|The Dreampipe Exhaust System||Short Cuts|
|by: Josh Lowenstein, Tech Editor
Edited by John Nutter
|Chuck Pennington, owner of Discount Muffler, showing off the Dreampipe.|
|The "old way" note the dents on the bottom of the "droop" pipe and lack of driveshaft clearance.|
|Keith from Discount Muffler was able to reuse the old Flowmaster muffler on our project vehicle.|
|The completed Dreampipe!! Tucked up high and dyno tested to add 20 HP over a dual 2" system.|
|Top is the OEM Wagoneer driver's side "wrong" manifold. Bottom is the CJ 304 "correct" style.|
Rockcrawler's Dream Exhaust
The Rockcrawler's dream exhaust system is for those who want ultimate performance without sacrificing ground and driveshaft clearance.
This system can apply to any domestic make or model 4x4. Jeep, Chevy, Ford and Dodge can all have the Dreampipe type of system. The vehicle for this article is a 77 CJ7, with a 360 cid AMC engine.
The problem with "piping" many 4x4s is where to put it. Most headers put the exhaust outside of the frame, causing mufflers and flanges to be placed right under the rocker panels. The drawbacks of this type of system are very hot floor boards, smashed mufflers and outlets that are in front of the rear tire. Headers limit overall ground clearance as well. Full size trucks have many more options but can still benefit from the Dreampipe.
Running stock manifolds with dual 2" exhaust pipe is often a very tight squeeze between the frame and transfer case. With dual exhaust you are forced to run two of everything. Doubling mufflers and expensive catalytic converters adds up.
Having a single 3" exhaust seems the best route, but where to put the y-pipe has been the age old question. Running the "y" under the front drive shaft is how it has been done for years. With high flex suspension systems the "droop" in the pipe going under the front drive shaft has to be huge and can mean sacrificing drive shaft diameter as well.
The Rock Crawler's Dreampipe (RCD) solves these problems and gives back valuable ground/shaft clearance. By routing the y-pipe around the oil pan 2" drive shafts can be used and suspensions can "droop" as far as you want. I have had the prototype RCD pipe system on my Jeep for 5 years and I have never hit the y-pipe on a rock.
One of the problems encountered installing this type of system is getting the correct driver's side manifold. The Wagoneer manifold dumps to far back. Finding a CJ 304 driver's side manifold does the trick. If you are having this system installed on a non-pollution controlled AMC engine the best manifold is one from a 304, 343, 390, or 401 Matador, Javelin, or AMX. These do not have AIR rails and flow much better. Chuck and crew of Discount Muffler in Denver have done the RCD pipe for over 100 vehicles. He will be soon marketing the system in kit form.
Get approval from your local emissions technical center or department of health mobile emissions program official before modifying any system related to emissions control. Good luck and great wheeling.