Re: 1985 61 Hatteras MY with De-Tuned 12-71 TIs 2000 Hours
Quote:
Originally Posted by
rtrafford
I don't see any real fuel savings, as horsepower is needed to push the boat at a given speed, and horsepower is achieved by fuel consumption. Detuning, you're limiting the potential stress on the engine, allowing it to live a perhaps longer life (usually), and lessening the attachments necessary for maintenance and repairs. 12v71TA can be rated at 750 HP, but peel away the turbos and after coolers etc, swap the injectors, and reset the fuel pump and you'll only get the 450HP.
However you'll run her at a higher RPM to achieve the HP needed for the wheels to spin and speed to be achieved. If you compare the horsepower curves o the configuration, you'll likely find that your 14-1500 RPM max displacement cruise at 750 HP is now requiring you to push her at 2000 RPM to hold the same speed.
But, if you then back down to a slower displacement, say 9 knots instead of 11, you're saving fuel and long term maintenance. In theory.
Thank you for your contribution. If we decide to proceed hopefully a good survey will give us a good understanding of what is going on with these engines.
