When it’s time to decide on power for any given project, the decision can be boiled down to two choices: do you build an engine from scratch, or do you buy a ready-to-run crate engine? There is no wrong decision, as both are viable options. A couple of years ago, we had the opportunity to follow along as Larry Dixon and his band of merry men updated his long-time ride, a ’66 Nova. In that series, Larry and the gang installed Chevrolet Performance’s then-new LT4 crate engine in the compact hot rod and proceeded to take on Drag Week in a quest for 9-second e.t.s. You can read all of the articles in that series by clicking here.
There is no denying the LT4 is a great engine. but like many enthusiasts, Larry is always on a quest for more — more power. To quench that power-hungry thirst, he has decided to do another swap. This time, by sliding the latest LT5 Connect & Cruise package under the hood of his Nova. You might be asking why? What’s wrong with the LT4? We asked the same question.
“I know it seems soon, but that swap was five years ago,” Larry states. “Man, time flies! The LT4 is a great engine. With almost 700 horsepower and it delivers 22 mpg — I love that engine. I’m not done with it just yet. I’ve got great plans for it.”
When your job has you traveling the quarter-mile in under five seconds, you could be considered the epitome of a horsepower junkie. So, when the need for more power in his Nova was a requirement, the 755-horsepower LT5 crate engine was a great option. In an interview in Chevrolet’s, The BLOCK newsletter, Chevrolet Performance engineer, Rocko Parker had this to say about the latest crate offering, “It’s something we’ve done with all of the more high-tech engines we come out with, [it’s from] the Corvette and people really like it,” Parker said. “It’s the latest and greatest technology, the highest horsepower, it’s just something we’ve done because people enjoy it. They want to get it in their ’69 Nova or their older hot rod.” Larry’s Nova might not be a ’69 model, but it’s definitely an older hot rod!
The LT5 crate engine is available to enthusiasts in essentially the same configuration as the engine motivating the Corvette ZR1. However, it took the team at Chevrolet Performance to come in and develop the necessary components to help enthusiasts with installation into a classic car. This required packaging items like the engine controller, wiring harness, and accessory-drive kit.
In case you looked and are a little confused, the LT5 Connect & Cruise configuration is not listed on the Chevrolet Performance website at this time, so we asked Todd Gallant, experiential marketing specialist for Chevrolet about that. “We do not have single part numbers for any of our Connect & Cruise kits,” he affirms. “Each package consists of various component part numbers, the sum of which makes each kit.”
Controlling It All
Larry decided to utilize the LT5 Connect & Cruise package with the 8L90-E transmission. Making the system function with the 8L90-E transmission requires two controllers, which are part of the engine controller kit (PN: 19418244). This part number supplies all components needed to run the GenV LT5 dry-sump crate engine with an eight-speed automatic transmission. This part number only offers calibration to support an 8L90-E transmission. If running an LT5 with a manual transmission, the information we found says you’ll need controller kit PN:19418270. Finally, in order to drive accessories like A/C, alternator, and the water pump, you will need PN: 19417240, which includes an alternator, tensioner, A/C compressor, supercharger belt, pulley, and bolts.
The 6.2-liter LT5 crate engine features all the technology as found in the version that comes standard in the ZR1. First and foremost, it is capable of 755 horsepower and 715 lb-ft of torque. I’m told no one really needs that much power, but it’s not about a “need.” Besides, everyone will really enjoy having it. An upgrade found on the LT5 over the LT4 is a new, larger, and more efficient supercharger, which maintains the same four-lobe design as the LS9 and LT4.
The Eaton compressor delivers 2.65 liters of displacement, making it 64-percent larger than the LT4’s 1.7-liter compressor. It is definitely capable of creating more boost. Coincidentally, the intercooling system relies on approximately 30-percent larger coolers, and that increase in size equates to about twice the intercooling capacity of the LT4’s system. Keep in mind, the larger supercharger combined with the larger intercoolers mounted above it do soak up substantial real estate and the LT5 is taller than its predecessor.
