Will a Cat quiet a car?

[rickdm]

The '87 Carrera I picked up this week has a pre-muffler in place of the catalytic converter, and no oxygen sensor. It also has a RUF muffler. Though it sounds pretty good from inside the car it is very loud for bystanders. My question is this; if I put the cat back, will it quiet the overall sound? Will there be a noticeable loss of power? If I do that should I also put back the O2 sensor? The PO has not had any trouble passing emissions tests here in Texas, so I don't think that is an issue. I just don't want the neighbors showing up on my front lawn with burning torches

Thanks,
rickdm

[masraum]

Rick, yes, the cat will quiet the car down some. I had an '88 with the stock exhaust and it was very quiet from inside and outside the car. I dhon't know what you'll notice for power, but it won't be that noticeable. I would also recommend putting the O2 sensor back. My '88 passed emissions with flying colors with 155K miles, completely stock, hadn't had a valve adjustment in 45K miles, and, I think had a blocken head stud. Your '87 should if in good shape pass with flying colors.

[Kurt B]

With a cat bypass and a bursch muffler, my car was prone to nuclear like backfires when shifting. I seriously scared the holy hell out of pedestrians at times, and I'll never forget the look of horror one guy had as a big old backfire went off...
I put my cat back on and that was the end of it.

[cicsprog]

My CAT was punched out by PO - too loud. Bought a used OEM CAT from fellow Pelicanite (had less than 50k on it). Put in new O2. Car is much quieter and runs much better.

Jason
88 CAB

[imcarthur]

Maybe if you stuff him in the exhaust tip . . . tight fit though . . .

Ian

[911nut]

In going from a cat to a test pipe in my SC the biggest change in sound was at the low frequency end. This was most noticeable at idle. Overall the volume wasn't objectionable to me.

[rickdm]

Thanks for your replies. This might be the first project I take on myself. I am just hoping those bolts aren't completely rusted on.

thanks,
rickdm

[Vintage911Racer]

Some cats even make them louder. Especially Calico cats....

Sorry I could not resist.