Photos Courtesy of Motion Raceworks
It has been nearly five years since Chevrolet announced its fifth generation small-block engine and it brought back the LT1 moniker to go along with it. The Gen V LT1 was initially offered in the 2014 Corvette model but has since made its way into other vehicles and has a supercharged variant, dubbed the LT4. The advertised 455hp (with an optional 460hp thanks dual mode exhaust) was a slight increase over the LS3 engine’s 430hp output, which the LT1 replaced. Some hot rodders feared the end of days was coming as the LT1 and LT4 engines utilize Direct Injection, rather than the more traditional port injection, as well as Active Fuel Management.
We are happy to report that the Direct Injection has not spelled an end to our fun and Motion Raceworks proved the Gen V small-block can be made into a strip runner. This past weekend, Doug Cook of Motion Raceworks ran 7.935 at 176.65 mph in his 1972 Chevy Nova. The engine is based on a Gen V LT1 engine block and was built by AES Racing. Cook worked with AES Racing’s Tony Schroeder to develop a package that took aim at Hot Rod Magazine Drag Week and have 7-second capabilities.
Displacing 388ci, the engine utilizes an OEM LT4 forged crankshaft that swings a set of Carillo connecting rods and custom CP pistons. The induction system is focused on a set of CID 6-Bolt cylinder heads, which were touched up by Schroeder. The valvetrain begins with a custom camshaft that was designed by Smallwood Race Development. Initial testing showed some valvetrain issues, leading Schroeder and Cook to add Manton tool steel pushrods and Jesel rocker arms. A Holley Hi-Ram intake manifold tops off the unique engine combination while a pair of Precision 6766 CEA turbochargers provides the boost. Chilling the boost is the job of a 417 Motorsports intercooler that has been sandwiched under the Hi-Ram lid. Cook relies on a Powerglide to transfer the power to the Mickey Thompson ET Street Radial Pro 275 tires. He was quick to add that the car features a leaf spring rear suspension with the aid of Caltracs bars.
An interesting engine management setup was utilized as the aftermarket ramps up Direct Injection fueling solutions. Working with Scott Clark of Realtuners.com, the Nova relies on a GM factory computer to operate the Direct Injection up until roughly 600hp. Once that threshold is achieved, supplemental fuel is delivered via port injection thanks to a customized MegaSquirt ECU, which Clark eloquently described as the proper tool for a “Science Fair project like this one.” The secondary engine management system also handles the ignition duties like launch limiters and timing-based torque management in order to get the Nova moving on the small tires.
Running the GM and MegaSquirt systems together required a significant amount of work, to which Nagel Performance is credited with building the wiring harness. Considering the LT wiring harness has nearly double the inputs and outputs of an LS-style harness, Brad Nagel and his shop had a tall task to accomplish when fusing it together with another system. “The thing is, literally, about four Pro Mods worth of wiring and Nagel did a beautiful job and it all worked flawlessly,” bragged Clark.
The road to tuning an LT-swapped, twin turbocharged muscle car was a long one but Clark and the Cook brothers approached it carefully. The first order of business was getting the Nova to idle properly and figure out “the weird things,” as Clark described it. Like any OEM-swapped combination there are missing factory items that the ECU requires; for example, getting the ECU to allow the engine to rev past 3,500 rpm at wide-open throttle. The team had to wire in a clutch switch to make that happen. Then there was the challenge of sending a wheel speed input to the GM ECU in order to keep the GM torque management strategy from triggering. Clark said the team resisted swapping over to a cable-driven throttle body many times when tackling each issue as it came up.
Once the factory ECU was working as expected, it came time to focus on the secondary ECU. Once the engine sees wide-open throttle and zero psi of boost, the secondary fuel pump turns on and the MegaSquirt begins delivering extra fuel through a second set of fuel injectors using rpm and boost as a reference. The second set of injectors is made up of Bosch 160 lb/hr pieces from Fuel Injector Development. The MegaSquirt is also charged with ignition timing controls, which was a point of contention with the GM ECU as they fought for control. The GM ECU initially won the fight by either closing the throttle or de-fueling the engine. Cook’s brother, Andy Cook, worked with Clark, Nagel, Jan Moeller of HP Tuners, and Tom VanVugt to keep the factory ECU from limiting maximum power.
The Nova made its highly anticipated debut during the 2017 Hot Rod Drag Week and while it didn’t go exactly as planned, it was a huge step forward for a project of this caliber. Simply getting on track and logging street miles was the biggest success. Cook needed just one month, following the world famous competition, to get the car sorted out. He knocked out the 7.935 at 176.65 mph at Cordova International Dragway, proving the next generation of small-block Chevy is more than capable of upholding the high performance heritage of the previous four generations.