How accurate is the Ph1 MPG on the Trip Computer?

[danzman1991]

I managed 43mpg on a careful 30 mile journey on an A-Road this morning!

Just wondering how accurate it is?

Cheers,
Dan.

 

[*Badger*]

The only way to tell is to work it out at the pump when you fill up.

My Mk2 Ph2 172 was uselessly inaccurate, yet my 182 is accurate to 0.1mpg.

 

[Rob]

My Ph1 is pretty much spot on.

 

[OldClio172]

Dan,
I used to find mine was very accurate on my 172 ph1, within 1mpg. If you fill to the brim and run it till the red light just comes on, I found that it would take almost exactly 10 gallons (45.4 litres) then you can easily work it out by moving the decimal point, so if you do 430 miles from full and it takes 45ish litres to fill back to the brim, it is doing 43 to the gallon

 

[Kam.]

Dan,
I used to find mine was very accurate on my 172 ph1, within 1mpg. If you fill to the brim and run it till the red light just comes on, I found that it would take almost exactly 10 gallons (45.4 litres) then you can easily work it out by moving the decimal point, so if you do 430 miles from full and it takes 45ish litres to fill back to the brim, it is doing 43 to the gallon

The easiest way is to fill it to the brim, reset the mileage. Then brim the tank and you have how many miles and how much fuel was used. Red lights are never accurate.

 

[big_yin]

As i have a slight miss trust for french electrics, i work mine out whenever it is un-usual i.e. over 33mpg. But its always right to within 0.1mpg.


The best mpg I've had is 41.2mpg on a careful drive down the M4.

 

[TheEvilGiraffe]

Fill tank to the brim, reset all counters.

Drive .. doesn't matter if you do 10 or 400 miles, then fill to the brim again.

1 Imperial gallon = 4.54609188 litres

Litres put in / 4.546 = Gallons.

Gallons / trip milage = MPG

Simplez ..


Best I saw in 50-60mph traffic over about 50 miles was 49MPG in the Clio between Dartford and Fleet services on the M25/M3. Easily saw 45mpg in mine.

 

[EllD90]

You mean trip mileage/gallons

 

[danzman1991]

Cheers guys.

I know how to calculate the average over a whole tankful..

I asked because I was curious as to whether it was accurate for just that journey, rather than the whole tankful..

 

[TheEvilGiraffe]

^ OP - It will work out the average since you last reset it. If you've done 200 miles at 50mph following a truck along a motorway, then the next day's 3 miles were nose to tail rush hour traffic to work, the mpg will still predominantly be reading high as the 200 miles will be the average still, so essentially inaccurate for your last trip.

If you reset it for a particular journey then it will tell you what ( I think ) you want to know...

Does that make sense ?

You mean trip mileage/gallons

Clearly I was putting in errors to enable a strange answer so people can use their brains for once haha.

Also it's Friday and my brain hasn't worked since circa 2003.

 

[danzman1991]

I reset it this morning, did 30 miles and it said 43mpg.. So I was just wondering if for this single trip alone, whether it was accurate or not..