After many years with our faithful campervan we upgraded to a short wheelbase Coaster only to recieve a shock with it's fuel consumption, 17 litres per 100 k's. That is 5.8 kilometers to a litre of fuel, and this was travelling on the new Pacific Highway north of Taree staying around 90 k's per hour.
It's a 1987 Coaster with a 3B 3.5 litre turbo diesel motor, seems to run very well and doesn't blow any black smoke.
At a recent camp a fellow inmate had a long wheelbase model towing a trailer, much heavier than ours and was averaging 13 litres per 100 k's, or 7.4 k's per litre.
Just not sure if these figures are normal and we should just put up with it, or have we got something wrong.
Any comments would be appreciated.
Sheba said
04:53 AM Mar 11, 2013
Ouch !!! That's nearly twice what my Hi-ace does. Think I'll stick with it.
Cheers,
Sheba.
johnnz said
03:28 PM Mar 11, 2013
I have an 87 Coaster and get around 7.5 kms to the litre. I think you will find the 3B engine is not turbo charged.
bill12 said
05:42 PM Mar 11, 2013
Get your self a can of diesel injector cleaner and add it to the next two tanks of fuel, about half each time.This will help, and give you a bit more power. I had noticably better fuel consumption and power when I Do it. Its not expensive at about $13 from super cheap.It can only help. Do not use petrol injector cleaner, only diesel. Bill
Baz421 said
09:22 PM Mar 12, 2013
Ok the old issue,, speed versus economy eh.
We have 4.2l Turbo Landcruiser ute towing 3t van with all up mass of about 6.5 tonnes. If we "push" the speed we markedly increase fuel consumption BUT if we slow down by 10k or so we have much better fuel economy.
Having said that I hate "dawdling on main highways" so take mainly secondary roads and slow down (and we smell the roses).
So what can you do? You have some advice already BUT if the engine, driveline AND tyres (fully inflated and wheels aligned) are not 100% you lose economy.
Also get the engine specs - but we really need the engine prefix number but I found this:
The 3B is a 3.4 L inline 4 eight valve OHV diesel engine. Compression ratio is 20:1. Output is 90 hp (67 kW) at 3500 rpm with 160 ft·lbf(217 N·m) of torque at 2000 rpm.
These above were in BJ model SWB Tojo's in the 70's and fuel consumption was terrible, especially if over revved.
However you need to look at engine number perfix to ascertain the exact specs and with diesels you need to look at when the torque develops (ie start to rise) and when its at near maximum and then drive to achieve best results - the MAX torque above is 217nm AT 2000 rpm.
Hope this helps
Gazook said
04:11 AM Mar 13, 2013
Thanks for the comments, I'm learning all the time. It was a Hi Ace we gave up for this one, so I won't go there. Heard the adding of injector cleaner could help but I seem to think that's just a band aid to the real problem. Baz, I have a dyno report from the previous owner when the turbo was first fitted back in 2009 and the highest torque was reached, with the turbo fitted, 238nm at 45kph, no mention of revs, dropping to 130nm at 80kph. Maximum power was reached at 66kph. So if we stayed down at that speed we would have great fuel consumption no doubt, but we don't and it's really a comparative thing. I am a slow driver and have trouble pushing the bus to 90kph on the freeway. It's just everybody I speak to are getting better fuel figures.
Johnnz, you didn't say if yours was a 3B? I'd be interested.
Baz421 said
05:45 AM Mar 13, 2013
Geoff
that is useful info you provided. I think you are on the right track in looking at the whole engine (not so much as fuel additives at this time). No smoke indicates that the engine is reasonably well tuned but I would take it to a diesel expert if it has an aftermarket turbo fitted to make sure the boost etc is correct.
On a dynomometer would be good also to find the torque range but this could be costly.
However you should be able to easily get the "feel" of when the torque "kicks in",,, ie drive into say 3rd gear normally and then accelerate smoothly and continuously, see if you can feel where she wants to pull and note the revs and then see where the power starts to taper off. On a slight incline is good for this.
You will then at least have an idea of what rev range to drive in. The most important thing for diesel economy apart from design and tuning is to drive in the rev range to give you the best combination of torque and economy.
As a LAST resort drive at different revs - ideally on flat terrain (outback QLD/NSW there's heaps of it) for say 200km and try to keep the same revs at all times (as far as possible). Top up diesel carefully/exactly using the same method and work out usage. Do this again but say 250RPM higher and then again at say 250 RPM higher. You should see a trend emerging either better economy or a worse economy. Repeat at higher revs if need be.
