We tested each upgrade one at a time to get accurate results for what each picked up. That included a stock computer tune, three SCT computer tunes, a K&N intake, and a MagnaFlow exhaust upgrade. We can spew numbers from the testing results for the next 20 pages, but to sum it up, we gained power with each setup, and that is what we were looking to accomplish.
SCT was a bit conservative with its 40hp and 75hp predictions. The 40hp setting netted a 44hp gain and the 75hp setup picked up 74 hp--at the rear tires. Not bad when you consider the SCT stuff is suppose to add 40 and 75 hp at the flywheel, and we saw those gains at the rear tires. We finished with a robust 302 rwhp and 547 rwtq with the exhaust, cold-air kit, and 75hp SCT tune. The K&N kit gave a 7-rwhp gain at peak, while the exhaust was good for a 10-rwhp increase. Boost went from 14 psi (stock) to 19 psi, but on the street our gauge is showing we are at 22 psi. This was most likely due to a greater load on the engine--it produces more heat, which in turn spins the turbo harder to make more boost. A Dynojet chassis dyno doesn't load the engine as hard as the street because it's not an inertia-style dyno. But it is consistent for testing and comparison purposes.
The third SCT tune was labeled as a 100hp increase over stock. We did not run it with the stock exhaust for fear of high EGT readings; in hindsight it probably wouldn't have mattered. Running it with the K&N cold-air kit and MagnaFlow additions gave us staggering results--307 rwhp and 559 rwtq. That's a 95-rwhp and a scorching 138-rwtq improvement. We attributed the 5hp increase over the 75hp program to the use of the stock downpipe. We were definitely ready to hit the streets and smoke the tires.
Installation of both the K&N and MagnaFlow parts was easy and straight-forward. Working our way through the battery of tests took pretty much all afternoon, while the installation took the better part of the morning.
In just a day we were able to increase total output, and on the way home fuel mileage shot up from 18.5 mpg to a much more acceptable 23.2 mpg. The 75hp SCT tune is used for daily driving. Thankfully, we have more power for towing and increased our fuel efficiency in these days of high fuel costs.
Which setup would you want?...
Which setup would you want? On the left is the crappy stock stuff, while the muffler on the right is what we installed. The MagnaFlow muffler added a better rumble to the truck when it is at WOT. Around town it is not too noisy or obnoxious, like other systems.
Here is the difference in...
Here is the difference in tailpipes. Not only is the MagnaFlow system providing better performance, but it also looks a lot nicer.
The system slips together...
The system slips together without any difficulty, bolting directly to the factory downpipe. We definitely would have seen a greater power gain if we had gone with the MagnaFlow downpipe as well. The extra boost was not as efficient due to the pipe's restriction. The rest of the exhaust system performed awesomely.
MagnaFlow provides clamps...
MagnaFlow provides clamps to join the system together. Welding is not required to install this exhaust, making it a simple bolt-on that can be done in your driveway. The truck sits high, so it is easy to roll underneath it with a creeper and get the job done. We used air tools to tighten all the clamps.
It took six straps--count...
It took six straps--count 'em--to tie the back end down for our dyno pulls. The lightweight back side had us worried it would spin the tires on the rollers, thus not showing true output. At one point there were four of us sitting in the bed of the truck to make sure everything was accurate. In the end, the six straps were all that were needed to secure this beast on the rollers.
This is a neat little piece...
This is a neat little piece that JPC Racing installed. It is designed to intercept the manifold pressure signal that goes to the MAP sensor. When the MAP sensor reads over 21 psi of boost, it triggers the Check Engine light. The valve on this piece bleeds off anything more than 20 psi of boost going to the sensor, so the Check Engine light is never tripped. Anything above the 40hp tune-up with any aftermarket computer upgrade for Power Strokes will trip the light due to the boost reading.
Here is an example of an engine...
Here is an example of an engine part that came out of a diesel engine that used Shell-Rotella T oil. Note the lack of sludge buildup.