By now everyone has heard of the recipe that involves turbocharging an LS, right? Go to the junkyard, grab a crusty, old 4.8L, 5.3L or even a 6.0L if you can score one, then add cam, springs and boost. The other option, the one we chose, was to leave the stock cam in place and simply add the boost to what was already there. Does the stock cam work well with boost? Trust me, they all work well with boost, but the question here isn’t what is the best cam choice for a turbo LS, but rather how do we make life easy when adding the boost? Now that we all know the worst kept secret in the performance industry, that the junkyards are actually full of race motors just begging for boost, we can look at ways to easily add boost. The turbo portion of the equation is easy enough, with many different affordable options available online. No my friends, the difficult part of boosting a junkyard motor is actually building the turbo system itself: the turbo manifolds, Y pipe and associated exhaust system designed to channel those spent gasses into, and out of, that low-buck turbo. Well, Hooker offers a set of turbo exhaust manifolds that make adding a turbo to your LS a snap.
The Hooker Universal GM LS Turbo Exhaust manifolds features high-silicone moly, ductile-iron construction. Exhaust from the driver’s side manifold is diverted to the passenger’s side manifold via a cross under tube. These cross-under tubes are application specific, meaning their fitment is determined by the combination of transmission, bell housing and oil pan, not to mention the chassis. Hooker also offered a DIY cross-under set up to allow you to build a dedicated system for any unique LS swap candidate. Heavy duty construction should allow these manifolds to last the life time of your engine. After all, when was the last time you saw a stock, cast-iron exhaust manifold wear out? The cast-iron construction also ensures all (at least most) of the heat energy from the exhaust gets channeled to the turbo. The best part about the Hooker manifolds is that they were designed with actual use in mind, meaning no burned plug wires. A definite problem with popular tubular (stainless) turbo manifolds, the Hooker manifolds simultaneously eliminated plug wire problems, while providing near unlimited access to spark plugs.
To put the Hooker manifolds to the test, we decided to run a set on a junkyard 5.3L. After a trip to the local yard, we came back with yet another well-worn, oil-soaked 5.3L LM7. Truth be told, the motor was run numerous times before this turbo test (we had to get our $300 worth). During the multitude of testing while on the dyno, it received new Fel Pro head gaskets and ARP head studs. On this application, we did not even disassemble the motor for increased ring gap, as was our usual practice. The rest of the components remained factory fresh, including the stock heads and cam. This motor was, however, treated to a Trailblazer SS intake upgrade along with a 90-mm throttle body. On the naturally aspirated combination, we relied on a set of Hooker 1 7/8-inch, long-tube, swap headers feeding 18-inch collector extensions. Run in this manner with the Holley HP ECU controlling 89-pound injectors, the 5.3L produced 359 horsepower at 5,200 rpm and 384 lb-ft of torque at 4,200 rpm. That’s pretty healthy...now, it’s ready for boost!
Off came the Hooker headers and on went the turbo manifolds. Installation of these turbo manifolds was no different than stock truck manifolds. We mounted the manifolds, installed the cross-under pipe then finished up with the custom elbow to mount the Turbo. The PTE turbo was installed first, followed by the wastegate and intercooler. In anticipation of the turbo test, we previously drilled a hole in the pan and installed an oil drain fitting. Oil was fed to the turbo through a fitting in the block, while the ProCharger ATW cooler was fed a constant source of dyno water. Running at a peak boost of 10.7 psi, the turbo 5.3L produced peak numbers of 601 horsepower at 5,600 rpm and 614 lb-ft of torque at 4,600 rpm. The turbo combo improved the power output of the 5.3L by 242 horsepower and 230 lb-ft of torque. Obviously, this was nowhere near the limit of the turbo system employed on the 5.3L, as the PTE turbo was capable of supporting as much as 1,200 hp on the right combination. What we liked about this set up was that these numbers came with zero drama...the manifolds bolted right on, never leaked or complained. The system just went about its business, providing all that heated exhaust energy to the turbo so the PTE turbocharger could do its thing!
As if one test wasn’t enough, we decided to go the extra mile and show the Holley manifolds on a combo with a little more zest. It should be noted that the Hooker manifolds were not designed to be a racing system, but that doesn’t mean they can’t make impressive power. To illustrate this once again, we installed them on a modified 5.3L with forged internals from Wiseco and K1. The 5.3L also featured a BTR Stage-2 turbo cam, a set of TFS 205 heads and Holley Race Sniper intake. Run in naturally aspirated trim, the modified 5.3L produced 451 horsepower at 7,100 rpm and 379 lb-ft of torque at 5,700 rpm. After combining the Hooker turbo manifolds with a Borg Warner S480 turbo from LJMS, the intercooled system (same ProCharger ATW) pushed 11.9 psi of boost to the combo. The positive pressure pushed the power peak to 800.3 horsepower at 7,000 rpm and 616 lb-ft of torque at 5,600 rpm. Imagine how much fun your Camaro, Chevelle or C10 would be with 800 horsepower under the hood. Now toss in longevity, ease of maintenance and no burned plug wires, and the Hooker Turbo Exhaust manifolds start to look pretty appealing.
