If you could add 20 HP more to your R25 Calssic would you ?

[hughesdave123]

I was told that the "Cummins" 150 hp engine can be upgraded to a 170 HP setting , but that would require a New ECM. and the engine is perfectly fine running at 170 hp with the upgrade . I'm tempted to buy the upgrade ECM , but I wonder if 20 hp would make that much difference.

This is from Mercruiser Diesel Factory tech in my Area . the engine /ECM combo had different settings that they sold to boat builders same combo but in a 130 /150/170 ECM setting.

 

[Two killicks]

Would that change the rpm operating level to be more economic fuel wise?

Correct me if I am wrong, but I do not think that it would faster because of the hull shape.

 

[dkoivu]

In your considerations of upgrading your horse power, your hull design is good for 18 knots I believe. You also want to figure into the equation the prop diameter and the pitch because you do not want to over rpm your engine. You can run at full throttle part of the time but I believe it is recommended to run at 80 percent. (Just food for thought.)

 

[tlkenyon]

I have a 2015 R25SC but have wondered the same thing about my D3-150 Volvo. The 150 and higher versions of the D3 engine appear to have the same basic specs (bore, stroke, etc) but have different HP ratings. If I could replace the ECU and gain more HP, I would certainly do it, if for no other reason than some increased speed on those unavoidable occasions when it is needed. Might be more economical at low speeds also, because lower RPMs might be needed at lower speeds. Interesting.

Happy New Year!!

TK

 

[rick&sue]

Everyone has their own idea of how fast they want to cruise and top speeds they want to obtain. But since you asked - Based on my experience, I would not do it. It takes LOTS of HP (and fuel) to push a boat above hull speed. Your fuel consumption will be very high for the small increase in speed. I purchased the 125HP yanmar (110HP standard at the time) thinking the extra 15 HP would be beneficial. I'm finding out that I cruise at 2200 to 2600 RPM (reasonably quiet and great fuel economy)- well below the maximum torque and well below 3700 max. continuous RPM. My understanding is that diesels in general, should be operated at higher power settings. I'm worried that I do not run the engine hard enough. The minor difference between the 110HP and the 125HP in speed is buried in the "noise" of actually measuring it - dirty boat hulls, clean hulls, wind and wave conditions, salt water vs. fresh water, engine and prop condition etc. I know HP sells, and that you cannot have "too much", but I think the 110 HP yanmar is really the "ideal" HP for the R25.

 

[dkoivu]

TK,
Can you actually get an ecu from Volvo for your D3-150? If so, what does that do to your engine warranty?

 

[tlkenyon]

Indeed, it does take a lot of HP to push a displacement hull past hull speed. The R25 (Classic and SC) are semi-displacement hulls, not true displacement hulls. These are designed to take advantage of both displacement speeds and planing speeds, albeit without the full benefit of either - a typical boating compromise. Once planing speed is reached; however, additional HP will result in more speed, and that it why there is interest in additional (free?) HP.

I do not know of the ECU in the D3's are interchangeable, but I suspect not, as that would diminish Volvo's ability to charge more for the higher HP models. I suspect if an ECU were available, the warranty would not remain valid, but that is only supposition.

There are a great variety of "chips" available for diesels, but I do not know if there are marine-specific chips, or how they would effect warranty.

TK

 

[nzfisher]

There is a R25 out there with a 180 hp engine. I have read posts from them in the past. I think it might have been a replacement engine. It would be good to find out who it is and direct some questions to them. Typically as you probably know this is just new chip like the folks use to hop up their Dodge trucks. I am relatively sure that a new prop would be required to take advantage of the extra power over the current prop you might be using. I often wish for more power (speed) on the flat days when getting out to the fishing grounds seems to take forever.

 

[Bruce Moore]

We had a classic R-25 with the 150 Cummins. It was plagued by a cold-start problem which was eventually solved after reprograming the ECM several times. Cummins offered to upgrade the engine to 180 HP. Knowing little about engines I said I thought it would be too much hassle to swap engines. The guy looked at me funny and said, "it's just code - I can do it in a few minutes." So, minutes later our 150 HP R-25 was a 180 HP R-25 as a result of a firmware update.

We were new to boating and had very little experience at 150, so I can't really compare. But we loved the boat and the engine. We tended to go fast back then - you know, get to the next marina. So, we did cruise at 12-15 knots quite a bit.

Cheers,

Bruce

 

[tlkenyon]

Does anyone "know" someone at Volvo well enough to ask the question? I like the idea of a software upgrade that some with more HP.

TK

 

[Levitation]

A number of variables here:

150 hp X .80 = 120 hp (continuous)

180 hp X .80 = 144 hp (for how long?)

The primary limiter of continuous horsepower is the removal of waste heat. When the engine is running below maximum allowable temperature at 50% of available horsepower, increasing to 80% and holding it there for some period of time will result in the temperature rising to a new value and holding there.
Further increasing the power to 100% will result in a further increase in temperature over time eventually exceeding the value the manufacturer has determined as desirable - at least according to my engine manual by reading between the lines.
The manufacturer has determined by various methods the amount of heat the QSD 2.0 150-HP can dispose of within the expectations of a long service life is 120 hp Continuous. The fact that we can simply squirt more fuel into the cylinders via electronic injectors to make more horsepower does not increase the ability of the coolant system to remove the excess heat generated in burning that fuel. To do that will require a larger heat exchanger, larger coolant passages in the engine block and heads, larger oil passages for more oil flow and a larger oil cooler. (oil is the second largest path for heat removal)

Now, jumping up to 180 hp will work for some time as the internal temperature of the engine will ramp up over time before exceeding the maximum that results in rapid wearing of components. The unknown factor (to me) is what that time period will be at 180 hp. Is it 5 minutes, or 15 minutes, or what? Wondering about that I went to the manufacturer, Mercruiser.
http://www.firmansmarine.co.nz/i/images ... sd_2.0.pdf
Looking at the sheet reveals interesting facts.
1. The manufacturer does not show a 180 hp value
2. The maximum horsepower value is achieved by an RPM increase (in the table marked 'Power Ratings') to 4000 rpm
To achieve that on our boats will require a prop change to go along with the increase in the governor rpm limit to the new value.
3. Notice the sharp jump in fuel consumption for the 150 hp engine for a 600 rpm increase (table marked 'Fuel Consumption')
3400 rpm = 5 gph
4000 rpm = 9 gph

The 170 hp fuel curve shows an increase in fuel consumption:
3400 rpm = 5.6 gph / 0.6 gph more
4000 rpm is 9.9 gph / 0.9 gph more

I am unable to find any thermodynamic tables published online to determine how long one can push 170-180 horses before an over-temp condition.
My gut feeling is that without a prop change we will not notice much difference in the power level between 150 and 180 (claimed).

 

[tugnnaweigh]

Good reply's here, very insightful. On the Power Ratings chart is appears with the 20 horsepower jump you get only 2 foot pounds of torque increase and have to spin 400 RPM faster to get that.

 

[doke01]

I have the 125HP Yanmar on a 2007 R25 (classic of the classics), hull #7. If I could change a code to get more HP I would do it in a second. There is no ECU on the Yanmar. It is all mechanical, which is great. When you really load up the boat to take a long trip or have extra people on board those extra HP make a world of difference.