How hard can I drive it

I'm all about making my vehicle work, but at the same time, not flog it, so I get the most out of it: How hard can I drive it?
For example, being a modern diesel (D40 MY10 2.5lt 6sp) do I drive it at higher revs or more under load (lower revs)?
I've always learnt (from my old-school truck-driver dad) that diesels like a load more than work at high revs, but as I drive this, I can feel and hear the engine just seems to shine at revs between 2k-3000.
Being a 6speed I cruise in top gear at about 2200-2300rpm but driving a lot on remote long straight roads I often run at the high 2K (2800-2.9k) and I like to drop back a gear when over taking so 5th gear at 3000rpm.
Thats on the open road; around town I like to run at 2k and under.
So which is best - low revs or higher?

Depends what you're driving it for and what you're doing with it.

If you want economy, limit your rpm to about 2500 and let the diesel's torque do the work. It certainly isn't as quick that way, but you'll be able to get down to (or below) the rated consumption that way.

If you want power, let it sing. I've cranked it up around the 4000rpm mark and it definitely has some pizzaz up there - but it consumes fuel to do it. I should add here that at 4000rpm the engine does sound like it's running itself hard and I wouldn't want to push too much beyond that - but that's me.

The big killer with fuel is speed. Sitting over 95km/h will start to drain your fuel tank, but if you don't mind the extra consumption then take it out to the speed limit. We took our caravan to Uluru last Christmas and on the way up there, I sat on 120-130km/h for part of the way (I was surprised to see a 130km/h zone) and with the 1.8T double-axle full-height caravan (pics in my garage) on the back, fuel consumption rose by 2LPHK.

Does that help?

Thanks for the post, but it's not really what I was after. I was more hunting for a wear'n'tear point of view as to run the engine regularly, with regular driving, with revs down low or rev it up some before changing gears.
I've found with mine (4months old and 25,000ks) that I average 10.8lt/100k and on a recent trip was travelling 130km some of the way and found that I only increased consumption by .4lt/100k (11.2). I've tried all sorts of combinations (being a new car I've tried to find it's sweet spot) and with air con and cruise on and off and at different speeds, and found that there's minimal difference between sitting below the speed limit (95'ish) and slightly above it (110) - but you got to love those Territory roads.
So, I'm more after how the engine is going to like me changing gears at 2000rpm or will like it more at 3000rpm?

I drive like an old man usually, both to conserve fuel & vehicle, and for safety. Also with only 62,000km on the clock, my (first) Navara is still a very young vehicle - so I have no experience to give you a definitive answer on your precise question.

That said, the little 2.5 diesel is not an ordinary motor. Designed by Renault, it's got some quirks and things that need attention to - like making sure the turbo is okay, trying to use good fuel and avoid dirty fuel etc - but I don't believe that driving it a little harder like you're suggesting would be overly detrimental to the motor.

Bosshog has one, has chipped it with a wickedly powerful custom tune and drives it hard - 30,000km and it's going strong (the MAF sensor isn't part of the engine).

I would imagine that changing at 3,000-3,500 wouldn't be a problem for this engine, but the same caveat exists for any engine - the harder you drive it, the sooner it will wear out. It is, no matter how well assembled, still made of metal and metal does have limitations.

I do recommend getting an EGT gauge and monitor the engine's output at the exhaust manifold before the turbocharger. If your EGT rises over 750C you should start backing off - that's the point where the alloys in the motor can be structurally affected.

You might also like to have a look at the rebuild that is going on at this link: Project: 300 (diesel hp...) nearly done! - Nissan Frontier / Navara Forum

This guy obviously isn't married or has oodles of spare cash lying around.....but 300 horses from the little 2.5...now that is something.

I am not afraid to give mine a boot full. Always have put the foot down to get around.

From what I have seen, especially with the GU 3L's. The ones that are worked and driven hard last.

Same goes for Ford Rangers. The young blokes with Telstra drive them hard and have no problems. The older blokes who baby them, have had cracked heads and blown head gaskets.

Putting the foot down and getting them working ain't a bad thing.

Red is bad...everything before that is OK.
In general and encompassing all internal combustion engines. A varied load and varied revs is better than a constant. Prevents glazed bore, burnt valves, carbon build up etc etc.

Sidenote and completely off topic but a bit relevant. Talking to my sister last week. She was talking about her old Holden Ute and that it was being a pig. Took it in for a service and a tune up....no better. Her solution? Take it "out the back and give it a floggin' ". "Should have seen the black smoke coming out of it at 160kmh!". "Heaps better now"
LOL she lives in Horsham.

Aido said:

Red is bad...everything before that is OK.
In general and encompassing all internal combustion engines. A varied load and varied revs is better than a constant. Prevents glazed bore, burnt valves, carbon build up etc etc.

Sidenote and completely off topic but a bit relevant. Talking to my sister last week. She was talking about her old Holden Ute and that it was being a pig. Took it in for a service and a tune up....no better. Her solution? Take it "out the back and give it a floggin' ". "Should have seen the black smoke coming out of it at 160kmh!". "Heaps better now"
LOL she lives in Horsham.

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haaaaaaaaaaaa, love the old school stuff!