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All of our curves
We recently had a request from a customer to show all of the power and torque curves of our VGT Series of engines on a single graph, for “at a glance” comparison purposes.
Take a look at the graph. Note how very flat power and torque curves are on our engines, and compare them to the curves of our competitors. The one below is for a Cummins QSB 6.7, medium intermittent duty (Comparable to VGT 450):
Note the spike in torque on the Cummins. Why does this matter? Well, the Cummins may have a higher maximum torque level, but it occurs at a spike, at a single RPM level. The VGT provides more torque, over a wider RPM range. This translates into lower cruising RPM (thus less fuel consumption) and more power at those speeds.
Size Matters: Comparisons Marinediesel Versus the Competition
On this site, we have often written about the compact size of the Marinediesel VGT Series, and how our engines will fit into cramped engine compartments when other engines will not. What is the real size difference? See for yourself in the table below!
|
Manufacturer |
Length (mm) | Width (mm) | Height (mm) | Total (m3) | % Difference | Weight (kg) |
|
Marinediesel VGT Series |
779 | 825 | 917 | 0.589 | 0% |
510 |
|
Cummins QSB 6.7 |
1097 | 910 | 857 | 0.856 | + 36.955 % |
659 |
|
Cummins QSB 5.9 |
1036 | 836 | 831 | 0.72 | + 20.015 % |
658 |
|
FPT N67 |
1089 | 724 | 786 | 0.62 | + 5.128 % |
600 |
|
Volvo Penta D6 |
1037 | 773 | 885 | 0.709 | + 18.49 % |
699 |
|
Yanmar 8LV-370 |
1133 | 884 | 823 | 0.824 | + 33.26 % |
435 |
| Yanmar 6LY3 – STP |
1071 |
802 |
793 |
0.799 |
+ 30.259 % |
640 |
| Yanmar 6CX-530 | 1340 | 886 | 934 | 1.11 | + 61.33 % |
837 |
Engine Comparisons: VGT500
This week, we will be highlighting several of our engine models and be comparing them with others that are in the market. Our engines stand on their own merits. All data on other engines is available online. Comparisons are based on closest models / ratings for each manufacturer.
We start with our flagship product: The MarineDiesel VGT 500. Using the Duramax 6.6L as a base, we have created the lightest, smallest, and most powerful marine engine in the market today. Ideally suited for small, very fast craft, the VGT 500 delivers the high performance standards that simply leave other engines lacking.
Figures are based on commercial rating, when possible (Some manufacturers only have one rating, others have multiple ratings.)
Some specifications:
| Engine Comparison | MarineDiesel | Volvo | Cummins | Yanmar | Iveco / FPT |
| Engine Model | VGT500 | D6 435 | QSB 5.9 | 6LY3-ETP | N67 560 |
| Retail Price (Manufacturer’s Suggested Retail Price, online. Prices may vary significantly. Add’l discounts may be avail) | € 41,552 | € 57,976 | € 44,144 | € 41,905 | €40,929* (UK Only, Sale Price) |
| BHP | 500 | 435 | 472 | 480 | 500 |
| kW | 373 | 320 | 352 | 353 | 368 |
| RPM | 3600 | 3500 | 3400 | 3300 | 3000 |
| Cyl | 8 | 6 | 6 | 6 | 6 |
| Displacement (l) | 6.6 | 5.5 | 5.9 | 5.8 | 6.7 |
| Bore / Stroke (mm) | 103/98 | 103/110 | 102/120 | 106/110 | 104/132 |
| Maximum Torque Nm | 1130 | 1040 | 1278 | 1280 | 1500 |
| Time Between Overhaul (hours) | 2500 | 1000 | 2000 | 1000 | 1500 |
| Time Between Maintenance (hours) | 100 | 50 | 75 | 50 | 100 |
| Dry Weight | 510 | 699 | 612 | 640 | 650 |
| Fuel Cons at Top Speed g/kWh | 230 | 208 | 232 | 228 | 215.5 |
| Power / Weight kW/kg | 0.73 | 0.46 | 0.58 | 0.55 | 0.57 |
| Euros per kW | € 111.40 | € 181.18 | € 125.41 | € 118.71 | € 111.22 |
| Overhaul Cost (60% of New) | € 24,931.20 | € 34,785.60 | € 26,486.40 | € 25,143.00 | € 24,557.40 |
| Cost at 10,000 hours (Purchase, Overhauls, and Maintenance) | € 141,279 | € 405,836 | € 176,579 | € 293,339 | € 204,647 |
| Fuel Cost at 10,000 hours, Fuel EUR 0.80 / Litre (Calculated at 435 hp) | € 710,476 | € 633,905 | €733,728 | € 696,830 | €656,761 |
| Total Cost of Ownership 10,000 hours | € 851,755 | € 1,039,741 | € 910,310 | € 990,169 | € 861,408 |
So, engine weights are listed in the table above. What about engine size?
