Muscle Mustangs & Fast Fords
Hellion Turbo System Install on a 5.0L Coyote
Better Boost Solution
What gives? Have we exhausted every possible combination for the Coyote and are now forced to duplicate testing? Well, the duplication part is accurate enough, but we're far from testing every combination. Fear not, we have good reason for running cams and the Hellion turbo system again on our Killer Coyote.
Loyal readers will remember from our previous testing that the Stage 2 cams offered significant power gains—if Stage 2 cams are good, Stage 3 cams must be better. On the turbo side, we were unsuccessful in our first attempt to test the Hellion system. It had nothing to do with the system itself and more to do with insufficient valvespring pressure. This inherent weakness has since been cured thanks to the installation of CNC-ported heads from JPC and RGR Engines.
With plenty of spring pressure, we had an obligation to retest and accurately demonstrate the merits of the turbo system on the Coyote. On the cam side, we were getting closer and closer to reaching 600 hp with the Coyote, so we wondered if a set of wilder cams might push us over the edge or at least get us closer.
For those just joining us, when we first started this Killer Coyote series with the 5.0L crate motor from Ford Racing Performance Parts our plan was to illustrate as many of the performance components available as possible. The motor initially produced 448 hp and 405 lb-ft of torque, and jumped to 462 hp and 411 lb-ft with headers from American Racing Headers. Thanks to the Controls Pack supplied by FRPP, running the Coyote was a plug-'n'-play operation, including control of the drive-by-wire throttle and variable cam timing. Next was a bevy of bolt-ons, including a Zex nitrous kit, a Kenne Bell supercharger, and the Stage 2 NSR grinds from Comp Cams (PN 191100).
The Zex nitrous upped the power ante to 554 hp, while the Kenne Bell Twin-Screw pushed this even further to 704 hp and 549 lb-ft of torque at less than 10 psi. Given the impressive output, we were thankful for the Aeromotive A1000 fuel system employed on the engine dyno. With tuning from SCT, the cams and JLT air intake pushed the power to 515 hp and 450 lb-ft of torque. The final (normally aspirated) step was to install the JPC/RGR heads and Boss intake, which finalized the power output at 572 hp and 449 lb-ft of torque.
Since we managed to properly test the Hellion system this time, a little review of the turbo kit is in order. Designed for the '11-'12 Mustang GT and Boss 302, the turbo kit includes all-stainless steel tubing, a 67mm turbo, Turbo Smart wastegate and blow-off valve, 52-lb/hr injectors, and a handheld tuner. Add to that an efficient air-to-air intercooler and all the necessary tubing, clamps and hardware, and the Hellion system is one complete turbo kit.
For extra snarl, we replaced the standard 67mm turbo with a larger 76mm unit from Turbonetics. We fully expected to exceed 800 hp at a reasonable boost level on this stock short-block, so we figured why not go big to keep things efficient? Besides, the 76mm Turbonetics turbo will allow us to crank things up once we upgrade to forged internals.
The tight confines of the engine bay necessitated a lowered turbo position (see photo 5). Oil drain back from the turbo was accomplished with an electric scavenge pump. The oil drained from the bottom of the turbo and was then pumped back up into an existing breather in the driver-side valve cover. This system eliminated the need to remove, drill, and tap (or weld) the oil pan.
Some may question the use of stock exhaust manifolds on the turbo kit, but what could be better than a set of stainless tubular manifolds that fit perfectly in the chassis? It may seem like the easy way out, but the factory stainless steel manifolds were designed to retain and channel the exhaust heat directly to the catalytic converters, making them an excellent choice for a turbo application.
The Hellion system features a dedicated Y-pipe to merge the exhaust from the two factory manifolds to a common T4 turbo flange. The Y-pipe also features a two-bolt mounting flange for a single 38mm Turbo Smart wastegate. Sized properly for the street and chassis dyno, the 38mm wastegate proved a tad on the small size to control boost on the engine dyno. The loads experienced on the engine dyno are never duplicated on the street or track (or chassis dyno), and this places additional strain on the wastegate. For dyno testing, we just installed a second wastegate in the system to maximize boost control. With boost properly controlled, we relied on a manual wastegate controller from Turbo Smart to increase the boost pressure from the 7-psi wastegate spring setting.
Located in the upper intercooler tube, the MAF combined with the position of Turbo Smart BOV (before the MAF) allowed the BOV to vent to atmosphere rather than recirculate the air through the intact tract. With a few sections of tubing, silicone bends, and couplers installed, the Coyote from hell was back in action.
Since we're fond of the Coyote motor and want to keep it in one piece for future testing, we made a few additional modifications, starting with replacing the Boss intake. We installed the factory intake to limit maximum engine speed.
We also installed a Boost Cooler water/methanol-injection system from Snow Performance to eliminate any chance of detonation. This combined with race fuel supplied by an Aeromotive A1000 fuel system to the 75-lb/hr injectors ensured we had plenty of fuel.
Once again, a big thanks goes out to Ken Christley of Kenne Bell for setting up the program that allowed us to dial in the air/fuel and timing values on the turbo application. Starting conservative, we worked our way up in boost and power. Equipped with the stock intake, Stage 2 cams, and CNC-ported heads, the normally aspirated Coyote produced 545 hp and 475 lb-ft of torque. Run at a peak boost reading of just over 7 psi, the killer Coyote produced 811 hp and 715 lb-ft of torque. Stepping things up to 10 psi resulted in peak numbers of 907 hp and 802 lb-ft of torque.
The combination of adequate valvespring pressure and our dual wastegates provided perfect and consistent boost control, never varying by more than 1 psi through the whole run.
Initially we ran the motor on the wastegate springs (7 psi), but upped the pressure using the manual controller. It's amazing what a couple of clicks on the controller can do for power. There was certainly more power to be had from the turbo, to say nothing of running the motor with the Boss intake and Stage 3 cams, but we called it a day at just over 900 hp to keep the bottom end alive.
The final test of the day involved the installation of the Stage 3 cams and the removal of boost. Having already run the Stage 2 cams on this motor, we were anxious to see what was available from the increased duration. The Stage 3 cams stepped the duration specs up from 228/231 degrees to 236/239 degrees. Both the Stage 2 and Stage 3 cams shared the same 0.492/0.453-lift split.
Cam swaps on the dyno were simple enough, requiring removal of the front cover, cam towers, and cam phasers, but everything was marked for easy installation. The limiters were still in place from the last test, so the cams went in, followed by the Boss intake. We knew the Boss intake offered more power than the stock intake (at least above 6,500 rpm), so we figured the Stage 3 cams would be a better match to the short-runner, high-rpm intake. Equipped with the Boss intake, CNC-ported heads, and Stage 2 cams, the Coyote produced 572 hp and 449 lb-ft. Stepping up to the Stage 3 cams resulted in a jump to 590 hp and 448 lb-ft of torque.
The Stage 3 cams offered more power at the top of the rev range, but traded power to the Stage 2 cams below 5,500 rpm. At this point we were wondering what it would take to get that last 10 hp, but our day on the dyno was done and any answers must wait until next time.
|NA vs. Hellion Turbo|
|NA 5.0L||Turbo (10 psi)|
|Comp Cams NSR NA Stage 2 vs. Stage 3 cams|
|Stage 2||Stage 3|