T180 Mpg With A Twist! Do Not Believe The Obc

[kanulondon]

Since half of the posts are about MPG or lack of in respect to the T180 I decided to undertake a brim to brim test.

Last weekend I filled up at my local Shell (the one at the Forth Road Bridge Charlie) and filled the tank with Shell V Power Nitro+ Diesel. I usually fill the car until the first click and then fill it again until another click kicks in.

Reset the odometer and on board MPG. I drove the car again today (it's normally in the careful hands of my wife) and did a 80 mile drive today. The cars tank was indicating about 1/2 and the odometer indicated 197 miles covered. The OBC MPG indicator suggested I had averaged 31.1MPG.

However upon re-fueling the car only took 18.7 Litres (£25!!) which works out at

18.7 Litres = 4.11 Imperial Gallons

197 / 4.11 = 47.9MPG

That's quite an astounding figure there. I have been driving it rather 'featherly' for at least 100 of those miles, getting up the speed limit and using cruise or just maintaining manually.

1. I assume everyone is fairly happy with my brim to brim methodology?

2. How can the OBC be so very wrong? Over 15MPG out

3. Could the Shell Pump be under reading the amount of fuel it's given out?

4. I thought the tank was 60 litres? How can it show 1/2 tank and I only need 20 litres odd to get it to show full again? When it shows empty I reckon there's about 1/5 of a tank of fuel left?

If this is the case (will check again next week) I am indeed a lot happier with the MPG and need to absolutely ignore what the OBC tells me.

KL

[Big Kev]

Almost certain tank holds 75 litres....?

[blue monster]

It's definitely a 60 litre tank as the wife goes through a full one every week and this is also what the handbook advises.

KL - the way you have calculated the MPG is correct & I have seen over 50 MPG on the OBC on ours when driving it like a granny however ours has also got the Kingo chip kit so that improves MPG as you know over the standard engine.

I think I would be checking the sender unit in the tank as something doesn't seem right

[anchorman]

THe OBC is only a guide.

The fuel gauge is only a guide.

The only constant is the low fuel light when it shows on level ground. Make a note of the mileage when it comes on then work out how much it takes to fill to the max 60 litres. You can then work out how far to go to empty and I would work on 30mpg at that stage so as a rough guide, 10 litres (from memory it is more like 15) would get you 60 miles.

I wonder if the nozzle blew back on the first fill? I hope you are right but it does seem rather high. Your next few fills will confirm so keep us informed. My auto has put me on first name terms with every shift at the Total garage.

[Big Kev]

Since half of the posts are about MPG or lack of in respect to the T180 I decided to undertake a brim to brim test.

Last weekend I filled up at my local Shell (the one at the Forth Road Bridge Charlie) and filled the tank with Shell V Power Nitro+ Diesel. I usually fill the car until the first click and then fill it again until another click kicks in.

Reset the odometer and on board MPG. I drove the car again today (it's normally in the careful hands of my wife) and did a 80 mile drive today. The cars tank was indicating about 1/2 and the odometer indicated 197 miles covered. The OBC MPG indicator suggested I had averaged 31.1MPG.

However upon re-fueling the car only took 18.7 Litres (£25!!) which works out at

18.7 Litres = 4.11 Imperial Gallons

197 / 4.11 = 47.9MPG

That's quite an astounding figure there. I have been driving it rather 'featherly' for at least 100 of those miles, getting up the speed limit and using cruise or just maintaining manually.

1. I assume everyone is fairly happy with my brim to brim methodology?

2. How can the OBC be so very wrong? Over 15MPG out

3. Could the Shell Pump be under reading the amount of fuel it's given out?

4. I thought the tank was 60 litres? How can it show 1/2 tank and I only need 20 litres odd to get it to show full again? When it shows empty I reckon there's about 1/5 of a tank of fuel left?

If this is the case (will check again next week) I am indeed a lot happier with the MPG and need to absolutely ignore what the OBC tells me.

KL

So Alex......we have a T180 in Scotlandshire that does nearly 48mpg.....? Your alarm better be working......ma mates are on their way....