Hope this helps Cheers Baz
johnnz said
05:32 PM Mar 14, 2013
My coaster is a 3b engine, I have just driven from the Gold Coast to Melbourne, using the New England and Newell Highways. I had fuel consumption of around 8.5 kms per litre. I cruise around the 80kpm.
John
johnnz said
05:33 PM Mar 14, 2013
I meant to add, my 3B engine has not been turbo charged
After many years with our faithful campervan we upgraded to a short wheelbase Coaster only to recieve a shock with it's fuel consumption, 17 litres per 100 k's. That is 5.8 kilometers to a litre of fuel, and this was travelling on the new Pacific Highway north of Taree staying around 90 k's per hour.
It's a 1987 Coaster with a 3B 3.5 litre turbo diesel motor, seems to run very well and doesn't blow any black smoke.
At a recent camp a fellow inmate had a long wheelbase model towing a trailer, much heavier than ours and was averaging 13 litres per 100 k's, or 7.4 k's per litre.
Just not sure if these figures are normal and we should just put up with it, or have we got something wrong.
Any comments would be appreciated.
Ouch !!! That's nearly twice what my Hi-ace does. Think I'll stick with it.
Cheers,
Sheba.
I have an 87 Coaster and get around 7.5 kms to the litre. I think you will find the 3B engine is not turbo charged.
Ok the old issue,, speed versus economy eh.
We have 4.2l Turbo Landcruiser ute towing 3t van with all up mass of about 6.5 tonnes. If we "push" the speed we markedly increase fuel consumption BUT if we slow down by 10k or so we have much better fuel economy.
Having said that I hate "dawdling on main highways" so take mainly secondary roads and slow down (and we smell the roses).
So what can you do? You have some advice already BUT if the engine, driveline AND tyres (fully inflated and wheels aligned) are not 100% you lose economy.
Also get the engine specs - but we really need the engine prefix number but I found this:
The 3B is a 3.4 L inline 4 eight valve OHV diesel engine. Compression ratio is 20:1. Output is 90 hp (67 kW) at 3500 rpm with 160 ft·lbf (217 N·m) of torque at 2000 rpm.
These above were in BJ model SWB Tojo's in the 70's and fuel consumption was terrible, especially if over revved.
However you need to look at engine number perfix to ascertain the exact specs and with diesels you need to look at when the torque develops (ie start to rise) and when its at near maximum and then drive to achieve best results - the MAX torque above is 217nm AT 2000 rpm.
Hope this helps
It was a Hi Ace we gave up for this one, so I won't go there.
Heard the adding of injector cleaner could help but I seem to think that's just a band aid to the real problem.
Baz, I have a dyno report from the previous owner when the turbo was first fitted back in 2009 and the highest torque was reached, with the turbo fitted, 238nm at 45kph, no mention of revs, dropping to 130nm at 80kph. Maximum power was reached at 66kph.
So if we stayed down at that speed we would have great fuel consumption no doubt, but we don't and it's really a comparative thing. I am a slow driver and have trouble pushing the bus to 90kph on the freeway. It's just everybody I speak to are getting better fuel figures.
Johnnz, you didn't say if yours was a 3B? I'd be interested.
Geoff
that is useful info you provided. I think you are on the right track in looking at the whole engine (not so much as fuel additives at this time). No smoke indicates that the engine is reasonably well tuned but I would take it to a diesel expert if it has an aftermarket turbo fitted to make sure the boost etc is correct.
On a dynomometer would be good also to find the torque range but this could be costly.
However you should be able to easily get the "feel" of when the torque "kicks in",,, ie drive into say 3rd gear normally and then accelerate smoothly and continuously, see if you can feel where she wants to pull and note the revs and then see where the power starts to taper off. On a slight incline is good for this.
You will then at least have an idea of what rev range to drive in. The most important thing for diesel economy apart from design and tuning is to drive in the rev range to give you the best combination of torque and economy.
As a LAST resort drive at different revs - ideally on flat terrain (outback QLD/NSW there's heaps of it) for say 200km and try to keep the same revs at all times (as far as possible). Top up diesel carefully/exactly using the same method and work out usage. Do this again but say 250RPM higher and then again at say 250 RPM higher. You should see a trend emerging either better economy or a worse economy. Repeat at higher revs if need be.
Hope this helps Cheers Baz
My coaster is a 3b engine, I have just driven from the Gold Coast to Melbourne, using the New England and Newell Highways. I had fuel consumption of around 8.5 kms per litre. I cruise around the 80kpm.
John
I meant to add, my 3B engine has not been turbo charged