Unlike mild-steel or even stainless turbo manifolds, the Hooker manifolds were built from high silicon-moly ductile iron. We liked the cast-in v-band flange designed to ensure a leak-free seal.
Designed and built with strength and longevity in mind, the passenger-side manifold features a twin-passage merge. Gases from both banks of the motor were channeled to a single outlet mounting the turbo.
Our junkyard jewel test motor #1 was a 5.3L LM7, straight from the ‘yard. It featured a Trailblazer SS intake, 92-mm TB and larger injectors to supply the necessary fuel under boost.
Before hitting it with boost, we ran the near-stock 5.3L in NA trim with a set of 1 7/8-inch Hooker headers feeding 18-inch collector extensions.
Tuning is critical on any boosted motor so we enlisted the aid of this Holley HP ECU to dial in the air/fuel and timing curves.
Before boost, the naturally aspirated 5.3L produced 359 horsepower at 5,200 rpm and 384 ft/lbs of torque at 4,200 rpm.
Bolting on the Hooker turbo manifolds was no different than a simple header swap. They looked like they belonged on the motor, offering plenty of plug and wire clearance, an important issue with turbo manifolds.
The passenger-side manifold exited in a 3.0-inch V-band. We liked the use of the heat shield to help protect important under-hood elements (like a radiator hose) from unwanted heat.
The cross-over (or under) tubes are chassis specific, but we built our own to fit the dyno, bellhousing and truck oil pan. Hooker also offered a DIY kit for custom fitment applications.
Using a custom elbow that featured a V-band on one end and T4 flange on the other, we installed a PTE 7675 turbo. Capable of supporting nearly 1,200 horsepower, we would only be using about half of its potential on this 5.3L.
The custom elbow also featured a provision for a wastegate, so we mounted this Hyper-Gate45 wastegate from Turbosmart.
Even low boost can benefit from an intercooler, so we installed this air-to-water intercooler from Procharger. Note the custom-fabricated, aluminum discharge tubing also featured a Race Port blow-off valve from Turbosmart. Run with the Holley turbo manifolds feeding the PTE 7675 turbo, the boosted 5.3L produced 601 horsepower at 5,700 rpm and 614 lb-ft of torque at 4,600 rpm at a peak boost of 10.7 psi.
Need more? How about a modified 5.3L with forged internals, a BTR Stage 2 turbo cam, TFS 205 heads and Holley Race Sniper intake? With the Holley manifolds flowing exhaust gases to a Borg Warner S480, the boosted 5.3L produced 800.3 horsepower at 7,000 rpm (at 11.9 psi).
Has it ever been easier to make so much for so little? These Hooker manifolds allowed us to easily add boost to any LS application, including our junkyard 5.3L. Sure, it was crusty and ugly, but the power curves produced in turbo form were anything but. With nothing more than a Trailblazer SS intake, a 92-mm throttle body and larger injectors, the Hooker-header-equipped 5.3L pumped out 359 horsepower at 5,200 rpm and 384 lb-ft of torque at 4,200 rpm. The Hooker manifolds made for an easy swap and allowed us to utilize at least a portion of what the PTE 7675 turbo had to offer. Running a peak of 10.7 ps, the junkyard jewel produced 608 horsepower at 5,700 rpm and 641 lb-ft of torque at 4,700 rpm. It’s just so easy, all without burning plug wires.
Sure, the Hooker manifolds worked on a stock motor, but what about something with a little more involved? For this test, we applied the cast-iron Holley manifolds to both a nearly stock, then much modified 5.3L. The near test motor featured forged Wiseco/K1 internals, but a stock cam, 706 heads and a truck intake. We first ran boost on this mild combo, then again after installation of a healthy BTR turbo cam, TFS 205 heads and Holley Race Sniper intake. Run with a Borg Warner S480 turbo from LJMS, the stock combo produced 549 horsepower and 571 lb-ft of torque. Running the same turbo combo on the modified 5.3L resulted in 800.3 horsepower and 616 lb-ft at just 11.9 psi. We think 800 horsepower is probably enough for almost any amount of trouble you care to get in to, but rest assured, there was plenty more left in this engine.