? for 380 DA owners with 8.1s engines

[Pseudomind]

What would you consider your normal cruising RPM range and speed. I am talking about relatively calm water and not attempting WOT, just a day to day cruise settings

Thanks

:thumbsup:

 

[Southpaw II]

3200 @ 22 kts.

 

[RollerCoastr]

Southpaw, have you experimented with bumping that up a bit?

I get better economy at 3500 than I do at 3200, albiet in a different boat and different engines, but Boattest's results also put the cruise speed of even more similar boats with that power in the 3500 rpm range.

 

[Pseudomind]

Thanks, I will look into this. These figures give me a ballpark to start

Have a great weekend

:thumbsup:

 

[osd9]

From my 2002 380DA with 8.1s...Speed was measured with GPS, GPH was taken from Smartcraft and sMPG were calculated.

This was an average of an East and West run up/down the Toms River in ideal slack tide conditions with 7/8 fuel, 2 POB, water empty, light wind and pristine bottom conditions...(Just put the boat back in the water after a bottom job and prop reconditioning) I had the props tuned for 4600 WOT RPM.

RPM----KNOTS----GPH-----sMPG
3200---19.9 ------27.9-----.821
3300----20.2-----28.1-----.826
3400----21.5-----28.5-----.867
3500----22.9-----30.5------.866
3600-----23.8-----31.9------.859
3700-----24.8-----33.6-----.848
3800-----25.4-----36.1-----.809

 

[Southpaw II]

I have no idea what my gph burn is......as I just run where it feels good. It's interesting to see what other people are acually getting. I'm on a land locked lake and can't go far anyway. My boat originally came from NY and had 7.4s, but were replaced under warranty after 175 hrs. with 8.1s. I bought the boat in Tampa about 5 months ago and have been impressed with the torque it has. Do all of these boats have the same drive ratio in the v-drive. I think mine is 2.5:1.....wondered how much it would affect fuel burn.

 

[Pseudomind]

I have the 2.5:1 ratio and will probably have to lower my RPM many times do to primarily boating on the St. Johns River and the ICW when traveling. there are some stretches though where one can open up a bit.

:thumbsup:

 

[Southpaw II]

3200 is really the bare minimum for me with no wind or chop...pretty normal on our lake. More typical is probably 3400.

 

[mawyatt]

3350~3450RPM at 0.65~0.75mpg seems to be the sweet spot for us.

 

[Pseudomind]

From my 2002 380DA with 8.1s...Speed was measured with GPS, GPH was taken from Smartcraft and sMPG were calculated.

This was an average of an East and West run up/down the Toms River in ideal slack tide conditions with 7/8 fuel, 2 POB, water empty, light wind and pristine bottom conditions...(Just put the boat back in the water after a bottom job and prop reconditioning) I had the props tuned for 4600 WOT RPM.

RPM----KNOTS----GPH-----sMPG
3200---19.9 ------27.9-----.821
3300----20.2-----28.1-----.826
3400----21.5-----28.5-----.867
3500----22.9-----30.5------.866
3600-----23.8-----31.9------.859
3700-----24.8-----33.6-----.848
3800-----25.4-----36.1-----.809

osd9

If these figures are from a 380 with 8.1s engines the figures at least for a given RPM and the speed are around what I got yesterday

I did not check all, like in your chart but for these RPM's, 3200. 3400, 3600, 3800 RPM's

 

[Feet From Satisfied]

Looks like the sweet spot is around 3400-3500:smt038