A new aspect of the LT5 that enthusiasts like Larry will need to get a handle on is the dual-fueling system. This system utilizes an extra set of intake-port-mounted fuel injectors to complement the standard Direct Injection system. This means a total of 16 injectors provide the required fuel. How it works is, during normal driving, the engine will operate solely on Direct Injection. When a heavier load is realized – like during increased throttle pressure — the port injectors will supplement the Direct Injection system. The LT5 also features the largest throttle body (95mm) ever on an LS or LT engine, camshaft phasing, an electronically controlled bypass for the supercharger, and unique rod and main bearings are also part of the package.
Cooling The Charge
Since the LT5 is supercharged, this means the incoming air to the engine is compressed and heated. The engine install kit from Chevrolet Performance is supplied with a supercharger intercooler pump. The liquid-to-air intercooler must be plumbed and incorporated within the vehicle to lower the incoming air charge temperature. If you purchase the Chevrolet Performance Parts (CPP) engine controller, it will have an electrical connector designed to connect the supplied pump. The CPP controller will run the pump when cooling is required.
Fire In The Hole
The Gen-V LT5 engine uses an advanced 58X crankshaft position encoder to ensure ignition timing is accurate throughout the entire operating range. The 58X crankshaft ring and sensor provide more immediate, accurate information on the crankshaft’s position during rotation. This allows the ECM to adjust timing with greater precision. This configuration optimizes performance and economy. It also aids with engine starting.
My first hurdle is going to be how to address the LT5’s dry-sump system. – Larry Dixon
In conjunction with 58X crankshaft timing, the LT5 also applies the latest digital cam-timing technology. Operation begins with a cam sensor located on the front engine cover. This sensor reads a 4X sensor target on the camshaft phaser which is attached to the front of the camshaft. The target ring has four equally spaced segments that communicate the camshaft’s position more quickly and accurately than previous systems. The dual 58X/4X measurement ensures extremely accurate timing for the life of the engine. Moreover, we’re told it provides an effective backup system in the event one sensor fails.
Fueling The Fire
As previously stated, the LT5 relies on a dual-fuel system. One is a low-pressure fuel delivery (tank to engine) that consists of a returnless, variable flow/pressure system that is incorporated in the engine control kit. Using a returnless fuel system reduces the fuel tank’s internal temperature by controlling the fuel pump’s speed and not returning hot fuel from the engine to the fuel tank. According to Chevrolet Performance, if using its engine control kit, a pulse-width-modulation-capable fuel pump that delivers 72 psi at 45 gallons per hour is required. If not using the Chevrolet Performance engine control system, then a fuel pump and a regulator that delivers 72 psi with 45 gallons per hour of flow must be used.
There is also a high-pressure fuel delivery system, which utilizes an on-engine secondary pressure pump. The eight Direct Injection components (primary fuel system) are made up of eight direct injection fuel injectors, two high-pressure fuel rails, a high-pressure crossover fuel pipe connecting the two fuel rails, a high-pressure fuel-feed pipe that connects the crossover pipe to the high-pressure fuel pump, a high-pressure fuel pump, and a low-pressure fuel-feed pipe. The injectors are each seated into their individual bores in the cylinder heads.
The high-pressure fuel pump mounts to the rear of the engine’s valley cover. Pump actuation is achieved by a hydraulic roller lifter and a tri-lobe actuator on the rear of the camshaft. A second set of eight primary fuel injectors (secondary fuel injectors) are mounted to the supercharger assembly. The secondary fuel injectors are present only to supplement fuel delivery to the engine when the primary fuel system cannot provide the total engine fueling demand. The secondary fuel injectors are only activated during high engine loads when substantial fuel enrichment is necessary for exhaust system protection or to achieve peak engine torque/power. This high-pressure fuel pump also regulates fuel pressure using an actuator in the form of an internal solenoid-controlled valve that is controlled by the ECM.
