The exhaust featured an oxygen sensor bung that provides real-time air/fuel readings to aid tuning. Turbo motors require a richer mixture and less total ignition timing than their normally aspirated counterparts. Where the NA engine might run best with 35 degrees of timing at an air/fuel mixture of 13.0:1, the turbo motor will require timing levels below 22 degrees and a richer air/fuel ratio near 11.5:1. Pump-gas tuning may be even more conservative.
Prior to running our 5.0L in anger, we hooked up boost/vacuum lines to the Turbo Smart wastegate, CX Racing BOV, and three-bar MAP sensor (used with the FAST). Plumbed inline between the manifold and wastegate was a manual wastegate controller that allowed us to increase boost pressure. Running first with no adjustments to the Turbo Smart controller (operating on the wastegate spring), the 76mm turbo produced a peak boost pressure of 7.2 psi; the turbo 5.0L produced peak power numbers of 386 hp and 463 lb-ft of torque. Stepping up to just over 10 psi brought 436 hp and 521 lb-ft of torque, while 13.5 psi brought 491 hp and 587 lb-ft. The final runs at 15.6 psi produced 521 hp and an amazing 631 lb-ft of torque.
It was here that we decided to call it quits with our stock 5.0L, as we had more than doubled the power output of the stocker and had already exceeded the torque capacity of the stock block. Basically our stock 5.0L block was living on borrowed time. It wasnÆt so much a question of whether the winds of change were about to break our blockùit was a question of when.
When everything was said and done, we had doubled the power output of the stock 5.0L for a total cost of $2,208 ($1,642 without the components from Turbo Smart).
|Parts & Prices|
|76mm turbo||CX Racing||$499|
|ATW intercooler||CX Racing||$140|
|3.0-in tubing kit||CX Racing||$83|
|Turbo exhaust kit||CX Racing||$199|
|3.5-3.0-inch reducer (1)||CX Racing||$14|
|3.0-2.5-inch reducer (1)||CX Racing||$4|
|Oil feed & drain kit||TRB-011-kit||$30|
|Turbo Smart 45mm wastegate||WG060-V-12||$429|
|Turbo Smart wastegate controller||0106-1001||$137|
|5 quarts of Lucas Oil||AutoZone||$25|
|FAST 36-lb/hr injectors||FST-30397-8||$399|
|1/8 pipe to -4AN (straight) fitting||G&J Fittings||$4|
|1/8 pipe to -4AN (90) fitting||G&J Fittings||$5|
|Steel 5/8-inch pipe fitting (oil drain)||G&J Fittings||$2|
|2-ft 5/8 heater hose (drain tube)||AutoZone||$3|
|5 hose clamps (drain tube & intercooler)||CX Racing||$0|
|2.5-inch V-band clamp and fitting (2)||CX Racing||$19|
|T4 turbo flange||FLNGT4||$19|
|90-degree mild steel bends (2)||Muffler Shop||$12|
|2-ft mild steel tubing||Muffler Shop||$6|
|3-inch Mild Steel 90-degree bend||Muffler Shop||$6|
|3-inch V-band clamp & fitting (exhaust)||TRB-Vband300-kit-1-1||$29 |
|ARP head studs||Jegs||$45|
|Fel Pro gaskets||Jegs||$65|
|Total with Turbo Smart wastegate & controller||$2,208|
|Total with eBay wastegate & boost controller||$1,642|
|Ford 302 NA vs. Low-Buck Boost (7, 10, 13.5, 15.5 psi)|
|NA||Stock||7.2 psi||10.3 psi||13.5 psi||15.6 psi|
7 CX Racing offered a number...
7 CX Racing offered a number of different turbos suitable for our intended power level, but we stepped up to the largest, a 76mm. Capable of supporting over 750 hp, the 76mm features a 4-inch compressor inlet and a 2.5-inch discharge.
8 CX Racing offered a number...
8 CX Racing offered a number of different A/R ratios for the turbine section of the 76mm turbo. We selected a 0.96 A/R ratio to ensure quick spool-up without sacrificing outright power potential. The housing featured a 3-inch V-band clamp to secure the downpipe. Note the aluminum oil feed and drain fittings and attending hoses. The center section was even plumbed for water cooling.
9 Here is a shot of the turbo...
9 Here is a shot of the turbo kit installed on the motor. The dedicated exhaust manifolds faced forward, with the crossover pipe connecting them in front of the motor. It was necessary to run a short oil filter with this kit, but CX Racing has promised to modify the system to accept the standard filter.
10 The crossover pipe features...
10 The crossover pipe features a provision for an oxygen sensor. We utilized this for our FAST management system.
11 Having boost control is...
11 Having boost control is paramount, so we elected to step up to a new Hyper-Gate45 from Turbo Smart. In addition to a new lightweight, compact-locking collar design, the Turbo Smart wastegate also offers a variety of different wastegate springs; we started at 7 psi.
12 Turbo Smart threw in a...
12 Turbo Smart threw in a manual wastegate controller. Unlike your typical aquarium valve, the detents in the mechanism provided precise and repeatable boost control.
13 We also stepped up big...
13 We also stepped up big on the air-to-water intercooler. The huge core features 3.5-inch inlet and outlets and is capable of supporting over 1,000 hp (already tested at this level). The core significantly reduces inlet temperature while minimizing pressure drop.
14 A blow-off valve is always...
14 A blow-off valve is always a good idea on any forced-induction application. Depending on the position of the MAF, it might be necessary to route the outlet of the BOV back into the inlet tract. Since the FAST XFI is a speed-density system, it was simply routed to atmosphere. For higher horsepower applications, it might be a good idea to either double up on this size or choose a larger blow-off valve.
15 CX Racing also supplied...
15 CX Racing also supplied the 3-inch aluminum tubing designed to connect the turbo to the intercooler and the intercooler to the stock throttle body. The tubing kit comes with the necessary silicone couplers and stainless steel clamps. The position of the intercooler and routing of the tubing will obviously be different in the car.
16 Run on the dyno, the low-buck...
16 Run on the dyno, the low-buck turbo 5.0L produced 368 hp at just over 7 psi, 436 hp at just over 10 psi, and 491 hp at 13.5 psi. For the final round, we cranked the boost to 15.5 psi, and were rewarded with 521 hp and 631 lb-ft of torque. The 76mm turbo is easily capable of supporting another 200 hp, but we doubt the stock block will withstand another 200 lb-ft of block-splitting torque.