I purchased a 1998 S70 non turbo with 113k miles. The car had a loud exhaust which was caused by a leak in the catalytic converter. I replaced the cat and the muffler. The exhaust noise is lower, but still is loud--especially under acceleration. I had a 1998 S70 with the turbo and don't remember it being this loud. Any ideas or is this normal for the car?

After installing a new Bosal cat and Starla muffler, the exhaust was still loud.
After doing an extensive internet search and talking to a Volvo mechanic, I discovered that the connection between the cat and muffler is a real problem. Very difficult to get this sealed and it usually fails after time. Also, after market exhausts don't have as much baffles as OEM and are noisier. In addition, the OEM stainless steel muffler( supposed to last 20 years) is no longer available from Volvo. I put the original exhaust system back on as it appeared to be in good condition except for the muffler end which was out of round. I cut off the flanges from both the muffler and cat and installed a 4 inch long 1 3/4" inner diameter pipe from Advance Auto. I put on muffler sealer and secured with two 1 3/4 " u bolts. The exhaust is now as quiet as new. A $15 fix. Wish I knew this before I installed a new exhaust system at considerable expense and time.

Replacing the cat means that you also replaced the flexible section on the down pipe. The muffler to tail pipe is one piece. So, that leaves just the connection between the cat and the muffler.

I needed 4 hands to do the connection properly. One person to shove the tail pipe forward, and me to tighten down the clamp.

The 850 with NA should be reasonably quiet with a stock exhaust. You should hear more intake noise than exhaust noise at full throttle.

Klaus
--
Why are Volvos so endearing? Its just a car.

I did not replace the flexible section from the exhaust manifold to the cat. It appeared to be okay. I had a muffler shop install the muffler( a Starla muffler that I purchased from eEuroparts.com). They put muffler cement between the cat and muffler to get a better seal. They said this connection is always a problem in the Volvo S70. They also welded on a resonator for me after the muffler. I thought this would make it less noisy. It did help some, but the problem still exists.