MyE28.com

It's not like I'm trying to copy off of Layton or anything, even though he's cool enough for me to copy off of. Oh damn, Shawndy please don't kill me for using a preposition at the end of my sentence!

Anyway, it's not like I'm trying to copy off of Layton, but I have some questions about the exhaust system for my eta.

I did an oil change Monday and found a gorgeous 1" diameter hole in my exhaust system about a foot or two before the muffler. Hmmm. . . so THAT'S what was so loud! It wasn't THAT much louder, but it was noticeable to me.

So, I've been thinking about what I might do for a replacement. I could go to Autozone and get their lifetime warranty thing and never have to worry about buying an exhaust again. Or, I could get a factory replacement and not have to worry about replacing the thing every year like I would if I bought an Autozone one.

Or, I could do some kind of custom thing that would be extremely expensive but really cool.

What do y'all think about this. . .

The eta cat is WEIRD. Check out these pics. In these pics, the Super Eta exhaust is on the left, and the standard eta exhaust is on the right. . .





As you can see, the two downpipes on the eta merge into a single-in-dual-out cat and then a dual-in-dual-out resonator and then a y-pipe to merge the pipes once again. The rest of the system is just a single pipe with a single-in-single-out muffler out back.

What the hell kind of sense does that make? Wouldn't you think that's extremely inefficient and just pointless to merge and separate the pipes TWICE?

What do you think about this. . .

Gut the cat. Either leave it hollow or weld some pipes into it so it's just a set of straight pipes. Then, cut off the y-pipe at the end of the resonator so that I have dual pipes after that. Then, I could just go with any number of dual-in-dual-out mufflers, my favorite being the Euro 535i muffler.

So, I would have a hollow cat, eta resonator, and Euro 535i muffler.

What do you think that would sound like and achieve. I'm not worried about performance right now. If I have to tune the FI system a little bit -- maybe adjust the AFM -- to richen up the mixture to compensate for the increased flow, then so be it. But, that just means I'd have more air and fuel flowing through the engine, not less.

I'm mainly curious about sound. I LOVE how a stock US 535i exhaust with no cat sounds, and I especially LOVE how a stock Euro 535i exhaust sounds. WOW that thing sounds great when you get on the gas! I was hoping to duplicate that sound as close as I can without going completely all out and spending nearly four figures on an exhaust system.

Another option is to just gut the cat and get a replacement eta system, but that won't sound too much different than stock, and it definitely won't wail at full throttle like the other options.

Go ahead, let's hear it. . .

Why do you wanna modify your eta? It's an ETA!!!

Isn't that kinda wasteful of a perfectly good Euro 535i muffler?

Get a 535i already!

Blah blah blah. Heard it before. I'm getting a second car next year, but for now this is what I have to play with. Besides, it's more about the project and playing around with the car than it is about the final outcome. Why else would I do a $1400 5-speed conversion on a $1500 eta?

Gut the Cat , take out the resonator,install Euro muffler of your choice Randy/Fla. aka:the Tanned One & BlueThunder LOL!!!

Beats the hell outta me what you oughta' do. But, when you finally give up on all other options, throw your hands in the air and say, "F*** it, I'm gettin' OEM!", call me. I've got a brand spankin' new one sitting out back doing nothing but getting older. Can you say, "NOS"?

After giving it some thought, I think I'm going to just replace the cat back for now. When I go down to Louisiana in April, I may look into gutting the cat. Then, some time in the future, I may see about having the rear half of the resonator outlet modified to accept a dual-pipe system and adding some other type of muffler (Euro 535i, maybe) to the back.

That way, I can go in steps and see/hear the difference between each change.

C.R., I may PM you in a few days if one of my deals doesn't work out. What brand is it?

Brad,

If you want to disable the cat, have a shop weld in a straight pipe. Remember how Lee's car sounded with a hollow cat? It was all raspy and funky. Another friend has an e30 325i with a guttet cat, and it, too, sounds crappy and raspy.

Just a thought...

Pat,

Thanks for the suggestion. I was actually thinking the same thing. I'm not just going to cut out the cat and put some pipes in -- I know you didn't suggest that, but I thought I'd mention it. I have to have the look of a cat, at least.

My first choice would be to have a pipe welded inside the cat as you suggested, but if that proves to be too costly, I hold off on that and just get it gutted. I kind of want to go in steps on this. First, do the cat and OEM exhaust, then have the rear of the resonator modified to take a two-pipe system, and then go back to a new, different muffler.

For now, I'm just going to replace the exhaust and then see about having the cat work done next time I'm in Louisiana.

Brad, why don`t you run the Super eta exhaust all the way back ?? Take one of the cats in Cut in 1/2 weld 2 thru pipes inside You`ll have "the look" of a cat. I`m getting ready to cut-out my resonator allready cut-out the kitty Just gonna run the 2 pipes straight back to the muffler "Should" sound good !! Adrian has done that to his "old" 87/535is & it sounds healthy ! food for thought ! LOL! See Ya Randy/Fla.

[QUOTE="Shifty"]C.R., I may PM you in a few days if one of my deals doesn't work out. What brand is it?[/QUOTE]

Hmmm. Gotta go wade through some snow to check. (It was whatever Rocky Mountain Motorworks sold as OEM - Bosal?) I'll get back to you on that.

Anyhow, it was never mounted and is in excellent shape.