Bhp Figures Etc.

[dave1]

Whilst I appreciate that a cars BHP has a bearing on its power, I would have thought that more significant was the power/weight ratio. Also where the power actually is within the range. For a road car the 0-62 time is surely of far less consequence than say the 40-60 or 50-70 figures as these are what affect you more in daily useage for safer overtaking etc.

I think that these figures should be shown by manufacturers in the same way as 0-62 figures. Also if they give figures for the 0-62/0-100 mph they should also give the relative stopping distances.

[TonyGoose]

Quote BHP but drive Torque ...

TG

[sparkystav]

Most companies do now show 40-60 and so on times these days.

But i admit as much as i like to know my BHP power to weight is a better figure.

[84Stoney]

Quote BHP but drive Torque ...

"BHP sellls car, Torque wins races."

Carroll Shelby, (many decades ago)

I think bhp and 0-60s are quoted because they have become universal and everyone can relate to them. If I you told me your car did 40-70mph in 3.8 seconds, I wouldn't know whether I should be impressed or not!

[dave1]

Quote BHP but drive Torque ...

"BHP sellls car, Torque wins races."

Carroll Shelby, (many decades ago)

I think bhp and 0-60s are quoted because they have become universal and everyone can relate to them. If I you told me your car did 40-70mph in 3.8 seconds, I wouldn't know whether I should be impressed or not!

I agree, but I think the majority of people would assume that a fast 0-60 time would also equate to fast mid range accelaration which is not neccessarily correct. We are constantly fed info which is probably not the best info that we could be given.

We can equate to 0-60 figures because the manufacturers etc. have implanted these things into our comprehension. Over time I am sure the same could be done with midrange too.

[84Stoney]

Yes, I see your point.

Also, this is an industry wide standard for all cars. You may find performance important in a car, as do I. But many will give more consideration to comfort, fuel econemy, tax/insurance costs and any number of things, even colour (women buy cars too these days) than they do to staright line speed. The fact that you sum up the whole performance aspect in one (0-60) or two (0-60 and bhp) stats, is simpler than listing many statistics. To those not performace orientated (or many not even that good with numbers!) this would be confusing and difficult to draw any real comparison from. They do this to cater to the industry as a whole. To be honest, as an idicator, the car with the faster 0-60 time will, more often than not, have better mid range acceleration!

When you are talkng mid-range acceleration times, you have to take into account gearing. Different cars are geared differently, and also have to shift at different times.This can skew the times unfavourably in some cases.

Also, if a car can do, 40-60 in XX seconds in 2nd gear. When you were driving in the real world, you would probably be in 3rd gear, and have a much slower time, for example.

These are just my thouhgts. Interesting discussion though!

[Mark W]

The figures the manufacturers quote are surely ultimately only an indication anyway for the typical joe bloggs on the street. I dont think there are many people out there stupid enough enough to think just because it has more bhp it must be faster - and usually the specs include the weight so its a simple calculation.

Theres also the fact that the bhp quoted is likely to be that produced by the engine - not that available at the wheels - depending on the efficiency of the parts between the two. So again should only be an indication - so power to weight doesnt work there either.

The 0-60 times quoted (or 0-100 km/h / 62 mph) figures quoted are also "calculated" by the manufacturer anyway - in reality - no-one is ever going to hit them...so again - its an indication

As for ranges of acceleration times - that opens a minefield as to which figure is more important- 20-50, 30-60, 30-70, 40-70 - Unless I'm on a racetrack or playing top trumps (remember that game?) with my mates on whose car is the best - I dont care......I take it out for a test drive and decide if its fast enough for me at the right times.

[Anees]

This is probably an old question, but when a manufacturer quotes the bhp of their car, do they quote the power at the flywheel or the power actually at the wheels?

I would assume flywheel because it sounds more impressive?

I agree that Power/weight is a very important statistic as well as torque and bhp.

[sparkystav]

Fly wheel AFAIK.

[dave1]

The figures the manufacturers quote are surely ultimately only an indication anyway for the typical joe bloggs on the street. I dont think there are many people out there stupid enough enough to think just because it has more bhp it must be faster - and usually the specs include the weight so its a simple calculation.

Theres also the fact that the bhp quoted is likely to be that produced by the engine - not that available at the wheels - depending on the efficiency of the parts between the two. So again should only be an indication - so power to weight doesnt work there either.

The 0-60 times quoted (or 0-100 km/h / 62 mph) figures quoted are also "calculated" by the manufacturer anyway - in reality - no-one is ever going to hit them...so again - its an indication

As for ranges of acceleration times - that opens a minefield as to which figure is more important- 20-50, 30-60, 30-70, 40-70 - Unless I'm on a racetrack or playing top trumps (remember that game?) with my mates on whose car is the best - I dont care......I take it out for a test drive and decide if its fast enough for me at the right times.

So according to the above, non of the figures are of any real value, so why the hell do they have so much credence put on them by the motoring press and the "typical joe bloggs".

Do people really play "top trumps"? Horses for courses would spring to mind there. My mate uses his car round town and short trips so from economy and parking his old corsa makes sense, but I would not want it for my driving which is often longer trips where the lack of power (let alone comfort) would not be very usefull..bringing mid range acceleration into play..for overtaking on anything but motorways. On that basis both of us have the "best car".....for our own needs.

[Mark W]

which was exactly my point ....it's just an indication of the type of car it is....manufacturers could list thousands of specifications covering every eventuality but in reality would anyone take notice of them?

Don't think anyone is being conned IMHO when they read these specs and even if they did release thousands of different measurements then still would be an indication only again as

1- they would be calculated values

2- bhp is usually that measured at the flywheel

3- different engines hit their peak power at different revs

4- different gear ratios

5- assumes we are all perfect at gear changes at exactly the right time

6- takes no account of how many people we have in the car or how heavy they are

7- I can go on and on

If I were a racing team manager I might be interested in all the different specifications but for buying a family car then the bhp and 0-60 times give me a good feel as to how powerful the car is- and of course I would never buy a car on that alone anyway