Fuel comparision/calculation Petrol 4.8 v. Diesel 4.2 supercharged...HELP!
Submitted: Wednesday, Nov 19, 2008 at 12:03
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Vicar
Hi all,
I'm having some difficulties, apart from the normal ones, of working out whether or not to keep my supercharged patrol 4.2 diesel GU. It has the usual fruit on it, but I'm only getting around 6.5k's per litre. I use the vehicle for work so I'm doing around 1000k's per week.
From what I've seen and been advised, the 4.8 averages around 16-18L/100k's. I'm getting a return on my current vehicle of 15.5-16.5L/100k's. And sometimes when towing, the 4.8's can blow out to 22L/100k's. And towing I do alot of, hauling cable trailers etc from site to site. Now one saving grace is my fuel is payed for work.
Now, diesel is substantially dearer in
Brisbane, some 25c - 30c/L dearer, and the 4.2 needs to be serviced every 5000k's, the 4.8 every 15,000.
Does anyone and has anyone done a comparison of late diesel v petrol (second hand)? Any advice would help.
Cheers and have a good one,
Vicar.
Reply By: ingo57 - Wednesday, Nov 19, 2008 at 15:11
Wednesday, Nov 19, 2008 at 15:11
G'day Vicar
I have the 4.8 patrol auto and the best I have achieved is around
18-19l per hundred unloaded no roof rack,
around town low to mid 20's (depending on right foot)
touring fully loaded mid 20,s
It can achieve 30's when your really ringing
the neck off it.
Thirsty but mighty fun to drive!!
On my last trip I did a dollar comparison between my 4.8 and a TD100, forget about litres used, just money spent at the pump for the same distance.... It was quite interesting to say the least.
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Follow Up By: Vicar - Wednesday, Nov 19, 2008 at 16:19
Wednesday, Nov 19, 2008 at 16:19
Gday mate,
Fair enough, just reading up on overall figures from another post. Not alot of difference in the comparison in your other post.
I'm just not sure what to do. I've been trying to find out when these motors start wearing out, but due to the age of them, not many have done over 200,000. The 4.2 is bullet proof, but not overly powerful, the supercharger has helped alot, but the fuel comsumption just doesn't make it worth while.
Thanks for your input.
Cheers.
Vicar.
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Follow Up By: ingo57 - Wednesday, Nov 19, 2008 at 19:09
Wednesday, Nov 19, 2008 at 19:09
Vicar
You got me thinking, I have just crunched the numbers on my last trip and I have come up with an average of 25 l per 100km, fully loaded roof rack, dual wheel carrier, draws Fridge recovery gear all the usual stuff no trailer
The worst was crossing the Simpson, a whopping 33lt per 100km
The best was really taking it easy 19 l per 100km
Accurate no bull figures....fantastic reliable engine
Hope this helps
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Reply By: Robin Miller - Wednesday, Nov 19, 2008 at 20:41
Wednesday, Nov 19, 2008 at 20:41
Hi Vicar
Your 16-18 for 4800 is abpout right - My manual has used 16.5 over its 175,000km.
I have compared both those cars directly over substantial drives and they are quite different vehicles. One is quiet very powerful with bigger brakes and better dynamics and the other is the venerable old plugger and the favorite of many.
The style is so different that I think its easy to make a choice your comfortable with.
The fuel consumption should always be better by about 25% for the diesel, but as you say the cost difference is minimal.
There is little reliabilty difference beteewn the engines - but the 4800 is definately easier to work on and play with as doesn't have the cooling issues. In fact I have long since removed the 2nd thermo fan from
mine to save a little weight.
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Follow Up By: ingo57 - Thursday, Nov 20, 2008 at 10:54
Thursday, Nov 20, 2008 at 10:54
G'day Robin
Besides yours being a manual the later 4.8's have been detuned (the earlier models 185kw as to the current 180kw) do you know off hand what was changed?
I have looked and compared both models in the engine bay and its nothing obvious in regards to the sensors.
One thing I will be doing is putting a switch to lock the convertor at highway speed, this should help with my km/l average when on a trip, but have you made any mods to yours in order for you to achieve those figures?
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Follow Up By: Robin Miller - Thursday, Nov 20, 2008 at 11:22
Thursday, Nov 20, 2008 at 11:22
I believe there have been varying states of tune for different countries from 175 to 195 kw Ingo.
Mine has no oxygen sensors in the cat or below whereas some autos in particular have , not sure when that came in.
So its really just ecu management , which is why things like the unichip can provide a bit more. (don't bother with my unichip much its usually out of car as they are more compatiable with auto's.
I have done no particular thing to achieve my 16.5 long term total average. Except I usually drive at speed limit , and generally run narrower tyres at high pressure on 7 inch rims.
I do often run a little homemade ecu that leans engine out on cruise , but this only saves a 1lt or so and this is often counteracted by pulling bike trailers and heavy 4wding.
You may know that the auto is actually rated lower in fuel use than the manuals however in real life acceleration and slipping torque converter operation makes it worse than manuals in practise around town.
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