Poor economy and trouble starting when cold.

[andy_d]

so feeding it 98ron (ultimate is 98?isnt it?) seems to be helping not only mpg but "felt go" ?
wonder if its the cleaning agents added to most of the "ultimates" as well as the extra octain rating?

[960kg]

Originally Posted by andy_d

so feeding it 98ron (ultimate is 98?isnt it?) seems to be helping not only mpg but "felt go" ?
wonder if its the cleaning agents added to most of the "ultimates" as well as the extra octain rating?

... Ultimate is 97ron...

[andy_d]

Originally Posted by 960kg

... Ultimate is 97ron...

ta
i feed mine asda's finest 95ron. it likes it a Lot better than shell "fuel saver" and better than bp 95ron. the only thing it disliked More than shell fuel saver is Tesco's 95ron. not a clue what "super" gets you in ron rating mine doesnt like it much.

[tt82]

I had an idea a few weeks ago and have been mulling it over.

I have fitted my car with 205/55R16 tyres instead of the 205/50R16 recommended. They are 3.35% bigger according to Car Bibles. That means for every revolution of the tyre I travel 3.35% further than what the odometer is recording, could this be giving the Info Centre and indeed myself a false reading on which to calculate the actual MPG used.

Yesterday me and my family went to visit my sister in South Wales while she is on Holiday. (Lives on Isle of Man so don't see her much). I put it to my dad that we should brim our fuel tanks at the start of the trip, zero the computers and then I would follow as closely as possible in his wheel tracks for the whole trip. Then when we return brim the tanks again and see what the difference is, in distance in Miles driven and Litres of fuel used.

Me - Y reg V40 1.8 Auto on 80k Miles
Miles Driven - 339.7m
Fuel Used - 44.31l
Info Centre Av MPG - 34.3
Actual MPG - 34.9
Also Av speed - 51mph
Miles remaining - 140

Dad - V reg Avensis 1.8 manual on 165k Miles
Miles Driven - 344.2m
Fuel Used - 39.08l
Actual MPG - 40.0

Now i was fully expecting to get worse than my dad as its Manual vs Auto and also his car has a CAI and Custom double exhaust so it breathes better. The difference in miles recorded is interesting though, especially as I drove a little farther than him when I lead the last few miles and missed a turn.

If you work out the economy on each others Trip computers it does alter the average mpg =

My trip of 339.7
Mine = 34.9
Dads = 39.5

His trip of 442.5
Mine = 35.3
Dads = 40

I also worked out the distance travelled on google maps as 349 Miles (without 2 wrong turns), that gives Average MPG readings of -

Mine = 35.8 Dads = 40.6

Its interseting that I can gain 0.4-0.9MPG just by using a different source of distance travelled. I would like to repeat the experiment using 205/50R16 tyres to see what mileage they recorded and how that affected the mpg.

[Volvon]

Regardless of tyres TT, that seems a little low. I do about 50 miles to the nearest city about once a week. I average 50-55mph and every single time I do it my info centre reads 41/43MPG depending on the load (Like the other day the seats were down and the car was loaded to the brim with timber, info centre read 41 MPG).

Obviously if you have to stop at traffic lights then that throws a spanner in the works as the MPG starts counting down like a stop watch!

[andy_d]

34*ish* mpg on a 1.8 auto , compared to 40mpg on a 1.8manual,
not that great a difference considering the auto/manual And they are not the Same car.
i get 32-34mpg mixed with mine
that bham traffic + motorways , so Heavy town stop start stuff and 70mph constant on the mway.
mines the 1.8 auto, S40, 110k miles , 2001 with the 5 speed auto box, no sticking brakes ,tyres @ correct pressure, correct sizes for mine 195/55/15 all 4 near new for tread depth, engine has had a full "stage 0" 95 ron "asda" (it likes it better than shell,,,)

[tt82]

Originally Posted by hyvää

Regardless of tyres TT, that seems a little low. I do about 50 miles to the nearest city about once a week. I average 50-55mph and every single time I do it my info centre reads 41/43MPG depending on the load (Like the other day the seats were down and the car was loaded to the brim with timber, info centre read 41 MPG).

Obviously if you have to stop at traffic lights then that throws a spanner in the works as the MPG starts counting down like a stop watch!

You have got remember the auto gearbox does affect the consumption massively. Generally I do 20-30 mile trips to work and then the same back. From cold the tourque converter will not lock up until the engine and gearbox are warm and then only in 3rd or above. This can take a few miles to achieve and the average mpg steadily drops until I hit the M-way. ( I actually can reach a motorway before the engine is warm, at 65mph I have 2,800 rpm until the tourque converter locks up and then it drops to 2,500rpm) Once on the M-way i steadily claw it back but that means im constantly playing catch up. Around town (visit to shops) and taking the dog to the quarry for walks really hurts my average mpg as usually the tourque converter will never lock up.

Whilst I accept poor mpg using a auto around town, I never seem to get the full potential on a long m-way run. If I reset all the info centre whilst on a m-way at a steady 65 mph i doubt i would get above 35 while the stats suggest i should get 43.

[tt82]

Just a little update.

Went to the Le Mans 24hr this year, car was fully loaded with 3 of us and camping gear. The info centre recorded an average of 33.6mpg for the 1118mile trip, i worked out it out with the fuel reciepts as being 35mpg and if add 3% to the distance for my theory about the larger wheels it comes to 36mpg. Considering the load amount and the fact we avoided some French toll roads by going down the A-roads I'm quite pleased with that.

The other thing of interest is just before the trip I had the EML come on, a local garage read the code as being the bank 2 Lambda sensor and cleared it. It came on again just before we left France, I'm assuming its the same reason but haven't had the code read yet. Despite this the economy hasn't suffered, if anyhting now that I'm using Tesco Momentum 99ron fuel it seems to be doing slightly better.

[Volvon]

Sorry TT, but having the larger radius tyres does the reverse;

I had 195/65 winter tyres instead of 195/55 and my info centre MPG was insane, hitting 50's! Now I have correct radius on I dropped 10MPG and back into the low 40's. It took me a few days to realise what the hell had happened. I had fixed sticky brakes and wonky toe-out and my MPG went down..what the hell! I was expecting it to go up! Until the penny dropped.

Sorry about that

[tt82]

Originally Posted by hyvää

Sorry TT, but having the larger radius tyres does the reverse;

I had 195/65 winter tyres instead of 195/55 and my MPG was insane, hitting 50's! Now I have correct radius on I dropped 10MPG and back into the low 40's.

Sorry about that

Is that working out the old way or according to the info centre?