Diesel Inboards - Improving Output ?

[AMac]

Hi
does anybody have information on upping the output on inboard diesels such as yanmar and volvo`s

[biffer]

How old is the engine you're thinking about. Bigger turbo. Remap ? If you haven't got an engine yet I'd suggest getting a bigger one rather than trying to squeeze more out of a smaller one

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[AMac]

thinking about a few different boats at the moment
all around 7/7.5m and want top performance from them
most seem to be fitted with either the yanmar/toyota unit with 240 hp or the kad series of volvo`s with slightly less hp and both engines seem to provide approx 40mph in this size of boat according to owners
i would like to have slightly more top speed i.e. 50 mph and be able to get onto plane quicker
i presume that if the torque produced was increased this would allow a larger prop and quicker plane?
what engines can have a remap or what engines would give me the performance without tuning

[Zippy]

The Volvos in our Hunton have been tweaked from 350 to just shy of 400 a side. This was done by remapping but then of course you need to look at props and importantly cooling.

Would look first at reducing any excess weight on the boat as in light boats, weight is a killer and position of weight.

Props are a dark art and can start to cost lots of money if you are just playing. its worth talking to a prop expert for their suggestions.

[biffer]

I would say look for a better hulled boat. I've got a yam 240 hp in my 8.3 cabin rib and that does 43 knts. The yam is a better package ( IMO ). Lighter. Simpler
I did a 7.5 with a yam when I worked at ribtec and that did 46 knts. I had a old Avon searider 7.4 with a yam and we clocked that at 55 mph. The yam did a 275 hp from the same block and head as the 240. As said cooling was beefed up

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[Erin]

Originally Posted by AMac

seem to provide approx 40mph in this size of boat according to owners
i would like to have slightly more top speed i.e. 50 mph

I think that's a bit more than slightly. 25% is a significant jump in speed, especially in a boat which may require more than a 25% power increase to achieve it.

[willk]

That extra 10mph could take 80-100hp extra to achieve with an offshore hull. Any extra power will require a suitably rated drive leg. 25% is a HUGE increase in speed!

Biffer is right. Get a bigger engine and/or lose some weight on the boat. Removing all the crap and polishing the hull can get you an extra 3 mph or so...

[Robbie Diesel]

If its a newer Electronic diesels like the Volvo kad series or 'D' series, or any of the newer BMW based Yanmars this company Diesel Tuning by Tunit Diesel Performance With Over 2900 Applications sells tuning boxes that simply plug in to gain around 35hp. But as mentioned above you'll probably only see a knot or 2 for your extra 35hp!

[Quickflash]

Robbie,
Do you know if such a tuning set actually works on a boat? I looked at their website and although they do make them for Volvo's ( in my case a D6 370), I cant read any reviews which mention marine applications.

Thanks

[Cookee]

Those tuning boxes have a mixed review - some work and others don't, to do it properly for decent benefits you need to have the engine "Chipped" - we are looking into working with a local company to do this but we would need the boat!

[jwalker]

Always worth a search on ribnet.

[Quickflash]

Interesting thread, thanks,

[AMac]

What about fitting large intercoolers and remaping the fuel as this works well on vehicles?

[LURCHER]

We have a Humber 8.5 offshore with Volvo kad 44 and top speed is 36kn but she does weigh 3 tons!