What's this bit called ??

[Lucky]

Toilet roll tube and a Gerbil.

I've just looked up "Gerbil" in that same dictionary !!! But "toilet roll tube" ?????????????????????????

[Guest]

I note you say you have KAD42's in your boat Luke. I thought I had the same engines as you, but I have AD41's, but from the photo they look the same from what I can see. Anyone shed any light on what the differences are?

Obviously anything I say about mechanics should be taken with a large pinch of salt but.... basically AD41's are turbo charged, KAD42's are supercharged. The engine block is basically the same and the same manuals cover both AD and KAD engine types.

I'll bet the main difference between the AD41's and the KAD42's is really down to how annoying the noise from the engines is!

[Lucky]

As you well know, I know nothing about engines, but I am pretty sure that the KAD42's are turbo and supercharged..

[mbird]

As you well know, I know nothing about engines, but I am pretty sure that the KAD42's are turbo and supercharged..

I think Adam and Suzanne have those engines in Sea Hunter, and I recall him saying his are both turbo and super charged. I think one takes over from the other as the revs rise. I suppose it would stand to reason they take a turbocharged AD41 and bolt on a supercharger too as Simon has intimated. That's where your extra 30 horses come from I guess!

[senator]

not sure about 42's but on the Kad 32's as in sea hunter the turbo and super charger do not work at the same time, there is some sort of magic clutch which cuts the supercharger in and out before the turbo cuts in, so it wouldn't increase HP

[Antares_9]

The turbo will and does increase the HP when it takes over from the blower, though a blower delivers the power lower down the revs because it is belt driven. The turbo takes over then and is capable of giving a bigger boost than a blower, also because the turbo uses waste gas to spin up it means that the clutch on the blower can disengage and stop using power from the motor thus releasing a bit more for the prop.

[mbird]

The turbo will and does increase the HP when it takes over from the blower, though a blower delivers the power lower down the revs because it is belt driven. The turbo takes over then and is capable of giving a bigger boost than a blower, also because the turbo uses waste gas to spin up it means that the clutch on the blower can disengage and stop using power from the motor thus releasing a bit more for the prop.

Smart ****, but thank you for the explanation

[Antares_9]

Just a clarification on cruising spares that is worth a mention. They are not just for emergencies at sea and it is well worth carrying stuff that you would not be able to change at sea. Imagine a bank holiday weekend and you have limped into somewhere safe, there is no chance of getting parts but there is often somebody available who can sort the job for you if only you could get the parts, that person might be you, it might be a mate or it might be somebody local, but if you don’t have the parts nothing can be done. Normally I carry enough components to carry out a full annual service plus injector seals and coolant hose repair kit and two extra of each primary and secondary fuel filters. You just use the bits you need each year at service time and replace them so you are carrying fairly new stuff all the time.

[mbird]

That's a good point I hadn't thought of David!

[senator]

by not increasing Hp I meant over the non superchaged version.

Both Ad41's and Kad 42's are turbo charged so the extra 30hp will probably be through remapping,

you will find a few bits have been changed to handle the extra power though so wouldn't advise having the AD 41's remapped.

[Antares_9]

I could be wrong but I'm not sure what you'd find to map on a KAD Ian, to the best of my knowlege even the very last ones were still mechanical injector pumps and EDC not EVC, one of the reasons we waited a few months and specced the D4 in Kingfisher

[Guest chriscraft]

hi,i can top my outdrives up in the engine room

[Antares_9]

Alpha 1 gen II ??

[Guest chriscraft]

bravo 3

[Antares_9]

That was a good idea Merc had there, I had the same thing on my Alpha 1

[senator]

You could be right David, I don't know the engines at all. maybe a bigger Turbo or some mechanical magic then, assuming it is actually the same engine as the AD41.

Our last boat had Mercs with Alpha 1 gen 2s and when a seal went in the drive you could see the water in the tank, trouble is it looked just like a bit of misting on the plastic so I didn't find out about it till I dropped the oil out. would spot it instantly now I know but for some reason Volvo don't do it.

Ian

[Guest chriscraft]

opps i stand corrected ,i have got alpha1 gen two,s,my mate,s bayliner has bravo 3,s!! he,s got mercrusers aswell

[Guest]

As you well know, I know nothing about engines, but I am pretty sure that the KAD42's are turbo and supercharged..

Yes that's right. I didn't word my post very well. The supercharger is effectively there to to boost power before the turbo kicks in which is around 2500rpm. On the AD41's the increase in power when the turbo spins up is instantly noticeable.

Like others, I am none the wiser as to why the KAD version is rated at 30hp higher than the AD version as I believe power is defined as the output of the engine at its max revs and technically both version should be running only the turbo at max revs so should be delivering the same power. Obviously they do not and I don't know why.