Chevrolet upped the game when it released the LT5 engine in the C7 Corvette ZR1 model, complete with 755hp from the factory. The supercharged combination quickly found its way into the Chevrolet Performance catalog as a crate engine and the performance engineering company Katech decided to have a little fun with it on their engine dyno with basic modifications and Direct Injection fuel supply upgrades.
The first pull made by Katech was in stock trim, albeit for a few modifications for its use on the dyno. It features a set of long-tube headers, an open element air-filter, and a Katech Direct Injection fuel system. On 93-octane pump gas it cranked out 788hp and 762 lb-ft of torque. Next on the list of modifications was to add a set of larger fuel injectors, which are 30% larger, and run the engine on E85 fuel. The gains were amazing with the LT5 knocking off 925hp and 859 lb-ft of torque with just the fuel upgrade. Adding a Grip-tec supercharger and the engine output increased to 992hp and 991 lb-ft of torque.
Round three of modifications included a ported factory supercharger and a Katech 103mm throttle body. The result was an amazing 1,013hp and 1,011 lb-ft of torque on E85 fuel!
Eric Suits, an engineer at Katech, says in the video that the company isn’t capable of tuning C7 Corvette ZR1 vehicles but these modifications are available for hot rod and marine applications.
The Chevrolet Performance LT5 displaces 376ci (6.2L), which is housed in an aluminum block, which it shares with the LT1 and LT4 platforms. Because this is the highest-ever engine combination to come from Chevrolet, a steel crankshaft is used to ensure durability and longevity, along with steel connecting rods. The forged pistons create a 10:1 compression ratio, the same as the supercharged LT4 engine combination.
The aluminum cylinder heads feature 2.13-inch titanium intake valves and 1.59-inch sodium filled exhaust valves. The camshaft is rather rowdy for a factory stick—0.551/0.524-inch for the intake and exhaust with duration of 200/207-degrees (intake/exhaust) at 0.050-inch lift. The lobe separation is listed as a wide 116-degrees.
Providing boost is a 2.65L supercharger that uses the Eaton Performance TVS2650 rotor package. Chevrolet sends it down the road set at 14 psi, a considerable jump from the 10 psi rating on the LT4 engine. Also a major note, the LT4 uses a 1.7L supercharger to achieve its 640hp rating.