80 Series RPM's

never belive what anyone let alone a "mate " tells you about fuel economy!! i have seen plenty of threads on here about it and some of the claims defy beliefe. Hell I bet I can get someone to say they got 15L per hundredout of there 4.5 tojo petrol 80 even though those telling the truth will tell you they ONCE got 18l per hundred running down hill with a tail wind but normaly it is between 20 and25 per hundred
I would say in ideal conditions at 110 if you are bettering 14-15l per hundred all is good

that extra 10km per hour will cost you a fair % of your fuel.
Going back a few years when I owned 80 series I got my best economy at 95km.

I had a Izusu turbo diesel in an old 1978 tray back, but we changed the diffs and this thing cruised allow at 120 - 130 no problem. It was just hard to keep it on the road at that speed.

I also had the same with a bombed up 350 in it, now that was scary stuff but a lot of fun.

Simply You cant have speed and economy.

Rob

Travelling with a troopy for years, 90-95 is the most economical speed, pushing it to 100 -110 could depending on the conditions increase consumption by 25%. Adding a roof rack chopped 2 mpg off, towing a camper trailer also took 2 mpg off.
Having both on together only took about 2.5 - 3 mpg off so wind resistance is obviously a big factor.
Gearing and engine revs do make a huge difference to economy, years ago when wider (10R15) tyres first became available lots of people fitted them in place of 7.50 x16's, the vehicle usually pulled better off the mark and up hills but to the detriment of economy due to higher rolling resistance and more revs at speed.
With a load and slower speeds though under some conditions economy actually improved as the engine was in its torque band with less throttle.
I've recently changed the auto in a vehicle from a 3 speed to a 4 speed with lock up torque converter, the difference is amazing, engine revs have dropped by 800 at 95kph and initial figures suggest a 20 to 25% decrease in fuel consumption as the engine is now sitting bang on max torque at 95 kph.

I have a n 91 Series 80 GXL Cruiser with an aftermarket turbo fitted to the 4.2 litre diesel. It is constant 4WD with 31 10 R15 rims and tyres and has just clocked over 250 000 km.

On the open road here in WA I normally sit on 100 kph (though the max limit is 110 kph).

I don't really look at the tacho, but at that speed I normally get about 14.2 litres per 100 km on Biodiesel. On normal diesel I was getting about 14.4 - 14.6 litres per 100 km.

When towing my camper trailer it goes up around the 16 litres per 100 km.

Bearing in mind that these figures are based on the average of the trip taken and my old brain trying to do the mathematical calculations :-))

Karl

I have a 94 standard 80.
Stell bars front, rear and sides also roof rack.
DTS turbo I/C running 18psi.
All on 33" cooper st's

On average I run between 14 and 16l/100 with out roof rack, city driving (Lotsa stop and go)
On the open road at 95 - 100km/hr I can drop it down to about 12.5-13.5l/100km.

On a recent long trip from Brisbane across the Simpson to Alice, west to Broome and then up to Darwin, over to Townsville and then back to Brisbane the cruiser averaged just under 17.5l/100km total for the whole trip
Considering the cruiser was fully loaded and it towed a camper across the sandy bits I was quite happy with it.

Of course when I give it the right foot I also can get some shocking fuel returns.

I have the 92 80 series with the 1HDT... I run 33" muddies which have stepped the tyre size up 7% so my revs will be a little out of step with yours..

Basically at 100kph (93 by the speedo) I am running at 2200 rpm.. you can get a calculator out to work it out when at 110 but I would hazard a guess to say it is less than 2800..

Even with the stockies on at 100kph from memory I was running 2400rpm.. still coming in under the 2800rpm you say you are at when driving 110kph

As for fuel economy I have the 33" muddies on 24/7 with a 3" lift and have a drawer system with fridge etc in the back and I get consistent fuel figures of around 13L/100klm...

The fuel figures are not that fantastic when I read what some others say they get but that is an honest figure taking into account mainly suburban driving with plenty of stop and go.. on the highway I expect to get better figures but to be honest I think my figures get slightly worse... must be more economical to run at lower speeds with t he weight and tyre size etc..

I did a run to Cape York fully loaded with the family and pulling a trailer... I was regularly pulling 16 -17L/100 on the highway... I got better economy once I got off the black top and slowed down through the tracks etc..

I have had my fuel pump rebuilt and have the injectors done also with a dyno tune.. I have plenty of get up and go (2 1/2" sports exhaust and K&N foam filter) and the revs will freely wind straight up to over 4000rpm...

I am happy with the trade off for a bit of fuel to have the bigger tyres and lift etc and the convenience of the drawer system and fridge on hand whenever I want it..

Hope this helps..

all manuel tojos get around 40kph per thousand revs in 5 th this varies just a little but probably not enough to notice dependng whether it is ute or wagon (stock form)
Some simple maths means at 110 you should be doing 2750 considering speedo accuracys tacho accuracys and what position you sit in when you read the speedo and tacho- sounds spot on

92 80series GXL factory turbo diesel auto box 2200 revs +/ - 50revs =100kph. Fuel consumption varies ,town /stop start /hway /roof rack on /off ,towing c/t , boat on roof ect ,,Best ever 1100 klm on h/way for 130 lt , Worst ever fully loaded with boat on roof and towing c/trailer all on sand , 350klm used 65 lt ... = best 8.5klm per lt ,, worst 5.4klm per lt. Average for vehicle = 20 miles per gallon over its life span.

Any motor will return its best economy at maximum torque rpm, which translates into maximum eficiency....the t/d is about 2200, so slow down and you will return 10l/100. If you own a 4.5 cruiser however, no difference in economy whether you rub it to 3500 max torque or idle around at 1500....they seem to use thesame no matter how you drive them...
Andrew

We have an 91 80 series auto 1HD-T
Transmission is 4 speed Auto with Lock up converter (Effectivly making it a 5 speed)

8.6 km/litre at 100 km/h

7.8 km/litre at 110 km/h

Shocking around town
as low as
4.5 km /litre. Start, stop, short local drives

Standard wheels 31 x 10R

2300 RPM 100 km/h

2500 RPM 110km/h

Mine is a 1990 model 80 series landcruiser with 1HZ engine and aftermarket turbo.
I just did a run into town and mine also sits on about 2800rpm at 110km/h.

Cheers,
Brett