Fuel Consumption

[AustHaflinger]

What are people getting fuel consumption wise and under what conditions. The book says about 31mpg but I am not getting anything like that.

As I have 14" wheels I appreciated that my speedo and odometer were under reading so I set up my GPS and went for a drive up the freeway and back where there are no traffic lights so the GPS distance will be almost spot on. I covered 35km by the odometer and 39.1 by the GPS so the odometer needs to be adjusted by 1.117x to show the correct distance. The same correction needs to be made to the speedo to get the correct speedo at slower speeds but it is almost spot on at 80kph.

I am a bit anal about keeping fuel records for my vehicles and the Haffie is no different. On the first fuel fill of 110km I returned 14.56l/100km (19.4 proper mpg) which is lower than the numbers predicted in the specifications - I accept that much of these kms were on the freeway with the engine high in its rev range but I would have expected a bit better. The second tank of 185km including about 120km of offroad work returned 13.6l/100km (20.77mpg) again not as good as I expected. By comparison my Range Rover Sport weighs 2.5 tonnes, has a 2.7 litre engine and when cruising at 120kph returns 9.4l/100km (30mpg) so the haffie even at the designated specs is not real economical.

So what do other people get in their haffie? I think I will put mine in for a full electronic tune up. One thing that did show up going offroad was the engine compartment really sucked in the dust so the air intake would have been doing the same so I think as a priority I will connect up the cyclonic air intake at the front to suck in fresh air as I have all the pipework in my spares.

Some interesting stats on the 40km freeway trip. The Haffie was able to pull the whole freeeway legs in 5th gear including the hills. Max speed was 86kph at 5200rpm, with a no assistance max speed of 80kph at 4800rpm (the tiny tach jumpas around a bit). Best cruise speed is about 72kph at 4200rpm and the Haffie seems to like that speed and revs. Average speed overall was 61kph which included the non freeway sections.

Certainly driving the Haflinger around town and to take me down to get my morning coffee is doable - even short freeway trips but I would have to stay away from Freeways in Western Australia as it is an offence to drive slower than 20kph under the speed limit.

garry

[heinkeljb]

Haven't managed to use a full tank on mine yet, been busy sorting other things like a more permanent position to park Lurch now he is on the road. Also have to make sure the Smart car continues to go as need it to get to work.

Once I know that Lurch is reliable, he might go to work and back a couple of times a week.

John

[Tennmogger]

I drive several Unimog gas engined trucks approximately the same vintage as the Haflingers. Mileage is always poor even thought they run very well. I believe the 'energy' quality of gasoline we have now is much poorer than the gas for which the ratings were first made. I often add about 10% Diesel to the gas to provide a little more energy (and prevent vapor lock). The Unimogs run much better but I don't have mileage comparisons.

Bob
(not yet united with my '68 Haflinger)

[Westernair]

My 62 I just drove to Seattle and back (side roads at less then 45 mph) and then around town. I am getting 36.4 with the new motor.

[heinkeljb]

Had to fill up Lurch over the weekend and although it is only the first full fill up which will allow me to work out fuel consumption. (27.7mpg) Obviously, a few more fill ups will give a better average of mpg than basing it on one tank.

Every journey is different and so mpg will be different. An average mpg over more fill ups will give a better idea of what distance you are likely to be able to travel on the fuel available. It will not be able to tell you for certain if you will ACTUALLY achieve that distance with the fuel available, but if fuel level was critical then you would be able to take steps to deal with the problem, driving slower, more gently, less braking / accelerating - buying more fuel!

John

[AustHaflinger]

Hmmm - looks like an electronic tuneup is needed on my engine.

Garry

[Callahan]

US gallons or imperial? Makes a difference.

[heinkeljb]

Those of us in the UK have to convert Litres to gallons now-a-days. We generally use 4.55 litres tot he gallon - so that would be imperial gallons for us.

John

[Callahan]

And a US gallon is 3.785 litres. I stay stick with metric!

[AustHaflinger]

Last 2 full fills I am still only getting 15l/100km (about 20mpg) so I do have an issue - engine runs well, choke is not sticking so I guess the carby (Solex 34pci) I have on the engine is not jetted right. Because of the 762cc I have and the larger carb I thought I would use a bit more fuel but then at cruising the engine will be working easier and with 14" tyres revving a little less so should balance out.

Time to put it in the garage to go onto the electronic analyser to see what is going on.

Garry

[AustHaflinger]

There is no obvious place locally to give the Haffie a proper tuneup as most people have never heard of one. There is a place called the "Beetle Exchange" that sells and services old VW Beetles and as my engine is now half beetle and has a beetle carby I thought I would enquire there today about getting the carby checked out and tuned up. Unfortunately they were a bit daunted by my little truck as they said that if jets were wrong they would not be able to help so would prefer not to do any work in case they could not deliver

They suggested a dedicated carby specialist but did not know of any - Canberra being a public service town is a bit of a backwater as far as cars go. Looking through the phone book there seems to be only one and that is Canberra's much smaller satellite city Queanbeyan which is across the border about 10km away. I will go and have a chat to them tomorrow.

While I am sure the jets in the carby are correct I guess I would rather have all this checked professionally rather than waste time and money on tune ups that may not work.

