Late Model Hemi Engine Upgrades - Hemi Hop-Up

Weather conditions on our test day were definitely not conductive for low e.t.'s. A barometer of 29.41 hg (an approaching storm came later in the day) along with high humidity worked against us on this 75-degree day. We're sure the atmosphere cost us a tenth or two compared to a good-air day. Bone stock 5.7 and 6.1 LX cars will usually run (on the average) 14.4 at 96 and 13.5 at 105 mph respectively. Still, on this bad-air day the Daytona showed us a best of 13.57 at 102.55, while the SRT8 managed an impressive 12.88 at 108.96 mph.

Naturally, we feel that if we'd used sticky meats, low 13's and mid 12's would have been possible for these two SLP-tuned runners. Nonetheless, we received impressive numbers from just a few simple upgrades. By the time you read this, the same goodies (plus a few more) should be available from SLP for the new Challenger.

Strip Test Results
2006 5.7 Hemi Charger
Temp: 86 Degrees; Humidity: 54 Percent; Barometer: 29.97 Hg

Here's the middle section...        read full caption Here's the middle section of the PowerFlo cat-back exhaust system. The PowerFlo is the quietest of the three available exhaust systems. All the cat-back systems feature a PowerFlo-X crossover pipe and, according to SLP, deliver a minimum gain of 12 hp and 11 lb/ft of torque at the wheels.	After the one-hour ride to...        read full caption After the one-hour ride to E-Town, we removed the plastic HEMI engine cover from the hot 5.7. We didn't ice the intake runners on either engine. We hoped to pick up 3-4 tenths on the R/T from the three new upgrades (cold-air induction, power programmer, and underdrive pulley). Previously, 13.8s were commonplace. On this day, though, a low barometer and high humidity would hamper our expectations.	Each of the three available...        read full caption Each of the three available exhaust systems feature polished stainless mufflers. Also featured are double-wall, 4-inch stainless polished tips. Everything necessary for an easy installation is included (clamps and hardware).
Hooking up was not an issue...        read full caption Hooking up was not an issue for the 5.7 Hemi Charger. Consistent 2.05 sixty-foots came even if the tires spun slightly. Our best quarter-mile was a 13.57 at 102.55 mph--quite an improvement from the bone stock's mid-14s. The small displacement Hemi makes remarkable power to haul the heavy LX down track.	Trying to launch the more...        read full caption Trying to launch the more powerful SRT8 was not an easy task. The 6.1 actually delivered its best e.t. during its third hot-lap. The Daytona did its best on its second hot-lap. These new Hemi's are the only motors we've ever tested that run stronger on a hot-lap. Remember, a cooler-than-stock thermostat (160- or 180-degree) is not recommended for any bone stock third-gen Hemi. Dyno and strip testing proves it.	If we only had drag radials,...        read full caption If we only had drag radials, mid 12s would have been easy. That's a second faster than stock from just a few bolt-ons.
Here's the graph showing the...        read full caption Here's the graph showing the 5.7's power increased from the 385 hp PreformancePac. As you can see, it's underrated. Increased drivability, performance, and efficiency will be realized from these well-engineered and tested components. Notice peak power for the 5.7 is at only 5,100 rpm.	Looking at this graph, it's...        read full caption Looking at this graph, it's apparent the 6.1 realized a broadened power band from the 475 hp PerformancePac (also underrated). The broad power band felt more like 500 hp for the heavy car to go so quickly down the track. The bigger Hemi made peak power at nearly 6,000 rpm.