The Helmholtz does not nessissarly have to be at a 90* angle to the exhaust either, you can connect it as a T and run it parelle to the exhaust if you want.

Almost like a small 2" section at a 90* angle, and then the length of tube you need for tuning connects to that at a 90* angle and runs parelle to your current setup.

PS Dr Phil, if you search "helmholtz resonator car" on google images your car comes up near the bottom of page 1.

It's a sign!

 

I did some figuring from the website on exhaust resonance. It seems as if the fundamental resonance of my current system is at about 4-5ft, which puts it just behind the mid-point of the system (the entire exhaust is 8ft long). I was thinking of putting a filled resonator or muffler at that point--the expansion and the damping could capture the resonance, still allowing me to run the chambered mufflers aft. The Hushpower resonator after the cat might also be causing some problems.
Anyone got a recommendation on an alternative to a Cherry Bomb?

 

When I was getting my setup up all figured out I went all burns stainless for components. How long are you thinking on the muffler/resonator? I am waiting for the funds to be able to pull off my setup.

 

I was hoping for something about 18" long (said the actress to the Bishop...) just to cover more of the potential fundamental wavelength range.

 

I'll try to call you later.

 

Right on so for the 2.5" in burns stainless is either 3.5 or 4.5 in O.D. for mufflers in the 17 1/8" overall length.

 

Dr.Phil:
Thanks for leading the way with all your work, posting notes & thoughts regarding the R53 straight-through exhaust. I'll be installing my own straight-through exhaust in <3 weeks & will post my results. In the meantime, I thought y'all might be interested in how Dr.Steve (Custom Mini Shop) did my battery delete & battery installation.

The batteries are from BigCrank.com (Big Crank battery specs) & can be installed in any orientation (except for being inverted). I'm thinking of trying out Corsa's 'Reflective Sound Cancellation' product: Corsa. Can you provide me a suggestion regarding resonator & better yet an online store to review exhaust tips?

 

Those are some serious batteries! Are you running lots of power amps for the stereo? My little Braille is doing fine--but it's a very mild winter here in Albuquerque this year so far.

ProFlo has a nice catalog of tips you can view on their website (it's a PDF). I am getting the black chrome 6" oval tip on my new system--unfortunately it is backordered so it will be another week before I can report on the system, sorry.
I'm constantly hearing that mufflers without absorption material are going to be really loud and potential drones on the R53 due to the supercharger.

 

Try FloPro instead.......

 

Just caught up with this thread.
Just want to throw out a warning. I ran my car several years back when it was still street/track. I used almost the exact system the Phil first installed. It was the Milteck resonator and that same Flowmaster. No cat.
My warning is about damaging your hearing, permanently. I'm an old guy compared to most of you here and I've abused my hearing quite a lot. But nothing damaged it more then driving my Mini with this system. I knew it within the first month of doing so. That's all it took, damage done. Something about the resonance and the drone that caused permanent hearing loss.
Just be careful. There are certainly good ways to get great flow a lot quieter. And no, the Supertrap just doesn't do it for the Mini.
Check out Steve Diniz's video here. http://www.vimeo.com/2728581 and the other ones there and you can hear how quiet that it.
Also, get the mufflers closer to the header if you want them to be quieter. Gotta get to the hot gasses before they cool to much.

 

onasled: steve's system was certainly impressive. what did you end up w/ to get to legal levels w/ your side exhaust?

 

This is great information. What I'm kinda confused about is using mufflers only w/ an baffled exhaust tip (as in Steve Diniz' setup) or resonator + mufflers?

 

I understand why some people think the more expensive the exhaust the better, but has anyone tried a dynomax super turbo muffler, you can get one at advance or most parts stores pretty cheap, like $30-40. I have heard these on everything from a 4cyl to a V8 and in every instance they give a deep throaty sound (obviously throatier in a v8 than a 4cyl), but still just a thought instead of spending hundreds on borla's, corsa's, and truely custom setups.

