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

 

Nothing much, it would appear that Evo have got it wrong..!

Check out hear for accurate conversions http://www.onlineconversion.com/

 

Erm - isn't 1310KG 1.31 tonnes?, and likewise 1260KG = 1.26 tonnes?

 

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

 

Tony is correct.
You must keep the same system!
Graham (ex weighbridge designer!)

 

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?

 

Evo's..!

 

Why are they everywhere?
Got a 430 ish bhp one in my class tomorrow....

Graham.

 

The bloomin' magazine not the souless "white good" (unless you were being amusing - which you weren't)

Graham,

Were my revised calcualtion correct?

J

 

EVO often get the P/W/R figures wrong.

 

Try THIS

 

Thats a fantastic little calculator and has been bookmarked. Thank you very much.

So my calculations were right - I was about to take my old maths teacher to court!

Thanks a lot chaps

 

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

 

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?

 

I agree. I had my car weighed the other day fully laden. All the mats, ICE, full tank of petrol etc (the only exception being the lack of spare wheel which has been replaced with tyre weld).

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

 

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.

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

 

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

 

Got to get the basics right first John. It'll be at about 340 /320 middle of next week - the rest of the season will be a shakedown getting evrything spot and then early next year I'll be looking to upgrade the VF29.

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