Should KAD engine not be run continuously in the supercharger range?

[Momac]

I have avoided running my kad32 engines in the supercharger range believing this to be not only uneconomical in terms of fuel consumption but also placing undue demands on the supercharger. Not only that the boat doesn't feel right when its not properly on the plane. I am happy at 6 knots or 20 knots but not much in between.
Am I correct in this thinking? Does running continuously in the supercharger range potentially cause any damage ?

 

[volvopaul]

I have avoided running my kad32 engines in the supercharger range believing this to be not only uneconomical in terms of fuel consumption but also placing undue demands on the supercharger. Not only that the boat doesn't feel right when its not properly on the plane. I am happy at 6 knots or 20 knots but not much in between.
Am I correct in this thinking? Does running continuously in the supercharger range potentially cause any damage ?

Running it just places wear on the clutch, charger and belts, plus it fills your bulge with black belt dust.
If you want to run without it on the river just disconnect the plug Andy remove the belt.
In Holland boat owners have a switch on the dash to bypass the clutch so they can have it on or off in the rev range it applies to.

 

[kashurst]

"the boat doesn't feel right when its not properly on the plane. I am happy at 6 knots or 20 knots but not much in between."
that's typical of most planning boats. If you drive them not fully on the plane, they ride very bow high and can wander about. Also the boat will also have heavy fuel consumption as you are pushing a great mass of water in front of the boat.

 

[RIN]

We had an off switch fitted to the compressors on our KAD32's as we were going to spend some time on a long river trip and did not want the compressors running all day. IIRC its the white wire that you can get access to in the control unit on the engine. The switch was actually fitted on the control box. It would have been better to fit the switches on the helm though.

 

[Momac]

The reason i ask is pal of mine ran at 10 knots and 2000rpm for a good couple of hours . This is not something i would do myself.
Might he have worn out his supercharger belt ?

 

[QBhoy]

Must admit, I'm not an expert on these engines (someone who is will be along shortly), but I would imagine firstly that being supercharged, the compressor would be running continually at any speed or revs...by its very nature and mechanical design ?
Secondly, should it be disengaged by any means, surely the ecu mapping in the fuelling sense would result in inefficient combustion ? The fuel/air mixture would surely be wrong, resulting in poor combustion, horrible black smoke and worst case carbon build up and glazing ?
Just a thought....

 

[Portofino]

Must admit, I'm not an expert on these engines (someone who is will be along shortly), but I would imagine firstly that being supercharged, the compressor would be running continually at any speed or revs...by its very nature and mechanical design ?
Secondly, should it be disengaged by any means, surely the ecu mapping in the fuelling sense would result in inefficient combustion ? The fuel/air mixture would surely be wrong, resulting in poor combustion, horrible black smoke and worst case carbon build up and glazing ?
Just a thought....

In theory ,kinda -but the VP
Supercharger system on its little compact sterndrives set ups is designed to get it up on the plane ,lift it out of the water -reduce drag after pushing through the bow wave .
To do this it has a electromagnetically energised clutch -.
Take the KAD 300 for eg .Clutch engages @1400 rpm and disengages at 2600 rpm , whereby the turbo takes over cruise s best at 3000-32,3 K ish ?
Sure it's all ECU mapped to operate like this .
Manual says avoid prolong use with supercharger running .
It's makes a winning noise too.
As the Op infers this means following the book there's a no go speed range .
Most annoying .
When I had a supercharged Vp it was between 6 knots and 22 knots ..
TBH being my 1st boat ,like most 1st MoBo it taught me moving on to the next what I did not want -steep learning curve etc .
There's 3 belts in all -one a supercharger
From a developing pov ,it just enabled VP to flog the same small block units with enough HP -just into the ever increasing size and more importantly weight market .
Until the 5.5 L D6 came long ,but you guessed it they soon supercharged that too .

At the end of the day there's no substitute for cubes .

So if a supercharger VP owner wants to spend or find s himself spending a lot of time in the supercharger range ,either
1- wrong boat -change it !
2- as suggested -- fit a cut off clutch switch .

