On a "stock" V-8 exhaust each side goes through it's own catalytic converter and then both sides enter a large single muffler. The earlier V-8's then exit the muffler on the sides, the later setup has a center exhaust from the muffler. The "cats" themselves do some quieting of the exhaust and the muffler does the rest. If you remove either (or both) the cats and/or the muffler the noise is a lot louder. Some owners either remove the cats or they hollow them out. Some owners remove the muffler. While it does increase the HP slightly, it makes the driving experience a LOT louder and less enjoyable, especially on long rides. There was a S/S muffler offered by Tubi but they no longer offer it. It didn't really change the volume but it did change the tone. Your '99 should have 2 catalytic converters (with the honeycomb catalyst bed still inside) and the one muffler with the two side outlets. If any of this is missing, it would account for the loudness.
David Teitelbaum

 

The cats are still there, and I witnessed the smog check before purchase and it had acceptable measured non-zero results. However, GMendoza told me not all of the readiness flags were set in the ECU so it was not up to "official standards."

I'm leaning towards the SJS part since it's about $300 cheaper than PUK's part, although PUK's photos look like a better product -- hopefully, this will work in quieting the cold start and low load noise. I'll be able to check the cats for sure when I remove the old muffler.

 

In most places you do not have to have EVERY readiness monitor "set". Depending on the local rules the # varies, very few require them all set. Some are more important than others and those MUST be set, like the O2 sensors. There is a work-around to get them set without the convertors but most places also visually inspect for the presence of the cats. That's why some owners will keep the cats but hollow them out. So, it sounds like you have the cats but no muffler. Loud!
David Teitelbaum

 

I have a 1997 V8 with a Tubi muffler. Factory cats still in place. It sounds much better than factory but definitely not loud where a cold start would bother the neighbors. Now for the couple of days where I had dropped the factory muffler but not yet installed the Tubi?... that was loud!

 

Note: the way the stock early V8s muffler is sideways. That allows it to act as part diffuser too.
You'll never be 'that neighbor' in a Lotus. And we're smart enough to not rev it while engine's still cold. I used to be that neighbor with the diesel F-250.

 

Part of C/C's philosophy to make every part do at least two things. The more the better. One of the clever ways he "added lightness".
David Teitelbaum

 

I got a 1998 V8 with just a couple of Flowmasters and no muffler. It does make that loud noise at start up, but hey, that's how it came when I bought it. I also have an Indian motorcycle with straight pipes, so I can't help it every time I go for a ride, but to say: "good morning neighbors! "