Boost Preasure?

[Captain Mike]

I have a 2016 25 foot with the Volvo D3 engine. I have been having some issues with trying to achieve full power. The issue was finnaly tracked down to the turbo fans so the unit was removed, cleaned up and re installed. the boat does have more power now but I am questioning if it is full power.
Does anyone know what the boost preasure should be, I am only getting 1.3 - 1.4lbs. This will give me a top speed of about 17mph at 2900 rpm.

everything I have read about this boat is that it should do a little better speed wise?

 

[S. Todd]

I don't have that model anymore so I can not verify the boost pressure, but your speed at 2900 RPM does not sound too far off depending on how you have the boat loaded and the condition of the bottom ( painted will slow it down about a mile per hour from what I understand and unwanted growth even more). Our maximum speed with our R25SC and that engine was generally 18 MPH and about 2920 RPM unless there was less than a half tank of fuel when it would get to 19 MPH and RPM of 2960. With a tail wind we could occasionally get RPMs of 3000 and hit 20 MPH (but never with full fuel and water on board). We were careful to take minimal and light weight cooking equipment and not load it down with too many unnecessary provisions not needed for that particular trip. Our hull bottom was always clean without paint (stored on its trailer and waxed every year). When we travelled with other Ranger Tugs that should have run with us, we always outran them at full throttle.

 

[BB marine]

I can not give Boost pressures for a 150 D3 but I can for a D3 220 hp. 2200 rpm 8.5 PSI, 3200 rpm 17 psi to 19psi, 3400 rpm 23psi psi, 4000 rpm 28psi

I can assure you that at WOT your boost pressures should be close to 20 +/- The fact that you are hitting 2900 rpm and not seeing all kinds of black smoke behind you I would say that your air temp/ boost sensor is not working or registering. I would suspect there should be a code for low boost pressure. I don't think you would see that performance if the boost was at 1.3 to 1.4.

 

[Mr Ben]

I just took my 2016 25sc for a short run yesterday. WOT I had boost of 20 with rpm at 3000 and speed of 16-17 knts. I do have a season of marine growth in a fresh water canal, but I think the engine is governed at that 3000 rpm. I also had my prop scanned and tuned at Holland Propeller in the spring that really helped with vibration.

 

[NorthernFocus]

Sounds like your panel might be set to read bar/atmosphere rather than psi. As bb said no way you could get that performance with that low pressure.