Nanni

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Tank

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Hello Gents & ladies
I wonder if any of you techy / smartarse types ;-) can tell me if it is possible to get more power out of my Nanni 5.250 TDI?
she puts out 85hp from 2.5 litres and 5 cylinders, it is a Kubota base engine, is it poss?, and if so , where would i start? and would it cost a bloomin bundle?
regards
Tank
 
Possible yes advisable no; tuning diesels is an expensive mug's game. Even the ones it's (relatively)easy to tune like the Cummins B with the electric brain, more often than not the outcome is **** fuel economy and grenade-like durability. If you want to go faster fit a more powerful engine; it will be cheaper to do that now rather than after you've spent money tuning the current mill and then had it put a leg out the bed and spoil your day's boating. For a marine engine 85 horse from 2.5 litres is already quite highly tuned, asking more of it is a bad idea.
 
Diesel tuning can be a doddle, depends on the engine. More modern engines can be tuned to good effect by re-mapping or inline chip kits. More often than not, the increase in power comes with an increase in MPG, provided it isn't run constantly flat out, which in a boat may almost be the case.

85 HP from a 2.5 litre 5 pot is hardly highly tuned. The 3.0 4 pot 4.390 Nanni turns out 200 HP, this was also produced in lower HP versions, so would not have been destructive to have increased the HP, may well have been very expensive though. The 1.7 litre Mercruiser is 120 HP and the new Nanni T4.170 produces 170 HP from just 2.0 litres. On the other hand, the Nanni N4.85 is a 3.0 litre 4 pot and puts out a mere 85 HP.

The real obstacle here is the base engine. It's a bit of a plodder really and is a bit old hat. I'd also suggest that this one isn't worth interfering with.
 
Leave it be

Boat engines are under load the whole time, no matter what revs you are pulling, the makers have decided what power will be good for their engine, and set it as such. You can get a lot more power from them but the reliability will suffer. Take F1 as an example.
 
PaulGooch said:
Diesel tuning can be a doddle, depends on the engine. More modern engines can be tuned to good effect by re-mapping or inline chip kits. More often than not, the increase in power comes with an increase in MPG, provided it isn't run constantly flat out, which in a boat may almost be the case.
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Clever trick; there's a lot of money to be made if you can subvert the laws of thermodynamics.;)

PaulGooch said:
85 HP from a 2.5 litre 5 pot is hardly highly tuned. The 3.0 4 pot 4.390 Nanni turns out 200 HP, this was also produced in lower HP versions, so would not have been destructive to have increased the HP, may well have been very expensive though. The 1.7 litre Mercruiser is 120 HP and the new Nanni T4.170 produces 170 HP from just 2.0 litres. On the other hand, the Nanni N4.85 is a 3.0 litre 4 pot and puts out a mere 85 HP.

The real obstacle here is the base engine. It's a bit of a plodder really and is a bit old hat. I'd also suggest that this one isn't worth interfering with.
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It is highly tuned for a non-common rail marine diesel, it will be leisure rated or perhaps light commercial. The other engines you have cited are (I believe) common rail which is a whole different ball game. They are more readily tunable; the example I cited, the Cummins B, the current QSB model is available with power ratings between 225 and 480 horse power. I would be surprised if the differences between the various models extended beyond the injectors, pump mapping, turbo and intercooler capacity.
 
Just for the record, I was always told that the Nanni 85Hp base engine comes from the Kubota digger. Basically a baby tractor engine.

As for fuel consumption, I believe Paul may have been referring to a bigger engine being used to push the same boat at the same speed?
If so I concur.

I have the Nanni 175 (4.380) which is the same base engine as the previously fitted 155 and also the 200 (which Paul has).

My new engine uses fractionally less fuel for the same cruising speed or a slightly faster cruising speed for the same amount of fuel as my previous 155.

Power to weight ratios???
 
Do a little reading on diesel tuning before you comment.

The Toyota base Nanni engine, which comes in three rating of 155 HP, 175 HP and 200 HP are all the same base engine, in different states of tune. All are NOT common rail. The Mercruiser/Cummins in actually an Isuzu engine, formally fitted to MK3 Astras and a few Cavaliers, it is also NOT common rail. The only one of the engines i mentioned that IS common rail is the new T4.

