jayloo said:
I have a guy that has his own shop and can do the custom job. I just wanted to get an idea of what others thought were the best mufflers and cats.
Supposedly, the single most restrictive point in most car’s exhaust systems are the catalytic converters. There is also a huge difference in the design and cost of various CATs. For example, a replacement cat for my old BMW 325e ran about $1000+ for an OEM unit! Apparently, this is due to the much greater concentration of platinum, palladium and other precious metals in the converter than there is in cheapo units from JCWhitney, etc. More catalyst = more efficient reduction of CO, NO and HC levels. Better Cats can usually be designed less restrictive since the exhaust doesn’t have to contact the internal grid for extended periods to fully oxidize the emissions.
I would check the flow specs on any cats you intend to fit onto your vehicle to assure that they flow better than the stock units, before you dump a big wad of cash out for them. Also be aware that they may not be as efficient as the stock units if they flow better, so you may have inspection problems in the future.
A twin pipe setup (w/ the original cats) will probably reduce the backpressure substantially but don’t go too large on the diameter. Two 2 ¼ pipes is probably plenty for the V6, don’t go larger than 2.5”, tops. After that, you can install tuned headers and/or less restrictive cats. However, I don’t think this will be necessary unless you also perform mods which greatly increase the airflow (ie: supercharger, high RPM cams/timing/tune running mods, etc).
If/when I make any engine mods, it will probably just be a catback twin pipe setup and CAI (cold air intake). These 2 mods (+ maybe a tune) will let it breath a whole lot better, rev a lot higher and thus produce a lot more power. HP = torque * rpm / 5252. I figure 240 to 250 HP from these mods alone.
But, first things on my car will be tires, springs and rear bar.