By Ken Payne

MBRP has been gaining traction in the diesel exhaust market for several years and it’s no surprise given the quality, sound and fit of the systems they produce. For the F250 6.0L Powerstroke Diesel project truck the stainless steel “Cool Duals” Pro-Series dual exhaust was chosen for its aggressive good looks and great sound. The MBRP kit arrived in a single large box (lower shipping costs than 2 smaller boxes) and included everything needed for a great system: pipes, down-pipe, hanger kit, gasket, bolts, washer, great looking huge exhaust tips with MBRP’s logo, muffler, clamps and full instructions.

The “Cool Duals” kit features mandrel bent 4 inch stainless steel pipes with low degree angles for maximum flow, a single high flow muffler with MBRP’s logo for a mellow, low rumble and great sound at wide open throttle and a larger than stock 4 inch downpipe. All these features combine to create a package which helps to reduce exhaust gas temperatures, increase performance and improve mileage if you can stay off of the throttle (hard to do with the great sound).

Until recent years dual exhausts were uncommon on diesels, usually requiring custom fabrication. Things have changed. MRBR let us know that nearly 25% of all diesel exhausts they sell are duals. Best of all, these kits aren’t more difficult to install than single exhaust systems. The “Cool Duals” kit can be installed in under a couple of hours by most anyone handy with a wrench. You can opt to take it to an exhaust shop if you prefer to have the pipes welded together instead of clamps or to have the best of both worlds while still saving money, install the system yourself and take it to a shop to have them weld the pipes.

Here’s the stock exhaust pipe. Not pretty, is it? Notice the rust on it after 3 years on Georgia's roads which are rarely salted. Just image what it would look like on a northern truck! This is another great reason to go with MBRP’s stainless exhaust systems… the exhaust will look great for years without worrying about pipes rusting through. MBRP manufactures the Pro Series made of T304 stainless which does not rust due to its low iron content and the XP Series made of T409 stainless which may develop slight surface rust (nothing like the flaking rust on the stock pipes, more like a slight brown color). Both are backed by a lifetime warranty.

The first step is to soak down the bolts on the clamp behind the catalytic converter with penetrating oil. I recommend Kroil. Its great stuff, much better at loosening parts than WD-40 and it’s the same oil Ford recommends for 5.4 3V spark plug removal. After letting it soak in, remove the clamp. MBRP’s instructions say to remove the exhaust from the converter back as 1 piece on 2003-2004 models to remove the passenger side bottom shock absorber bolt. We found it easier to simply cut the exhaust in half with a Sazzall and drop it from the truck in 2 pieces. If you don’t have a Sazzall follow the procedure to remove the lower shock bolt because this will be quicker than trying to cut the pipe with a hack saw. For 2005-2007 models you can remove it as one piece without removing the lower shock bolt.

Remove the nuts on the inlet flange of the catalytic converter and remove the converter. At this point the stock down pipe is the last part to remove.

Next remove the stock down pipe by first soaking the nut on the clamp by the turbo with penetrating oil, then removing the nut and sliding the clamp back out of the way.

Cut the down-pipe in front of the transmission cross-member and pull out the pipe. The spacing is tight getting out the stock pipe and you may think it will take a contortionist to do it but with some wiggling, turning and knuckle busting it will come out.

Install the MBRP downpipe in the same place as the stock downpipe using the stock clamp. Next attach the mid-pipe to the downpipe using the supplied clamp.

Attach the catalytic converter to the mid-pipe. For those interested in knowing, I tried this exhaust system with and without the catalytic converter. It was slightly louder without but there was virtually no change in EGTs and performance. I opted to keep the converter so it will be street-legal and not contribute more pollution to the already hazy Atlanta summer skies! The photos below show the system without the converter.

Cut the extension pipe to length (MBRP’s instructions have the length needed for each cab/bed configuration). Since the project truck is a Crewcab long bed the extension pipe did not need cutting.

Install the extension behind the catalytic converter and then attach the muffler to the back of the extension. I recommend you not fully tighten the clamps at this point and have something available to help prop up the pipes.

Install the over-axle pipe to the top outlet of the muffler and clamp the driver side exhaust pipe to the over-axle pipe.

Attach the passenger side exhaust pipe to the lower outlet of the muffler.

Now move and adjust the pipes as needed so they extend from behind the wheels evenly. Your primary concern here is getting the angle of each side the same and their exit points the same distance from the rear tire. Don’t worry if one pipe sticks out a little further, the exhaust tips can be adjusted to get an even look. Once you have everything evenly hung from the hangers and where you want them tighten down all the clamps. Start tightening at the front and work your way back.

Install the tips and adjust them so they stick out just past the lower bed sheet metal and tighten them down once they are even.

Doesn’t that look great? 100% better than the stock system!

Start up the truck and listen for any leaks and re-tighten any clamps as needed. Take it for a test drive, and again re-tighten as needed.

Impressions

The truck’s turbo certainly spools faster with the exhaust, and I’m seeing lower exhaust gas temperatures on average. This will come in handy when I tow. The “Cool Duals” exhaust looks and sounds absolutely great. It has a nice, mellow rumble at idle. At wide open throttle the truck sounds incredible with a throaty rumble like a big-block V8. During normal driving it does not overpower you inside the cab. It definitely doesn’t sound stock and it’s not obnoxious at all… but at wide open throttle it will get people’s attention.

For more information about MBRP exhausts or to find a local dealer, please visit http://www.mbrp.com/ .

Here’s a video/sound clip of the exhaust. It’s split into 3 parts: wide-open throttle from outside the truck, wide open throttle from inside the truck and idle.

Launch in external player

(Copyright 2008 Ford Truck Enthusiasts, Inc., All Rights Reserved. This article is used by Internet Brands, Inc. with permission.)