Fuel economy v engine health

[jimb]

Hi.
I spoke with mechanic before picking up 110 a month ago. He gave me some advice: gentle with handbrake, don't let it idle, drive it between 2000-3000 revs for the first few thousand Kms. ( good for engine "bedding in'?)
( this mechanic got rave reviews from multiple auto members)

So I was getting between 7.9km - 9km a litre (had some high luggage etc on one trip). The last tank I used lowest revs possible (that sounded ok with engine) eg used 5th at 70kph etc, and I just got 10.2 km/ litre.

I don't know much about engines.

Q. Is it bad for the health of a desiel engine to be in lower rev range?

I did that


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[isuzurover]

Lugging an engine (operating at too low revs for the gear) is bad for the engine and bad for the gearbox/driveline. You will have high torque pulses - especially with a 4cyl.

My old engine rebuilder's motto was: revs/working hard doesn't kill an engine - sitting at a constant speed on the highway is what kills engines.

That may only be partially true, however I find that hard work and occasional high revs don't hurt a diesel in the slightest. On the contrary, it probably helps remove carbon deposits...

EDIT - not letting an engine idle is very good advice. Driving as smoothly as possible (brake/clutch etc.) is also good advice. Sitting between 2000 and 3000 is also good, but don't be afraid to put the boot in from time to time.

[isuzutoo-eh]

Essentially, if the engine struggles it'll try to pump more fuel in until it isn't struggling. But most of that extra will be going out the exhaust pipe unburnt or clogging up the internals since you aren't letting it rev up.
Without a tacho you won't have any hard numbers to know what is working best but you'll soon learn by feel. Ideally you'll have a bit room to move both faster and slower in whichever gear is most appropriate.
I don't know the Puma's gearbox ratios but you'll probably find that 1st does the 1st gets you moving, 2nd will get you to 25ish, 3rd to 55/60ish, 4th to 80ish, 5th to 110+and 6th from 100 onwards if you aren't ascending.

[jimb]

[QUOTE=isuzurover;1605976]Lugging an engine (operating at too low revs for the gear) is bad for the engine and bad for the gearbox/driveline.

What is too low revs for the gear?
Sound, ability to accelerate, under 2000revs???


I certainly don't want to do the wrong thing.

The dealer told me to 'drive it like I stole it'. That all the press vehicles were always in best condition .(press being media outlets that reviewed them but drove them very hard)

Btw. Not scared to give her a
Kick in the guts, but does it need to be driven like that 100% of time to avoid things you mentioned : carbon build up?


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[Slunnie]

My thoughts are:

lugging the motor just soots it up and makes it inefficient.
Loading the motor, especially when running in is good for the motor as it beds the rings etc in properly. You can drive it like you stole it without revving the ring out of it.
Reving the motor increases wear - I believe that wear rates go up exponentially with revs used based on my experiences with racing motors.

I think you'll find a rev range where the motor is happy and it makes power. Thats about where you would stay. On a LR turbo diesel thats probably somewhere between 2000-2500 for cruising and then up to 3000 maybe 3500 for fanging. On a Toyota 1Hz thats probably from about 1000-2000.

[isuzurover]

What is too low revs for the gear?
Sound, ability to accelerate, under 2000revs???

Normally you can tell you are in too high a gear or too low revs if the vehicle accelerates slowly or roughly/hesitantly. With the lower NVH levels in a Puma, that may be harder to tell. I would try to keep it >2000 rpm and definitely >1500 rpm personally.

[jimb]

Thanks.

What does NVH level stand for?

Pretty easy to keep it 2000-3000. Sounds natural comfortable without being thrashed.


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[isuzurover]

[FONT="Tahoma"]Thanks.

What does NVH level stand for?

Noise, vibration, and harshness - Wikipedia, the free encyclopedia

[Naks]

Drive it gently until it's warmed up, esp in winter, and then drive it like you stole it.

[pannawonica]

Drive it gently until it's warmed up, esp in winter, and then drive it like you stole it.

I could not agree more, however this is not always possible when we are in built up area. Too this problem we have 2SO. Just ask white van man how hard Transits are to kill, not for the want of trying. Got to go now cyclone Heidi on the way must tie things down!