Previously, we bolted on American Racing Headers’ stainless long-tube headers and cross-pipe into a 2014 Corvette (“Better Breathing Stingray,” May ’14). We got substantial gains on the dyno and a significant reduction in elapsed time at the track. The exhaust changes laid the groundwork for future mods, so as soon as we learned Comp Cams introduced a new line of Gen V camshafts, we had to get one.
Comp’s new bumpsticks are designed to work with the direct injection, VVT (Variable Valve Timing), and AFM (Active Fuel Management) lifters featured in GM’s Gen V (LT1/L83/L86) engines. As this was being written, there were four grinds, two for the 2014 Corvette’s engine and two more suitable for the truck version.
Matt Hauffe and his experienced staff at Tune Time Performance (Lakewood, New Jersey) would handle their first LT1 cam swap on Matt’s new 2014 Corvette. This was to become a good learning experience for future swaps that TTP will perform on the redesigned C7 and LT1. While we love a good track test, this install happened in the dead of New Jersey’s winter, so this month you’ll have to be satisfied with just a dyno test. As soon as the ’strip opens, we’ll be shooting for 10s. For now, follow along for another new adventure with the C7 Corvette.
1. The Tune Time Performance (TTP) 2014 Corvette is a pretty sweet test mule. It will receive lots of upgrades and more testing over the course of its life. Here, Matt Hauffe eagerly begins to dive in to his personal C7 Corvette. When we put in our parts order, Comp informed us we were the first publication to request one of its new XFI AFM (Active Fuel Management) hydraulic roller camshafts designed for the new Gen V LT1.
2. Tune Time’s top tech, Justin Knapp, begins the teardown. At this point, the valve covers, coils, air intake, and electric and vacuum connections were removed. Check out the 2014 Corvette’s unique intake manifold, throttle body, cylinder head, and valvetrain layout.
3-4. With the belts and hoses disconnected, the water pump housing can easily be removed for access to the timing cover. The sway bar and the C7 Corvette’s new electric steering rack were removed for access to the harmonic balancer.
5. It was a welcome sight to see a keyway groove in the LT1’s balancer. No more drilling and pinning the crank and balancer when upgrading to a belt-driven supercharger.
6. Unfortunately the LT1 timing cover and oil pan do not utilize reusable gaskets like the LS engine family. Notice the gray-colored RTV silicone. The dry-sump pan needs to be dropped in order to move the oil pump forward for removal of the cam phaser gear and timing chain. Another reason the oil pump needs to be out of the way is to see and line up the dots on the timing gears and/or degree the cam.
7. Comp offers four different cam grinds of its new XFI series GM Gen V camshafts that work with the new LT1’s direct injection, AFM (Active Fuel Management) lifters, and VVT (Variable Valve Timing). We chose the most aggressive grind of the four. It specs out at 0.572/0.529-inch lift intake/exhaust, 224/236 intake/exhaust duration at 0.050 inch, with a 118 lobe separation (PN 624-536-13). Comp rates the power range from 2,000 to 7,100 rpm, with outstanding top-end power. We couldn’t wait to find out! Each of the four cam grinds will require custom tuning.
8. Notice the lower lobe has three noses. This triangular-shaped lobe is for the direct-injection (DI) fuel pump. This (DI) tri-lobe is unique to the new Gen V family.
9. A notable advancement in camshaft design for the Gen V is that the cam lobes feature a larger base circle and a wider ramp (nose) for the AFM deactivation cylinders. Another benefit of the larger lobe is faster valve action (opening and closing), along with less stress for better durability on the valvetrain parts.
10. This is after we removed the timing chain and phaser gear without removing the oil pump (for now). As mentioned earlier, we’ll need to remove the oil pump and dry-sump pan to install the cam and timing set.
11. The light is shining on the DI fuel pump. It presses down on the cam’s DI tri-lobe and needs to be removed to slip out of the old cam (and slip in the new one).
12. The DI fuel pump has a spring at its bottom to put pressure on its lifter. The pump’s spring has a function similar to a valvespring.
13. The camshaft was rotated to raise up the lifters. Then we placed the wooden dowels underneath to hold the lifters up in place. This dowel trick worked on the LS engine, and now the LT1 for camshaft swaps. Here are the specs of the stock stick: 0.551/.524-inch lift, 200/207 duration at 0.050-inch intake exhaust, with a 116.5 lobe separation. Comparing the specs, it looks like the additional duration (26 degrees intake, 29 degrees exhaust) from the new camshaft should broaden the powerband and raise peak power from 5,800-6,000 rpm (stock) to somewhere in the area of the mid-6,000.
14. This Comp Phaser Limiter Kit (PN 5456) is required with use of the new Comp XFI Series camshaft. The Phaser Limiter will limit the range of camshaft movement from 62 (stock) to 22 crank degrees, thus requiring VVT program tuning. This kit contains the special tools to safely disassemble the cam phaser and install the cam phaser limiter block.
15. With the cam phaser kit tools installed, the phaser was safely disassembled to install the limiter block. The limiter block will mechanically limit the camshaft movement, making it safer when running a big cam and helping to prevent valve-to-piston contact at high rpm.