(L) X (W) X (H), in mm
MarineDiesel VGT 500: 779 X 825 X 973 (Note: MarineDiesel engines always allow for remote location of some components, such as the grid cooler, filters, or starter motor. Dimensions, particularly height, can often be reduced considerably or shifted around to a great extent.)
Volvo Penta D6 435: 1,456 X 753 X 897
Cummins QSB 5.9: 1,255 X 836 X 858
Yanmar 6LY3 – ETP: 1,458 X 801 X 793
FPT N67 560: 1,063 X 843 X 766
Curves:
When comparing power, and especially torque, curves, you need to keep in mind how the vessel will be used. All engine manufacturers rate their engines differently, many times with several different ratings under a single model. Others, like MarineDiesel, can change the ECU and engine programming to suit a vessel’s mission. The curves below are the most common ratings, but when reviewing, attention must be given that these curves can be different or altered due to rating.
MarineDiesel VGT 500:
Volvo Penta D6 435:
Cummins QSB 5.9 472:
Yanmar 6LY3-ETP:
FPT N67 560:
Comparing Torque Curves – VGT 400 vs Volvo Penta D6
MarineDiesel’s VGT Series of high speed marine engines are the lightest and most powerful engines in the marine market today. Don’t just take our word for it, though. Compare for yourself! In this article, we compare the torque curves of the VGT 400 with the Volvo Penta D6:
Volvo Penta D6 Torque Curve
VGT400 torque
Note the “flatness of the VGT’s torque, as compared to the “spike” on the Volvo Penta.
Diesel versus Petrol: What’s the advantages and disadvantages?
We occasionally get asked by our customers whether or not they should put a diesel engine in their vessel, or a petrol engine. As with everything else in life, there is no single “right or wrong” answer. We manufacture both types of engines, so we are truly non-biased in our opinion. The answer is, “It depends.”
Ask yourself these questions:
What is the purpose of the vessel?
How will the vessel be used?
What are the emissions regulations in my area?
What is my budget?
These all have an impact. So, to make things easier to break down, we will use diesel as a starting point, listing advantages and disadvantages versus petrol.
Advantages
- More efficient combustion versus petrol. Diesel engines have a much higher output of torque than petrol engines. Given the same horsepower on two engines (see below), the diesel will provide more work for the fuel spent.
- Much longer life cycle that petrol engines. As much as three or four times longer. Petrol engines work “harder” to produce the same power, and are more complex, thus needing more frequent maintenance.
- Diesel is cheaper than petrol (At least in most of the world).
- Much lower fuel consumption.
- Petrol has a greater risk of explosion and fire. Requires greater ventilation.
- Diesel engines produce much less heat, and are cooled more efficiently. Petrol engines can require substantial cooling systems at greater cost.
Disadvantages
- Diesel engines are usually more expensive than petrol engines, often up to twice the price.
- Diesel engines produce more smoke with dirty fuel (Though ULSDF required in Europe and the USA is actually cleaner than petrol).
