Hello fellow motorists,
I recently purchased a Akropovic down pipe from WMW for my 07' cooper s (super stoked) Anyways, I was looking to do a full exhaust on it, but seeing as the DP was quite a pretty penny and i still need to get it tuned to the new DP, I'm currently looking for alternatives. I was thinking of possibly cutting off the resonator and leaving it a straight pipe until the muffler. What are your thoughts on that? I don't know how restrictive the stock muffler is compared to an after market Cat-Back. Obviously I'm looking for sound and performance.Would i get any performance out of deleting the resonator and leaving the stock muffler? I'm assuming not, but i do believe it would sound good. I am seriously thinking about putting this exhaust on it but I'm unsure if it will bolt up to the Akrapovic DP, (http://www.cntracing.com/CNT-Racing-.../cb-07mini.htm) . Does any body know if it will?? If anybody has any ideas or suggestions i can or should do id love to hear them.
Thanks so much, Ray

 

^ AFAIK the most restrictive piece of exhaust is your DP. Which you ponied up and got rid of
The rest of the plumbing is 3" or more, which many say is more than enough for a 1.6 turbo engine.

As for removing the resonator and 2nd cat, it will let the "pop & burble" be more obvious, which is music to our ears.
It'll make the car sound like the turbo rally-ready car that it is.
Removal of those two ship anchors will run you about $40 at your local exhaust shop.

If you don't want to mutilate your exhaust system, there are cheap alternatives like the CNT Cat-back.

Other custom exhaust systems will run you a >$500 easily, if not into four digits. I won't name the brands here because there's plenty.

 

oh cool Cranker625! Thanks for the feedback! You read my mind, I just updated my post and i put in that CNT exhaust system, Im really curious about it. Do you know much about it? Sound? Performance? I like the look and the price, but i really want that pop and burble sound that you talked about.

 

Also Cranker625, Do you know if that CNT exhaust will fit the Akropovic DP????
Thanks so much!!

 

If your stock system will mate with the Akropovic then the CNT will also. I like my CNT system, but have not replaced the DP yet. I will recommend you replace the supplied clamps with the "U" type stainless clamps.

 

You can keep the resonator as the car will get crazy loud but delete your 2nd cat. Also if you do end up going with a flowing exhaust don't go bigger than 2.5" piping. This small turbo isn't worth the 3" piping, most tuners would agree.

 

Okay cool, vetsvette, how do you like the sound of the CNT cat back system?i want a nice aggressive sound and that pop and gurgle sound the minis seem to make .I just don't see the point in spending 1,000 or more for a cat back after spening almost 1k on the down pipe, especially if the cat back won't give anything but sound to the car; as far as Way Motor Works claims.
And RobMuntean, thanks for that heads up, i don't want it to sound ridiculous but a nice "throaty" sound is exactly what I'm looking for, ill start with just the 2nd cat for now. I completely agree with your piping recommendation as well, 3" seems a little overkill since i had 3" tubing on my 5.7L Trans Am. Although i do understand the purpose of a large diameter tubing, i just think its too much for a 1.6L

 

My car actually sounds like a sports car now. Not too loud in normal driving, but has a nice sound to it under hard acceleration. Pop and burble depends more on the programming by my understanding. My car doesn't have that feature although it does have a nice growl when decelerating. No drone at highway speeds (65-70) either.
The CNT is 2.5" stainless steel. Very nice system, especially at the price. I Like the blue tips with my car also.

 

Wha???!?!?!??? to both comments... Oh, I would PAY to get rid of the idiotic "pop & burble", but what do I know?

 

lol. i'm glad someone agrees w/ me that pop and burble is a joke on the mini. i absolutely hate it!

 

Awesome Vetsvette, great news. I believe i am going to get that for my mini, it seems like a great deal. i appreciate the help!

 

Have you talked to NM to see if they could tune out the pop and burble?

 

Not a problem. Glad to help. Where are you stationed in Germany?

 

Im currently stationed in Hohenfels (Bavaria). Its close to Austria and Czech Republic so South East corner. A really small army post. Are you prior service?

 

Retired MSgt, USAF. Spent all my time in the Far East, SEA, and Latin America. I retired in '88, long before you enlisted I'm guessing.

