Which Model Borlas for 1997 ETC?

[Cadillac Jim]

The mufflers I have are about four inches shorter than the stock mufflers. They are actually wider, and about the same thickness. Mine are XS series, which are the performance line, as opposed to the general replacement turbo mufflers that most people use on Cadillacs. When I saw them, I could see two inches of daylight through them and was concerned about noise. I've had them a couple of days now and have driven them in a number of driving conditions, from stop-and-stop to high speed cruise.

Noise is very acceptable and quite pleasant. In normal driving in traffic, the traffic is noisier and you have to pick out the sound of your own exhaust. When you step on it, some will notice. When you nail it hard, it will turn heads. But, it will never get you a ticket. I love the tone -- low, gentle, and reassuring V8 sound. At high-speed cruise with the windows closed and the radio on, you can't hear the exhaust.

The XS series uses the same 304 stainless steel and all-welded construction, with 1,000,000 mile guarantee, as the other Borlas. Better quality may be out there, but I don't think that better quality would get me anything. I would have considered a cat-back system but I couldn't find one for the Eldorado. Borla once made one for the STS. I did look elsewhere but saw none for the Eldorado. Perhaps I should have called Magnaflow and asked; sometimes they have, or will make, things that aren't listed online. The Eldorado cat-back system would be identical to the STS cat-back system, except that the pipe back from the cat to the rear Y-pipe will be 3" shorter.

I have a noticeable increase in fuel economy, about 2 mpg. I think half of this is due to the fact that I had to drive two weeks with the damaged mufflers. I do think the other half is due to lower in restriction relative to the stock mufflers. I think that if you drive with the lightest possible foot you may have a higher "best-case" fuel economy.

[JasonA]

Aww man, I can't WAIT to hear the sound of those Borlas! We've had a Borla system on a Grand Cherokee before and it sounded QUITE nice. Took that thing through two Jeep Jamborees and dented the muffler all to heck, but it kept on ticking. Borla quality is among the best out there.

[Cadillac Jim]

JasonA -- yes, the sound is everything I expected and more. I'll figure out something this weekend. For openers, I'll do the camera video thing in the driveway. If it's too quiet, I'll ask my wife to help out in a parking lot or something.

abad95 -- Brude's page on Borlas for his STS says that he opted to keep the stock cat-back piple because his muffler shop wanted $700 to fabricate one. I find this boggling, because all there is to it is a cat connector, five feet of 2.5" pipe with a couple of easy bends, and a Y to two 2" muffler pipes, each with one easy bend. Mine is galvanized steel, but was not at all rusty so I kept mine too.

What part number were the Mangaflos? Your rating of excellent quality, near-stock but very nice sound and essentially direct replacement for the stock mufflers sounds attractive, and a part number will help others to find it on the web.

[Cadillac Jim]

I didn't get time to set up and record the sound of the new Borlas today. I did reset the codes from the car HVAC controls, not using the CalEquip OBD II code reader, before the last couple of trips. Sure enough, I get no codes at all, not even the usual P0603 that I get when I clear the codes with the CalEquip. I figure that there must have been some water shorts when they power-washed the engine and underside to cause the tranny code and injector codes. The CalEquip clears only the P codes and the PCM sets P0603 when it is cleared with the CalEquip.

The power band has shifted from the bottom end to the top end, and the feel is very much that of a VIN 9 engine; the old mufflers must have been restricting. After the engine swap, I felt that the torque curve had moved down in RPM, and the highway gas mileage seemed to be lower although the in-town and overall mileage was about the same. That's an early sign of catalytic converter failure, and I wasn concerned about the cat. Clearly, it wasn't the cat, it was the mufflers, even before the accident damage. Since both of the mufflers and one set of tips was damaged in the accident, I was very right to change both mufflers. Since all of my driving has been in high-traffic, time-sensitive commutes, I haven't had time to take it out to a low-traffic 65 mph zone and get a feel for performance improvements yet.

My wife likes the sound.