Originally Posted by Mach&Roll

So you are leaning towards borla huh? They are spendy.

Originally Posted by Ralph Greene

Get a tune, and have the tuner turn your cat light off in the computer.

When I took my stock catback off, we cut it just behind the muffler. So I could look into the muffler.

I couldn't believe how small the pipe is coming thru the muffler. I would guess in the 1 3/4" range. A major cork.

Ford saw fit to use a 2 1/2" mid pipe and 2 1/2" catback on the 05's, on an engine making slightly less power than we make. Does that tell you anything?

BTW....3" is way too big for 300 HP....someone above mentioning that. You want exhaust free flowing enough to exhaust, but not so large as to slow down the velocity. Keeping velocity up is important. I have some tuner friends who like to tune around LT's, X pipe, and stock 2 1/4" pipes with good flowing mufflers welded in. They get great street power. And the smaller pipes are quieter than larger pipes...,a lot of the drone from 2 1/2" systems comes from the larger pipes.

Originally Posted by wolfstang360 (Post 295239)

X-pipe Question... I've installed a BBK X-pipe with flowmaster 40 series and sounds are great at idle. When I open the throttle up a quarter or higher it sounds like I have a rattle in the system. I've taken it to my local shop and they could not find anything loose and no solution. Oh yea it also does it when I crank it up. Does any one have any insight on this? I no my worst fear is I will have to replace it all with another system.
thanks in advance

Originally Posted by Orange whip 04 (Post 291437)

I thought I would take a few minutes and express my opinions of exhaust systems and for people that are trying to decide what they want in a exhaust system.
In todays 03 and 04 mach1's there are three basic parts to the exhaust system.
Exhaust manifolds/headers. However they resemble that of exhaust manifolds to me. The catted H mid-pipe which is the middle section of the exhaust that holds your converters and 02 sensors. And lastly, the "Cat Back" as most people call them which is of course the last part of the exhaust which contains your mufflers, tail pipes and exhaust tips.
When we are contemplating a exhaust upgrade we should consider a few things. First of all lets think of the engine as a big air pump. More air that enters the engine needs to exit quickly with the least amount of restriction in order to create more horse power (Air in.. Air out). To achieve this we allow for bigger exhaust systems. Meaning, upgrading to bigger exhaust pipes
(2 1/4) to
(2 1/2) or 3 inch, removing the converters and deciding what mufflers have high CFM flow rates. Higher CFM flow rates will allow less restrictions. By making all these combined upgrades we are also decreasing the heat and high back pressures with in the system. With less heat and less back pressure we are allowing the air pump (engine) to work more efficiently at higher rates of effort which will free up horse power at the same time. The down fall from this is that we may lose some low end torque. I consider this a small disadvantage since torque could be made up in other areas of the engine. All these are aspects in deciding performance for your exhaust.

Alot of people are looking for exhaust tones and higher sound levels in a exhaust system. Less restrictions in a exhaust system will alow the exhaust to emit louder exhaust levels. A huge part of why a engine is quiet is because of the fact that cats are in place and mufflers with low CFM rates keep sound levels at bay. It seems almost sacreligeous to have a mustang mach1 sound as quiet as it does from the factory. Thank god for aftermarket exhaust systems. In most cases the mufflers (chambered & straight through), resonators, packs, will set the tone for your exhaust. Depending on there CFM rate they also can allow for louder sound levels as well. Here are some simple guide lines to follow when considering a exhaust system.

Offroad mid H = Absolute loudest aside from open headers, retains classic muscle car tone.

Offroad mid X = Absolute loudest aside from open headers, retains a Euro/Raspy exhaust tone no matter what cat back or mufflers have been installed. This is because of the X design that it sounds the way it does.

MAC prochamber = A design that incorperates both H and X pipe technology but shares no physical characteristics between the H and X pipe. This pipe will also retain the classic muscle car tone and should be considered as a off road pipe since it does not have cats. Though, a catted version is avaliable.

All three mid pipes are loud but your choice of a cat back or type of mufflers will determine how loud the total system is. If you are installing one of the off road mid pipes and are also considering a cat back system, now is the time to decide how loud you want it to be. With this in mind the only two mufflers i have heard that will quiet the mid pipes down are the stock mufflers and the regular performance magnaflows. All other mufflers/resonators/packs that i have heard be it either chambered or straight through designs seem to be loud and are frightfully exciting.

If you are deciding to just upgrade the cat back, aisde from open pipes or no mufflers, you can install just about any chambered or straight through muffler, resonator or pack and the sound levels will be some what managable. Many people decide that this is not enough sound level for them so they go with a offroad pipe or performance catted pipe for the extra sound level. Here are some more guide lines: Cat backs / mufflers

Chambered mufflers = Sets exhaust tone, can effect sound level depending on higher or lower CFM rates. Manufactures exhaust sound signature varies. Chambered mufflers have areas with in that contain aranged blocked sections which causes the exhaust to bounce off each other before they exit through. Think of this as a maze. Some chambered mufflers are loud like for example the 2 chamber Flowmasters. This type of muffler has a distinctive sound which many desire.

Straight through muffler designs = Sets exhaust tone, can effect sound levels and higher CFM rates are more prevelant. Straight through designs are typicaly louder than chambered mufflers and contain perferated areas with in the pipe along with revolving steel wool packing for example, the Dynomax race magnums which also have there own distinctive tone. Manufactures exhaust sound signature varies.

Resonators / Packs = Sets exhaust tone, will effect sound levels, higher CFM rates are more prevelant. Since resonators and packs are not considered mufflers many of them do retain straight through designs. They do not have chambers or areas of exhaust storage which will effect the exhaust tone in a different way. The straight through design in reguards to the resonator has a shaped pipe through the center which again, effects the exhaust tone. These types of resonators and packs are also considered loud Since they are close to open pipes.

Hope this helps guys. If you want to add your thoughts and concerns please feel free to add it in the post. Thanks