how hard to drive an older turbo charged KAD

[simonfraser]

so your KAD is 20 yrs old, you're no speed merchant
the boost on the older turbo is now 20-30% lower than when it was new
service is up to date

still run it at WOT, personally i don't think so

what do you guys do / suggest as to max revs ?

 

[Momac]

I don't go over 3500rpm regardless.
No idea if the boost is lower then new .
Turbochargers can be reconditioned.

 

[Orthop]

Started a similar question days ago and I´m with Martyn to handle the engines gently, avoiding max revs.

 

[[2068]]

3500rpm is a good cruising limit for a KAD, but only if you can actually reach rated revs at WOT (e.g. 3900rpm - value varies slightly with engine).

If you haven't reached 3900rpm in the last 3 years, how do you know that your 3500rpm isn't actually "very close to full power due to fouling or damaged props or some other problem".

What I usually do early in the season is to have one full power run for a minute or so once fully warmed up.

This gives me increased confidence at cruising revs knowing :
- The cooling system can cope and isn't just about to fail on me
- The engine can reach rated RPM and isn't being overloaded at cruising revs
- Turbo still has what it takes

Then I settle back to a sensible speed for the rest of the season.

It's always possible that something might break at WOT, but chances are that thing would have broken anyway shortly. If the engine is very smoky, rough running or blowing past the rings, it might not be such a good idea.

 

[Mr Googler]

My KAD42’s are 28 years old.

run then at WOT for a few minutes every time I come back into harbour.

i do this so I know they and the boat make WOT and to highlight any issues. This worked as I picked up temp creep on one engine. Impellers new...cooling system cleaned but still remained. On lift out did the water pickup seals on the effected outdrive. Temp creep gone.

Temps where always rock solid under 3500 so I would never have known.

in 2 years of ownership they now run better than ever....27 knot cruise at 3400 - 3500.

give em a rip now and again. If something goes sideways....it was there lurking anyway IMHO

 

[BruceK]

WOT 'e sed. Especially if you're cruising in company with a highly polished tugboat called Starfish, showing a clean pair of heels is not just the compulsion to race but to show a clean pair of heels doing so.

 

[andy59]

I will always do a minute or so at WOT on the way back home just to check everything is still able to perform as it should, as Farsco said, if you don`t check, there could be problems lurking that will bite you on the bum when you might need to run hard one day. Have done this with D4s , KAMD44s and TAMD75s .