Revs for turbo to cut in

[silverback]

My 6lpa stp yanmar revs to 3800. Has anyone an idea as to what revs would be the minimum to have the turbo happily spinning. I read that it is not good for them not to be used. Carbon build up etc. fuel being expensive down under we tend not to thunder round at 80% available power.

 

[MYTraveler]

I bet they start producing boost at a fairly low rpm. This is from memory, but on my Cummins QSM 11s, I have about 0.5 psi at 1,000 rpm and 3 psi at 1200 rpm, but since my engines are rated at 2300 rpm it is likely not directly comparable to yours. Perhaps it is worth the investment in boost gauges.

 

[Cigatoo]

The turbo on my 4LH Yanmar spun up at about 1400 RPM. Your results may vary

 

[Ski in NC]

The turbo is spinning even at dead idle. When it starts making boost depends on both rpm and load. At 3000rpm and no load, turbo will barely be making any boost, maybe 1psi or less.

There is not one rpm where it "kicks in". Its performance follows a set of curves on the performance map.

And even if you took a 1000nm trip at low speed of like 1400rpm, the amount of soot stuck to the turbo bits will be minimal. Just once a day or two take it up to like 2500-3000rpm (under load) and it will cook off what ever has built up.

Turbo will be happy however you run your engine.

 

[Cigatoo]

Ski is correct. I should have stated that boost pressure started building at around 1400 RPM.

 

[silverback]

Sounds good i tend to cruise at a stately 23/2400 revs. I do give her a bit of a burst approaching anchorage. So i am now relaxed. Thank you