Running at lower RPMs for a Volvo D4 300

[Maximus]

Gents,

I know I read this topic here at some point, but I can't seem to find it.

I need some Tugnuts expertize on the Volvo D4 300H engine in an R-31S.

I'm concerned about extended running of the engine at an RPM that is too low. When I want to get somewhere, I run her at up, which depending on conditions, gets me into the 12-14K range.

My wife prefers "African Queen" speed 5-6K which was down around 1790 RPM in the Bay yesterday. I'm worried about not loading the engine enough and running at lower RPMs for extended periods.

Am I too old school? Do these high tech Volvo engines need to run up at higher RPMs for best engine life?

Help and thanks!

Rob

 

[baz]

When I owned our R-25 (Classic) with the Yanmar 4BY2-150 diesel engine with it cruising along for most of the time at around 8 to 10 kts I would run close to WOT for the last 5 mins of the cruise just before dropping my fenders for docking at my marina. I always alerted 1st Mate I was about to start WOT so she could turn her Hearing Aids OFF and for her to brace herself in the V-berth if the going was to be rough and bumpy. More than once she ignored me and found herself pinned to the underside of the foredeck. :lol:

 

[trailertrawlerkismet]

Hi Rob:

I listened to this question asked at the Volvo Penta Q & A session at the Roche Harbor Rendezvous week before last. The answer was you can run the engine at low RPM's for extended periods of time without concern. The caveat was that when doing so you should also run the engine at a high RPM, enough to get the turbo engaged, so things gets cleaned or cleared out....for 5 to 10 minutes before you end your trip. I'd suggest following up with an authorized Volvo Penta rep to verify but this is what I heard.

Jim F

 

[baz]

Jim & I are in sync with this advice. 😀

 

[Maximus]

Thanks guys! I figured that was the answer. It makes sense to run it up o that the turbocharger engages. I did finally find the old thread and that seems to be the general consensus.

Thanks again!

Rob

 

[bill46]

We usually cruise our 31CB at 1800 which makes for great fuel economy, 3mpg at about 8 -9mph, and a happy Admiral. I try to go to max RPM every trip for a few minutes and stay around 3000 for 5-10 min to exercise the turbo. We also have to run at about 1100 for 2.7 miles in minimum wake canals from and to home. That is about 5mph at 9 mpg.

 

[Maximus]

Bill -

That is exactly my new plan. Just run at about 1800 for fuel economy and a happy First Mate 🙂

Rob