2001-2008 GM Diesel and Duramax
|See an increase in horsepower and torque from your GM Duramax Diesel! Our 4" Exhaust System improves the efficiency of your vehicle by enhancing the following key areas:
* Improved throttle response
* Improved launches
* Increased fuel economy
* More passing power
* More pulling power
* about 100 degrees lower EGT
Dyno Tested real performance specifications!
Precision Mandrel bent
Put the fire back in your Duramax while increase towing power and mileage on your GM Diesel Pick-up with our new 4" Exhaust System. and 4" Down Pipe Kit exhaust improves launching and pulling performance. Reduces turbo lag and helps to cool your engine down, our 4" exhaust system is a must-have if you would like to get increased fuel economy, performance and durability.
Performance benefits are immediately realized in the form of HP increases you can gain 18 HP and 30 ft/lb of torque at the rear wheels. Increase fuel mileage up .5 to 1 MPG. Complete bolt up kit. Hangers, Brackets and Clamps included. Stainless tip no welding required. The advantage of the larger down pipe is not so much the HP and torque increases, but the much lower Exhaust Gas Temperatures (EGT's about -100.
Chevrolet & GMC Diesel Products
This is can be a (DIY) do it yourself project. See installation instructions before you spend your hard earned money.
1. Locate the turbo under the hood. Remove the band clamp from the downpipe at the turbo. Loosen the bolt enough to unlatch, then pry clamp away from the flange at three spots with a flat head screwdriver. Remove clamp.
2. From under the truck, cut the exhaust in two places. First, the downpipe next to the transmission, and second in front of the muffler. Spray the hangers with WD-40 and pry from the rubber to remove the stock exhaust. DO NOT discard the catalytic converter, if equipped with catalytic converter it must be reinstalled per Federal Law. We suggest cutting out the 3 _" inlet and outlet then welding the 4" to it and reinstall.
3. Locate the bolts attaching the exhaust heat shield to the brackets and cut off the threaded end to keep it from rattling on the new exhaust. In some cases it may be necessary to end the bracket closest to the muffler for more clearance.
4. From under the truck install the downpipe. Automatic transmission- rotate downpipe in as needed. Standard transmission- start with the flange up, point outlet towards the left front tire and rotate up and back to transmission. Remove the two transmission mount nuts and the transmission cross member then jack the transmission up an inch or two. Once this is done finish rotating the pipe past the transmission. Reinstall the clamp at the turbo (use stock clamp for this). Use bungie strap to hold the downpipe in place to align at turbo. Snug clamp down so it will hold but can be moved.
5. Install the muffler to the stock rubber hangers.
6. Install the first section of straight pipe. Use the one with two slight bends. Attach it to the downpipe with the clamp. DO NOT TIGHTEN.
7. Hold the second section of straight pipe between the first section and the muffler or measure and cut for correct wheelbase. BE SURE TO MEASURE LONG ENOUGH FOR THE TWO SLIP JOINTS.
8. Install both hangers after rotating the bent pipe to clear the heat shield. It may be necessary to modify the hanger to prevent rattles. Then install the muffler clamps at the straight pipe joint and the muffler. DO NOT TIGHTEN.
9. Install the two-piece tail pipe. Align between the shock and spare tire. Install the tailpipe hanger to the stock rubber hanger and align to clear the leaf spring. Then install the last two clamps
10. Starting from the clamp, tighten and align from the front to the rear, checking clearance as you go. We also suggest two welds at each joint to minimize movement. DO NOT WELD THE CLAMP.
11. Last, finish tightening the clamp at the turbo.
Warranty: 1 year materials & workmanship, must have part to warranty.