These days horsepower is easier to come by than ever before. While we certainly aren’t complaining, the rising tide has had a tendency to elevate enthusiasts’ expectations in turn.
Case in point: General Motors’ Gen V LT4. A supercharged, 6.2-liter V8 that boasts 650 horsepower and 650 pound-feet of torque in its C7 Corvette Z06 and sixth-generation Camaro ZL1 iterations, straight from the factory, while also delivering the enhanced efficiency of direct injection. In showroom stock form it’s enough to get the 3,500-pound Z06 to sixty miles per hour from a standstill in about three seconds flat on the way to a quarter mile time in the low 11s. But for some people, that kind of power still isn’t enough. We are those people.
We recently procured a dry sump LT4 crate motor from Chevrolet Performance, a mill that’s bound for the engine bay of one of our vintage project cars in the not-too-distant future. But before introducing the powerplant to its new home, we brought it to the speed freaks at Lingenfelter Performance Engineering to dial up the grunt even further. Here we’ll take a closer look at Chevy’s crate motor package, along with Lingenfelter’s LT4 kit, and check out what the engine made on the dyno when all was said and done.
Supercar Horsepower On Demand
Chevrolet Performance offers both a wet sump and dry sump version of the LT4. While wet sump systems offer simplicity, we opted for a dry sump package, as the latter’s remote reservoir setup allows the system to potentially hold more oil and use a shallower oil pan. That not only offers benefits in terms of lowering the car’s center of gravity and reducing the chance of oil starvation while out on the track, but should also make packaging a bit easier in an engine bay that wasn’t originally designed to have an LT4 installed in it.
The crate motor is nearly identical to the mill you’ll find in GM production cars, so that means goodies like rotocast A356T6 aluminum cylinder heads, titanium intake valves, forged powder metal steel connecting rods and, of course, the 1.7L Eaton TVS blower are all part of the deal. However, there are a few distinctions between the crate motor and the engine you’d find in a new Z06 that are worth noting.
“The physical engine itself is exactly the same, but in crate form the accessory drive is a separate offering,” explained Curt Collins of Chevrolet Performance. “Part of the reason for that is because we know that there’s a lot of aftermarket options out there for builders, and depending on the application, somebody may want to move an alternator or an AC compressor. It’s something we learned from the LS3 – we understand that if we put an accessory drive on there that doesn’t fit in a customer’s application, it can cause frustration.”
Chevrolet Performance also made a few other alterations in the name of simplifying the installation and delivering the level of drivability that customers have come to expect.
“We also use an engine controller that’s specific to the crate application,” Collins said. “The reason why is because the standard production controller looks for things like the ABS module and the radio module, OnStar, and all those things that you’d find in a production vehicle like the Z06. But those may not be present, or calibrated the same way, in a customer’s vehicle. So with all of our crate applications we also offer kits that include the controller, the wiring harness, the oxygen sensors, and the throttle-by-wire gas pedal. In that software we also deactivate the Active Fuel Management and the Variable Valve Control systems. Our engineers spend countless hours validating the calibrations for those two features, so they’re very specific to a particular car at a particular weight, with a specific wheel and tire size. So the concern for us is that, unless you replicate all of those parameters in your application, the drivability could be affected.”
Snagging a ready-to-go LT4 is a great option for folks who’re looking to install big, factory-proven horsepower in their projects with minimal hassle. “The LT4 represents General Motors’ latest technology with this generation of small-blocks,” Collins added. “And the fact that it offers 650 horsepower and 650 pound-feet of torque with a two-year warranty makes it one of the best engine options out there in terms of performance-per-dollar.”
While that’s undoubtedly true, being the horsepower junkies that we are, we just have to go a step further. With that in mind we sent our LT4 over to Lingenfelter’s headquarters in Brighton, Michigan to coax even more power out of it.
Lingenfelter’s LT4 Kit
One of the reasons the LT4 is such an attractive foundation to build power from comes down to the fact that it has a blower installed from the factory, so the most straightforward way to get more power out of it is to just turn up the boost. And that’s the general concept behind Lingenfelter’s LT4 package.
“What we do is we overdrive the supercharger pulley – you’re basically running the blower faster to create more boost,” explained Mark Rapson of Lingenfelter. “We’re adding a little over three pounds of boost to the engine to help generate that additional power. Of course we also have to recalibrate the ECU to make sure the engine knows what to do with the extra boost, and we also run a different balancer on the crank, which in turn runs the supercharger faster.”
Peak horsepower is the obvious benefit here, but are there other benefits that might be less apparent? “It’s important to remember that while you certainly gain horsepower, you also gain even more torque,” said Rapson. “When you have a positive displacement supercharger, you can produce a tremendous amount of low-RPM torque. The reason these kits are so popular is because, yes – they make additional horsepower – but the seat-of-your-pants difference is really coming from that extra torque that’s generated on the low end.”
Of course 721 horsepower and 750 pound-feet of torque is plenty stout, yet we can’t help but wonder where we can go from here if we wanted to get even crazier with the LT4 down the road. However, it’s not just a matter of cranking up this blower even more. “The superchargers on these motors are 1.7 liters, so they’re spinning really fast,” Rapson noted.
When you have a positive displacement supercharger, you can produce a tremendous amount of low-RPM torque. The reason these kits are so popular is because, yes – they make additional horsepower – but the seat-of-your-pants difference is really coming from that extra torque that’s generated on the low end. -Mark Rapson, Lingenfelter
“With what we’re doing here, we’ve really reached the maximum efficiency speed of the supercharger. And with superchargers, the faster you turn them, the more heat they generate. So driving this supercharger more than we’re doing here won’t necessarily make more power, but you will start generating a tremendous amount of heat, and that’s detrimental.”
Ligenfelter LT4 720 Horsepower Package parts list
– Lingenfelter LT1/LT4 dry sump damper
– Lingenfelter 9.17 inch supercharger drive damper pulley
– Supercharger drive belt
– GM crankshaft bolt
– NGK Iridium spark plugs
– High Flow air intake kit
– Handheld diagnostic & programing tool
– Professional assembly & engine installation
– Custom engine control module reprogramming
– Chassis dyno testing before & after installation
– Lingenfelter chrome fender badges & personalized stainless engine badge
– Lingenfelter certificate of authenticity
– Cleaning & detailing, full tank of 93-octane fuel before delivery
– Lingenfelter 1 year/ 12,000 mile warranty on added components
For folks looking to make over a thousand horsepower, Lingenfelter has them covered as well – and without the need for a supplemental fuel system. “In those builds we’re using the TVS2650 supercharger,” he told us. “We started work on that fuel system back in 2013, so we’ve developed a new big-bore fuel pump and injectors – which are direct replacements for the OEM stuff – that are capable of delivering enough fuel for that horsepower level and beyond. We’ve made as much as 1,680 horsepower with that system with no supplemental fuel at all.”
Sounds like we’ve got a clear upgrade path to look forward to in the future. In the meantime, 720 horsepower should do the trick.
We just got our hands on this dry sump LT4…first stop was, of course, Lingenfelter.
Posted by LSX Magazine on Tuesday, October 9, 2018