Mpg and mileage hdi

[Welshy_Pete]

I run my 306 hdi empty and the light comes on for 100miles. So then I filled the car up £90 to the top nearly in shock at this point lol

Thinking when its going to end but luckly £90 was it lol.

I thought I wont be doing this again in a rush lol

The main reason was to see the fuel gauge working correct doing to being low along time. Its now working fine after I cleaned it up also filled it up to.

So for the £90 works out 271.5miles each £30 but full £90 used
815miles on 30mph, 40mph and 60mph roads full tank to empty.

I then just put in £30 each time 286.5miles till I did £90 on 3 times £30 giving
860miles on 30mph, 40mph and 60mph roads full tank to empty.

I was using the same roads on the same conditions etc. But my mileage went up with filling the car up less. Also there plenty of fuel stations around so I pass them easy without driving off out the way etc.

I only use big brand fuels like shell and Bp. But also use Texaco and Esso as well.

I got 60mpg which I'm happy with.

[Anton]

Price you paid per litre?

[declantg]

Why is everyone so fussed about mpg?

Jeeeeeez

[Poodle]

Useful input, thanks Dec.

As Anton says, we need to know price per litre before we can work out your mpg. I can explain the difference you're seeing between filling the tank and only putting in £30 a time though.

Assuming all other conditions are the same, you'll get more mpg if you've only got a maximum of £30 in the tank rather than filling up, purely because of weight. Keeping it down below 1/3 of a tank means the car weighs 40kg less than it would do with a full tank, so when accelerating that's 40kg less work for the engine to do. You notice it as you're doing a lot of local driving - start/stop and short journeys, etc - if all you did was motorway commutes there would be barely any difference, as it's only really during acceleration it'll make a difference.

[Welshy_Pete]

Why is everyone so fussed about mpg?

Jeeeeeez

I'm just interested that's all to see. Not being tight with money or anything. I'm just impressed how well it goes on diesel that's all.

[Poodle]

He's just jealous now he's realised driving to the fuel station to fill up is going to cost him a tenner.

[declantg]

Meh, fuel costs aren't bothering me currently. Plus I'm getting a raise in a couple of weeks
Also, the sound of a straight6 bouncing off the limiter is worth the fuel bill

[Poodle]

Dammit, smug sonofabitch, who wants a straight six anyway?

/ido

[declantg]

Would upload a vid but don't think anyone would care haha

[Poodle]

Do it man, would be interested to see what one is like as standard. Been out in loads of tuned ones as my bro is a bmw enthusiast, but never standard lol.

[declantg]

Will do in a bit man x

[rd070707]

dec's in denial about the fuel bill lol, really he misses the 306 mpgz

[declantg]

Not in the slightest, getting rid of my 306 is the best move I ever made

[Dum-Dum]

Assuming all other conditions are the same, you'll get more mpg if you've only got a maximum of £30 in the tank rather than filling up, purely because of weight. Keeping it down below 1/3 of a tank means the car weighs 40kg less than it would do with a full tank, so when accelerating that's 40kg less work for the engine to do. You notice it as you're doing a lot of local driving - start/stop and short journeys, etc - if all you did was motorway commutes there would be barely any difference, as it's only really during acceleration it'll make a difference.

Actually 2/3 of a tank wont be 40kg. Assuming that your tank is actually 60l (I've had 70l in a 306 in the past) 2/3 is only 40l but diesel is significantly lighter than 1kg/l (this is why it float on water) its only about 800g/l depending on temperature so 2/3 of a tank actually only weighs 32kg

Petrol is lighter still though at about 750g/l

Still 32kg is a significant weight extra to lug around all the time, itll be about 3% more weight in the car assuming about 1200kg for the car


Actually this puts me on to a thought, when I've stripped about 100kg out of a 306 its added about 5% to my mpg figure so allowing for driving like more of a hooligan with a stripped car then it would probably be even more of an improvement

[Toms306]

Not really an accurate way to calculate MPG tbh. Pence per mile yes, but for mpg, record your miles and gallons (or litres to convert later on).

But assuming diesel is averaging £1.36.9 (as you also used different stations so probably different prices) it works out as 56mpg and 59mpg...............my HDi struggled to hit 50mpg so that maybe slightly out tbh!

[Poodle]

I know how much diesel weighs mate, cheers lol. Those were rough mental-arithmetic figures i based on the usual averageish tank capacity of 68 litres - if i don't round up it comes to something like 37.9kg, assuming he pays ~£1.41/l for premium brand fuel. Sorry i'll be more specific next time. Oh and by the way, your assumptions are incorrect as you've failed to take into account the parts of that which are unsprung and/or rotational and weight any calculations accordingly. :p

[Dum-Dum]

^^^ Interesting. I thought you'd of gone with the book figure like any normal person would of. I forgot that your about as normal as I am.

[Poodle]

Peas in a pod mate.

[C.A.R.]

I just take it that anything over 600 miles from 1 tankful is a good thing. 630 miles is 53mpg, assuming that's the 54 litres (full tank).

[Toms306]

Chris, the tank in the hatch/estate is 60 litres....plus the neck as well.

[Welshy_Pete]

I just checked up on this I get 60mpg which I'm very happy with.

[Jesskendall123]

I get 50mpg which I'm happy with

[Dum-Dum]

I really need to get through working out why mine is so bad.