Yanmar 4JH4HTE Abregeldrehzahl erhöhen | Posts 16+

Hello gnasch,

I have a table with speed and velocity data, as well as a motor datasheet and some graphs. I'll attach them.

According to the information on the boat's data plate, the transmission should have a gear ratio of 2.45, and an 18x19 propeller is installed.

Actually, a gearbox with a 2.04 ratio and an 18x18 propeller are installed.

I'm not sure how much weight should be given to this table. The Volvo D3, which was the alternative engine option, a 2.4L common-rail turbocharged diesel, only runs at 3040 RPM and is supposed to achieve 2 knots more speed than the Yanmar with the same propeller and gear ratio, despite having 200 RPM less maximum speed. It weighs around 70 kg more than the Yanmar, including the transmission.

I just bought the propeller from Gröver in Cologne; it will be bent to a size of 18x20.

The maximum torque of approximately 270 Nm is achieved at 2200 rpm, but only for about 36 seconds. The power curve increases smoothly to 3200 rpm; this is actually quite unusual for automotive engines (I assume this is due to the speed reduction; if it were running at a maximum of 4500 rpm like most cars, the power would likely drop back down to the regulated speed).