Say no more! Nizpro 633RR - photo © Nizpro Marine

The King is dead. All hail the King. There is a new top dog in the World's Most Powerful Outboard title fight. The benchmark is now 633hp. Full stop. And probably with a few exclamation points after it, as well!!! Nizpro Marine has blasted past all comers to have the flag securely planted atop the hill with their brilliant-in-its-simplicity, and yet technologically advanced, 633RR.

If you're like me, you probably shed a tear when Seven Marine's 627 was put out to pasture. What wasn't there to like about the Corvette's force fed V8 as the powerhead? OK. Purchase price and thirst for sure. However, unlike Big Arnie's statement to the creature from outer space, the outboard Predator that took its styling cues from Hollywood's giant warrior just looked plain wicked.

Purposely designed to resemble 'Predator' - Seven Marine - photo © John Curnow

Of course Mercury were smiling away, for not too long after all that their atmo V12 arrived with a couple of novel features, and a very much on tote 6, 0, 0 going down the back of the cowling. Hello. New Order.

The Predator and the Merc do have physical size and accompanying mass issues to go along with their thirst. Mind you, the purchase price was/is also a little eye watering, but the boats they were going on were much larger than your average runabout. The ace in the deck was pace, and boy could they do that. If you wanted to do 40knots cruise and 60plus WOT, it was no problem. Two, three or more of them guaranteed that, and took up much less room on board than several, flat-mounted bent eights with huge, belt driven, screw blowers atop them.

The Vetus-Mercury Marine solution for boats with twin or more Verado outboards 530-Scout Carolina Quad-V12 600hp - photo © Vetus

Remember the Red Alien?

So the Nizpro Marine 633RR is closely related to its 'baby' brother, the 450S, in that it shares the basic common architecture, and induction system. After that, however, it gets well serious, and for good reason.

Red Alien? The outcome is anything but evil. Nizpro 450S is the most wicked outboard in the segment - photo © John Curnow

The point being stressed here is that there is a lot to like about the Nizpro Marine 450S. At the time, I wrote that it offered the responsiveness of a petrol donk, with the grunt of a Diesel. You had a motor that would not die when either turning in hard, or getting over the waves outside, and it spun an aggressive four-bladed screw. So you were not on the throttle that much, and it made the driving oh so pleasurable.

I preferred driving the vessel with the single 450S, over the similar craft fitted with a pair of 300s so much, that every chance I got to say 450S, I did, and then again, as well.

Back when the 450S was launched, there was really only the Predator, the 400 from Mercury and then Yamaha's own 425 V8. The market has certainly expanded since then, as too has the number of boats being offered with multiple large outboards. Recent Covid and then supply chain issues have all conspired to keep the market small by unit volume, but my how that is changing now. All I know is that the 450S owners are as addicted to them as I am.

'The Brig Day Out' - 8m Brig with Nizpro's wicked 450S outboard - complete thrill package - photo © John Curnow

I reckon they'll be ordering some of the new 633RRs, and you'll need to do so now, for there will be a bit of a wait, but it will be worth it. Promise. And the 633RR has a few cool aces in its deck, not the least of which will be a lower barrier to entry than supposed competitors, along with the ability to run 16-inch wheels, and deliver said number on cowling no matter what the ambient or water temp might be where you go boating.

Talk It Up Cup

I could. No problem. However, it might be a good time to get into what makes the engines so good. You start with Yamaha's brilliant, and dare we say venerable, 4.2l V6. You add a custom plenum (hence the red alien), separate, additional raw water cooling, and Eaton's R1900 supercharger on top. Yet the really brilliant effort is in the re-map of the factory brain.

Look how flat that torque curve is - Nizpro 633RR - photo © Nizpro Marine

Now the 633RR adds a bigger pulley, new injectors, forged pistons, new valve springs, ported heads, and billet conrods, then some other more incidental bits too, like throttle body and injectors, as well as a new drive leg. All very cool stuff, and the reason the whole thing is as bullet proof as the standard 300hp from Yamaha.

Nizpro Marine's Simon Gishus adds a bit of background from the last five years since the 450S arrived: "It wasn't long before we produced a small number of 475hp engines and calibrations for existing Supercharger owners. These were making 496hp in truth, running 93 octane US pump gas. Our own boats had a slight power increase to 520hp. I had been testing these in the Australian Offshore Series prior to Covid, and as expected the Yamaha base V6 handled these power levels without any problem."

Where there's smoke... Fire all right - World Champ - Nizpro 633RR - photo © Nizpro Marine

"Most powerful V6 was not really what we would say was our kind of thinking. World's most powerful outboard, full stop, is what I had always been thinking. Nizpro is more like Shelby or Calloway, hotting up Fords and Chev's in years gone by or companies like Koenigsegg nowadays. They simply don't produce big volumes, but if you want to enjoy the very fastest, the most efficient, and the most exclusive in the marine outboard space, then you purchase a Nizpro," said Gishus.

Tabled up it looks like this:

So then. How does one compare it all?

If you take the 633RR against the 600, then it becomes all about the weight. There is a staggering 304kg difference per engine. It is more than the 633RR weighs in the first place or 113.43% again, on top. That's the equivalent of a large motorbike per engine, and if you have four 600s, then that is a Ford Focus or Mini Cooper S Cabrio you have just lifted off the transom. Imagine what that will do for the ride characteristics?!

Mercury Marine at Dubai Boat Show - photo © Mercury Marine

If it is all about cubes, then the 633RR and 450R are similar, and they both sport a supercharger, but there is a chasm in output; to the tune of 183hp per engine. Again, all these sorts of donks are found as twins at a minimum, and more likely as triples, quads and quintuples. Talk It Up Cup right there, and you burn nearly the same fuel, which puts the exclamation mark on efficiency, and also the bold and underline. Don't forget, each 633RR hands back 35kg; three is one large guy, four is two smaller souls, and five is just about all of that.

The real deal

Reliability of the Japanese unit has never been a question, and the last 14 years has seen them deliver outstanding service around the globe. Gishus added, "We used this fantastic design and added forced induction. Now you will certainly hear arguments about the power level we are making and '...the thing won't last five minutes in a marine application etc', but if you consider the Mercury 400R makes 153hp per litre, and we are at 150hp per litre, then that barrier has already been well and truly tested."

Nizpro 633RR on the dyno, just letting off a bit of steam on the way to becoming the world's most powerful outboard - photo © Nizpro Marine

"The Yamaha also has variable camshaft timing, which is a great benefit when adding a supercharger, because you can map the cam timing to suit the forced induction, and it also adds great fuel efficiency.

"The Yamaha 60 degree V6 will buzz at 7000 rpm until you are sick of putting gas in it. It is just that good. It doesn't have the balance and vibrations issues a V8 has with similar V angle configuration.

"The 633RR comes in a choice of lower unit gear ratios - 1:35 or 1:5, as well as left or right-hand rotation. The lower units have a torque rating of 650 ft lbs, and use a Mercury spline, so a wide variety of propeller are available. Although we have used the SHO Yamaha engine with its 20-inch shaft length, we are able to produce the same package for Yamaha Offshore models," said Gishus.

Well. Here it is. There's a new Sheriff in town. Some will read 'em and weep. Others will simply be on the phone right about now. Your call...

Finalising installation of the four Nizpro Marine 450s outboards on the Al Hareb Marine 56-footer - photo © Al Murzem Tradin

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Finally. Please look after yourselves.

John Curnow
Global Editor, Powerboat.World