Brice Lopez's #4: Hydrospace S4 World Exclusive

Anti SX-R weapon


Ahead from the pack, Frenchman Brice Lopez rode in a smooth rhythm, showing off the remarkable top speed of the highly tuned S4, beating the fastest SX-Rs and some of the most famous world champions. How good was the Hydrospace and how did Lopez managed to shear the competition? Lets find out.

Words: Vasilis Moraitis



Personal water craft racing had a magnificent finale this year especially in the Pro classes at the World Finals. As a matter of fact two years ago when Chris MacClugage won the Pro Runabout on board of his 15F Supercharged he marked the start of a new era. He set up the basis of four stroke racing proving that the bulky, heavier and more expensive in regards of tuning four stroke runabouts can actually out perform the much lighter and cheaper two stroke rivals. This year Frenchman Brice Lopez followed the steps of MacClugage and he came out of nowhere, well prepared and beat the highly tuned SX-Rs, showing in a class of his own that four stroke stand ups is the future of personal water craft racing. A well done job for the young rider who wrote history in personal water craft racing by gaining the first four stroke world title in Pro Ski class.


When Hydrospace entered the scene of personal water craft racing most people believed that its progress will be slow at least in respect of racing, since its experience in this field was limited. Additionally, the stand up world market is small, actually very small compared to the Runabout market, so the manufacturers do not invest a lot in the particular class. They still include the Skis in their model line up for reasons that are known only to them. On the other hand Hydrospace entered the international personal water craft market by having a different strategy. They headed straight to the racing side of the sport rather than the recreational. Therefore, Hydrospace technicians and mechanics by having a different vision and by working hard, their crafts started winning World titles from the very first time that they appeared to the world class terrain of Havasu. This year after releasing their contract with MacClugage and Chris Hugest they hired the hungry for win, Brice Lopez to do the job for them in the Pro Ski class. Lopez is a remarkable rider and proved all year long at the European Tour that he is capable of giving a hard time to the riders that have won multiple national and world championships. Last year while I was having a chat with Steven Dauliach, I asked him Who do you afraid off most of all these Pro riders? Without bothering thinking at all he replied Brice Lopez. He is fast and very aggressive. I was surprised knowing that out there in the racing field were at least five or six riders that were able to win the world title even blind folded and Brice Lopez was not included in my list.


Extracting the tech spec out of the Austrian based company was not the easiest thing in my journalist carrier since the company keeps such information confidential. What is their scope? To outperform in every Ski class and be ahead of the pack. Though, new sales manager Thomas Breuss and racer Ludo Gaumond made everything possible for me and supplied me with the right information.


The most important aspect is that Lopezs Hydrospace S4 is not a Factory race craft, as everyone may think off. It was prepared by an Austrian firm APW and its tuner was Alfonso Willy Sieber. Sieber is mostly known, for his great experience in Bosch fuel injection systems and programmable ignition units. Also, he has cooperated with Ford in rally cars. Sieber paid great attention to the ECU unit of Lopezs race craft. Originally the engine was equipped with the 160hp kit that is available for every racer. Though, Sieber starting messing around with the various parameters. He enhanced the fuel injection system by putting larger injectors. In order to achieve a better fuel burning, he modified the piston crowns and fitted a different head gasket, having in mind to achieve the required compression. The horse power hit the 185hp limit, though for reliability matters he decided to lower it to 176hp. After all, there is a saying To finish first you must first finish. The motor was equipped with a larger Intercooler since the demands of the engine had been increased. Also, the turbo pressure was readjusted as well as the Pop-off valves. Sieber made minor changes to the balance shaft by putting different weight in order to smoothen out the engine operation and enhance the rev up.


Power was translated into thrust through the Solas pump which utilizes stainless steel veins which withstand the additional pressure. Sieber has equipped the pump with a stainless steel, 14/23 pitch impeller, a combination that offered good acceleration without sacrificing the required top speed. Additionally, Sieber carried a lot of testing with the nozzle diameter before he selected to use an 82-85mm (reduction and steering nozzle) for Lopezs craft. The Solas pump has removable nozzle rings, a feature that makes testing much easier. The drop nozzle is activated via a hydraulic system by using the Magura left lever on the bars. The stock steering cable was replaced with a heavy duty one, to compensate with the hard demands of racing in Havasu and minimize the possibilities of failure.


According to Ludo Gaumond, Brice Lopez had tried an intake grate and a ride plate made by Tim Bushman during his practice. Though, he was not satisfied with the results and he preferred to use the stock ones for his race craft. Lopez practiced a lot in South of France by riding the race prepared Hydrospace in big waves in order to get used to the power delivery as well as the handling of the four stroke race craft. Lopez also preferred to use a shorter handle pole, a feature that enhanced the ergonomics in such a way that enabled him to push the crafts limits without getting tired.


Lopezs Hydrospace was equipped with a set of front sponsons which were made by APW. These sponsons create a larger surface area at the front of the hull, as a result the hull does not have the tendency to sub during aggressive cornering, a phenomenon that was actually seen a lot last year especially in Pro Ski with Chris MacClugage and other riders. Lopez had ditched the stock, angled tray mat and he had put a set of APDesigns Kevlar mats and sides with build in lifters.


