Need an opinion, IPS or Zeus?

K1W1, thanks for the heads up, will try and find out. There saying it's the 3rd Generation 13ltr (12.8ltr) series. Cheers

Far

One difference that matters to me is the fact that the zeus mounts vertically (90' to the waterline). The IPS sticks out of the bottom at whatever the deadrise angle is.
I drove one IPS boat that banked so hard in a turn that I thought it was going to throw us all out. Speed sensitive steering made that even worse if you throttled back in the middle of a turn. The angle of the IPS drive makes it act more like an aileron than a rudder. When you turn the wheel to starboard, the starboard drive pushes water up and the port pushes water down. There is as much rolling force as turning force.
When was the last time you saw rudders on an inboard boat that didn't stick straight down perpendicular to the waterline across the transom? In a typical inboard, the struts may be angled but the rudders are usually straight (vertical)
(I could draw this better than I am explaining it)
I am guessing Volvo did this to make adapting existing hulls to IPS easier but I don't like how it feels and it does not make sense to me.
As another poster noted the Zeus requires cutouts/tunnels in the hull which would increase the cost to make the change and also change other aspects of the hull performance due to reduced buoyancy in the stern. However, in my opinion this is the correct way to do it.

If you are developing a hull just for this kind of drives, you can of course find solutions to the problems you describe. But you have to build it in full scale to test it out, which can be expensive if you are totally wrong...

Mitsubishi relationship is long gone

K1W1, You do know your history. But that relationship is long gone. The IPS 2 is powered by the D11. This is the D9 with additional stroke and built in France actually. While the previous D4 and D6 are Volvo Penta only, larger stuff comes from Volvo Powertrain. Like in Volvo truck, Mack truck, Renault truck, Volvo bus and Volvo construction equipment besides Penta. The IPS 3 announced in London is a D13. This one is a 13 liter displacement, built in Sweden, and it has been in trucks for a while. The pleasure vessel rating is 900HP inboard so far. Also an in-line 6 but with twin aftercooled turbos, no supercharger.
As you well know, the emissions regulations keep things advancing faster perhaps than boaters can really afford.

Back to IPS or Zeus. First the boat better be designed from the start for this, not just a force fit to breathe new life into an old dog that is a poor fit. As was said, LCG must be right. Volvo has two positive things here in my eyes, experience with a wider variety of applications (they even tried catamarans I think in New Zealand), plus they have an entire system design for engine, drive and transmission. This means there are few others to point the blame at (finger pointing as we know it).
There does not seem to be enough information about Zeus installations to gather good information. Lazzara did try it in the 76, but it was not in the shows like the 75 (quad IPS 1)and the 92 (quad IPS2). What about Sea Ray? Why are there not more models and more domination in the market? I read about their quad in a fishing style boat on the web, but I am told it was a striped hull with no interior.
I have questions like all of you do. I am sold on these pleasure pods as my knees still hurt from 20 years ago when I reinstalled all the running gear on a 60 Hatteras. But only when done right.

60 Hat?

Shazam, was this a complete vessel or was the interior not included? I heard just a rumor about a boat they may have bought for test that was not the same as a finished product should be. Curious as well about why it was such a failure. Certainly a dramatic change from tradition. Can the blade area of the props possibly carry such a load?

You are correct in the above, if hull deadrise is very flat then exhaust gasses can sit under the hull and be sucked back up the intakes. Volvo have put out a solution to this with a water inlet that bolts directly to the current inlet but has a nozzle that protrudes down a couple of inches so any air is trapped above the water inlet and not taken in!

Efficiency

To me you simply look at prop size! IPS can use a 435 hp engine to swing its props and via the Zeus system to swing same size prop CMD need to use almost 600hp! And a 4" exhaust above the waterline, I don't need that kind of droaning noise from any boat!

If you look at the drive, the raw water pick-up could be blanked off and sighted elsewhere while the exhaust exits through the drive.

http://www.marinepartserurope.com/en/volvo-penta-explodedview-7744980-44-21417.aspx

Hi,

Dave- What is the diameter of the sea water inlet on one of these drives?

I think it is a 2 inches.

Hi,

Thanks Lars, My question here was a double barreled one.

Firstly I was curious to know if the Raw Water Inlet was the same size as the exhaust pipe would be, it would have to be pretty close for it to work without increasing the back pressure a lot when running.

Secondly, I have never seen an Out-drive where the water was drawn in from the centre of the prop where many Out-drives have their exhausts, if the exhaust was elsewhere on the drive in place of the Raw Water inlet, what effect would all that gas have on the props function?

I look forward to an IPS Enlightenment.

K1W1,

The intake is flush with the hull surface on the fixed portion of the drive unit, the outer half of the sandwich that seals the enormous hole. It is a flat ss grate, and feeds a 2" hose to the pump. After its cooling circuit, the same size hose then ties into the exhaust and exits out the rear of the unit in the wash of the forward-facing props.