From memory ,prolonged use -not sure it's a clutch issue -cos it's engaged or a belt -cos if adjusted correctly like any car poly belt -go on for ages .
It's actually the thing itself the supercharger ,it's an old fashioned gear operated thing a throw back from the 1930, s
Prolonged use will just simply wear the supposedly air tight ish gears -leading to loss of boost slowly , and another big VP bill , that will put sterndrive servicing in the shade .

Constant running @ engagement or disengagement rpm runs the risk of the electro magnetic component of the clutch mechanism buring out a clicks in and out ,but you will hear it hunting and should be able to adjust the throttle so it's either fully engaged all the time or disengages preferablely in the KAD 300 over or around 3000 rpm
Away from 2600 rpm .

 

[QBhoy]

Ah...thanks portofino. Interesting stuff. Totally see what you are saying.

 

[[2068]]

Ah...thanks portofino. Interesting stuff. Totally see what you are saying.

Sadly, most of what he is saying is wrong.

The manual does not say to avoid prolonged use with supercharger running.

The number of cases of superchargers "wearing the supposedly air tight ish gears -leading to loss of boost slowly" is small enough that you should be more worried about being hit by a whale falling out of the sky. It's all lubricated by oil inside: wear rates on the vanes are low.

As VolvoPaul has said, the main issues around running in the supercharger engaged range are around belt dust, the clutch, and the annoying noise.

.

 

[Portofino]

The oil lubs the gears at the back only .it does not lub the vanes on the air side .although I did use the word for the vanes on the air side .It s not intended for constant running .

The poly belt ,s friction is on its flat side on shinney smooth pulleys .The main cause of "black dust disease " from the kad series is from the other V belts .Specifically the v sides on the rusty v ,s of the v pulleys .Alternator ,power steering in the Stb .
Those pulleys are made of a base metal that rusts and abraded the SIDES of the v pulleys .

The kad 300 has a flat none dust inducing belt pulley for the supercharger .
Kad 32 looks like depending on modal variant ,it could have either a V or poly belt .I was reffering to Kad300 ish poly belt set up

This one has a ploy belt --IMHO that will not create the "black dust "

(Note the rusty turbo housing ---big bill on its way ?)


Btw "black dust disease "is treatable ---you rub down the v pulleys and paint them with waxoil .Basically convert the abrasive sides of the V to somthing smoother .I did that as you can below nil black dust -I smoothed only the V pulleys not the supercharger poly belt .

Think the actual clutch is ok fully on or off preff -as I said -it's the constant switching in and out -hunting that needs avoiding .
But here more info which makes sence ---regarding the bearings ,oil change etc and the circuitry overheating in the control box .I had that once ,you can reset it with a pop out trip --from memory .
http://www.marineengine.com/boat-forum/showthread.php?335308-KAD300-TurboSupercharger-Problem

** not sure on the maths of a bearing failure - and "whales falling out of the sky " .I,am not familiar with that .
But I can see after a few seasons of running with supercharger engagement - knackered bearings -a € 3000 bill which as I said put outdrive service in the shade .

http://www.marineengine.com/boat-forum/showthread.php?335308-KAD300-TurboSupercharger-Problem

Some body will be along soon to confirm what the owners manual says about prolonged supercharger running -
I sold the boat in 2014 -the manual went with it ,apollogies for fading memory ,but I do recall a warning to avoid prolonged running .

As the bearings start to fail oil will seep across from the gearbox into the vane chamber ,probably when it stopped and cools down and then left for a prolonged period of the leaky oil to turn into a stiky residue -gluing the vanes .
Hence at restart the clutch won,t like that .
Checking the oil level with the dip stick -and if it's dropping ,no signs of external leaks -you got to ask where it's going .

If you are gonna run around with it running I would sugest a more regular oil change over the book 100 hrs .
If its coming out clear fine .If its dark brown coffee looking -start saving up !

If regularly used so the vanes don,t stick ( clutch not knackered ) and you keep feeding it with oil after checking - then the shafts/spindle s will --
start to have excess play and the vanes will develop facets ,wear facets where they have been glancing off each other .
It,s allready dreadful wining will increase buts that's come on gradually
Eventually it will loose boost pressure ,but gradually and along with usual worn turbo vanes --
Somebody will post a thread about difficulty getting on the plane , after replacing the turbo !Foggeting to mention they have been running around all day in the supercharger engagement zone until post # 100 as is usual with forums .
In the mean time there will be loads thread drift and some forumites will appear be rude to each other

 

[[2068]]

The engines aren't supercharged to increase HP from small blocks.
They are supercharged for more torque at lower RPM, which provides better acceleration over the "hump", which isn't the same thing at all.

