Ok gang, I've got a doozy for you.....

Here's the scoop.....I have a 2011 Mini Cooper S model, manual transmission with 1600 miles on it. The only mod done was to install a Cat back system from NM Engineering at about 800 miles.

I did the install myself on my buddy's lift and everything was square and tightened properly. I tightened the exhaust coupler bolts past snug, but no to the "snap the bolt" setting.

After that install I began to notice my car made a really high piched whine or whistle at exactly 5k RPMS and it would keep doing it until I shifted.

When the Tach got to 5k again in the next gear it would do it again.

I asked my buddy about it and he said it was "turbo whine" and that possibly the new muffler was allowing me to hear a resonating tone that was masked before. I was still suspect.

Tonight we had a local club meeting and I gave two knowledgable Mini owners a 200 yard sprint in my car and they both heard the noise. One seemed to believe it was coming from the rear of the car and the other thought it was the brake cooling ducts whistling. I don't think it is an air duct issue because it is not speed related, but RPM related. I get no whistling at 100MPH in 6th gear, but I do get it in 1st, 2nd, 3rd gear as soon as the tach hits 5k.

The best way I can describe it is that it sounds like the whine you year when you rub a wet finger around a fancy wine glass rim and it makes that constant high pitched squeal/whine.

Someone suggested that I climb under the car and re tighten the exhaust coupler, since it sounds like a high pressure exhaust leak and the escaping gas "screaming" out of a small gap.

I made several passes up the road for the club and all could hear my car "whistle" as I got up to 5k in first and second gears and was even 100 yards away.

Anyone have any suggestions of what to try?

(I am reluctant to go to the dealer because today I installed my Defenders of Speed intake and cut a hole in my bulkhead. Since this sound occurred for the past two weeks before I did the intake, I didn't want to cloud the issue by mentioning the intake above. The whining sound did not change at all when I added the intake...still the same.)

Thanks,

Larry

 

I wouldn't be too worried about it. I started hearing the same thing after I installed my DoS CAI.

 

Today I climbed under the car and snugged all the exhaust bolts including the flange that came with the NM exhaust and the coupler that was installed when I cut the factory muffler off.

All bolts took about 3/4 of a turn and snugged up further. I warmed the car up and took her out on the road for a few sprints.

Now it seems on the three sprints from a dead stop that the whine is gone in 1st and third gear, but it is still there in second gear at 5200 RPMS.

I didnt redline it once I heard the whine, since the car is still breaking in.

Now Im really confused. I might call NM Engineering and see if they ever heard of their exhaust causing odd sounds.

L

 

Did you use a torque wrench? Ask NM how tight everything should be. Could be it isn't tight enough since you got rid of the whine in 1st and 3rd.

Don't be afraid of the red line. You cannot over-rev it. See the string on "break in procedures." You need to run it a little harder.

 

Check to make sure that the new exhaust is not rubbing against anything. Is it rubbing on the heat shielding? A suspension component? Etc?

 

Missed the whole part about it happening two weeks BEFORE installing the CAI, didn't you?

 

C'mon Larry, who REALLY needs second gear?!?!?!?

 

Haha! I noticed it as soon as I clicked post! Lol!

My bad!

 

Today I went to Flow Mini and gave a tech a test ride and made the car "sing" for him so he could hear it.

A couple of observations were noted:

Even though it only does it at 5000-5300RPMS, it will only do it when my foot is mashed to the floor on the gas. If I accelerate slowly to 5000, it will not whistle.

Also, the sound is coming directly under the rear seat. That also happens to be right where the coupler is for the NM exhaust.

When we got back we put the car up on the lift and checked to make sure nothing was rubbing and the heat shield was not flapping like a reed in a harmonica. Also as a test the tech ziptied a little block in place to sort of stabilize the long straight pipe and possibly prevent harmonic vibrations. He said the JCW kit comes with one and is used for that purpose.

I road tested it again and it still did it....

Sooooo I called NM and the guy said that whenever anyone complains of a whistle it is almost always a loose connector. So he suggested I re-tighten the bolts a third time and maybe even loosen them first and recenter the gasket. So tomorrow I will do that.

