Join Date: Apr 2008
Location: City of Trees
Welcome to the forum. Looks like you're off to a good start. What kind of tuner did you get? How is it set up? What kind of exhaust? What kind of intake? The mods. to the engine/transmission that you're after really depend on how much $$$ you want to spend, whether or not you want to adversely affect driveabiliby, and how much power you're after. Also, you should do the mods. in a logical order.....i.e. don't do a mod. that you'll only get partial results out of until you've made other mods. I started in this order....intake (cheap, easy modified stock system), then custom exhaust with headers, tuners, cam/underdrive pulley, throttle body, and finally coils. I didn't do heads because they don't give a very big bang for the buck (~30hp. for $2000) and it required significantly more engine teardown. I did my cam and valve springs/pushrods without removing the heads. My cam change only required removal of engine valve covers and front timing cover. Here's my take on building a quite a bit better street Hemi. I did mine with what I considered a minimum of expense. The header back exhaust and the cam/kit were the biggest expenses, but also delivered the most horsepower gain. See my signature for my list of mods. Also, I figure I am up around 100 hp. over stock and have cut more than a second off my quarter mile times.
As far as headers go, your options are pretty limited.....from easiest/cheapest to most expensive/difficult.....stock LX exhaust logs (outlet collector goes from 1 3/4 to 2 5/8 in.) and requires "Y" pipe modification; stock SRT manifolds, a fairly efficient improvement requiring a modification for the EGR to work properly and minor cutting on the transmission case for clearance purposes; aftermarket SRT long tube headers requires the same EGR and case mod., extensive "Y" pipe modification and rear O2 Sensor extensions; find someone to build you a custom set like I did. With all of the above, you should be running a 3 in. tube exhaust (or duals if you want to spend a bunch more $$$), preferably with a straight through muffler and resonator. The resonator keeps the "MDS drone" to a minimum. If you don't mind the drone, you can leave the resonator off. A good header back system is worth about 30-35 hp.
After a good header back exhaust, a properly selected cam is by far the best bang for the buck.....about 50 hp. for less than $1000. There are a number of good cams available from several cam grinders. Here is where you can make or break your driveability. That's why you must chose carefully based on your goals and preferences. I used a Frank's Racing Sidewinder (made by Comp. Cams) cam, because it has been well dyno proven for years over on the LX platform vehicles. I also have the same cam in my Hemi LX.....modified the same as the WK. If you also want to increase your fuel economy, buy a cam that is MDS friendly. With mine, I now routinely get 22-23 mpg. on the highway, running at 2200-2400 RPM in 4th gear, at ~65-68 mph.
There are quite a few makers of CNC ported/big valve heads, if you want to go this route. A recent article in Mopar Muscle Magazine showed the difference (increase) in airflow between the stock and ported heads.....between 4 and 41 CFM from .100 to .550 in. valve lift on the intake side, and between 6 and 43 CFM from .100 to .550 in. on the exhaust side. IMO, not worth the difference on an otherwise pretty much stock Hemi. The only time I'd do this mod. is if I broke the engine and had to do a major teardown. Then I'd go larger displacement and some more serious mods. Like I said above, heads are worth about 30 hp. for around $2000 on a NA engine.
If you're going to do a lot of drag racing, a torque converter will make a big difference in getting the 4700+ lb. WK mass moving. It'll get the launch RPM up to a range closer to the torque curve of whatever cam you buy. You'll generate more heat in the transmission and your in-town fuel economy will probably suffer, but once you get full lockup you'll be good. IMO, before you do something like this you should give the rest of the transmission a little help first.....i.e. a line pressure booster, a shift kit, and the Superchips Advanced Transmission Tuning Application. These things help it quite a bit, but a stall converter would be nice if I did a lot more racing than once or twice a year. Again, to me, the bang for the buck and practicality just isn't there for this mod. Just my 2 cents.
06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS Tuner, Cust tubular hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, SRT Reps with 265/45&295/40X20's.