[Isaiah5411]

Can someone confirm for me that the diameter of the PE's midpipe (red arrows below...between the welds) for the 328i E92/3 (arrows) is 2.25" vs. 2.5"? It looks like it could be 2.5 (or larger)...from staring at this picture for two days.

Thanks! (See post #9 below as to why I care about this. It'll also explain the need for the yellow arrows.)

[Taskmaster]

I thought it was 3 inches...

[StealYourFace]

I think the ID is 2.5"

[GTKrockeTT]

2.5" on all ends

[Isaiah5411]

Well...I just jacked up my car, crawled under it from behind and measured the circumference of that specific section pictured above, which was approximately 8.75", which makes the (outside) diameter 2.75". So, 2.5" inside diameter should be right....right?

[mmmnot]

For what it's worth, my mid pipe (N52 - between headers, replacing 2nd cats) was 2 1/4" (ID)

[Route 16]

55 mm

[Isaiah5411]

Originally Posted by Route 16

55 mm

Thanks for the reply, but...that would make it 2.17", which is impossible by my circumference measurement. I could believe that it is the diameter of the two pipes entering the resonator of the stock exhaust (which I could measure for myself). However, the picture above and my quick circumference measurement suggest 2.5" ID as others have posted for that mid section of straight pipe.

I'll get under it again this AM and double check my C measurement.

[Isaiah5411]

Ok...

Crawled under the car again this AM to do a more precise measurement. This time I got 9" for the circumference of the pipe marked by the red arrows above. That translates to 2.86" outer diameter of this section.

On the other hand, I measured the pipe between this straight section after the hanger but before the dent (in other words, the first bend, marked by yellow arrows) and found it to be 8.25" in circumference, which translates to 2.63" outer diameter.

So...why do I care about this??? Some of who have already read that I have mixed feeling about the sound of PE with the top down. It gets loud (or intrusive) at times when I'm just cruising/talking with the top down, especially when traveling on an uphill grade in 6th gear (I have auto), when it comes as close to droning as the PE ever does.

Note to the critics: There is a world of difference between listening to this exhaust with the top down vs. top up or even with top up with all windows open. (It is probably twice as loud with the top down than top up with windows down.) I have also followed my car in another convertible and listened to it drive around town. I have had friends do drive-bys in all gears while I'm standing still in a parking lot. I have, in fact, listened to this thing every way possible, and my conclusion is:

I wish it was 25% quieter, had a little less "drone" at cruising speeds of 40-55 mpg, and that it had 25% less burbling. That would be MY ideal exhaust note (again...convertible).

So, I am considering adding a Vibrant bottle-style resonator where the denoted straight section of pipe is....thus needing the measurement to be precise.

I was assured by a forum member that I needed the part #1790, but that is 2.25" ID/OD. The 1792 is 2.5" ID/OD, which even seems too small, but....that might slide right inside the cut ends of this section??? However, Vibrant also offers the 1794, which has 3" inlets/outlets (slide over the cut ends of this section?). A positive thing is this PE midsection is 12" from weld to weld and each of these resonators are exactly 12" long tip to tip, with the bottle itself being 9.5" (so each resonator tip is 1.25" long).

Sooo...think this would work? Think it would produce the results I'm looking for...or would it totally destroy the sound of the PE??

Thanks!

[pinoye90]

Originally Posted by Isaiah5411

Ok...

Crawled under the car again this AM to do a more precise measurement. This time I got 9" for the circumference of the pipe marked by the red arrows above. That translates to 2.86" outer diameter of this section.

On the other hand, I measured the pipe between this straight section after the hanger but before the dent (in other words, the first bend, marked by yellow arrows) and found it to be 8.25" in circumference, which translates to 2.63" outer diameter.

So...why do I care about this??? Some of who have already read that I have mixed feeling about the sound of PE with the top down. It gets loud (or intrusive) at times when I'm just cruising/talking with the top down, especially when traveling on an uphill grade in 6th gear (I have auto), when it comes as close to droning as the PE ever does.

Note to the critics: There is a world of difference between listening to this exhaust with the top down vs. top up or even with top up with all windows open. (It is probably twice as loud with the top down than top up with windows down.) I have also followed my car in another convertible and listened to it drive around town. I have had friends do drive-bys in all gears while I'm standing still in a parking lot. I have, in fact, listened to this thing every way possible, and my conclusion is:

I wish it was 25% quieter, had a little less "drone" at cruising speeds of 40-55 mpg, and that it had 25% less burbling. That would be MY ideal exhaust note (again...convertible).

