Look, there is no getting around the “junkyard LS” trend of grabbing a 5.3-liter truck engine out of a scrapyard, slapping a turbocharger on it, and making stupid amounts of power for not a lot of money. While we’d love to think that everyone took care in assembling their engines with their final goals in mind instead of treating 5.3s like disposable paper towels, that just wouldn’t be realistic.
Turbo system manufacturer Armageddon Turbo Systems, along with Titan Racing Engines, both see the writing on the wall, and have decided to team up on the research and development of budget-friendly twin-turbo kits aimed directly at the junkyard 5.3-liter market. Additionally, they are working on a budget-oriented line of 5.3L long-blocks that are gone through from the junkyard and brought up to factory specs — save for some additional ring gap added — before being sent out. More on that a little later.
While typically specializing in premium turbo kits, Armageddon’s owner, Dave Rochau, decided that the market needed a solid, reliable turbo kit for those budget builds, to help steer enthusiasts away from eBay specials. Aimed specifically at bone-stock take-out Vortec engines, the turbo system he’s testing uses more value-oriented components while still providing reliable boost.
Using a pair of cast upswept turbo manifolds with a T4 exhaust housing flange and integrated wastegate V-band flange, the kit positions the turbos above the engine, making packaging concerns more vertical than lateral as the turbos sit evenly with the top of the factory intake manifold. For turbos, Rochau went with a pair of 64mm turbos with a billet 10-blade wheel compressor, that is still in the prototype phase. “They are really similar to a Garrett GTX3582R turbo, which is what we use on the main line of Armageddon systems,” explains Rochau.
Testing The Waters
The first step of the whole process was to procure a 5.3-liter engine from a junkyard as a testbed. The only modifications performed on that engine were Titan opening up the OEM ring gap slightly to prevent the rings from contacting each other under boost. The first baseline with the budget system netted an awesome 720 horsepower at 17psi from the twin 64s. 17psi is what Armageddon considers a safe level of boost to run the combination at on the street.
However, Rochau wanted to see what more boost was worth. After all, the point of this whole exercise is testing and gathering data. With the turbos maxed out at 30psi, the combination made an astonishing 968 horsepower. From a stock 5.3-liter LS engine. Repeatedly. Without blowing up.
Finding The Limits
With that data in hand, it was time to get to part two of Rochau’s plan, and the reason he teamed up with Titan Racing Engines, modifying the engine on a budget. The aim of this package was an increase in reliability without a commensurate increase in price tag. So to start, the team replaced the OEM guts with a forged rotating assembly. Using a forged crank with the stock stroke length of 3.622 inches and Callies connecting rods, they opened up the bore by .020 inch and fitted a set of CP forged pistons.
The team also swapped out the camshaft, but not to what you might expect. They decided on Armageddon’s “naturally aspirated” camshaft, with specs in the neighborhood of .500-inch of lift with 230 degrees of duration at .050 inch, and a 110-degree lobe separation angle. Other than that, the cylinder heads are cast factory replacements, with as-cast ports and combustion chambers.
Sealing those heads to the block are a set of ARP head bolts and a factory .051-inch head gasket. Pay attention there, as that will play a part later in the article. A Holley EFI HP system was used to control the combination, since it was available at the dyno, is easy to use, and has plenty of ability to control the turbo combination.
Getting to the dyno testing, the first thing the team did was test the combination naturally aspirated. The resulting 440 horsepower at 6,500 rpm. That’s a 120-horsepower increase over the engine in factory form, and that is with the one-point loss in compression ratio over the stock 5.3-liter engine. That said, after sorting out the tune up on 17 psi, like the first test, the dyno showed a much-improved 923 horsepower at 7,300 rpm and 808 lb-ft of torque at 5,500 rpm.
That is a solid 200 horsepower gain at the same boost level over the stock junkyard 5.3 with opened-up ring gaps. Neither boosted power number is anything to sneeze at, but the R&D wasn’t done yet, as there was still the maxed-out boost number to compare. The turbos made the same 30 pounds of boost, but this time, the power number read to four digits. 1,144 horsepower at 5,900 rpm and 1,068 lb-ft of torque at 5,500 rpm to be exact.
While that wasn’t near the maximum capabilities of the twin 64mm turbochargers, it was the limit for this 5.3. On a subsequent pull at 32psi, the head gasket let go in spectacular fashion on the number seven cylinder. This wasn’t a surprise as the team expected that head bolts wouldn’t be able to offer enough clamping force to keep the cylinder heads sealed at that level of boost.
“We lost clamp load at 1,160 horsepower and blew out the head gasket,” Rochau explains. “We’re going to go back and figure out where and why we lost clamp load. If it was the number of fasteners, or if we just ran out of tensile strength on one of the fasteners, we’ll figure that out.” Additionally, the improvements in power numbers with the new rotating assembly and camshaft encouraged Rochau and the team.
Remember how we mentioned a line of budget-oriented long-blocks a little earlier? The plan, going forward, will be to have Titan Racing Engines keep several 5.3-liter long-blocks on the shelf, which have been verified to be in-spec, with the rings at the appropriate gap to run serious boost from an Armageddon turbo kit. A second option will be to do the same thing as was tested on the dyno, with a forged rotating assembly, camshaft, and new cylinder head castings, ready to take 30 psi and make over 1,100 horsepower.
We certainly don’t like seeing engines used as disposable commodities, but we also realize that not everyone has the means or resources to crack open junkyard engines and bring them up to snuff. While the final details are yet to be announced, this new in-between option appears to have some promise in the world of junkyard LS engines.