Tuning a 200bhp Volvo penta

[Nick_H]

The question then comes whether the cost of the diesels, plus the tuning (we're now into £10000's) still make it worthwhile...

You need to use A LOT of petrol with your standard 330bhp V8's petrols to recoup the difference

That assumes the mods don't add any value when you sell. If they do then the calculation is a bit more complex.

I'd try to sea trial the boat with the 200 hp diesels if you can, they may be fine. Once on the plane the law of diminishing returns kicks in, so the extra 260 hp of the petrols may only get you an extra few knots, and at that speed you'd be burning twice the fuel of the diesel boat.

 

[oldgit]

"But have you actually heard of any 300s letting go?"

Always been curious about the number of very low houred boats that have had engines replaced ,it could of course be all down to neglect and poor maintaince..

 

[scottie]

The 40 series engines 6Cyl 3.6ltr block

Basically Volvo designated their engines originally as MD marine diesel with gearbox
Other prefixes were T turbocharged A aftercooled or just to confuse AQ. For aqumatic which was then shortened to A
K was used to indicate kompresser

The number indicated 4 ltr the original engine of this series was 40 when they made minor changes the added a suffix ie A B C
A major change increased the base number ie 40 became 41 etc

So the TAMD41 would be called AD41 with an outdrive

And KAD300 just caused total confusion as it used hp as a designation

 

[The swede]

That assumes the mods don't add any value when you sell. If they do then the calculation is a bit more complex.

I'd try to sea trial the boat with the 200 hp diesels if you can, they may be fine. Once on the plane the law of diminishing returns kicks in, so the extra 260 hp of the petrols may only get you an extra few knots, and at that speed you'd be burning twice the fuel of the diesel boat.

Good point indeed.

I'm an economist. So if it costs me 30K more to have a powerful diesel than a petrol... I'll stick with the petrol.

You do raise an interesting point. An engine, whether diesel or petrol, starts to use fuel excessively once you go beyond its natural cruising speed.

So if I have two 200bhp diesels, and they turn out to be pretty "thight", they'll get me to 30 knots, but I will be wringing every last bit of power out of them and I'll be using 80LPH. To get the same speed with two V8's petrol, the'll be nicely cruising, and maybe even using less fuel. ?

 

[Questor]

.So if I have two 200bhp diesels, and they turn out to be pretty "thight", they'll get me to 30 knots, but I will be wringing every last bit of power out of them and I'll be using 80LPH. To get the same speed with two V8's petrol, the'll be nicely cruising, and maybe even using less fuel. ?

And sounding considerably sweeter

 

[The swede]

And sounding considerably sweeter

I do like the sound of those blowing and whistling 6 cilinder turbos also

The sound like unstoppable machines.

Then again, here's the guy who's trading up from his 5m 70hp outboard speedboat

 

[vas]

The question then comes whether the cost of the diesels, plus the tuning (we're now into £10000's) still make it worthwhile...

You need to use A LOT of petrol with your standard 330bhp V8's petrols to recoup the difference

I think the consensus is that you drive away from a hull that has engines that are not fit for purpose (your purpose that is) and try a bit harder to find the right combo. Took 5 hulls in my case (but have to admit that engines wasn't my problem...)

Easy solution is to add the keyword diesel to your search criteria

V.

 

[volvopaul]

Is it possible to increase the power of a Volvo Penta AD41 (200bhp) ? How?

Its actually 192hp,. and no you cannot change the hp without changing the pump and injectors from a kad 43 as the plunger size in the pump is bigger to give more fuel, if you do that you wont be able to cool it properly, the camshaft profile is slightly different, the list goes on and on, the other thing is the turbo doesnt boost till 3000rpm so you will have loads of lag, if your boat pulls max rated rpm at WOT you cant just repitch the props to give more speed as the torque at low rpm where you need it isnt there till it boosts, so you wont get the boat out of the water, thats where the supercharger comes in, matched with more fuel (from the bigger pump) it all works better than the ad41.

Quite frankly along with the electrical side to make the charger cut in, you will need wiring loom, a new timing cover for the speed switch...... lets just say unless you bought 2 scrap engines for next to nothing I just wouldnt bother for another 30hp.

Do this to your ageing 41 and all you will end up with is a bill for a full rebuild you might even need a crank and rods.

Out of interest are cols engines over 300hp? did he have then dynoed before they went in as there only 12 valve heads.

 

[The swede]

Thanks, Paul. Puts a clear spin on it.

So unless I think the 2x200bhp Pentas in the Sunseeker 34 XPS are well sufficient, I should steer clear and get the petrol one.

 

[rosssavage]

I looked into this a few years back, with a tuning company at the TRL in Crowthorne. They had means of "optimising" (pre common rail) diesel engine performance, and had been successfully doing so for years on cars

However, given the huge difference in cost over vehicle injection pumps and the injection pump on an AD41, it's probably best to leave well alone.

Van Aaken?

 

[Questor]

Van Aaken?

Very good

I was very impressed with their outfit, and was sad to learn that they are no more.

Gerd Van Aaken seemed a very knowledgeable guy, and seemed good at proving others wrong.

Friends of yours?

Do you know what happened?

 

[The swede]

Where I come from, we don't touch anything to do with Dutchmen with a bargepole

 

[Jegs]

TMD41B

Its actually 192hp,. and no you cannot change the hp without changing the pump and injectors from a kad 43 as the plunger size in the pump is bigger to give more fuel, if you do that you wont be able to cool it properly, the camshaft profile is slightly different, the list goes on and on, the other thing is the turbo doesnt boost till 3000rpm so you will have loads of lag,

A spot of thread drift : - the max revs on my tmd41b are 3800/3900 [handbook not clear], does the above mean that the turbo does not have any effect until 3000 or does that only apply to the tamd41?

Thank you,

John G

 

[The swede]

Its actually 192hp,. and no you cannot change the hp without changing the pump and injectors from a kad 43 as the plunger size in the pump is bigger to give more fuel, if you do that you wont be able to cool it properly, the camshaft profile is slightly different, the list goes on and on, the other thing is the turbo doesnt boost till 3000rpm so you will have loads of lag,

A spot of thread drift : - the max revs on my tmd41b are 3800/3900 [handbook not clear], does the above mean that the turbo does not have any effect until 3000 or does that only apply to the tamd41?

Thank you,

John G

3000rpm sounds really high, especially for such large capacity engine. It means you got to go full throttle, go and make yourself a cup of coffee, come back, drink the coffee and then bring your cup back to the sink so you're ready for when the power sets in and you get your boat to plane ...

 

[Wiggo]

The 4x series turbos are spinning up from around 2500 rpm, and delivering a healthy bit of boost by 3000, ISTR.

Fred drift: I don't know if Col dyno'd them, but the pumps were set up for a little over 300hp, I believe.

 

[volvopaul]

Thanks, Paul. Puts a clear spin on it.

So unless I think the 2x200bhp Pentas in the Sunseeker 34 XPS are well sufficient, I should steer clear and get the petrol one.

Diesel one every time unless your in the US.