Economical Turbo Kit - Wind Of Change

In case you haven't noticed, the winds of change have shifted the economy. Whether you blame the policies of the past or our current government, the reality is that times are tough. Fact is, this uncertain economy has forced performance enthusiasts to tighten up the old purse strings and make every dollar count.

Count yourself a real car guy (or gal) if you look down nearly any isle in the boneyard and see nothing but potential! Do you ponder the aerodynamics of an old turbo T-Bird? The potential of a stripped Fox Mustang? Or how about the sheer nostalgia of an early Comet or Ranchero?

If you see more than some old, rusty parts cars, then you, my friend, are a real car enthusiast! Real bang-for-buckers reside somewhere in betweenùwhere you maximize performance and minimize cost. Sure, we can drool over the 1,000hp turbo strokers, but can we really afford them?

For our low-buck turbo build, we are trading effort and elbow grease for cubic dollars (there is no free lunch). The extra work pays for itself twofold, as not only do we save money, but we are also rewarded with a sense of pride that only comes from doing it yourself. The icing on the cake is when you motor past a guy who spent three times as much on his combination!

To illustrate the low-buck approach, we applied our knowledge to the legendary 5.0L Mustang. The goal of this exercise was to more than double the power output of a stock, high-mileage 5.0L for about the cost of a set of aluminum heads.

Are we crazy? The answer to that question is a resounding yes, but when it comes to 5.0L performance, let's just say we're crazy like a Fox!

Though low-dollar turbos abound on the internet, we were concerned about both price and performance. What good is an affordable turbo if it disintegrates after a month or two? Having had excellent results with its products in the past, we went back to CX Racing (www.cxracing.com). We selected the largest turbo availableùthe 76mm. In truth, we had previously run one of these turbos successfully on a 4.6L mod motor for our sister book Hot Rod with impressive results.

The 76mm turbo features a 4-inch compressor inlet, a 2.5-inch discharge, and a 3-inch exhaust outlet. The 0.96 A/R, exhaust side worked well in previous testing, so we knew it would be at home on the torquey 5.0L. The turbo was combined with a massive air-to-water intercooler (air-to-air versions are also available). In truth, the intercooler was oversized for our stock 5.0L application, but it's always nice to have an intercooler core that will support 1,000 hp should you upgrade at a later date. The turbo and intercooler set us back just $639.

While the turbo and intercooler were the major components of the turbo system, we also needed a wastegate, boost controller, and aluminum tubing to connect the turbo to the intercooler and the cooler to the throttle body. CX Racing once again came to the rescue with an affordable aluminum tubing kit. For the paltry sum of just $85 (after a little haggling), CX Racing offered an eight-piece tubing kit that included 3-inch (other diameters are available) polished aluminum tubing with beaded ends to minimize leakage, along with a complete set of silicone couplers and T-bolt clamps. You can even choose the combination of bends needed for your application.

Along with the tubing, we snatched up a couple of extra reducers (2.5 to 3.0 inch and 3.5 to 3.0 inch) to attach the turbo to the tubing and the tubing to the intercooler (in and out). CX also supplied an oil feed and return line kit, a couple of V-band clamps and even the T4 turbo flange needed to mount the turbo. Rather than go the homemade route for our turbo kit using the factory exhaust manifolds (or shorty headers), we snatched up a complete kit from CX Racing for just $199.

The availability of the turbo tubing from CX Racing means we can eliminate the do-it-yourself welding portion of the low-buck kit. For any single-turbo application, it's necessary to direct the exhaust gases from the factory exhaust manifolds (or shorty headers) to the turbo. The common practice is to flip over the stock manifolds or shorty headers and build a common Y-pipe to mount the T4 turbo flange.

If you take this route, don't forget provisions in the exhaust for a wastegate and oxygen sensor(s). CX Racing offered an affordable wastegate (less than $100), but we opted to run a new wastegate design from Turbo Smart. Its Hyper-Gate45 combined exceptional flow; a smaller, lightweight package; and revolutionary new locking collar to ease spring changes. It costs a little more (you can always go with the more affordably priced gate from CX Racing), but boost control is a critical element in a successful turbo application.

For the true low-buck approach, forget the tubular headers or mandrel-bent pipes--just get the exhaust to the turbo. It doesn't matter if you route the crosspipe under the pan or in front of the motor, just make sure to leave sufficient room for cooling as the exhaust side of a turbo motor gets pretty hot. The kit from CX Racing features 15?8-inch primaries and a 2.0-inch crossover tube.

To test the merits of our system, we went to a local wrecking yard and snatched up a bone stock 5.0L. If you have a 5.0L, your motor is essentially ready for low-buck boost. Nevertheless, we made a few minor changes to our "stock" motor prior to cranking it up. Knowing we're looking to more than double the factory output, we elected to replace the stock head bolts and head gaskets. We installed Fel Pro gaskets and ARP head studs. No changes were made to the stock heads, though it was difficult to resist the temptation to install a decent set of aluminum performance heads.

To properly illustrate the gains offered by the turbo kit, we first had to run the motor in normally aspirated trim. The 5.0L motor was run sans accessories, with a Meziere electric water pump and a set of stock exhaust manifolds. Naturally the MAF and attending air intake system were ditched on the engine dyno (the motor was tuned with a FAST XFI management system). In bone-stock trim, our high-mileage 5.0L produced a whopping 252 hp at 5,100 rpm and 306 lb-ft of torque at 3,600 rpm. Obviously tuned for torque, the 5.0L H.O. EFI motor offered 286 lb-ft all the way down at 2,500 rpm.

Prep for the turbo system included drilling a hole in the oil pan to serve as a drain for the turbo and upgrading the stock injectors to 36-pounders from FAST. The stock 19-lb/hr injectors were simply not going to get the job done. We installed the exhaust manifolds and crosspipe supplied by CX Racing. On went the 76mm turbo along with the oil feed and return lines (fittings supplied by CX Racing). Next, we positioned the intercooler and ran the supplied aluminum tubing from the turbo to the intercooler, then from the outlet of the intercooler to the throttle body. The position in the car would most likely be different, but the results would be the same. We then installed the supplied 3-inch downpipe section using the supplied V-band clamp to serve as the exhaust.

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).