Anyone who's had the pleasure of taking a cruise around town in a new SRT8 Challenger knows there is plenty of power and torque, especially from a small-block. With a quick look at the numbers-425 hp and 420 lb-ft-it's easy to see why they're so much fun to drive. But by looking at another number, the 4,132-pound curb weight, we can see where more power to motivate all that weight wouldn't hurt. We will do so by using the old-school mentality of upgrading to a bigger cam and better exhaust to deliver more power.
We start this project off with a moderately modified, manually shifted '09 SRT8. Under the power bulge hood we find a K&N intake. Owner of Coastal Dyno in Tampa, Florida, Sam Lippencott, and his head tech, Horacio Ramos, tied the behemoth to the rollers of his Mustang Dyno to give us a baseline of 395 rwhp and 381 lb-ft of torque.
The American Racing Headers...
The American Racing Headers are made from stainless steel and feature merge collectors with velocity spikes. This design has its roots in racing and has been proven to make a few extra ponies-a very cool design feature.
To make these numbers a little more impressive and add some serious sound, car owner Aziz requested that Coastal install a nice group of parts. First on the agenda was improving the 6.1L Hemi's respiratory abilities. To do this, Coastal will be installing a set of stainless steel American Racing long tube headers with 17/8-inch primaries which converge at a 3-inch collector. From there, off-road 3-inch mid pipes remove the catalytic converters and reduce exhaust restriction (not smog legal). Behind the ARH exhaust, the factory exhaust with aftermarket mufflers will be replaced with a full-stainless system from Magnaflow that reuses the factory exhaust tips.
With the Hemi's breathing increased, it makes the installation of the custom grind Comp Cam more effective. However, to accommodate the increased valve lift and duration, Comp beehive springs and pushrods will also be installed. This should make for smooth sailing and reliability. The specs on the cam are .547/.550-inch lift, and 224/228 degrees of duration on a 114 LSA, which should make for some nice sounds. Now follow along as we tear into this late-model Challenger and try to unlock more power and a set-to-kill idle.
Conclusion
The final results have proven the potential of these late-model Hemi engines for daily use and for serious power. "The car really woke up and I was surprised how much faster it felt. The seat of the pants indication has made the SRT8 an amazing driver. The idle through the new exhaust is equally as impressive and enough to put a smile on any Mopar fanatic. Why didn't they all come this way?" said Sam.
Parts Installed
| PN | Part |
| 112-502-11 | XFI Street/Strip Camshaft |
| 26918-16 | Beehive Valvesprings |
| 762-16 | Titanium Retainers |
| CHRY78NC | 1 7/8-inch Headers with 3-inch Connection Pipes No Cats |
| 16510 | Stainless 3-inch Challenger System |
The aftermarket performance...
The aftermarket performance mufflers that were welded into the factory exhaust system made some cool sounds, but the factory pipes aren't stainless and restrict flow. Therefore a 3-inch Magnaflow system will be installed after the header mid pipes and feature dual mufflers and an X-style crossover.
The Comp cam will be installed...
The Comp cam will be installed along with new titanium retainers, valvesprings, and hardened pushrods.
Sam Lippencott and Horacio...
Sam Lippencott and Horacio Ramos start by removing the factory exhaust. The factory system is a combination of steel and aluminized steel and is only 2.5 inches in diameter. Installing the 3-inch system all the way back without cats should free up some breathing room.
Under the hood, Sam and Horacio...
Under the hood, Sam and Horacio immediately removed the K&N intake setup and unplugged the coils. After that, the valve covers were a simple job to remove.
If you haven't seen underneath...
If you haven't seen underneath one of the new Hemi valve covers, here's a good look at the factory rocker and spring setup.
With both valve covers removed,...
With both valve covers removed, next Coastal removes the fuel rails and intake manifold.
In case you're not sure, the...
In case you're not sure, the plastic plugs under the intake are for the MDS system found on non-SRT models.
From this point, Coastal thought...
From this point, Coastal thought it would be better to remove and install all of the parts with the engine cradle lowered away from the car. The Coastal team then unbolted all of the suspension and hardware holding the cradle in and carefully lowered it onto their engine support stand.
With the engine out of the...
With the engine out of the car, it was easy to access and remove all of the valvetrain components and the timing cover.
Next, the guys swapped out...
Next, the guys swapped out the camshaft after preparing the new one with the supplied break-in lube. The original timing set was reused.
The ARH system cuts it close,...
The ARH system cuts it close, but the primary tubes are carefully shaped to avoid any interference with the vehicle. Once installed, the headers don't sit any lower than the factory exhaust.
The cat-less mid pipes are...
The cat-less mid pipes are mocked in place and left loose until the rest of the exhaust can be positioned.
It was late at night as the...
It was late at night as the Challenger's new rumble echoed off the walls during the dyno session.
The first few pulls were showing...
The first few pulls were showing excellent gains even though no custom tuning software was used. Fuel was bumped up but there were no changes to timing. With a peak gain of 54 rwhp and 23 lb-ft of torque, the owner was very pleased with his new numbers. Notice where originally the torque drops off after 5,000 rpm, but with the new cam and exhaust it holds strong all the way to redline. Even more impressive are the average gain improvements with the 6.1L averaging 348 rwhp and 387 ft-lb across the full rpm spectrum. Imagine what a custom tune could unleash!