kossie

This is how boring life as a Graduate is... i think of shit like this. Based on a 1700 Puma run around i have now ive sold the KaRS:

70mph in the Puma is @ 3200rpm. So, obviously you will do 70 miles in one hour.

35mph is @ 1800rpm, and will subsiquently take you 2 hours to do the said 70 miles.

So at 35mph it takes you twice as long to do 70 miles, but you think its ok as your only doing 1800rpm... But 1800rpm is just more than half the 3200rpm for 70mph... and your doing it for twice as long, so esentially comes 3600rpm over the same distance?



... if you get that, WOW i was bored today, saying that i always thing of random shit.

Anonymous

Yes because in order to maintain 3600rpm against the wind resistance you have to put in more fuel per cycle of the engine.

Hope you didnt think about it for more than 5 seconds

Anonymous

PS

half of 3200 is 1600 by the way

If you car reads 3200 @ 70
1800 @ 35

your speedo is wrong

kossie

Not really true that thou is it? just cos your RPM is doubled, doesnt always mean your speed will be exactly double as well all the way through the range.

Anonymous

Only if your fucking clutch is slipping or you change gear

foreigneRS

i think that you're absolutely right chip - gcse's are obviously far too easy

there's some retards about

ballin

iTrader: (1)

fpmsl, no of course not your engine speed isn't related to wheel speed at all!

cossie4i+

iTrader: (15)

The faster you drive the sooner you arrive the less fuel you use

Steve.

rssteve

the cog in the gearbox much change size when he goes faster.

MB7201

I've heard somewhere that the optimum is somthing like 60 in 5th, probably the best compromise

Turby2

Is optimum fuel use the same as optimum VE ie max torque ?

Lee Reynolds

If you drive faster then you get to work earlier so earn more money and can set off home later and earn even more so its more economical to get the foot down

Anonymous

Far more inteligent question that one.

The answer is "maybe" though im afraid, LOL

S1

The most economical speed to drive is as fast as you can go before wind resistance becomes a factor, around 50-60mph. Above that and you use more fuel to overcome the wind resistance. This is why manufacturers quote MPG at a steady 56.

PhilM

I recall we worked out the optimum speed for fuel effiency in a Mondeo during one very boring A Level Physics lesson, needless to say the board was full of numbers, and I don't recall the equations usede, but it was about 55mph

Really noticable how much less fuel you use doing 65 down the motorway rather than 80.

Anonymous

I bet you didnt REALLY work it out, i bet the teacher didnt know half the things you needed to take into account really (just like i suspect I also dont)

MB7201

Find someone with an on board computer and experiment

PhilM

Don't know to be honest mate, I think it way OK for a good guide, we took into account frontal area, coefficient of drag etc, but like you say, there will be a lot more to it! (More than one whiteboard's worth ). Things like rolling drag would need to be accounted for aswell, but it was a good guestimate I'm sure

Anonymous

Not to mention barometric pressure, LOL

Ginge !

i know that my bmw DRINKS fuel at 120mph along the m1


as for what it does at 55mph,,,,,,,,,,,, I DONT FUCKING CAR AS I WOULD RATHER SPEND 10 QUID TO GET A EXTRA 3 HOURS SLEEP



OH AND MONDEO ZETECS use 50 quids worth of fuel at 130-135 ish from bichester to london i also heard



and dancossie managed to get his diesel to go from london to blackpool and back on 50 quid



the following day i used 60 quid in diesel driving from london to derby,,,, so there shite on fuel too when i drive


but then i also get 380miles to a full tank in the works transit when the other drivers can get 510