The first or second step in adding power is to replace the restrictive factory exhaust. Though you can "chip" your vehicle first and do the exhaust second, it is better to help your engine to breath easier before introducing it to higher stress loads.

It would be kind of like taking a week or two to get in shape before trying to run a timed mile (increasing your cardiovascular ability first so you aren't huffing and puffing your way to the finish line).

Changine out the cheap, restrictive factory exhaust increases your engines ability expel combusted gases more quickly and easier (no power is robbed trying to push out the exhaust gas).

The increased airflow gives your engine the potential to make more power. Remember that the power your engine makes is a function of how much and how efficiently it can combust the air/fuel mixture.

4" diameter exhaust seems to be the magic number for most turbo diesels (many 4" systems have 5" tips).

The second benefit of an exhaust system is the great sound they generate?in other words, your sports car doesn't sound like your little sister's Toyota Corolla.

While adding a nice, chrome tip makes your ride look good, it does nothing for performance.

There are three types of exhausts or exhaust "systems". The difference lies in where the exhaust system starts.

An exhaust system has three parts...a muffler, a center pipe, and a "down" pipe (which typically contains the main catalyst in a turbo diesel) The down pipe is what connects the exhaust system to the engine/turbo).

Muffler

The muffler is the end section of the exhaust. It is what "muffles" the sound coming out of the engine. Some people prefer loud mufflers and large tail pipes...it's your choice as long as it is a high flow muffler and it delivers the look and sound you want.

Note that many truck come without a muffler or the exhaust is actually muffled soley through the cat...like the new Powerstroke 6.0.

"Cat-Back" (replacing from the Catalytic Converter?Back to the tailpipe)

A "cat-back" exhaust system begins at or rather connects to the factory catalytic converter. The larger than factory tubing then runs to a less restrictive muffler (that is louder and sounds more powerful) before venting exhaust gases to the atmosphere. Exhaust gases still leave the engine and pass through the low cost, restrictive factory catalytic converter (if they come from the factory with a cat).

Turbo-Back Exhaust

A turbo back exhaust, on the other hand, replaces everything from the turbo to the tail pipe. It removes the factory catalytic converter (if the factory has a cat in the down pipe...many turbo diesels do not have a cat in the down pipe like the 7.3 L Powerstroke) and replaces it with either a straight pipe or a high flow catalytic converter.

With a higher flow capability, a turbo back exhaust has greater potential for more horsepower. Typically, with all things being equal, on a properly tuned, forced induction vehicle (turbo charged) a "turbo back" exhaust will net 10+ more horsepower than a "cat-back" exhaust.

With reduced backpressure coming off the turbo, a "turbo back" exhaust will theoretically allow the turbo to spool up quicker too (i.e. 100-500 rpm).

Turbo back exhausts range from $700-1,500 where as "cat-back" exhausts range from $450-750. The bottom line is that a turbo back exhaust and "chip" combo give you the most "bang for the buck"!

Furthermore, a "turbo-back" exhaust provides you with a good foundation if/when you plan to pump up the power even higher than the typical preprogrammed power stages.