03/12/25 12:00 PM
This 5.3 LS-Based Marine Motor Was Designed by the Hellcat's Lead Engineer for MasterCraft
This 5.3 LS-Based Marine Motor Was Designed by the Hellcat's Lead Engineer for MasterCraft
A man much wiser than myself once said something to the tune of "On a long enough timeline, everything gets an LS." This obviously applies to cars and trucks. But it also applies to more oddball stuff. In the past, we've seen a few LS-swapped airplanes and even helicopters. But an LS-powered towboat? That sounds right up our alley.
Thanks to Chevrolet's new-found partnership with the boat fabricators at MasterCraft, by which the Silverado pickup is the official tow vehicle, why not just take the Silverado's LS-based engine and apply it to a marine application? The result of this line of thinking is the MasterCraft XStar family, a line of Chevy-powered towboats so oozing with machismo and cool factor that they might as well be a Corvette on the water. It comes to us via MasterCraft's long-standing partnership with Ilmor, a Michigan-based engine fabricator just as adept at building marine powertrains as they are for IndyCar and F1, who they also work with.
Admittedly, I'm no expert in automotive to motorboat conversions. But Michael Lindberg, VP of Marine at Ilmor, sure as heck is. Before his time at Ilmor, he spent the better part of 20 years working at Chrysler in a powertrain design position. Among the projects he was involved with included multiple variants of the Pentastar V6, but that's not all. That's right, Michael was the lead engineer on none other than the Hellcat motor program.
So to say, he knows more about big power and big displacement than almost anyone in the industry right now. It should speak to how important it is that a man of this caliber of talent finds himself borrowing automotive tech for use on the marine side of things. In his own words, choosing GM over Mopar, or frankly, any other OEM engine provider, was a decision made with a great deal of thought. One that goes well beyond the "long enough timeline" explanation that inevitably brings the LS to a new platform.
"We have researched over the years who's the best partner to provide engines to us. The way engines come shipped is in long block form, which is basically a block with cylinder heads and maybe an intake manifold, so they come in pretty bare. What we do is what we call 'marinize' them, which is to put on all the accessories that turn it into a marine product," Lindberg said of how Ilmor secures GM engines for MasterCraft boats. "We've explored a lot of different companies both in Detroit and outside of Detroit regarding getting engines, and we felt that GM Marine had their business very well laid out for customers like us."
In short, GM makes it relatively easy to secure bulk orders of long-block LS V8s, whose compact dimensions and high power output make them perfect for marine applications. But there's far more method to the madness than just the obvious. With a prolific support system behind it complete with engine techs, fabricators, and engineering consultants who liaison with marine and aviation outlets to supply engines for their products, GM and Chevy by extension was Ilmor's clear favorite from the get-go.
"We tend to be a forward-thinking, innovative company on the whole; we always want to do things that have a technology perspective to them and to create the best," the Ilmor engineer explained. "General Motors and the products they support on the automotive side are world-class. As you're out-driving your Escalade, you know you have confidence in its capability, and you can translate that into your MasterCraft. There's a level of confidence associated with that."
Coming to the market sized at 25 feet, seven inches, and 23 feet, seven inches, respectively, the MasterCraft XStar series is loaded with tech to go along with the beefy LT4 motor. We're talking a 26-speaker stereo system, a Z100 power-folding power tower, dual digital displays at the driver's position, and a lightweight yacht-inspired hull for maximum efficiency. It provides the perfect foundation for Lindberg and his team of engineers to go hog-wild with the engine mods. Across their fleet of boats, including the XStar, Ilmor uses a couple of different GM V8s, including 5.3-liter, Silverado-sourced LT motors.
More specifically, the much-beloved supercharged LT4 V8 found in the C7 Corvette Z06, the Camaro ZL1, Cadillac CTS-V Blackwing, and the Escalade V. As Lindberg was eager to share, MasterCraft customers were thrilled to see these additions. "Everybody since we've launched it, there's been such a love for it [the LT4]. The volumes are increasing, there's a following now that we could never have dreamed of when we originally proposed it to MasterCraft." Surprisingly, it was almost as easy for the Ilmor team to marinize a modern LT as the tried and true LS. That is, apart from that big dumb supercharger we all love and adore.
"That was our first supercharged engine that we brought into the MasterCraft fold. There were definitely some lessons learned there. The overall architecture is very similar. But just, things that we just weren't normally talking about that you would have with a naturally aspirated engine," Lindberg said of the LT4 in marine form. "So now we're having discussions about supercharger whine, how much is enough? I personally like a lot of supercharger whine. But now you have a customer base that's on the water at 4,000-plus RPM for extended periods of time. That could be problematic, that could become old versus when you're in a street car."
For Lindberg, this dedication to honing in a supercharged engine must harken back to his days on the Hellcat motor team. As he explained, there are certainly similarities between the two gigs. "Very early on, there was definitely that sort of distinction between different people and different needs. When I was at Chrysler, we had the same kind of conversations where we asked, 'what's enough, do you want to hear it in the parking lot or only on the highway or the racetrack?' That was big for us, and the LT4 is a beast. It is the most powerful towsport engine in the market, and it's also the cleanest engine from an emissions standpoint of any engine over 500 horsepower in the market."
Indeed, Ilmor's dedication to emissions regulations is admirable in a sector that's not always as stringent as the automotive side of things. In that respect, sourcing an uber-efficient V8 from a supplier who did most of the R&D themselves is another win-win situation. Compared to traditional marine V8s from Yamaha and Mercury Marine, they're powerful and capable for sure, but nothing beats an LS. With all this in mind, a thumping great LS V8 could even be less obnoxious for folks in and around the vicinity of the boat. "If somebody is surfing behind this boat at 10 or 15 feet back, you got to have very clean emissions. You've got to make it where people feel like their kids and their families are safe," Lindberg said.
