Finally! It's really quiet!

When I got my '93 Caprice wagon, it had a pretty massive exhaust leak that soon became even more massive...to the point where it was tripping the service engine soon light, keeping the oxygen sensors from working properly (it was running very rich) and then it got even louder. At that point I could actually perceive exhaust getting into the car through the ventilation system. I knew that the top of the muffler had rotted out.

Now it sounded somewhere between amusing and "badass", but I have strong reason to believe that my neighbors (the ones who aren't into cars) might not like this. And I knew it wasn't good for the car or probably its catalytic converter. So about a month ago, I went shopping and picked up a Walker stainless steel muffler from RockAuto. About two weeks ago I had it put on ... and there was little improvement. From the time I bought the car, I suspected that the manifold to Y-pipe flanges were missing the gaskets and not making contact any longer. This confirmed it.

I finally got that fixed today. Oh my, what a difference. Not only is the car a lot happier (the SES light blinked on once, perhaps because the computer was running from bad learned data?) but it's darn near totally silent...so much so that I wondered if it might have stalled at an intersection!

It should be interesting to see what this has done to the fuel economy. I was getting around 19-22 (almost 23!) with the leaky exhaust. More to come when I have numbers...

I just replaced a number of exhaust manifold bolts whose heads had popped off... driver's side #5, and passenger side #5 AND #6. No more tickety exhaust noise and now the PCM will actually get accurate data.

Next up is to clean out the throttle body, idle air passages, MAF (using CRC MAF cleaner spray), and clean out the PCV piping and a new PCV valve and the car should run like a top.

If you haven't done all these to your LT1 lately, you might want to.

Good deal Bill, glad to hear you got that done and hope it helps your MPG.

-Mike

81X11 wrote:

Good deal Bill, glad to hear you got that done and hope it helps your MPG.

After a goodly amount of fun this weekend, traveling various roads in Illinois...I'd say it has. I went from getting about 22.6 MPG to 26.79 MPG!

I am quite honestly stunned by this. I was driving 70-75 MPH most all of the time, and felt the need to "race" someone off the line from a stop light more than once!

If I kept my hoof out of it, I think it'd do even better still!

Obnoxious opinion: So, tell me again why if I were to buy a modern car I couldn't buy a nice big comfortable automobile? (Yes, I know about city mileage, but that's pretty bad in any car. The 26.79 MPG figure does include about twenty miles of city driving!)

I'm very jealous of your mpg. That's awesome!

Would that be a three-fitty or weency L03 in your pirate ship matey?

Sprocket wrote:

Would that be a three-fitty or weency L03 in your pirate ship matey?

L05 "three fitty"...



...which is good, because it is the engine I'd much rather have!