Turbocharged Hemi Engine - 627 HP for $3,831
http://www.hotrod.com/techarticles/engi ... index.html
Follow the link for a parts list, full dyno results, and more photos!Building a Homemade Turbo System, Using eBay-Sourced Parts, and Forcing a Junkyard 5.7L Dodge Hemi To Make Big Power on the Cheap
Having successfully applied low-buck, 76mm, eBay turbo systems to both the Chevy LS and Ford Modular engines (Apr. and May '11 issues, respectively), we decided to finish things off by doing the same thing to a modern Dodge Hemi.
Right off the bat, the Hemi has two strikes against it compared with the Ford and Chevy: price and availability. The Ford 4.6L was introduced in 1991, so it has enjoyed the longest production run and is therefore the most available and least expensive of the three. The GM 5.3L LS was introduced in '99 models. The 5.7L Hemi wasn't released until 2003, and it wasn't until the following year that the Hemi became universally available throughout the product line. The market pricing reflects this shortened production run. Where the Ford can be had for as little as $200 and the Chevy for $500 to $600, the Hemi came in at more than twice the price of the Chevy. A little haggling finally netted us a complete 5.7L takeout from a local wrecking yard for $1,500. Expensive compared with the Ford and Chevy, but still a bargain considering the price of a new crate motor.
Though the exact numbers vary slightly depending on the application, figure around 345 hp and as much as 390 lb-ft of torque for the stock 5.7L Hemi. Over the years, Dodge upgraded the Hemi with a variety of trick systems including variable cam timing, multiple displacement systems, and active intake manifolds. Our '06 5.7L featured none of these upgrades but still offered more displacement than either the Ford or Chevy, cylinder heads that were at least the equal of the Chevy (and significantly better than the Ford), and the highest rated normally aspirated power output of the trio (45 hp more than the Chevy and 85 more than the Ford). According to so-called experts on the web, the weak link in the Hemi is the factory cast pistons, but we know from experience that the factory slugs will withstand some serious power given the proper, safe tune-up. For our turbo add-on, costs were kept in check with the use of the factory Hemi exhaust manifolds. Not only are they plenty stout, but their design helps maximize heat energy to the turbo to improve both boost response and power production. The 6.1L SRT8 manifolds might be an even better choice, but the cast truck manifolds performed well during our testing. To speed up the process of installing what we had dubbed the 30-Minute Turbo Kit, we reused many of the eBay-sourced parts from our earlier Ford buildup—including the turbo, intercooler, exhaust merge, clamps, and reducers—but they are accounted for in the bottom-line cost.
Tuning was more critical on the Hemi than the Ford or Chevy. As with the Ford, we relied on a FAST system on the dyno for simplicity's sake. To illustrate the power gains offered by the homemade turbo kit, we first ran the motor in normally aspirated trim. Changes to the stock Hemi included a set of SRT8 exhaust manifolds and swapping out the factory injectors for a set from Kenne Bell that flows 55 lb/hr. Westech's Ernie Mena nearly nailed the tune on the first run (using a file he made for an LS motor of all things), and we were eventually rewarded with peak numbers of 383 hp at 5,200 rpm and 420 lb-ft at 4,300 rpm.
After establishing that our $1,500 motor was at least a real runner, we installed the turbo kit. Initially, the motor was run with the wastegate spring set for 8 psi. After some tuning (11.5:1 air/fuel ratio and 18 degrees of total timing), the turbo 5.7L Hemi belted out 571 hp at 5,300 rpm and 619 lb-ft of torque at 4,300 rpm. Equipped with a Turbo Smart wastegate, the boost varied by less than 1⁄10 of a pound! The Turbo Smart gate may cost a little more than the eBay stuff we used on the Ford, but boost control is not something to skimp on. Using a manual wastegate controller (also from Turbo Smart), we cranked up the boost to a maximum of 10.4 psi and saw 627 hp at 5,500 rpm and an amazing 689 lb-ft of torque at 4,300 rpm. Torque production exceeded 650 lb-ft from 3,600 rpm to 5,000 rpm, making for some serious grunt.
When all was said and done, the Dodge cost more than the Chevy or Ford, but this shouldn't come as a shock to most Dodge enthusiasts. More important, in our impromptu, all-American, 76mm shootout, the turbocharged Hemi produced the highest power numbers at the lowest boost level.
Power Numbers: Turbo 5.7L Hemi
Equipped with a set of SRT8 exhaust manifolds, the stock 5.7L Hemi produced 383 hp and 419 lb-ft of torque. Torque production was 400 lb-ft or more from 3,600 rpm to 5,000 rpm. Adding 8 psi of boost upped the power numbers to 571 hp and 619 lb-ft, while 10.4 psi pushed them to 627 hp and 688 lb-ft. In deference to the factory internals, we stopped here, but the low-buck turbo system had plenty more to offer.
That's what I like to see -- a modern turbo HEMI.
