2003 Power/SFC Curves

[JackFrobisher]

Just been reading some fascinating threads on power/prop/fuel consumption matching. Many quoted data from power and sfc curves. Can anyone point me to a source of curves for the Volvo 2003? I've looked at the paperwork that came with the boat and searched here and the net with no joy...

 

[DavyMac]

Can anyone point me to a source of curves for the Volvo 2003? I've looked at the paperwork that came with the boat and searched here and the net with no joy...

The old brochures are on Volvo Penta's website and contain the curves, I can't post a link as it's buried in the Javascript (other may be able to) but try here, then search for 2003 as engine type and select Product Bulletin 2003 from the list of documents which comes up.

http://www.volvopenta.com/volvopent..._engines/Pages/out_of_production_engines.aspx

 

[pvb]

I've looked at the paperwork that came with the boat and searched here and the net with no joy...

The curves are here.

 

[macd]

Just a shorthand answer that may be useful to some: best Specific Fuel Consumption always occurs at peak torque rpm.

 

[Tranona]

Just a shorthand answer that may be useful to some: best Specific Fuel Consumption always occurs at peak torque rpm.

Yes, but as you will see from the curves, both torque (and therefore SFC) are fairly flat over quite a wide rev range - ie between 2-3000 which covers the usual cruising range.

 

[macd]

Yes, Tranona, that's often the case with diesels in particular, but applies to all ic engines, as I'm sure you're aware. Peak torque revs is often known where SFC curves are rather more esoteric. I offered it simply for that reason.

 

[JackFrobisher]

2003 Curves

Thanks to all. The axes and labels are a bit fuzzy even when printed on my photo printer but I get the picture.

The thoughts (2) behind the question were:
a. Cruising revs - habitually I have been setting the throttle at about 2250 because it "felt right" ... and it appears to be so. Hoorah!

b. I've seen engine power curves where the power drops off as the revs rise towards the manufacturer's stated maximum rpm: in Volvo terms between "maximum continuous" (2800) and "maximum one hour" (3250). Does this apply to the 2003? It seems not.

My prop is pitched to allow the engine to achieve 3200 but if the maximum power was lower than that my thoughts were should I increase the pitch? I did try increasing the pitch by half a dgree last summer and it pulled the maximum down to about 3000 so I put it back to allow 3200. Now that I've seen the curve I'm happier and I think it's OK.