Find the right ski/wake engine for your boat
The job of a ski boat engine is one of the most challenging in the marine industry. They are part racehorse, having to produce a lot of power with snappy acceleration, and part Clydesdale, needing huge amounts of torque to extract skiers with ease. Then it has to have a smooth gallop with a flat power curve in order to avoid peakiness, which would upset a skier’s balance, and sensitive controls to make quick, smooth adjustments. One-trick ponies they are not.
In California this year and everywhere else in the U.S. starting next year, all inboard engines, except engines that produce more than 500 hp and those built by low-volume manufacturers, will require a catalytic converter in order to reduce harmful emissions such as carbon monoxide. While it will raise the price, it won’t cause a loss of power like many boaters had feared. Many models are actually showing an increase in fuel economy to help offset the cost. So, ready or not, here come the ‘tens.
The Players
Currently, there are three main manufacturers that produce the lion’s share of inboard ski boat power: Indmar, Pleasurecraft Marine Engines (PCM) and MerCruiser. While all use GM blocks, each company is responsible for its engines’ subcomponents, and maximizes performance for each application to give boaters a wide variety of power and budget options.
Indmar Indmar has been family owned and operated for 30 years by Dick Rowe in Millington, Tenn. Although the manufacturers get their engines from GM in a fairly finished state, Indmar builds many of the subcomponents itself including pulleys and intake and exhaust manifolds in its 112,000-square-foot factory, which even includes its own emissions lab.
Indmar’s major clients include Malibu, MasterCraft and Skiers Choice (Supra and Moomba), and it takes the extra step of providing each customer with a unique look. Both Malibu and MasterCraft brand their engines with their own company’s name, while Supra and Moomba chooses to display the Indmar name. Indmar doesn’t publish its horsepower or torque ratings, but they are reported by others to range from 310-450 horsepower.
Circle 32 on reader service card, page 33
MerCruiser Founded in 1939, Mercury Marine is the elder statesman of the group and has been building MerCruiser engines since 1961. The company currently manufactures its lineup of four Tow Sports inboard engines, which range in power from 270 to 380 hp, at its Stillwater, Okla. facility.
MerCruiser’s major American client list includes Centurion and Supreme ski boats. Circle 33 on reader service card, page 33
Mercruiser 5.7L MAG
See More PhotosPleasurecraft Marine Engine Company (PCM) In 1998, PCM acquired Crusader, which has been building quality gas-powered inboards for sportfishermen and cruisers for more than 50 years. PCM, itself, has built gas-powered inboards for 32 years and with the combined expertise of its sister company, they form a formidable engine group. Manufactured in Little Mountain, S.C., PCM has won the J.D. Power and Associates award for the highest rating in the EFI inboard four-stroke segment for four years running.
PCM’s major American clients are Nautiques (Correct Craft), Tigé, Wakecraft and MBSports, and the company offers its builders three popular engines from 275 to 409 hp, which are all branded with the PCM name.
Entry Level
Indmar’s entry-level 5.7L V8 model is called the 320 LCR by Malibu, the RTP1 by MasterCraft and Assault 325 by Skier’s Choice. Although this is a 3-star Ultra Low Emissions engine, because Indmar is considered to be a low-volume manufacturer (as is PCM), it has been granted a one-year extension to the EPA mandate, but still can’t sell this engine in California this year.
Although PCM’s 5.0L Pro Sport EFI is the smallest engine in this lineup in terms of displacement, it still produces 275 hp and a whopping 305 foot-pounds of torque. Like its bigger siblings, it features multi-port fuel injection and can be equipped with the CATANIUM Clean Emissions System that makes it legal to sell in California this year and everywhere else in the U.S. in 2011 when the new EPA regulations become law.
MerCruiser’s 315 hp 5.7L MAG MPI fuel-injected version is getting a face-lift to be 2010 compliant with the addition of MerCruiser’s Emission Control (EC) system, because the EPA considers the company to be a high-volume manufacturer.
Mide-range
Indmar’s version of GM’s 5700 VORTEC V-8 is known by many names: the Monsoon 350 by Malibu, MCX by MasterCraft, and Assault 340 by Moomba and Supra. Although Indmar doesn’t reveal horsepower ratings, Malibu and MasterCraft call it a 350 hp engine while Moomba/Supra is slightly more conservative and says it’s a 340 hp model. All use Indmar’s ETX/CAT catalytic converter, which was the marine industry’s first ever and solved many of the major problems like dealing with excess heat.
MerCruiser’s Scorpion 350 is its newest addition and cranks out 330 hp using a high-performance Tunnel Ram intake manifold and makes sure throttle response is snappy with a 90 mm throttle body. It is currently 2010 compliant.
PCM’s Excalibur 343 uses a 5.7L V-8 to crank out 340 hp as well as an astounding 430 foot-pounds of torque. All that horsepower is leveraged when coupled to PCM’s 1.23:1 Power Plus transmission – the equivalent of 4.11 gears on a street rod to help even multiple riders get out of the hole quickly.
High Performance
MerCruiser’s biggest and baddest is the Scorpion 377 HO, which takes a 6.2L GM block and extracts 380 hp, using tricks it gleaned as a racing engine, like using a long-stroke custom-ground cam, custom hot-spark calibration and a 10:1 compression ratio. For those who don’t want to use the 91 octane fuel it requires, a lower compression, 340 hp version runs on regular.
PCM’s big momma, the ZR-409, uses a special formula for power including high-performance aluminum heads and a new HO pyramidal exhaust system to coax an amazing 409 hp from a small-block 6.0L V-8.
Next year, Indmar is discontinuing its big-block 8.1L model. In its place MasterCraft and Supra/Moomba will use a small-block, 6.0L 400 hp V-8 that is derived from GM’s Gen IV truck motor. Instead of clunky truck, think stump-pulling, mountain-climbing power that uses an electronic throttle body with built-in cruise control and Variable Valve Timing (VVT) to achieve peak performance at every speed. Malibu uses a slightly bored-out version of the 5.7L engine (6.2L) called the Hammerhead 383 to reach the 400 hp mark.