The new Hemi Ram trucks are...
The new Hemi Ram trucks are the most powerful trucks in their class. As might be expected from the folks at Edelbrock, they were quick to get one on the dyno to look for ways to add even more muscle.
What's old seems to be new again at Chrysler. and when old refers to the revival of Hemi power plants in production Mopars, we definitely call it a positive trend. The 5.7-liter Hemi engine came onto the scene with a vengeance. Replacing the very good 5.9-liter Magnum engine (that's a 360 for us old-time, non-metric guys), Chrysler raised the bar substantially with the new Hemi. With a class-leading 345 SAE net horsepower on tap, the output is a staggering 100 hp greater than the previous engine's 245. That Chrysler's newest mill is blessed with the legendary Hemi configuration is just the icing on the cake.
With all that horsepower on tap, it's only natural that hardcore power junkies would look for more. In the old days, finding more power was easy to do, but with many of today's highly developed engines, Detroit didn't leave a lot of easy-to-get horsepower on the shelf. But that is not enough to stop the aftermarket from trying, and often succeeding, in taking a good OE package and making it better.
We heard Edelbrock was developing tubular exhaust headers for the 5.7 Hemi, and we decided to stop by their R&D facility for a first-hand look. In the old days, you could take just about any engine, slap on a set of headers, and reap substantial rewards in increased output. These days, we've seen numerous exhaust tests where ditching the factory equipment barely goosed output enough to be worth mentioning. We have to confess to not being familiar with the 5.7 Hemi's factory-fitted exhaust manifolds, so we really didn't know what to expect.
We had the opportunity to see the prototype installation of Edelbrock's Hemi headers and were impressed with the quality and fit. There was no denying they are nice pieces. More importantly, we had a chance to see for ourselves on the dyno what they were worth, and the numbers were impressive. Here's the lowdown on what we found out.
Here's the source of the excitement...
Here's the source of the excitement around Dodge's new truck offerings-the 5.7 liter Hemi mill. With 345 SAE net horsepower on tap, these engines set the standard for V-8 performance. Who would've thought Chrysler would be back to packing Hemis under the hood?
The stock exhaust system is...
The stock exhaust system is configured with these crude-looking, cast-iron, log-style manifolds leading into a rather uninspiring Y-pipe arrangement. This seemed to be an area with the potential for improvement. Edelbrock is a major producer of exhaust-upgrade components, primarily for late-model vehicles.
In contrast, the Edelbrock...
In contrast, the Edelbrock headers and Y-pipe look much more conducive to a Hemi engine's flow requirements. The headers are constructed from 1 5/8-inch primary tubes, made of 409 stainless and mated to sturdy 3/8-inch flanges. The units are designed to last and are finished in either nickel/chrome plating or a ceramic coating. The tubing terminates in a collector, which mates to a 2 1/4-inch Y-pipe. To let the cat out of the bag-these pipes pick up power big time, even through an otherwise stock single-exhaust system.
Looking down the spout of...
Looking down the spout of the factory logs, there is little evidence of any attempt to streamline the passages for airflow. Headers should definitely prove better, but with this late-model stuff you can never be sure until the prototypes are made and the testing is completed.
Edelbrock's exhaust-system...
Edelbrock's exhaust-system components are manufactured in-house at a dedicated exhaust products plant. The emphasis is on quality control. Here, we have a flange with a header tube fitted. note how the formed shape of the 18-gauge steel tube's end fits tightly to the laser-cut hole in the heavy, 3/8-inch steel flange. This will be precision welded with automated machinery.
With the gasket overlaid across...
With the gasket overlaid across the flange, note how the form closely mimics the exhaust gasket, which closely follows the net shape of the cylinder head's exhaust port.
Still not impressed? Eyeballing...
Still not impressed? Eyeballing a competitor's product shows just how far off the mark fitment can be if attention to detail takes a back seat to getting a product out to market.
The Hemi engine is set back...
The Hemi engine is set back deep in the engine compartment, but there is ample room for tubular exhaust headers. Here, we have a clear view of the passenger-side extractor, as fitted in Edelbrock's prototype installation.
Switching to the helm side,...
Switching to the helm side, the routing is a little more confined because of the steering coupling and shafts, but the team at Edelbrock came up with an effective pipe routing.
At the outlets, the Hemi headers...
At the outlets, the Hemi headers feature a stock-style 2 1/4-inch collector to mate with the Edelbrock Y-pipe. This arrangement offers a system much less prone to leakage, as compared to a flat-gasketed flange.
Aft of the headers, Edelbrock's...
Aft of the headers, Edelbrock's Y-pipe is sensibly routed, providing a smooth transition into the system merge and joining with the stock catalytic converter.
At the controls of Edelbrock's...
At the controls of Edelbrock's Superflow chassis dyno, an Edelbrock technician sets the Hemi Ram for some power pulls. Testing is a big part of component development at Edelbrock and is done in-house.
What were the headers worth...
What were the headers worth where the tire meets the tarmac? In torque, output was up by as much as 34 lb-ft with the biggest gains in the upper midrange at around 4,000 rpm. Peak torque, which was recorded at 4,600 rpm in the stock Hemi, moved up by 11 lb-ft. The largest gain in horsepower was again in the midrange, boosting output at 4,000 rpm by 28 hp and adding 9 hp to the peak output, recorded at 5,400 rpm. These results were through an otherwise dead-stock truck pushing through the stock single-exhaust system. These tubes definitely work.