[FenixMike]

Well, since round 1 with just resonator deletes and taking all the restrictions out of the mid pipes actually made zero change in sound (but did add some increased top end) I thought id take another crack at it!

This time around I replaced the stock mufflers with a pair of Borla XR1 16 inch 2.5 inch diameter mufflers and some M5 knock off rolled edge tips (may do a M5 bumper later if I keep this car and put some nice tips on there). I also removed the pinch under the rear differential so now from front to back its all smooth round piping with no creases or restrictions.

The only resonance is at 2,000 rpm doing 80 mph, you can hear a bit of drone which is gone with the radio at normal volume, and anything above or beyond is still silent (sport mode puts it back to grandpa mode at 2400 rpm). Power is definitely noticeable up top and it feels like it comes on much smoother than before. Unfortunately at wide open throttle I cant hear much inside the car with the windows up and AC on, but around town at lower speeds it has a nice grumble to it.

Now to the sound... Its nothing less than intoxicating. Startup sounds like it should, the nice deep rumble of a twin turbo V8 ever so slightly muffled, but not overly loud or obnoxious... no rasp or cackle on decel. Basically it came out perfect, just as I imagined it would.

Unfortunately iphone videos arent very good for exhaust so I need to get a pro camera and take some good idle, startup and flyby vids, but I snapped a couple pictures at least (it was hot and VERY muggy today so I was in a rush to get it done and go shower!) Mufflers are installed vertical as pass side clearance didnt allow for a large full size muffler, but I have no issues with ground clearance and they really arent visible from back unless youre on the ground.

Videos down below

[747flyboy]

Good looking car Mike. Beautiful welds.

Joe

[FenixMike]

Originally Posted by 747flyboy

Good looking car Mike. Beautiful welds.

Joe

Thanks Joe! Im definitely getting a bit rusty on a Mig having been out of a shop for a while but I still enjoy building exhaust here and there when time permits.

Heres the rest of the exhaust from attempt 1 where I used the stock mufflers. I kept the mid section the exact same and its quite a bit quieter than I expected so I will likely leave it like this. I had plans of doing larger turbos and downpipes then building a 3 inch system but without the ability to tune my car it just wont have near the gains it should for the money invested in steel, so this is likely as far as it will go.

[Bmw doubles]

Build a j pipe to eliminate the drone. Here's a forum post that breaks down the math.

http://flg8cc.com/vb4/showthread.php...nd-application

[FenixMike]

Originally Posted by Bmw doubles

Build a j pipe to eliminate the drone. Here's a forum post that breaks down the math.

http://flg8cc.com/vb4/showthread.php...nd-application

ehh not my thing. If it bothers me enough I will just toss a magna flow cross flow muffler in the middle. I don't care much for silencers or restrictions (most OE manufacturers use the same concept on intake systems).

[lsturbointeg]

Sweet! Always appreciate people who try things themselves!

[FenixMike]

Originally Posted by lsturbointeg

Sweet! Always appreciate people who try things themselves!

ehh interest is fading fast I really want a N63tu car or M5, but when I look at how often I exceed the speed limit (never), go to the track (also never), or why I actually need more power (I don't), I find I just tinker out of a background in it and really don't need to keep wasting money. If I end up in a newer one, I may go chase some records for fun.

[Autobuffoonery]

Definitely post some videos, I was going to put on the same borlas but got the Megan's instead. I would like to hear what I could of had.

[FenixMike]

Originally Posted by Autobuffoonery

Definitely post some videos, I was going to put on the same borlas but got the Megan's instead. I would like to hear what I could of had.

Its almost funny how few people own a real camera anymore these days... so settling for trying to find a go pro at this point.

[Bmw doubles]

FenixMike you're running the the OEM DP?

If so, and your gaining top end I might have to go back and install OEM DP and rethink the exhaust system.

[FenixMike]

Originally Posted by Bmw doubles

FenixMike you're running the the OEM DP?

If so, and your gaining top end I might have to go back and install OEM DP and rethink the exhaust system.

Yes I am, granted I have 58,000 miles now so I'm sure the cats are a mild restriction with age, but I picked up a NOTICEABLE gain from just removing all the restrictions the first time around (turbos spool faster and its just smoother overall) and now with the mufflers off you can actually feel it charge up top under heavy load. I will give more of a report after a couple days and update. I was skeptical the exhaust would do much with most saying its not a huge restriction, but I have to wonder how many are testing a complete downpipe-back setup as compared to those who are just doing axle backs. I wish I took pictures, but some of the restriction points, specifically after the rear resonator, pinch down to about one inch wide with hard angles severely reducing flow. Most of the dyno results ive seen are on M5 only systems which don't have the restriction points the 550i has.

Oh and if anyone is in Phoenix and has a camera, you're welcome to meet up with me for some videos and you can drive my car while I film

[lsturbointeg]

Reading post like these makes me think twice before dropping money on $2k+ systems so I have to decide what I'm going to do? Really want to go with the Armytrix for the simple fact I'll have control to open/close my valves and being able to monitor all my data on my phone. Some people probably think it's not necessary to have all that but this is something I can think about when the time comes next spring. Or I can just go with some Megan's just so I BBC an hear some sound.

[FenixMike]

These were done with a Go Pro and the best I could obtain, if anyone is local with a better camera, you are welcome to do some filming.