If you decide to get the CNT Racing system, you definitely want to get two of the stainless "U" clamps instead of using the hose type that come with it. If you try the supplied clamps, you'll most likely end up having to tack weld it to keep it straight and secure. I've had no issues with mine in the last few months. The tips match up nicely with the rear bumper too. Couldn't be happier with my system.

 

I ended up going with the wide (3"?) Strap clamps from O'Reillys. They are about $10 each but work nicely on my CNT exhaust.

Sent from my XT926 using NAMotoring

 

My understanding is going with a larger diameter piping loses torque but gains more HP, that's why I'm staying at my stock 2.25" inch diameter. I want velocity versus volume!

 

Oh cool! always nice to hear from veterans, my brother was air force, stationed in Arizona. Nice place. Yes definitely before i enlisted, i was still a 'swimmer' back then lol.
As far as the "U" type clamps, I've heard that before, possibly from you, i know you commented on one other link i posted awhile back. Only thing I'm worried about with that CNT system is it being too quiet for my liking, i don't want it crazy loud but i definitely want it heard. These minis have a great sound and i was super impressed when i first heard them. But I'm also thinking that since i have the akropovic DP that will make it a little louder as well? Am i correct assuming that?
Thank you for your help and your service. Hooah

 

It will definitely be louder, because it also eliminates the second cat. Your service is appreciated too Brother.

 

Oh right, Okay great. Someone mentioned earlier in this post that i should only eliminate the second cat because removing the resonator would make it crazy loud, do you agree? I was thinking of keeping the 2nd cat and removing the resonator. What do you think? Thank you MSgt, i appreciate that.

 

I've tried most of these variations. Here's what I found (somewhat subjective):

1.) Removed resonator - made it a little louder and drone increased ever so slightly on the highway.

2.) Removed resonator and 2 cat - made it little bit more loud than #1. I does make a raspy sound until it warms up and all the condensation is out of the pipes. I do not like this raspy sound.

3.) Removed resonator and 2 cat and replaced DP with catless DP - made it really loud, so loud that I really didn't want to go wide open throttle. This only lasted one day.

I now have a factory JCW muffler on order and I will probably put the resonator back in after I install the new muffler. A lot of people really like this muffler so I'm going to try it out.

 

I would keep the resonator to improve the tone but lose the 2nd cat for performance. I liked the CNT cause I didn't have to hack up my stock exhaust and I can swap it back on for inspection time.

Next up, I will probably try a catless dp. I have run catless before on another turbo car and it is loud but the turbo does mute it some.

Sent from my XT926 using NAMotoring

 

Great, that was exactly the response i was looking for. I think ill start with just removing the 2nd cat for now. Im currently waiting for a Akrapovic DP, so i just wanted a cheap way to make a nice sound until i can buy the CNT, I've heard great things about that cat back system and its affordable. Thanks a lot!

 

Nine5raptor, Thanks for that, i would like to run a catless DP but I'm stationed in germany and the inspections here are brutal so i have to wait until I'm back in the states to run that, ill just remove the 2nd cat until i can purchase the CNT cat back system.

 

The second cat is just an unmonitored emissions reducing device and as a rule very restrictive. The resonator on the other hand serves a couple of purposes and is not very restrictive.
Simple explanation : A resonator, well, it resonates. It reflects sound waves back. Within a given frequency range, this creates destructive interference, canceling out sound.

So, if you want to get rid of the "fart cannon" sound, you'll need to add a resonator that will cancel out the frequency that your exhaust is generating that you dislike, place it at the correct location in the exhaust path (it matters a lot where it is) to allow it to do so, and go from there.
Most small diameter systems require a resonator to keep them from just being annoying. Most systems are designed with this in mind, the CNT being one.
Not so much a requirement in large displacement engines using large diameter systems. My Vette and Suburban have no resonators, but both have 3" maganflow dual exhaust systems. No annoying frequencies inherent in a V8.
Just my opinion and YMMV.

CNT Racing is listing the system for $389 on their web site. I have seen it cheaper when they have a deal listed, like their resonated DP is on sale now for $199 instead of the regular $249.
Not sure what the restrictions are these days on packages going to APO or FPO, but it's not a real big box.