I'm sure this will provoke immediate disagreement, but here you go anyway:

Two identical engines,
LHS is D4-260 (sterndrive) version with a supercharger.
RHS is D4-260 (inboard) version without.

Torque up to 2500rpm is substantially greater on the sterndrive boat. Power beyond 2500rpm is identical.
I guess Volvo think that shaftdrive owners are happy to wait for a while until their boat starts to plane?

 

[[2068]]

Another thing to consider:

KAD series engines are not common rail engines. The non-EDC versions don't have any kind of "brain" there: it's mechanical pumps and injectors.

So the pump is set up to deliver the correct amount of fuel at each RPM / throttle load, given that there is a supercharger pushing air through from 1500rpm to 2400rpm.
Ah, but hold on a minute, we have turned off the supercharger!
That means there is a lot less air being delivered to the intake.

Is there some magic message that the pump receives that says "please tone down the fuel delivery because the owner has switched off the supercharger"?
No, there is not.
I'll leave it as an open question as to what you think happens to that extra-rich fuel mixture, and where you think it might wind up (valve stems? combustion chamber top? turbo vanes?)

.

 

[[2068]]

Manual says avoid prolong use with supercharger running .

Manual does not say this.

Older versions of the manuals (e.g. KAD42) say the following, which is not the same thing at all:

Newer versions of the manuals have this section omitted completely.

 

[petem]

As VolvoPaul has said, the main issues around running in the supercharger engaged range are around belt dust, the clutch, and the annoying noise.

Anyone who has kept a boat in Port Solent will certainly recognise the noise and belt dust issue.

 

[Portofino]

I think you are splitting hairs a bit here using the same block ,a newer coman rail vs too .
I was talking old school. Kad series .
My coment on adding a supercharger was aimed @ 3.7 kad 300 block ,the unsuperchargd earlier vs have less Hp .
It's a natural Vp evolution trick .We saw in in the D6 ,310 ( for liesure ) -superccharged in the 350 / 370 .
Can,t be exactly sure happy to be corrected on exact modal designations of D6,, and Kad series 42 44 300 etc of when the supercharges arrived and what effect that had on Hp ----in the total package as builders were going larger ,VP marketing machine responded .As any sensible buisness should ,much cheaper to just bolt bits on the existing blocks .

The the concept of bolting them on to get more oomph out of the same block is a fair statement ,not missleading ?
Quicker time to plane for a given displacement or stick it in a bigger boat either way works .

Do not disagree with your post on torque curves for the common rail D4

Many engine manufactures knock out diff versions for diff applications ,wider target market out of one base block the better
In your example looks like its the end vs ? There will be limiting factor to holding the hp in the D4 .
Torque curve can be shoved around with simple remapping .

At least I think we agree that they should not be run constantly in the supercharger engagement range ?
I,am trying to encourage folks not to do it and hopefully a helpfull tip on "black belt disease " from experiance treating it .

I have n,t got a copy of the kad300 manual I was reffering to .Thx for the image of the kad32 - @ least I was right about not running at engagement or disengage ment --"hunting " I reffered to .
Once in the clutch does not wear ,it's the wiring in the black box that cannot cope prolong periods .
Obviously clicking it in and out will constantly will burn out the thing out and most likey knacker the electro magnetic actuator to boot --which is what happens .

As for as the actual clutch material and part it's self it actually a Japonise part found on car air con pumps .
So it's either on (in ) or off (out ) -unless the driver is constantly switching the AC on and off for a long period .
So the clutch is fine -it will not burn out or wear much of signifance once on or in the kad series engaged .
That's clear from the manual you have posted and this is the reason above .

So that just leave thing itself -supercharger ,since I have already covered the belts and clutch .

It's not designed for prolong running .

How ever it's a neat solution to get more can we agree on power ? -and low down torque before the turbo,s spool up ,and a clever way of keeping VP in the game using the same block size .

Does any one know of another marine engine maker that uses supercharges ?

