more expensive. Or I could remove a few unwanted bits and bobs, trim panels, heater, etc and sign into a health farm, be pampered and lose 10 or 15kg of blubber, cost about £1000. So there you have it, the most cost efficient way to increase your power to weight ratio is to go to Champneys and be pampered for a week or two..... Now, just off to convince Mrs FBB.... Quote
juansolo Posted January 3, 2009 Posted January 3, 2009 Absolutely. It always amuses me when people get carbon this and that and really could save the same weight by losing it themselves (they seem to forget that they need to be there to drive the things). I'm a prime example, I'm at least 4st overweight. Until I can be arsed to get rid of that, then sticking carbon stuff on my car would be complete nonsense. Then again, adding carbon means I could eat more pie to offset it... Maybe this is what they mean by carbon offsetting? There might be something in it after all! Quote
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