In the water

The first thing that makes a great difference when you get on board of a Hydrospace stand up is the fact that the side walls are much shorter than on any other stand up. This small and to some riders insignificant detail plays key role to the way they ride the craft, since some riders apply force to the gunwales by their knees in order to drop the craft into a lean while approaching the buoy. Therefore, things are getting even more serious when you ride a world title winning craft with much more power than the stock S4.


As soon as I hit the start button the twin cylinder engine came into life by roaring a nice, heart braking bass noise out from the twin, free off silencer, exhaust system. The engine response is good but not abrupt, not as sharp and crispy as in a highly tuned two stroke. Power in Lopezs Hydrospace is translated into thrust in a linear way. There is no sudden hit in midrange or top rpm, though it accelerates nicely with the pump hooking up in such a way that the speed builds up progressively and certainly even with no instrumentation you can sense the difference in top speed. Yet, the S4 remains stable, steady as a rock, even at this level, enhancing your trust and making put less effort to keep it on the line. I could actually feel somewhere in midrange a noticeable pull by the engine though still remains so smooth, comparing it to a two stroke that after a while you hardly pay attention to it.


Approaching a buoy at high speed in done in a totally different manner than on any other stand up. First of all you do not ride it in a point and shoot way in other words, by shutting of the gas just a few meters before the buoy and then coming on to it when you are on the buoy. This is not the proper way to ride Lopezs race craft. You always make sure that you keep the engine rpm at the right level while approaching the buoy, and by using the hydraulic trim you maximize braking by applying more of hull surface in touch with the water. Then you preset the gas, and hit it when the nose of the craft has passed the buoy. The Hydrospace hull will respond instantly with absolutely no hesitation and it will turn sharply. The APW front sponsons play key role to the steering since they provide better handling without letting the front of the hull to dive and result in a sub. That usually happens in a stock Hydrospace due to the heavier nose which becomes even heavier under deceleration. Though, when you go in and out of the turn on Lopezs craft everything is accomplished in such a smooth manner, that makes you wonder. This actually was proved by Lopez himself too and everyone who had watched him in those three motos he would have realized that Lopez was riding in a class of his own, in totally different rhythm than any other rider. His top speed advantage gave him the opportunity to relax even for a short time before entering the parallel slaloms of the Havasu race course.


The fact that the power delivery is so smooth and linear with absolutely no sudden acceleration makes it more difficult to bunny hop the craft. In other words, to prepare the launch of the craft for the prestigious log jump of the Havasu race course. Though, Lopez was dealing fine with the log jump he actually decelerated quite a lot in comparison with other riders. On the other hand, he did not spend much time being airborne, his jumps were small, enough to clear the log jump.


No matter how hard I was accelerating Lopezs Hydrospace was smooth, without porpoising it was building up speed by hooking up nicely. The hydraulic trim was easy to use and its respond was immediate and accurate. It did not seem to bother my left index and my hand had no sign of arm pump during the test. Though, the extra weight of the four stroke engine makes you put less effort on keeping the nose of the craft done under acceleration, mainly by using the trim rather done by body shifting. The steering system is smooth, neither too lose nor too tight. Lopez had adjusted the steering plate on the 2nd hole, a fact that gave a sharp overall feeling without making the nozzle reacting aggressively. Nevertheless, it was a set up for racing use and hardcore riding and not a set up for the average rider. I could change direction at the straight line or drop the craft from one buoy to the other without ridding on the line with the fear of highside.


The overall performance of the World title winning Hydrospace was remarkable, still is not the type of race craft that will engrave your memory. When you ride it everything is so smooth, so accurate and so normal that it does not give you the idea that you are on board of a powerful race craft. No arm stretching acceleration or aggressive handling, so is this actually the way that the things will turn to be in the future? Will the new four stroke Skis will calm down the rhythm and feeling in the class? To be honest I do not think so. I already know that a top world class racer has already developed a powerful package for the Hydrospace engine, which will make it operate like the Runabout monster of Chris MacClugage. Stay tuned to find out



Brice Lopez #4F: Hydrospace S4


Hydrospace OEM crankshaft

Hydrospace OEM crankcases

Hydrospace pistons & rings reworked

Compression: 9kg

OEM exhaust system with no silencer

Balance shaft with different weight

Modified head gasket

Pop off valves

Black fuel injectors

Stock flame arrestors

Intercooler from 160hp kit

Cooling lines in: 2 lines in

Cooling lines out: 2 out


APW ECU 160 kit remapped

Hydrospace stock flywheel

Hydrospace stock charging system

Spark Plugs Champion Platinum RC7PYCB

Pump and driveline

Stock Solas pump, 12 vain pump

Solas stainless-steel three blade (14/23) impeller

Magura hydraulic drop nozzle system  

Reduction nozzle diameter: 82mm

Steering nozzle diameter: 85mm

APW front sponsons

Hull and Handling components

Stock hood

AP Designs Gunwale pad covers with lifters

Hydrospace ride plate

Hydrospace intake grate

Steering assembly

Stock handlepole

HSR black handlepole pad

Stock Alu  4 degrees handlebar

Stock turn plate

Renthal grips

Stock trigger throttle lever

Magura trim lever

Power:176/8.200 hp/rpm

Torque:173/6.000 lbr/rpm

Top Speed: 64mph (short impeller) 67mph (long impeller)


Team Sponsors

APW Racing Company

Alfonso Sieber

OMV Fuel

Solas pump