Btw -not all superchargers are designed for intermittent use ,the Mercedes car Kompressor runs all the time without a turbo .

 

[oldgit]

Chum of mine has pair of these in Brava 36 on the Thames, suspect for the last 10 years it has never exceeded 5 knots.
Does not appear to have had any serious issues regards reliabilty or extra belt/clutch maintainance as a result .
Shame it is impossible to sit in the cockpit and not develop a headache from the banshee howl coming constantly from the engine compartment when underway.

 

[CX54WEK]

Chum of mine has pair of these in Brava 36 on the Thames, suspect for the last 10 years it has never exceeded 5 knots.
Does not appear to have had any serious issues regards reliabilty or extra belt/clutch maintainance as a result .
Shame it is impossible to sit in the cockpit and not develop a headache from the banshee howl coming constantly from the engine compartment when underway.

If the SC is whining away at 5 knots then it isn't adjusted right!!

 

[Andromeda9866]

Had. 3 different boats with kads in and was told under no circumstance should a switch be fitted for the supercharger as it would cause over fuelling issues which could cause a lot of piston damage the engines. I was informed by Volvo when I purchased a new kad 32 engine that they are designed to run with the compressors running if needed all the time it is only the noise that makes you not want to do it for long periods

 

[[2068]]

Had. 3 different boats with kads in and was told under no circumstance should a switch be fitted for the supercharger as it would cause over fuelling issues which could cause a lot of piston damage the engines. I was informed by Volvo when I purchased a new kad 32 engine that they are designed to run with the compressors running if needed all the time it is only the noise that makes you not want to do it for long periods

This matches up with what I was told by Volvo back in 2002/2003.

 

[Anders_P42]

I think you are splitting hairs a bit here using the same block ,a newer coman rail vs too .
I was talking old school. Kad series .
My coment on adding a supercharger was aimed @ 3.7 kad 300 block ,the unsuperchargd earlier vs have less Hp .
It's a natural Vp evolution trick .We saw in in the D6 ,310 ( for liesure ) -superccharged in the 350 / 370 .
Can,t be exactly sure happy to be corrected on exact modal designations of D6,, and Kad series 42 44 300 etc of when the supercharges arrived and what effect that had on Hp ----in the total package as builders were going larger ,VP marketing machine responded .As any sensible buisness should ,much cheaper to just bolt bits on the existing blocks .

The the concept of bolting them on to get more oomph out of the same block is a fair statement ,not missleading ?
Quicker time to plane for a given displacement or stick it in a bigger boat either way works .

Do not disagree with your post on torque curves for the common rail D4

Many engine manufactures knock out diff versions for diff applications ,wider target market out of one base block the better
In your example looks like its the end vs ? There will be limiting factor to holding the hp in the D4 .
Torque curve can be shoved around with simple remapping .

At least I think we agree that they should not be run constantly in the supercharger engagement range ?
I,am trying to encourage folks not to do it and hopefully a helpfull tip on "black belt disease " from experiance treating it .

I have n,t got a copy of the kad300 manual I was reffering to .Thx for the image of the kad32 - @ least I was right about not running at engagement or disengage ment --"hunting " I reffered to .
Once in the clutch does not wear ,it's the wiring in the black box that cannot cope prolong periods .
Obviously clicking it in and out will constantly will burn out the thing out and most likey knacker the electro magnetic actuator to boot --which is what happens .

As for as the actual clutch material and part it's self it actually a Japonise part found on car air con pumps .
So it's either on (in ) or off (out ) -unless the driver is constantly switching the AC on and off for a long period .
So the clutch is fine -it will not burn out or wear much of signifance once on or in the kad series engaged .
That's clear from the manual you have posted and this is the reason above .

So that just leave thing itself -supercharger ,since I have already covered the belts and clutch .

It's not designed for prolong running .

How ever it's a neat solution to get more can we agree on power ? -and low down torque before the turbo,s spool up ,and a clever way of keeping VP in the game using the same block size .

Does any one know of another marine engine maker that uses supercharges ?

Btw -not all superchargers are designed for intermittent use ,the Mercedes car Kompressor runs all the time without a turbo .

New CAT C12.9 has supercharger, I read this motor designed by FPT.