 

Actually that style muffler is also really like a resonator. You could almost say that Steve has a resonator and a muffler, or two mufflers, both basically the same thing.
My race car ran two, side by side Magnaflow resonator/mufflers at the end of the system. Wasn't that loud, but being it was side exhaust it was aimed right at the sound police. I ended up getting a cheep "two in" and "one out" packed oval muffler that was better. Then tried the Supertrap at the end of that but it really made no difference at all,
With these center runs, I would just get the muffler closer to the header, and that will help a good amount as far a noise.

 

Yes, that's fine to get cheep and it's what I did, but you just need a "packed" muffler for the Mini, not a baffled one. The Mini S is just so loud!

 

the super turbo's are (by what I believe you mean packed) fiberglass filled and baffled, which is what I believe helps them produce such a pleasant, not loud tone.

 

my 03 already has the battery in the hatch. did they not come that way?

 

I did a lot of research when I was designing and creating my exhaust, and I chose a Borla Turbo muffler; and it has served me very well.

The pipe going through the muffler (golf ball in, golf ball out) is peforated ss. It is wrapped in quite a few layers (I forget how many) of ss to absorb sound. There is also a blanket of ceramic material to cope with sound deadening. For its size, Borla claims to be most effective sound-absorbing device available...

I've had my straight exhaust for over 5 years now, and I love it. It is not overly loud by my standards, and most who hear it agree. My hearing is just fine .

I got a center/offset (2.5") Borla Turbo muffler. Here is some info:

http://www.borla.com/products/produc...Turbo+Mufflers

This muffler can be had at Summit Racing for a little over 100 bucks. At least that was the price a few years ago...

It mates up with a SuperSprint center pipe, with resonator:

http://www.promini.com/product-exec/...arch_model/100

As far as my header, I have a SuperSprint (Craigslist find for like 200 bucks), ceramic coated it, with the stock cat flanged-in for easy swaps or replacements... I remain very happy with this combo. My wife still drives with me, although she does say it's loud. My mom loves it! No tickets, warnings or even looks from the police here in CA...

 

Looking back, Tony, the Borla muffler and SuperSprint center resonator would have been a cheap option for me !! Nowdays I'm stuck with a whole lot of worthless pipes and hangers that I call experience by trial and error.

I'm really glad you're happy with your mod (you were one of the first to do this - kudos for being a surviving pioneer!) and thanks for adding your information to the thread.

cheers,

 

Yes, they came that way, but they are in a "well" that hangs down in the way of doing a center pipe, so the process here is to remove that well.


Yea, Tony was the first I remember doing this mod!

 

Great info Tony! I'm going to start placing my orders.

 

Fracky, I see that you are somewhat near me. If you are in the Bay Area, let me know. I'd like for you to hear it before you invest your time and money. I'd feel bad if it didn't meet your expectations...

Of note, you need to weld an extension onto the SuperSprint center pipe so it goes to the very end of the tunnel. I seem to recall that it's about 9 or 10 inches. This then mates-up to the Borla, the center end, with the offset end going to the tip, and you'll be golden.

It's a fun project. Good luck.

 

I had 9 different exhausts on the floor at one time before I started cutting them up to make newer ones to test mufflers with.

I think I have tried about every muffler that will fit behind the axle. I have also tried resonated tips, chambered mufflers (like vette mufflers) resonators, multiple mufflers, etc, etc.

Trial and error is what I found it takes to perfect something like this.

 

You're way to modest... NAM is recreating your work from years ago....

one thing I think everyone finds who rolls their own exhaust is that it's very hard to get it right the first time. My single side 2.5" exhaust is sitting next to a shed because it was so freakin noisy that I thought it was hurting my kids ears and even the guy with the Ferrari F355 with a race exhaust said it was lauder than his exhaust! Anyway, be prepared to buy a lot of mufflers, and taking more than one trip to the welders (if it's not something you do at home...) Good luck to all who try!

Matt

 

One of the things I started doing was using slip connections with Walker band clamps to stop wasting so many midpipes. I was making a new midpipe for every muffler.


I would suggest just using one of these Walker clamps till you find the muffler you enjoy the best and then weld it all up. (Plus Summit will take back mufflers as long as they look new, if you don't like the sound)