Cheers

Garry

[AustHaflinger]

As I have mentioned here and a few other places my Haffie does not have the correct Zenith carby and has a 34mm Solex on a modified Zenith manifold. When I got the Haffie it ran well and had a reasonable turn of speed on the highway but was strangled on really steep hills and would die. Fuel consumption was always below 20mpg (usually around 18mpg) which according to the specs was quite poor.

As time went on performance got worse though it always ran well to the point that it would not climb a a steep hill on the road let alone in the bush.

I had enough of this and decided to change the carburettor back to original etc. I couldn't find a Haffie Zenith for a reasonable price so bought one off a Unimog 404 which is close to the Haffie version. Jim LaGuardia from the US gave me the haffie specs and hopefully the carby will go in next week for a rebuild to be jetted for the Haffie. I also received a new manifold from Haflinger Technik last week to go with the carby.

While waiting for these parts I decided to see if I could find what was the problem with the current arrangement as was clearly flooding on hills. I looked at the electric fuel pump and while I could not the specs on the specific pump but the specs of similar pumps indicated to me that pressure was up around 5psi - really too high. So I changed it to a 2-3 pump and things improved but not completely. I then took the top off the carby and there was nothing obvious - float level was about right and the seat looked OK however the needle was something I had not seen before as it was double action with a spring centre ball bearing - as the fuel float rises it closes the needle but if it continues to rise further it pushes on the ball bearing - not sure why.

I have a couple of spare carbies and took the top off one and noticed that its float needle arrangement was different in that it was the traditional single piece needle - I put this top on and the engine ran perfectly. On taking the car for a test drive to my big hill, the car was purring along and I looked down at the speedo which was showing 80kph so about 83 in real speed - on the hill it just shot up where before it struggled - 10-15kph faster and able to do it in 4th and 5th where before I was down to 2 and 3rd.

The issue was clearly the fuel pump pressure pushing past the a non sealing float needle which was OK on the flat but was flooding the carb on steep hills. Lower fuel pressure and a better float control makes a difference but fuel consumption is still poor.

However it will be good to go back to the original carb arrangement. It will be interesting to see how the Haffie runs then.

Garry

[heinkeljb]

Hi Gary,

As you will have read, I took Lurch for a long drive the other weekend. I haven't really checked on the mileage proper, I know it was 190 miles getting there, but then we messed around in the wood and I came a slightly different route home.
Overall, I would at this moment put the mileage done at about 380 round trip (I try to remember to get a better total). I lost one of the slips for filling up so will have to guess at what the amounts were.
My rough estimate over that journey (bearing in mind Lurch was fighting a good head wind most of the way there) is 22mpg.
I have had the carb apart once - see previous posts, but at the time did not have replacement jets, pump etc. I have those bits now (but no gaskets left..... Doh). SO when I mange to get some more gaskets I will have the carb apart again, put the the new bits in and see if that improves things.

John

[AustHaflinger]

Thanks John - what sort of speed did you maintain on the main roads - this is where fuel consumption is worst as the vehicle is close to being driven flat out. With my larger pistons and 14" wheels I can get just over 80kph flat out but that is in the zone that the governor would be kicking in if i had one so I only do that in short bursts - I have set myself a rev limit of 4100rpm for highway use and this gives about 70kph which is not too bad.

I would have thought that 22mpg was a bit low but I guess it depends on what speed you were cruising along at.

Cheers

Garry

[heinkeljb]

I have a governor on mine and basically just foot flat on the floor unless going down hill! GPS speed wabbles a bit between 40 and 43mph ~ approx 68kph but as I said, there was a pretty good head wind going so that could have had a big effect on the MPG.
I have just found a program called ViewrangerGPS which lets you do all sorts of things like mapping your route and allowing you to store it so you can look at it later. I am sure it does other things as well, but I haven't had the chance to look at all the options yet. I have also downloaded a program called Fuelio which allows you to enter your mileage / fuel / total cost of fuel, even use GPS to register where you put fuel in. Then it gives you various charts, logs etc which can build to give you average mpg (or kms/l) costs per month, fuels prices etc.
I shall have to start using these more to get a picture of what my vehicles are used for and how much they are costing me!

John

[AustHaflinger]

All hi-tech - I just record the distance off the oddometer, multiply it by 1.17 to get real distance and note fuel added to the tank and - presto l/100km

Since the early 90s I have recorded fuel usage in all of my vehicles and the haffie is not different - have recorded every drop of fuel that has gone into since I put it on the road.

[AustHaflinger]

I have finally got the correct Haflinger jets for the Unimog Zenith 32NDIX carby I have and as the nearest carby builder is 50km out of town I decided to take the Haffie. (I live in the Capital, a city of 400,000 but I have to go to a small country town of 2000 people 50km away to get work done )

Cruising between 60 and 70kph the trip was quite pleasant (a bit hard on the back) and I actually managed to get 23mpg . This is by far the best I have ever got so hopefully when the Zenith back, take off the Solex I have off and get the Haffie tuned up fuel consumption will get back to normal.

Garry

[heinkeljb]

Things are looking good then. If you can get it nearer the 25 to 30 mpg then you have probably done all you can without changing things like hub ratios, frontal area, weight being carried - oh, that one you can change! I was talking about tool box you carry!

John