Latest journey 36 MPG roughly (diesel)....

[BongoBongo123]

591KM (367 miles round trip) Just slightly less than a 1/3 of a tank by the meter (14.3gallons/65 litres/ if there is 4 gallons left, I think about 36 MPG at a guess) Not sure how much would be left in the tank exactly and how far I would get and I would not like to test that either. 2 people and a load of camping stuff in the back, water bottles etc. This was with air con on for a significant portion of the round trip 50pct of the journey and very much stop/start driving up the M25/M1/A roads with some periods of stand still / lengthy very slow traffic at junctions and just under 50mph runs through long roadworks. 3 roadside service/food stops on the round trip. It was not a smooth uninterrupted run by any means. Was driving around 50-55mph most of the way. I think this is ok mpg (I added the double dose of Millers as per usual for my longer journeys). Also includes 8 miles of local urban.



I will do the brim test again on another journey and try and equal my record of 43mpg. So much is to do with traffic.

[cmm303]

Presumably this is back on the road with your newly fixed engine!

Having followed the same additive process you use, I measured our 1800 mile Scotland trip mpg.
36 mpg on the motorway haul up there. 55-60 mph. Record mpg for me!
24-26 mpg around the isles. Quite surprised how low this was because speeds were low and a lot less stop/start than town driving. Very few cold starts. Hills both up and down. (funny that!!) I wonder if it's low because there was very little time locked in 4th gear.
31 mpg on haul back south. Probably spent a bit more time around 60mph or just over than on the way up.

To me it says speed, or lack off, is key so long as the transmission is locked up in 4th. Nothing new there. At slow speeds (15-30 mph) in lower gears, however near constant, I am amazed how the potential benefits of slow speed were outweighed by presumably the inefficiency of lower gears and auto transmission combined with the inevitable deceleration and acceleration for corners, hills and occasional traffic.

That all said, it didn't even blemish our holiday .

[BongoBongo123]

Glad to hear it ! Yes speed is the key, the good engine maintenance and additive side maybe squeezes that extra 2-3 mpg I suspect and as such is still worth it, it's good practice whatever mpg you get. For a really Alan Partridge type "sa-a-ad" view of MPG I even factor in..how straight a line you drive (constant corrections cause friction), listening for the quietest point in the revs on the engine.. the quieter = the least friction = most miles traveled for least revs. (I call it the aural equilibrium) Tyre pressures as well, reading the road properly, gauging revs required to maintain safe momentum for road situation.

I am guessing the winding roads at 40mph or so would be killing mpg somewhat, friction slowing you down on the bends and the up downs of the hills. It seems constant revs are the one for highest mpg performance. As soon as revs are up and down economy drops off very sharply.

36MPG well there you go, you can do it to. Anyone with a diesel should be able to with a few tweaks.

Sometimes it does seem like you are not moving/progressing on the journey but if there is no rush why not, whooshing along not taking in our country side is a bit of a shame really. At 70mph the difference in mpg achieved is big. My tank would be on empty if I was doing 70mph I estimate. The Mrs. appreciates being able to look out and see the landscapes.

And with this article I saw yesterday, needless pollution seems irresponsible in this age.

http://www.metoffice.gov.uk/news/releas ... oaCO2_2016

(Also just to add I have a fresh bottle of Millers for my Petrol car and the old bottle had gone off I think and smelt of... well... frankly... fishy wee wee - I kept it in the boot and it seemed to go off quicker due to the temperature variations from -2C to +45C - Now I am putting this new bottle in I seem to be getting a super smooth drive in the 19 y.o. Chrysler I have. I keep the additives on the car maintenance shelves now under the stairs)

[mikeonb4c]

It takes a lot of work to accelerate 2 tons of Bongo. Once done though, the vehicle is invested with significant momentum. Every time that energy, for any reason, is braked off (as it may be on twisty/hilly roads) the momentum gets thrown away and the cycle must be repeated. Also, that big diesel burns fuel when revving, regardless of whether it has work to do. For efficient touring, open roads, optimal speeds, and lockout in top gear are required. I welcome 50mph sections on motorways - an irritation acquires a silver lining

[BongoBongo123]

I think we sing from the same hymn sheet Mike !

[sotal]

I've only monitored ours once and it was around 28mpg average over a trip to Scotland, around Arran, back down, then down to Cornwall and back.

We are normally fairly well loaded up though.

Full length, half width roof box on the roof rack.
2 adults, 2 kids, 1 dog.
Every other space taken with luggage!

[cmm303]

I ran my cycling GPS during the trip and just uploaded all the tracked 1800 miles. The graphs of speed and height vs distance make for interesting (for a short while!) comparison. You can also easily see when my co-driver, SWMBO, was driving on the motorway as she doesn't use cruise control and goes a wee bit faster. It turns out the return motorway trip was only 2-3 mph faster in just a few places. Hard to see how that wiped 5 mpg off the 300+ mile leg. Must be other factors like wind and rain as well.

