View Full Version : indmar 340hp

04-17-2005, 12:22 PM
can any one tell me what I should expect an outback to do top end with the new 340hp engine. Does anyone have an outback with that motor.

04-17-2005, 02:49 PM
water ski magazine clocked the outback with a 310 at 44.7 mph if that helps.

04-18-2005, 06:57 AM
He's right........I want to add.......the prop is about the same pitch (if not exactly) on the 340hp as the 310hp, so i think all you are getting is a little more lower end torque. I do not believe you're looking at any higher top end.

04-18-2005, 05:02 PM
Thanks for the feedback.

I currently have a 310hp and I agree that top end is approx 42mph pulling a footer. But, I wonder what is the effect of RPM. The new 340hp runs at 5250 rpm, which is 450 rpm more than my 310 carb motor.

If my math is correct, that is an additional 27,000 revs per hour. (450*60minutes). With a one-to-one drive ratio, I presume the prop is turning an additional 27,000 times per hour.

Therefore, thrusting the boat forward by its pitch, for instance 12" per rev, for an additional 27,000 revs per hour, hence, increased speed.

Let me state, I do not know much about prop pitches etc, but logically, and according to my math, an increase in rpm calculates to an increase in speed which I calculated to be approx 4 to 5mph gain. However, experience has taught me that actuality is always different. So I am wondering if it is really more like 2 to 3mph.

Does anyone have any experience with the 340hp motor.

Anyways, let me know your thoughts :)

Wake Master
04-18-2005, 07:48 PM
I have an 04 Mobius LSV with the 340 and top end is about 46 MPH with 2 people and smooth water.