Revving and neutral

cruise and then floored it (when I let off, camera fell)

low speed driving towards the camera

low speed driving away

Fly by

[Autobuffoonery]

Sounds goodthanks for posting!

[Autobuffoonery]

Fenixmike, what did you do with the vacume lines that went to the exhaust valves on the stock mufflers? I just tucked mine in the diffuser and forgot about them till right now. Do they need to be plugged or are they fine the way I left them?

[Bmw doubles]

Sounds great

[FenixMike]

Originally Posted by Autobuffoonery

Fenixmike, what did you do with the vacume lines that went to the exhaust valves on the stock mufflers? I just tucked mine in the diffuser and forgot about them till right now. Do they need to be plugged or are they fine the way I left them?

I plugged them

[lsturbointeg]

Cool videos!

[Bmw doubles]

FenixMike I just did a muffler delete and I hate it.

What are suggestions for resonators? (I have the stock resonator still in.)

Where along the piping is a good placement for resonators?

Should I also install an xpipe?

Should I also couple the resonator and xpipe install with a high flow muffler?

I will say I like the gurgle and popping when down shifting, but hate the honda sound and droning all over the rpm range. Like when I'm doing 20mph at 120 decibels.

[FenixMike]

Originally Posted by Bmw doubles

FenixMike I just did a muffler delete and I hate it.

What are suggestions for resonators? (I have the stock resonator still in.)

Where along the piping is a good placement for resonators?

Should I also install an xpipe?

Should I also couple the resonator and xpipe install with a high flow muffler?

I will say I like the gurgle and popping when down shifting, but hate the honda sound and droning all over the rpm range. Like when I'm doing 20mph at 120 decibels.

The Magnaflow Magnapacks are the resonators I use on all 4 and 6 cylinder applications. They are cheap, work fantastic and small enough to fit anywhere
http://www.magnaflow.com/automotive-...ound/products/
My rule of thumb is buy the largest one you can fit in there (24 inch if possible) to reduce resonance. The stock resonator is really just meant to be coupled with the stock mufflers so it isn't exactly efficient (I proved that by removing both of mine and having zero change in sound). Beyond that, pick your muffler combo. If you want to stick with magna flow (which I recommend, you would be hard pressed to find a better quality muffler, and they are extremely cheap for what you get, all stainless, etc. Anyone who says "mine is better" either doesn't understand anything about exhaust, or just wants to make a lot of money off you) they work well, but a lot depends on your interest in sound. Magna flow, Borla, Dynomax etc all make fantastic mufflers and will give off a deeper rumble since they are packed straight through mufflers, if you want the more exotic M3 sound with rasp and resonance, you will need a muffler built for that sound and it will likely be priced accordingly from an expensive source.

X pipe only works if you have true dual exhaust, since the N55 has a single turbo, the canceling effect wont work as it doesnt have any way to scavenge exhaust. Running it in the "dual" section of your exhaust wouldn't have any purpose.

Ideally you have to first determine what "sound" you want. Unfortunately there aren't many single turbo inline 6 cars these days to listen to, but you have two ways to approach this. First you can just add single components at a time such as either two rear mufflers (magna flow 12 or 14 inch mufflers) or a large center resonator. Typically the resonators don't have a lot of ability to quiet the exhaust down, they just reduce drone and interior noise in conjunction with other components... I use them when doing cat deletes as it helps out the noise added by removing them and keeps the rasp down. The other option is start with a full exhaust and remove components as you don't want them... obviously the more expensive route but it depends how bad you hate the noise and how often you have time to make trips back to the exhaust shop. A nice 3 muffler combo is ideal for zero noise but it may be too quiet if you still have a cat on there so plan accordingly with small body mufflers and large resonator if you want to hear it, or large body mufflers if you want it quiet. Also remember, Performance straight through style mufflers don't rob power, so don't be scared to have a couple large ones on there. There are also different styles of mufflers which I change up depending on the sound I want. Magna flow for instance has different shapes of mufflers each with different characteristics, so one will be more of a racy car sound, another a deeper rumble, some just completely silent. I went with Borla XR1 because its a slightly more exotic sound while being fantastic at killing resonance, but they are more tailored to a V8... that being said the Borla XS series mufflers are fantastic and about the same price range as Magnaflow.

If you were in AZ id just build you a setup until you were happy, but the best I can do if you want is design something for you based on what I have had luck with, show you what to buy, and the rest is up to your local shop. If it was me though, large center resonator, two small rear mufflers and call it a day.

[RSBro]

Originally Posted by FenixMike

ehh interest is fading fast I really want a N63tu car or M5, but when I look at how often I exceed the speed limit (never), go to the track (also never), or why I actually need more power (I don't), I find I just tinker out of a background in it and really don't need to keep wasting money. If I end up in a newer one, I may go chase some records for fun.

I had this same realization just the other day. I saw a glorious AW F10 M5 and wondered what it would take to upgrade but then figured it wouldn't be as comfortable to drive nor have the Executive Seats options plus some other stuff and I'd always been wanting to gun it and then have to slam on the brakes, which I already do enough of in my 550... It does more than I could ever use as is.

[Bmw doubles]

Thanks FenixMike super appreciate the insight.

I'll start with magna's.

Stock mufflers 19.2 lbs each
14" mangaflow 6.8 lbs each

Total reduction weight = negligible : )