The cast-aluminum LT5 block is the standard six-bolt design that uses cross-bolted main caps. Inside the LT5 block is a forged steel crankshaft, and powdered-metal connecting rods connected to a set of forged aluminum pistons. A hydraulic-roller camshaft with dual, equal phasing delivers .551/.524-inch lift and .200/.204 degrees of duration at .050-inch lift. Lobe separation comes in at 116.5 degrees. Cylinder heads are 356-T6 aluminum with 65.47cc chambers.
This is the area that will probably cause pause for many enthusiasts looking to tackle a swap to the LT5 — at this time, it is only available in a dry-sump configuration. Engine lubrication is supplied by an external two-stage oil pump assembly. The oil pump assembly consists of a primary vane-type variable-displacement pump and a secondary gerotor-style pump. The primary pump contains a pressure relief valve that protects the oil pan mounted oil filter from over pressurization during cold engine start-up. If system pressure exceeds 87 psi, the pressure relief valve will open and return oil back to the oil pan. The front or forward gear set is the secondary pump. The rear or rearward housing contains the primary pump.
The pump assembly is mounted at the front of the engine and is driven by the crankshaft. The vanes of the primary pump rotate clockwise and pull oil from the external oil tank. The oil is pressurized as it passes through the primary pump and is then sent through the engine block lower oil gallery. Pressurized oil is directed from there to the full-flow oil filter.
Oil exits the oil filter and is then directed to the external oil cooler — which is another accessory you will need to find a space for mounting. The external oil cooler is a liquid-to-liquid cooler and consists of an oil pan mounted core and coolant lines that connect the oil cooler to the engine cooling circuit. Oil returns from the oil cooler and is then directed to the upper engine main oil galleries. The LT5 and the LT4 share the same engine block, and since the LT4 is available in a wet-sump configuration, there might be a way to convert the LT5’s dry-sump to a wet-sump system. We’ll let you know if we confirm that possibility.
“My first hurdle is going to be how to address the LT5’s dry-sump system,” Larry affirms. “There’s not much room left in the engine compartment for an oil tank. I don’t have the answer just yet, but as people saw with the LT4 install (boring a hole in the oil pan to run the drag link through) we’ll do whatever it takes, and it’ll be well thought out.”
The LT5 engine also features oil-cooled pistons, in which eight oil-spraying jets drench the underside of each piston and the surrounding cylinder wall with oil. The oil spray reduces piston temperature, promoting extreme output and long-term durability.
The 8L90-E eight-speed transmission is part of this Connect & Cruise package, and we are curious to see how Larry deals with the large-by huge dimensions of this modern transmission. We’re certain that floor mods will be required, but we’ll have to see what is actually needed. What we do know is the 8L90-E features a numerically high 4.56 first gear ratio. This ratio offers strong take-off performance while a 0.67-overdrive ratio manages high gear for great highway manners. Currently, Larry’s ’66 Nova has a 10-bolt rear. However, he plans to be upgrading the 10-bolt rear with a tried-and-true 12-bolt, and gear selection will be made accordingly.
We’re curious to see what changes need to be made to Larry’s Nova for this install, and you can follow along for the entire build as he chronicles every aspect of the install for us at ChevyHardcore.com.
LT5 Tech Specs
- Part Number: 1941417105
- Bore x Stroke (in.): 4.06 x 3.62
- Compression Ratio: 10:1
- Crankshaft: forged steel
- Pistons: forged aluminum with polymer-coated skirts
- Cylinder Heads: Rotocast A356T6 aluminum
- Valve Size (in.): 2.13 titanium (intake) and 1.590 sodium-filled (exhaust)
- Supercharger: R2650 (2.65 liters)
- Supercharger Drive: 11-rib belt
- Max Boost: 14 psi
- Throttle Body: 95-mm diameter
- Fuel System: Direct injection (primary) with port injection (supplementary)
- Horsepower: 755 at 6,400 rpm
- Torque (lb-ft) 715 at 3,600 rpm