So, I am considering adding a Vibrant bottle-style resonator where the denoted straight section of pipe is....thus needing the measurement to be precise.

I was assured by a forum member that I needed the part #1790, but that is 2.25" ID/OD. The 1792 is 2.5" ID/OD, which even seems too small, but....that might slide right inside the cut ends of this section??? However, Vibrant also offers the 1794, which has 3" inlets/outlets (slide over the cut ends of this section?). A positive thing is this PE midsection is 12" from weld to weld and each of these resonators are exactly 12" long tip to tip, with the bottle itself being 9.5" (so each resonator tip is 1.25" long).

Sooo...think this would work? Think it would produce the results I'm looking for...or would it totally destroy the sound of the PE??

Thanks!

Why sounds like the measurements are accurate. Test it out!!!

[hassmaschine]

I would add a muffler there instead of a resonator. a resonator is just going to change the tone, it's not going to decrease any volume. a 2.5" borla would probably sound nice and not restrict things much if at all.

[Isaiah5411]

Originally Posted by pinoye90

Why sounds like the measurements are accurate. Test it out!!!

Think it'll do what I am wanting it to do: A little less volume, a little lower tone and a slight reduction in burbling?

Gonna run the idea past my muffler shop in the next day or two (after the AA retune tomorrow) and make sure it's all reversible.

[supergoat]

Originally Posted by hassmaschine

I would add a muffler there instead of a resonator. a resonator is just going to change the tone, it's not going to decrease any volume. a 2.5" borla would probably sound nice and not restrict things much if at all.

Have to disagree here. I have used resonators very successfully in the past to quiet down an exhaust as well as eliminate drone.

[Isaiah5411]

Originally Posted by supergoat

Have to disagree here. I have used resonators very successfully in the past to quiet down an exhaust as well as eliminate drone.

Dat's what I wanna hear!

But seriously, I have continued to read on this and heard enough positive things about these resonators (that are sorta like glasspack mufflers, containing sound dampening material) to "donate my car's body to science" (or this forum) and give this a try.

One more plus is it being placed in the stock location for the 328i resonator. The only question is whether a single 9.5" long resonator (length of resonator body) will do enough. We'll soon see. Hopefully, this will end up being a viable alternative for E93 owners who want an upgraded...but refined...performance exhaust.

[pinoye90]

Originally Posted by Isaiah5411

Dat's what I wanna hear!

But seriously, I have continued to read on this and heard enough positive things about these resonators (that are sorta like glasspack mufflers, containing sound dampening material) to "donate my car's body to science" (or this forum) and give this a try.

One more plus is it being placed in the stock location for the 328i resonator. The only question is whether a single 9.5" long resonator (length of resonator body) will do enough. We'll soon see. Hopefully, this will end up being a viable alternative for E93 owners who want an upgraded...but refined...performance exhaust.

I have read threads on 3" piping being successful in toning down sound. Along with vibrant resonators added as well. Both are options. Not sure which is better for inline 6 motors.

[Dylanize]

Aw, don't hack up the PE!

Just put your OE midpipe back in and keep the PE Muffler...

Is that not the obvious solution here? (no offense to anyone)

[Isaiah5411]

Originally Posted by Dylanize

Aw, don't hack up the PE!

Just put your OE midpipe back in and keep the PE Muffler...

Is that not the obvious solution here? (no offense to anyone)

No offense taken. I was just afraid that the OE midpipe (with IT'S resonator) would do too much in the way of dampening the sound (and perhaps be more restrictive to exhaust flow). The straight-thru resonators like the Vibrant should do nothing to reduce flow, but...one 12" may not be enough to do what I want to the sound.

But...I'm intrigued enough to try (once I get this AA tune thing settled, but that's a whole 'nother thread). And, if it ain't enough, then we go with your idea...if I haven't decided that I DO love the PE enough to keep it as is.

[Taskmaster]

Borla muffler, 3 inch single!

[Isaiah5411]

Originally Posted by TheAxiom

Borla muffler, 3 inch single!

So ya think that would do it? I looked at them. Are you thinking about 3" center/center 12" oval Sportsman Racing muffler? I think it would fit and makes sense. Ever heard that set up by any chance? I don't to take too much sound out.