P.s. Fixing my warped leaking exhaust manifold noticeably improved low end torque and therefore mpg.

[teenmal]

I think we sing from the same hymn sheet Mike !

Do you guys by any chance attend the same Angling Club.

[mikeonb4c]

I think we sing from the same hymn sheet Mike !

Do you guys by any chance attend the same Angling Club.

Methinks you're fishing there teenmal

Returning to the matter in hand, I got 35mpg on a trip last week that involved going from South Manchester, up,down, and through the Yorkshire Dales and on to Sutton Bank and then returning using motorways (substantially at v sensible speeds, including the long 50mph section around the M60/M62, though there was a big trafffic jam around Manchester). Overall though, I was impressed with that.

[teenmal]

Do you guys by any chance attend the same Angling Club.

Methinks you're fishing there teenmal

Returning to the matter in hand, I got 35mpg on a trip last week that involved going from South Manchester, up,down, and through the Yorkshire Dales and on to Sutton Bank and then returning using motorways (substantially at v sensible speeds, including the long 50mph section around the M60/M62, though there was a big trafffic jam around Manchester). Overall though, I was impressed with that.

Ah bet you were using the FLY.

[BongoBongo123]

It is an odd fixation the fuel economy thing. I mean, ultimately I bet we can all afford the £5.00 ? £10.00 ? £15.00 ? we save per tank but it is quite satisfying all the same. It brings a moment of glee when I do the fill up measure and refill to see the mpg. I think it also relates to knowing your Bongo is working ok as well. All those £15.00 add up over a year I guess... you can look at it as going towards your insurance costs.... or maybe your new head

That style of driving befits such a vehicle. The way some people rag their vehicles around crunching gears tearing off and slamming the brakes on is a bit odd to me. Normal cars don't last 5 mins with kind of heated driving. They generally last much longer, along with the consumables (brake pads, disks, tyres, suspension, linkages, steering rubbers etc.) if you drive with with a touch of sympathy for all those moving parts.

If you drive a Bongo you will recognize ours and a couple of others by the looks of it by being in the left lane as you fly by in the middle or fast lane. Some people bomb along in their Bongos which is fine of course if within the limit. I always think it feels a bit touchy/unstable at 65mph and above. Though clearly it is no trouble whatsoever for the engines. With a no ABS Bongo I would not like to have to apply the anchors at those kind of speeds personally.

[mikeonb4c]

Someone very close to me has taken theirs up to an indicated 100mph, when there was no wind, just so he could say he had. But i wouldn't recommend it. Much best driven sedately, as you imply.

[geoffmcv]

Well guys, I've been looking into mpg's. The news may surprise you unfortunately. Here it is.
Only one gallon of fuel out of ten gallons propels you from A to B. The other nine gallons
is losses. A petrol engine is only thirty per cent efficient, so that's seven gallons lost.
The remaining two gallons drives things like alternators, steering and the oil pump.
Then add to these losses, skin friction, due to air rushing past your vehicle. But a major
loss is due to the lack of streamlining. Most van type vehicles have a vertical back.
The effect of this is to hold your vehicle back. This takes fuel to overcome.

So what can be done to alleviate this situation. 1. Get your vehicle tuned to run at minimum
fuel consumption. 2. Before a long trip, wash and polish your vehicle. This dramatically reduces
skin friction. 3. Remove all the weight you can from the vehicle. 4. Fit side deflector plates at
the rear to reduce drag. 5. Never accelerate uphill, this burns a lot of fuel. Instead cruise uphill.
Then speed up on the downhill. This uses gravity to your advantage. 6. On motorways drive at
the point of maximum thermodynamic efficiency. This will be around fifty eight mph. Deviating
from this speed (well velocity really) will seriously affect your mpg, even by one or two mph.
You can tell where this point is, because your engine will go really quiet. 7. Choose your departure
times to avoid traffic. Like night time driving, or very early morning driving. This is also less
stressful.

[mikeonb4c]

Interesting info there. It occurred to me mind you that we spend 25% or more of our lives asleep and wouldn't have it any other way. Some things are worth the waste, especially if you're sleeping with the one you love.

[phedders]

It takes a lot of work to accelerate 2 tons of Bongo. Once done though, the vehicle is invested with significant momentum. Every time that energy, for any reason, is braked off (as it may be on twisty/hilly roads) the momentum gets thrown away and the cycle must be repeated. Also, that big diesel burns fuel when revving, regardless of whether it has work to do. For efficient touring, open roads, optimal speeds, and lockout in top gear are required. I welcome 50mph sections on motorways - an irritation acquires a silver lining

So we need an eBongo with KERS.
Sorted.