- Diesel fuel breaks down rapidly. If engines will sit for long periods of time, the fuel will need to be stabilized or drained.
The pictures below illustrate two MD engines’ power and torque curves, showing a big difference in torque, but producing the same horsepower.
MD VGT 400 diesel power and torque curves.
Life Cycle Cost Calculator
At MarineDiesel, we often come across potential customer who are confused about which engine to purchase. Yes, there are brand loyalties at play in any power decision, yet, more often than not, cost and price usually plays the biggest part in purchasing decisions, often eclipsing performance or technical requirements.
However, when choosing between two engines, much more goes into the cost calculation than simply purchase price.
Yes, very inexpensive engines are available in the market, usually, but not always, produced in China. Though these engines may be cheaper to purchase outright, their real cost becomes evident when maintenance, service life, and fuel consumption are taken into account.
When choosing an engine, you need to look at the following factors:
Purchase price
Engine rating
Life Cycle
Time between overhauls
Time between service
Fuel consumption
Cost of engine downtime
Cost of spares
Cost of service / labor
All of these factors add to the real cost of an engine, and in comparing one engine to another.
Therefore, in order to make your purchasing decision easier (Whether you choose us, or not), we have made the calculator below available for download for your use, free of charge.
Simply fill in the blanks indicated by yellow, and your real cost is indicated at the bottom. The spreadsheet is pre-loaded with the data from our VGT Series.
We hope you find it useful and helpful in making engine comparisons.
VGT Series vs Cummins QSB 5.9 – How do we Compare?
The VGT Series of marine engines is MarineDiesel’s flagship product. We originally aimed to make the lightest, most powerful, most reliable engine available in the market, and we succeeded where others have not.
So, how does the VGT Series compare to others?
Price:
MarineDiesel VGT: Mid-range
Cummins QSB 5.9: Low
*Price will vary greatly based on many factors, including import duties and dealer markups, but in general
Cost of Spares:
MarineDiesel VGT: Mid-range
Cummins QSB 5.9: Mid-range
*Note: The Cummins engines are sold and serviced through the CMD network, which is largely focused on the recreational market
Rating:
MarineDiesel VGT: Commercial / Military Medium to Heavy use
Cummins QSB 5.9: Recreational
Engine Block:
MarineDiesel VGT: V-8
Cummins QSB 5.9: Inline 6
*Inline cylinder arrangements tend to produce higher levels of vibration
Weight:
MarineDiesel VGT: 500 kg
Cummins QSB 5.9: 658 kg
Fuel Consumption:
MarineDiesel VGT: Max 220 g / kWh
Cummins QSB 5.9: Max 235 g/kWh
Curves:
Cummins QSB 5.9 Power Curve
MD VGT 450 Power and Torque Curves
VGT Series vs Yanmar 6LY3 Series – How do we compare?
The VGT Series of marine engines is MarineDiesel’s flagship product. We originally aimed to make the lightest, most powerful, most reliable engine available in the market, and we succeeded where others have not.
So, how does the VGT Series compare to others?
Price:
MarineDiesel VGT: Mid-range
Yanmar 6LY3: Inexpensive to Mid-range
*Price will vary greatly based on many factors, including import duties and dealer markups, but in general
Cost of Spares:
MarineDiesel VGT: Mid-range
Yanmar 6LY3: Expensive
Rating:
MarineDiesel VGT: Commercial / Military Medium to Heavy use
Yanmar 6LY3: Recreational
Engine Block:
MarineDiesel VGT: V-8
Yanmar 6LY3: Inline 6
*Inline cylinder arrangements tend to produce higher levels of vibration
Weight:
MarineDiesel VGT: 500 kg
Yanmar 6LY3:640 kg
Fuel Consumption:
MarineDiesel VGT: Max 220 g / kWh
Yanmar 6LY3: Max 221 g/kWh
Curves:
MD VGT 450 Power and Torque Curves
MD VGT450 Fuel Curve
Yanmar 6LY3 ETP Power, Torque, and Fuel Curves