[bigend]

I constantly get 55+ with my xt3 all my calculations are brim to brim, most I've managed to put in is 49ltrs, thats fill up click off wait 30secs fill again till click off, Once had it up to 69mpg on run to york, steady 60mph, cruise on,NO WIND as that is your biggest enemy as regards fuel consumption. now wether you believe me I couldn't care less

Keith

[voyager t180]

What rarely gets mentioned when calculating mpg is the road terrain and weather conditions..
Some regular journeys I make show a gain of 5mpg on the return leg because even it doesnt appear so its slightly more downhill,with the wind usually in your favour.
Driving to Cumbria on the M6 from Bury I once had 63mpg with cruise set at 65mph ('09 Rav 2.2d).
Helped by a tailwind and a very slight downhill most of the way.
Sounds unlikely but its true.

[kanulondon]

I constantly get 55+ with my xt3 all my calculations are brim to brim, most I've managed to put in is 49ltrs, thats fill up click off wait 30secs fill again till click off, Once had it up to 69mpg on run to york, steady 60mph, cruise on,NO WIND as that is your biggest enemy as regards fuel consumption. now wether you believe me I couldn't care less

Keith

So perhaps it's clear that the Rav 4 gets a far worse rep than it should?

Out of interest, what does your OBC indicate? Just wondering whether I should bother getting it looked at. Our car had a new engine and had a piggyback ECU modifier to eek out greater MPG.

KL

[kanulondon]

It's definitely a 60 litre tank as the wife goes through a full one every week and this is also what the handbook advises.

KL - the way you have calculated the MPG is correct & I have seen over 50 MPG on the OBC on ours when driving it like a granny however ours has also got the Kingo chip kit so that improves MPG as you know over the standard engine.

I think I would be checking the sender unit in the tank as something doesn't seem right

Thanks Martin.

I've also got a chipkit, I used to have the Lindop but it put the car in Limp mode. The we have no seems to work without trouble but I was about to remove it due to the false OBC readings. It's funny as when we got the car the OBC indicated the previous owners averaged 29MPG. After resetting it, the most I've ever seen was 37 on a trip downhill to London. I can't remember if I did a brim to brim calc but it's clear our OBC for whatever reason is well off.

[kanulondon]

THe OBC is only a guide.

The fuel gauge is only a guide.

The only constant is the low fuel light when it shows on level ground. Make a note of the mileage when it comes on then work out how much it takes to fill to the max 60 litres. You can then work out how far to go to empty and I would work on 30mpg at that stage so as a rough guide, 10 litres (from memory it is more like 15) would get you 60 miles.

I wonder if the nozzle blew back on the first fill? I hope you are right but it does seem rather high. Your next few fills will confirm so keep us informed. My auto has put me on first name terms with every shift at the Total garage.

It sounded like all my usual re-fills no major dramas. But I will follow the same methodology next week and report back

[kanulondon]

Well I did another interim check today and I noticed something funny about the receipt . . . they charged me for unleaded fuel! Basically they charged me for the wrong pump #8 instead of the usual #5 no wonder it was so cheap and I didn't notice this before hand. I can't find out what my actual calcs were but a for the top up re-fill today

140 miles travelled

20 litres used

Equates to a God awful 31.8 MPG

Normal service has been resumed

Oh well

[Big Kev]

......will tell mates to return vehicle transporter they had hired to come get your Rav, then Alex......bloody inconvenient, mate.....

Me being thick though.....what caused the false readings......? Wrong diesel? Nah......Human erroneousity...?

[kanulondon]

Human erroneousity...

I should have noticed the fact the receipt read UNLEADED Petrol . . .

On the plus side I must have got away with about 30 litres of diesel for £25

[Big Kev]

.......or they gave you somebody else's receipt....? Sorry....am I still being thick.... . Price and distance covered not related surely...?

[three5]

My method of brim-to-brim testing is the same as the rest of you guys. Each time I refill I reset the OBC MPG display. Over the last 60 tankfulls the error between the OBC and the B2B is 13.14% - i.e. the OBC is optimistic by that figure. Spoke to Anchorman about this and he felt that NOT resetting at every fill-up should yield a more accurate result. My daughter, who lives near Abingdon ( fairly flat terrain ), achieves a regular 47+ mpg in a vehicle identical to mine. Anchorman has previously bemoaned the Derbyshire and Yorkshire hills in terms of fuel consumption. I ( and I suspect he ) will put up with it for the stunning countryside! You pays your money.......