Now I explained to the tech that the bolts were almost tightened to the point of shearing, so I can't imagine getting them much tighter. (I'm 5'8", 200 pounds and have been lifting weights for 20+ years. I currently bench press 340+ and deadlift close to 500.....not saying this to brag...but when I say I tighten a bolt its TIGHT )

So I will re-center the gasket and try to get a better seal and see whats going on.

On a positive note....I have been at a loss for a month on what to name my car.....Slim Jim Tell said the club is gonna call me "Whistler"

Kinda catchy.....

 

Haha.

+1 for Whistler...

 

 

I just heard this same noise on my 2011 MCS. Only mod I have done is resonator delete. But the sound I hear is on idle. I only have 340 miles so I'm trying to keep it under 3k rpms. I don't thinks it's turbo spool because when I accelerate is doesn't get louder.

 

Well I took the car to Grass roots for service yesterday and gave Dan a test run in the car. He said he has never heard that before, but if he had to guess there was a burr or odd weld in the muffler that is causing the whistle. he said if its in the muffler, where it seems to be its harmless....

The local club thinks its funny and I discovered that the vanity license plate "WHISTLER" is not taken......but it is now

Should be here soon.

"ThatCooper S".....you can read a lot of posts about break in, but most (or alot of people including Dan at Grassroots Garage) think you should break your engine in more aggressively to seat those rings. Modern engine cylinders are honed a lot better that our grand father's cars, you dont need to run them easy for initial break in. I got my car and for the first 500 miles drove it and varied the RPMs up through the range, but never kept it pinned at redline, of course.

You can read more here: http://www.mototuneusa.com/break_in_secrets.htm

For what its worth Dan @ grass roots used to work for BMW and Bently. He is Bently trained and has been to their England factory. He is THE authority on MINIS in the Triad. He said that he sees more problems with engines and oil issues in cars that were never taken above 3k during break in than those that were "driven" like the car should be. But its totally up to you how you break your engine in.

At 1800 Miles we went to VIR and did two 25 min sessions on the track and the week before that the club did aMini run though wine country and it was quite a workout.

I just changed oil at 2400miles and installed rear sway bar and am ready for the Dragon.

 

Mini15235 - the article about breaking-in is interesting and makes a lot of sense. Did you change your oil to petroleum, as the article recommended, during the break-in period?

 

No I didnt run different oil because I didnt learn about that article until about 1000 miles into having my car. I found myself in the front of a pack of mixed cars for a local run to a winery at about 700 miles. After the 30 min run at mixed speeds in mostly 2-4 gears I felt guilty for not following my traditional "go easy/short shift" break in procedures. I didnt hammer the car, but we were riding pretty fast on some twisty roads and I was certainly going through the range of RPMs.

The someone directed me to that site and explained that I probably actually did a good thing for my engine being on that winery run .

I just changed the oil at 2200 because we have two more club runs coming up and then a 3 hour drive to and from The Dragon, so I wanted it to be fresh.

 

Thanks...this break-in info is definitely something to keep in mind when i get to drive my MCS.

 

Hey gang,

A friend pointed out to me that in this video the car makes the same whistling sound as mine does at the 1:22 and 1:55 minutes. Turn your speakers up loud.

http://www.youtube.com/watch?v=vZjO0...e_gdata_player

You can hear a whistle. It's an NM exhaust on a Cooper S in a Dyno. Hi RPM and it whistles.

Maybe its a normal characteristic of the design...I dunno.

Larry

 

Weird yet interesting. Thanks for sharing.

-Clint

 

Only the 4th day with my 2011 MCS and I have the same whine/whistle sound. No mods...yet.

 

Check this thread for more info on the NM Downpipe back exhaust as it seems similar to your problem original poster: https://www.northamericanmotoring.co...e-problem.html

 

This is suspected by me to be cause by the design of the after market flanges(inner lip)

 

My M3 did the same thing when I installed an El Diablo exhaust, the manufacturer agreed it was defective so I returned it, I suggest you contact your manufacturer.