3. Cats and Catless

Cats, or catalytic converters, are one of the great inventions to come out of the green era (sarcasm). What a cat is exactly, is an element (usually platinum) that heats up and reduces one harmful gas to a less harmful gas. This section will cover three areas of cats: OEM cats and their configurations, hi-flow cats, and no cats.


OEM Cats

OEM cats on the F150 series have changed from the 1997-2011 range. 1997-2005 trucks have a 4 cat system that includes a pair of small cats, called pre-cats, and a pair of large cats down stream that handle the majority of gas conversion. The main goal of pre-cats is to act like a resonator, canceling out unwanted engine and exhaust noise (mostly catered to the elderly and the feminine ). Trucks with a 4 cat setup are in general extremely quiet. Many users opt to remove the rear "fat" cats and only use the pre-cat, which sounds quite similar to hi-flow cats. Some members with 97-03 trucks have had issues with CEL's popping up soon after the removal of the rear cats has been accomplished, but can easily be corrected with a custom tuned programmer or "fooling" the computer with an O2 sensor mod.

The 2 cat system came around halfway through 2005, and every truck after that point has only had the one pair of cats. The 2 cats are just 2 large cats that handle all of the gas conversion and some sound cancellation. Trucks with the 2 cat system tend to still be extremely quiet, but slightly louder than the 4 cat trucks. Nothing can be done to these cats besides removing them all together, or replacing them with a good set of hi-flow cats.

Hi-Flow Cats

One of the greatest mod one can do for their exhaust. Hi-flow cats drastically increase sound quality, volume, and overall aggressiveness of any exhaust. They do this while still complying with emission tests. Hi-flow cats accomplish this by being much shorter than OEM cats, but still having enough of the catalyst material inside to fulfill its job. Depending on the engine size dictates which cats should be used on a given vehicle. Most cats have it specified that they are to be use only on vehicles with equal to less than XX.XX liters or cubic inches.

Many members who have invested a great deal of money and time into their exhaust opt for hi-flow cats. The most widely used cats on the F150 series is the Magnaflow 94106 cats.

No Cats

Going back to the days when cats were first mandated on all US vehicles, people were taking them off. Today is still the same, but not quite as common as it once was. Going catless greatly increases the sound quality, volume, and overall aggressiveness of an exhaust system while also being extremely cheap depending on how you go about it. There are some problems that one may face while running a catless system on a vehicle that comes from the factory with a set on.

A CEL can come on, and usually does, because the O2 sensors pick up on the exhaust gasses being too rich and try to lean out the A/F mixture. This also reduces performance because engine is setting itself out of its ideal parameters to try and correct the issue. This can easily be corrected with the help of a custom tuned programmer, by using the O2 sensor mod, or by installing O2 eliminators.

Even if a CEL has been turned off by means of a programmer, O2 sensor mod, or eliminators, it will not pass a "sniffer test" that many emission shops use. So if you live in a town that requires strict emission testing, going catless is not a good option.

Another possible issue with a catless system is that if police officers are especially strict on cat mods, they will be able to smell you out. Even by just driving by, they can easily smell the "illegalness" of your vehicle.