"So we put a lot of effort into making sure that emissions were a big part. Because let's face it. It's a big engine, it burns a lot of fuel, it's got to be as clean as it can be." Essentially, big power and clean emissions go hand in hand at Ilmor. Even if their supercharged LT motors could theoretically be exempt from emissions regulations in its class, Lindberg and his team added catalytic converters and an emissions-minded engine tune out of pure instinct. Even if the US threw caution to the wind and de-regulated the entire industry, MasterCraft is a global brand, so each model needs to meet the same worldwide emissions requirements.
Thanks to close-coupled catalytic converters mounted close behind the engine to minimize back pressure, the LT4-based Ilmor V8 still jets 630 horses with no problem. Add the tantalizing boat hull with all the features, and we can't wait to get behind the wheel of a MasterCraft XStar as soon as possible.
Admittedly, I'm no expert in automotive to motorboat conversions. But Michael Lindberg, VP of Marine at Ilmor, sure as heck is. Before his time at Ilmor, he spent the better part of 20 years working at Chrysler in a powertrain design position. Among the projects he was involved with included multiple variants of the Pentastar V6, but that's not all. That's right, Michael was the lead engineer on none other than the Hellcat motor program.
So to say, he knows more about big power and big displacement than almost anyone in the industry right now. It should speak to how important it is that a man of this caliber of talent finds himself borrowing automotive tech for use on the marine side of things. In his own words, choosing GM over Mopar, or frankly, any other OEM engine provider, was a decision made with a great deal of thought. One that goes well beyond the "long enough timeline" explanation that inevitably brings the LS to a new platform.
"We have researched over the years who's the best partner to provide engines to us. The way engines come shipped is in long block form, which is basically a block with cylinder heads and maybe an intake manifold, so they come in pretty bare. What we do is what we call 'marinize' them, which is to put on all the accessories that turn it into a marine product," Lindberg said of how Ilmor secures GM engines for MasterCraft boats. "We've explored a lot of different companies both in Detroit and outside of Detroit regarding getting engines, and we felt that GM Marine had their business very well laid out for customers like us."
"We tend to be a forward-thinking, innovative company on the whole; we always want to do things that have a technology perspective to them and to create the best," the Ilmor engineer explained. "General Motors and the products they support on the automotive side are world-class. As you're out-driving your Escalade, you know you have confidence in its capability, and you can translate that into your MasterCraft. There's a level of confidence associated with that."
Coming to the market sized at 25 feet, seven inches, and 23 feet, seven inches, respectively, the MasterCraft XStar series is loaded with tech to go along with the beefy LT4 motor. We're talking a 26-speaker stereo system, a Z100 power-folding power tower, dual digital displays at the driver's position, and a lightweight yacht-inspired hull for maximum efficiency. It provides the perfect foundation for Lindberg and his team of engineers to go hog-wild with the engine mods. Across their fleet of boats, including the XStar, Ilmor uses a couple of different GM V8s, including 5.3-liter, Silverado-sourced LT motors.
More specifically, the much-beloved supercharged LT4 V8 found in the C7 Corvette Z06, the Camaro ZL1, Cadillac CTS-V Blackwing, and the Escalade V. As Lindberg was eager to share, MasterCraft customers were thrilled to see these additions. "Everybody since we've launched it, there's been such a love for it [the LT4]. The volumes are increasing, there's a following now that we could never have dreamed of when we originally proposed it to MasterCraft." Surprisingly, it was almost as easy for the Ilmor team to marinize a modern LT as the tried and true LS. That is, apart from that big dumb supercharger we all love and adore.
For Lindberg, this dedication to honing in a supercharged engine must harken back to his days on the Hellcat motor team. As he explained, there are certainly similarities between the two gigs. "Very early on, there was definitely that sort of distinction between different people and different needs. When I was at Chrysler, we had the same kind of conversations where we asked, 'what's enough, do you want to hear it in the parking lot or only on the highway or the racetrack?' That was big for us, and the LT4 is a beast. It is the most powerful towsport engine in the market, and it's also the cleanest engine from an emissions standpoint of any engine over 500 horsepower in the market."
Indeed, Ilmor's dedication to emissions regulations is admirable in a sector that's not always as stringent as the automotive side of things. In that respect, sourcing an uber-efficient V8 from a supplier who did most of the R&D themselves is another win-win situation. Compared to traditional marine V8s from Yamaha and Mercury Marine, they're powerful and capable for sure, but nothing beats an LS. With all this in mind, a thumping great LS V8 could even be less obnoxious for folks in and around the vicinity of the boat. "If somebody is surfing behind this boat at 10 or 15 feet back, you got to have very clean emissions. You've got to make it where people feel like their kids and their families are safe," Lindberg said.
"So we put a lot of effort into making sure that emissions were a big part. Because let's face it. It's a big engine, it burns a lot of fuel, it's got to be as clean as it can be." Essentially, big power and clean emissions go hand in hand at Ilmor. Even if their supercharged LT motors could theoretically be exempt from emissions regulations in its class, Lindberg and his team added catalytic converters and an emissions-minded engine tune out of pure instinct. Even if the US threw caution to the wind and de-regulated the entire industry, MasterCraft is a global brand, so each model needs to meet the same worldwide emissions requirements.
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