New Exhaust

[slayer129978]

Ive got a 98 STS and i want to make it sound like a real v8 should and im just wondering if i take off the old stock mufflers and maybe put on flowmasters do you think if i just do the mufflers instead of a whole cat back system ill get a noticeable sound difference

[Cadillac Jim]

The 1993-1999 Northstar exhaust system consists of shorty manifolds feeding a Y-pipe very close in that feeds a cat at the front of the car. The cat has a 3" inlet and a 3" outlet. The outlet goes to the rear of the car, ending in a Y pipe that feeds two 2 1/4" pipes to the mufflers. The mufflers are 2 1/4" in, 2 1/4" out (center/offset). A final Y-pipe on each side feeds dual tips on each side.

Cat-back systems are hard to find for year models more than about five years old. Although a few people did sell cat-back systems for the 1998 model year STS, you can't find them any more.

That said, the Northstar exhaust system is inherently pretty quiet. I've heard systems that had the mufflers removed entirely and they are acceptable by legal standards. Turbo mufflers, such as the Bora 40658, remove the harshness with essentially no back pressure, and several people swear by them.

Whatever you do, note that your Cadillac (and most other cars these days) comes with a stanless steel exhaust system. Don't buy galvanized mufflers or use a muffler shop that doesn't weld using stainless steel. Use stainess steel exhaust system components with stainless steel welding rod or you will find yourself replacing rusted-out (or rusted-off) exhaust system components sooner or later, sooner if you live in the salt belt.

I was rear-ended at a time when Borla was out-of-stock with the turbo mufflers and an online supplier sold me Borla 40357 mufflers, which he said were "equivalent." When they arrived I quickly noticed that I could see two inches of daylight through them. I found the exhaust note very nice, and my wife likes it. I get complements on my exhaust note from car people. I found the part number in Borla's Pro XS series of performance mufflers. The difference is that turbo mufflers are straight-through but have an S-curve within the mufflers, while the Pro XS mufflers are simply straight through. Beware changing your tips -- keep your existing tips; new ones are expensive and styles that look like they belong on your Cadillac are rare.

I love my Borla Pro XS mufflers on my VIN 9 (300 hp) Northstar. On a bowtie or Ford V8, Flowmasters have an instantly identifiable sound that a lot of people love, and they now come in stainless steel. There are lots of good alternatives out there in stainless steel. You can't go wrong with any of them for sound, performance, or gas mileage (but don't let people exaggerate about that!).

[Riverfurm]

Ive got a 98 STS and i want to make it sound like a real v8 should and im just wondering if i take off the old stock mufflers and maybe put on flowmasters do you think if i just do the mufflers instead of a whole cat back system ill get a noticeable sound difference

I had a pair of flowmasters installed on my 99 Eldo at an exhaust shop. They welded them on and used the factory chrome tips. I like the sound NOT LOUD. I don't get why loud is a good sound, I like that low rumble sound. It cost me about $400 but the exhaust shop I use does a great job.