Nanni T4.200 cruising revs?

[hchawner]

Hi,

I have a Beneteau Antares 8 with a 200HP Nanni T4.200 engine. Quite often I cruise at WOT (c 3600 rpm) which doesn't see to do any harm to the engine (temperature and oil pressure are fine).

However this obviously uses a lot of fuel, and may put some strain on the engine (although it seems fine).

My question is what rpm do others use for cruising in similar (or identical) engines/boats?

Also, does it do any harm running these engines at WOT.

The max rated rpm is 3400, and I have been advised that 3200 is a good cruising rpm for the nanni T4.200.

Thanks
Hugh

 

[Spi D]

You have received good advice. Keep it at least 200 rpm below max achieved rpm @ wot for extended periods.

 

[PaulGooch]

The OP has also been advised to run the engine at 2720 RPM. IMO, this is too low and the boat will not be fully on the plane at this RPM.

Be interested to hear what other Series 8 or Antares 760 owners use as a cruising RPM.

 

[Spi D]

As you appear not to have the owners manual you can get it here
http://www.nannidiesel.com/images/stories/manual/M1KD/Notice de conduite M1KD ENG.pdf

Check bottom of pg.2:

The recommended cruising speed is 200 rpm below the maximum rpm speed at full throttle

 

[hchawner]

Thanks Spi D, yes I see the manual recommendation.

As Paul says, I would be interested in the experiences of other Antares 8, or 760 owners, or Merry Fisher 805 owners (I believe the MF 805 has a similar engine setup).

 

[mm1]

max rpm

hi correct me if i have misunderstood but you appear to be over revving @wot,so your cruise speed should be less than 3200,how would you like to run your car all day with the rev counter 200 rpm in the RED secter,these are leisure engines i beleive & as such are not meant to be run flat out for extended periods,(imho)regards mm1.

 

[Spi D]

Engines that are allowed to run flat out for extended periods are reduced in output and/or rev limited, often equipped with extra oil capacity and instruments like pyrometers etc. for closer monitoring of things happening. This is why commercial series of otherwise identical leisure engines are rated lower hp.

The base engine in question (1KD Toyota) has a redline at 4200 rpm and is rated for 3600 rpm in some configurations. The boat's weight has a huge impact on rpm, so bringing an extra person or gear may change things (as will growth on the bottom).

In general it is beter to overrev (slightly) than to 'underrev' at WOT because struggling puts the engine under way harder load. Like a car: Uphill and full load takes a lower gear and easy spinning - not a higher gear and full throttle.

When manufacturers recommend rpm @ wot as a range you aim for the upper limit - at normal load & use - to get performance and mpg

 

[hchawner]

Thanks guys.... will experiment at 3200 rpm.... once the wind drops below 30 mph !!!

 

[hchawner]

One further point. I actually get 3600 rpm at WOT, but the rated max rpm is 3400.

Will still go for 3200 rpm for cruising...

 

[Latestarter1]

Your vessel appears to be propped spot on if you are getting 3,600 'clean' with RATED RPM of 3,400. And 3,200 would appear just about OK for cruising.

However there is much misleading terminology in this thread.

This is a light duty automotive base engine pulling 67Hp/liter, treat it the wrong way and it will have the durability of a disposable cigarette lighter. This bears NO relation to the engine color just the engine class.

Our friends at Nanni have produced an pretty decent spec sheet with a few glitches in translation.

#1 No such thing as over revving a diesel engine, lets put that term in the bin.

#2 Rated rpm is the point on the power curve where engine produces maximum power. Engine will rev higher however governor is gradually reducing the amount of fuel (power) after rated speed is reached. This is referred to as the governor 'droop'. Why do we have 'droop'? Automotive applications would be horrible if near impossible to drive if engine had isochronous (zero droop) governing. Normal industry practice is for non electronic marine engines to have 10% governor droop, electronic engines far less. In the case of our Toyota base is an automotive engine, therefore droop is around 12% i.e. 4,000 rpm high idle.

#3 Because vessel is sensibly propped and able to pull 3,600 rpm at WOT, this figure must NEVER be used as the headline rpm# if manufacturer quotes cruise at 200 rpm 'off the top'.

#3 Why is this vessel sensibly propped? Quite simply that you can never expect to pull 100% of spec sheet power out of any engine, particularly LDA and expect it to live. Taking a look at the prop curve we are asking no more than about 170 hp at rated rpm. Realistically you can never have ALL the power you have paid for.

#4 Looking at cruise rpm another way, regardless of how HP has gone up per liter over the years and the quality of the base product has gone up with it (it really has), you'll find that if you want 10-15 yrs of engine life running at say 200 hrs/yr in recreational service in the typical planing boat that is sold for its "performance" qualities on plane, you should restrict your consumption to NO more than 2 gallons hr/liter.

Stick to the rules and life will be good.

 

[Nahlu]

Hi,

I have a Beneteau Antares 8 with a 200HP Nanni T4.200 engine. Quite often I cruise at WOT (c 3600 rpm) which doesn't see to do any harm to the engine (temperature and oil pressure are fine).

However this obviously uses a lot of fuel, and may put some strain on the engine (although it seems fine).

My question is what rpm do others use for cruising in similar (or identical) engines/boats?

Also, does it do any harm running these engines at WOT.

The max rated rpm is 3400, and I have been advised that 3200 is a good cruising rpm for the nanni T4.200.

Thanks
Hugh

What size of propeller do you have please?

 

[rpetersson]

TS was last seen here in 2015. I can share my propeller properties as I have the same boat model, with original propeller from 2010. This is the imprinted text on the prop:

1. ZF-FPS
2. D.22 P.20 VRH
3. E.A.R.0.75NA