Increasing the power of a diesel engine usually results in better economy, fact. The extra horses get the engine up to cruising speed quicker, for one thing. There will be exceptions, one of which will be where the engine is run WOT, it will then usually use more.

There are lots of examples in modern car diesels where the only difference in HP ratings is the mapping of the ECU. This is why they are so easily tuned. For example, the VW 1.9 TDi PD engine was available in a variety of rating, from 100 BHP to 150 BHP, all the same basic engine. Even the 150 BHP was conservatively mapped and capable of further tuning.

Doesn't alter the fact that in the case of the OP, it's better left alone.
 
PaulGooch said:
Do a little reading on diesel tuning before you comment.

The Toyota base Nanni engine, which comes in three rating of 155 HP, 175 HP and 200 HP are all the same base engine, in different states of tune. All are NOT common rail. The Mercruiser/Cummins in actually an Isuzu engine, formally fitted to MK3 Astras and a few Cavaliers, it is also NOT common rail. The only one of the engines i mentioned that IS common rail is the new T4.

Increasing the power of a diesel engine usually results in better economy, fact. The extra horses get the engine up to cruising speed quicker, for one thing. There will be exceptions, one of which will be where the engine is run WOT, it will then usually use more.

There are lots of examples in modern car diesels where the only difference in HP ratings is the mapping of the ECU. This is why they are so easily tuned. For example, the VW 1.9 TDi PD engine was available in a variety of rating, from 100 BHP to 150 BHP, all the same basic engine. Even the 150 BHP was conservatively mapped and capable of further tuning.

Doesn't alter the fact that in the case of the OP, it's better left alone.
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Paul I certainly agree with your last paragraph, not too sure I concur entirely with the rest.

Digging into my data bank pretty sure Kubota 5.250 is an indirect injection motor, 23.5:1 compression ratio is the clue. Indirect injection motors do no lend themselves readily to being juced up. Temperature gradients in pre combustion chamber engines take off like a rocket ship leading to potential head cracking, also adding more juce also reaches a stage where you are tending to quench the charge in the pre-chamber.

Hot rodding marine motors is not smart, as suggested it is better left alone.
 
Latestarter1 said:
Paul I certainly agree with your last paragraph, not too sure I concur entirely with the rest.

Digging into my data bank pretty sure Kubota 5.250 is an indirect injection motor, 23.5:1 compression ratio is the clue. Indirect injection motors do no lend themselves readily to being juced up. Temperature gradients in pre combustion chamber engines take off like a rocket ship leading to potential head cracking, also adding more juce also reaches a stage where you are tending to quench the charge in the pre-chamber.

Hot rodding marine motors is not smart, as suggested it is better left alone.
Click to expand...

If you read the first line and the last two lines of my first post, you'll see that we're actually in agreement regarding the OP's engine :)
 
Thankyou for all your reply's gents
After reading all your posts and getting slightly confused
i believe that i will let well alone,she is a sweet engine, but, wait a mo, what about a bigger prop? would that work? or is that another Pandora's box? i may be clutching at straws here i know, surely jeanneau would have propped her to perfection? but from what i have read on this and other forum, proper propping ( does that sound right ) is a dark and sinister art, or would trim tabs help? or , should i do as SHMBO say's and be bloody gratefull for what i have now :-)
regards
Tank
DSCF6990.jpg
 
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The simple answer is; it depends. If when carrying a full load(fuel, water, kibble, beer, equipment and pax) and giving WOT, the engine is whizzing up to the limiter, then a change up would be beneficial. If it reaches peak power revs or slightly higher the prop's a good match, leave well alone. If it bogs and struggles to get over 2000rpm, then down propping is called for. This is complicated by hull form, planing characteristics, trim, fouling, price of bananas etc. Gerr's Propellor Book is a good read for this.

Trim tabs; try adjusting trim using ballast. If it has a big effect on speed, fit some. If not, don't bother.
 
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