andy59
Well-Known Member
Just double check you are not missing 300 rpm Trev, they should make 3800 , unless she has dirty bum / props
Aquastar 38 purchase - Survey & Sea Trial tomorrow
- Thread starter superheat6k
- Start date
rafiki_
Well-Known Member
Sounds very promising Trevor.
superheat6k
Well-Known Member
I wonder if the governors require adjustment. They topped out both at 3500 and seemed to have bags of power left. I reckon the props are too small, and possibly due to being sized for the original likely smaller engines. I will see if I can find out what those were.Just double check you are not missing 300 rpm Trev, they should make 3800 , unless she has dirty bum / props
kashurst
Well-Known Member
what engines are they? If they are some version of volvo Kamds there can be a lot of little reasons (easy to sort) for that last 300 rpm before messing with props. Most likely being a fuzzy bum or props - it doesn't take much.
Bandit
Well-Known Member
If your props were underpitched she would over rev and the governors would cut in about 3900 to 3950 and she would not achieve the speed. If the props were over pitched she would have too much load at a lower RPM and would not achieve the RPM or the speed. How clean is the hull of the boat and what are the engines? With a clean hull and correctly pitched props she should achieve 3800 or slightly over.
petem
Well-Known Member
The only EDC boat that I can see that's on the market and marked as sold has KAD300's (KAMD300's actually).
AFAIK, these are normally fitted to smaller planing boats.
Are they a good match for the boat? I'd be concerned if the normal cruising speed of the boat requires the superchargers to be constantly running (noise and potential supercharger wear).
If normal running will be above supercharger range then that would be better.
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petem
Well-Known Member
If they're KAD300 / EDC then there's no governor that can be adjusted. It's all controlled by EDC.
Pete
Bigplumbs
Well-Known Member
If the props are too small surely they would over rev the engine.
petem
Well-Known Member
On the plus side, there's plenty of experience and knowledge here on how to keep KAD's running 
!
!
Bigplumbs
Well-Known Member
On the plus side, there's plenty of experience and knowledge here on how to keep KAD's running
My KAD32 is the most scary of all my engines
kashurst
Well-Known Member
I think the prop comment is a red herring. The KA(M)D 300 has max power at 3500 rpm (200Kw @ 270 hp) - there after although RPM increases, output power has plateaued and the torque drops off fast. My own experience with the same engines, in a similarly sized boat also on shafts, is that anything at all on the props/shafts and they won't readily go past 3500 - 3600 rpm. The most likely cause of lack of the last few rpm is fouling. Otherwise it's a probably minor fuel or air supply issue. If it's the same boat I saw advertised it was re-engined - To get a guarantee from Volvo the new engines must have been signed off by a Volvo approved person - which means they will have needed to see 3800 rpm after they were installed. According to the Volvo manual max operating rpm should be between 3700 and 3900 rpm) Unlikely someone has since buggered about with the props. A serious hull clean and a proper service, change the rubber fuel supply pipes too! and I bet it will run beautifully.
kashurst
Well-Known Member
I wondered that too, however there are two things, I can't find anywhere anything official from Volvo that says you cannot run the engines for extended periods in supercharger mode. There is a LOT of guff on the internet promising hell fire and damnation if you do though. The only thing I did find is it is better to not run the engines at exactly 1000 rpm or 2800 rpm as this is the cut in/out point so you get excessive clutch wear. Bearing in mind they sold lots of these to 'muricans - if there was an issue they would have said something. Imagine the class action lawsuit otherwise! Secondly the advert indicates a max speed of 23 knots and a cruise of about 17 knots. That is remarkably similar to my Rodman 38. I get a max speed of a totally scary 24 knots!!! and a cruise (with a clean bum) of 18 -19 knots at 3200 - 3300 rpm well over the 2800 supercharger cut in/out point. So in the Aquastar that leaves a fair bit of speed room in turbo only mode. The only downside of running in supercharger mode is the engines are a bit less efficient (superchargers use power) and the extra noise.
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Portofino
Well-Known Member
Ideally any marine diesel should be mated to a prop to achieve approx 4% or few 10s of excess rpm…..easily .
If it can’t then it’s over loaded .
If it can’t then it’s over loaded .
Portofino
Well-Known Member
That compressor manufacturer says it’s not designed for continuous running .
There are compressors and compressors do not confuse them all together .
Agura ( VP s ) have low inertia sos they do not fry the clutch instantly when it’s applied ,and can shock itself up to the required rpm . Think coming off the revs, the kick at re- engagement at 2600 rpm as well !
Don,t confuse these Japanese lightweight Aguras that VP use with say a Whipple use in the auto world which is heavily built constantly running , no clutch engagement and built to last . Or what ever Merc use in Komoressor of Bentley in “ Blowers”
Suspect you are peddling this mantra ?
There’s zero comp oil cooling with the VP for example .
Anyhow PeteM Q the SC range thingy on this re powered boat remains unanswered.
Who said the engines were ( KAD s ) brand new?
Remember ,…….happy to repeat until the cows come home - “ try before you buy “
@ Trevor is it a river boat now ? Used on a river ?
Just trying to figure out why some one would fit motors designed for high speed planning boats into that slug of a hull ?
Seems unfit for purpose as they had a wide choice.
Vetus ,Nanni .Iveco , Mitsubishi, FPT , Yamaha , Cummins , Perkins , + many more etc etc.
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kashurst
Well-Known Member
I'm not "peddaling" anything, just explaining what Volvo say in the manual. If Volvo had any concerns re continuous supercharger use they would have said so/put a limiter of some kind in other wise they would have been sued to hell and back. As to how the boat will operate with the superchargers engaged - almost certainly very well.
KAMDs turn up in quite a lot of semi displacement and slower speed planing hulls. If you get a competent engineer to service them they work very well.
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Portofino
Well-Known Member
What does Volvo exactly say ?
kashurst
Well-Known Member
From the Volvo KA(M)D user manual:
"KAD/KAMD44P* and KAD/KAMD300* are in-line, direct injected 6-cylinder marine diesel engines, specially developed for planing boats.
They are equipped with electronically controlled fuel injection, a mechanical supercharger, turbocharger, intercool- er, heat exchanger for thermostatically controlled fresh water cooling, electronically controlled engine speed con- trol and shifting.
The supercharger provides the engines with air at low speeds, and at higher speeds the turbocharger provides the air supply. This interaction gives the engines extremely high torque at all engine speeds."
Nowhere does it say you cannot/should not run the engines in supercharger mode continuously.
Portofino
Well-Known Member
That’s just a description.
Where is the operators instructions ? How to use it ?
Like a car manual …..Left peddle is clutch .Middle brake , right accelerator.
“ No where does it say you cannot / should not “[ press all three at once ) and hold down “continuously “
You wouldn’t suggest that to a potential purchaser .
Same again just a description of the three peddles what they do .It ain’t how to operate the car .
Your link fails to say you CAN run them continuously in the SC range .
stelican
Well-Known Member
Bandit mentioned in an earlier post that he looks after a few of these (maybe also with other engine options) in which case his contribution should be very valid.
fred247
Well-Known Member
Kompressors on the KAD's / TAMD's are electroincally controlled and on my Kad's cut in at about 1800rpm and out at about 2200rpm , where the turbos take over the job of boosting, there is a very small adjustment to these revs.
Unless the wiring is changed cannot be run continusley
Unless the wiring is changed cannot be run continusley