[kanulondon]

.......or they gave you somebody else's receipt....? Sorry....am I still being thick.... . Price and distance covered not related surely...?

Yes they gave me someone receipt the first time round. In reality I 'guess' the car took about 30 litres, but I wasn't looking. So my first calcs were absolutely wrong.

Second calcs are correct

[kanulondon]

My method of brim-to-brim testing is the same as the rest of you guys. Each time I refill I reset the OBC MPG display. Over the last 60 tankfulls the error between the OBC and the B2B is 13.14% - i.e. the OBC is optimistic by that figure. Spoke to Anchorman about this and he felt that NOT resetting at every fill-up should yield a more accurate result. My daughter, who lives near Abingdon ( fairly flat terrain ), achieves a regular 47+ mpg in a vehicle identical to mine. Anchorman has previously bemoaned the Derbyshire and Yorkshire hills in terms of fuel consumption. I ( and I suspect he ) will put up with it for the stunning countryside! You pays your money.......

I will just keep the receipts and work out the difference between B2B and OBC, won't reset. Instead will just average out

[three5]

My method of brim-to-brim testing is the same as the rest of you guys. Each time I refill I reset the OBC MPG display. Over the last 60 tankfulls the error between the OBC and the B2B is 13.14% - i.e. the OBC is optimistic by that figure. Spoke to Anchorman about this and he felt that NOT resetting at every fill-up should yield a more accurate result. My daughter, who lives near Abingdon ( fairly flat terrain ), achieves a regular 47+ mpg in a vehicle identical to mine. Anchorman has previously bemoaned the Derbyshire and Yorkshire hills in terms of fuel consumption. I ( and I suspect he ) will put up with it for the stunning countryside! You pays your money.......

I will just keep the receipts and work out the difference between B2B and OBC, won't reset. Instead will just average out

I'll be very interested in the result - thanks!

[4.1GX]

KL, am I correct in asssuming you have had the engine modification done by Toyota?

If so did you have a new engine (new engine numbers on the logbook) or did they just do the required modifications in the dealership?

[kanulondon]

New Engine, I've had to send away for a new V5

[CharlieFarlie]

For some bizare reason my OBC is very close to the figures I get when checking brim to brim..

I have only ever given figures that I have checked after re filling the tank though I have of course looked at the OBCs figures as well... So Alex now has the best T180 in the UK fuel wise...

I used to be a little paranoid about MPG but now the mileage has tumbled I care quite a bit less.. Though with fuel so expensive its still a major expenditure ! As a point of interest during the two years before we moved we used to spend more per week on fuel for the cars than we did on food for the two of us !

[kanulondon]

Unfortunately my figures were erroneous . . . They were based on calculations from a entirely different pump. I only realised when I checked another receipt the other day.

Car was driven to Aberdeen and back today. 240 miles, 35 litres used = 31.3 MPG

I changed the EGR valve and gave the air filter a clean out. Let's see if it makes any difference. The EGR was pretty clogged up

[bubbles41]

Hi have you had any success after changing the EGR valve?

My OBC was indicating a better reading on short runs than on longer jaunts which I thought was a bit odd.

So I decided to do a brim test and while the OBC indicated a all time high 36MPG average which I was quite happy with the test came up with a lower figure of 30MPG.(250 miles/39 litres)

So now I wished I never bothered

Is this about normal for a T180?

[anchorman]

As Tom Jones would say - "it's not unusual". Our D-CAT engines vehicles have a 5th injector that sprays neat diesel into the exhaust for the puurpose of raising the temperature inside it and burning off any soot in there that would otherwise clog it up. VWs and some other brands have to be treated at the owners cost to have it done so I suppose we don't have that expense to worry about.

Welcome to the club.

[kanulondon]

Funny, we recently got our best ever MPG. We did a 250 mile round trip on undulating roads and the OBC and Brim to Brim were exactly the same. 39MPG

Back to city driving and we're down in the doldrums at 30MPG