Hello-
I decided to post this here instead of the problem forum, as I thought this may related to the JCW in particular. I saw another related thread during a search, but I didn't quite see the answer I was looking for.

I recently purchased a new 2012 JCW hardtop and I've noticed that under full throttle in the higher gears (3,4,5 & 6), when I am on the full throttle for extended periods of time, the motor's power isn't constant/linear up to red line. It feels like it is surging somewhat and the power isn't being delivered in an even fashion. It isn't as extreme as the other thread I found where someone was suggesting that it was reaching the boost limiter (22 psi) and then backing off to 5 psi. It feels much less severe than that; but definitely noticeable. My car does not have a boost gauge. Car is stock without any modifications. I run California 91 gas.

Has anyone else experienced this? Is this normal? The car has about 4800 miles on it now. It has done it probably since new.

 

I experienced the same thing on mine before I put the Aquamist system on. The way it was explained to me was that this surging is due to 1)over boost function 2)how the cars 'call for boost' depending on engine load. The result is constant, slight changes in the overall boost pressure and at WOT this is experienced as surging.

Hopefully someone can give a more technical reason.

 

Thanks for the reply. I really don't want to add any injection system; I'm was hoping that Mini will be able to correct the issue. It sounds like it is a programming problem.

 

I also have a '12 JCW and I experience the same thing, I am pretty sure it is over boost and it is suppose to do that.
From left lane news below

With a top speed of 147 mph and a zero to 60 mph time of 6.2 seconds, the John Cooper Works is built for thrills. The twin-scroll turbocharger provides enough power for the 1.6-liter engine to make 192 pound-feet of torque under normal driving. An overboost function allows the JCW to eek out an additional 16 lb-ft for a total of 207! Offering more than just a hood scoop and impressive engine the JCW is further set apart from the Cooper and Cooper S with standard with 17-inch alloy wheels and an Electronic differential lock.

 

Likely Overboost.

Also, although turbocharged cars have a pretty linear torque and power curve, they do still have power peaks at certain engine RPM. If you look at the specs for the JCW, it has huge low end torque following by a HP peak later on.

 

I've noticed something similar on my JCW. It seems to happen in 2nd gear when I am accelerating moderately hard with a constant position on the throttle. When it gets to somewhere around 3000-3500 rpm there will be a slight stutter. If I am accelerating more gently, it doesn't seem to happen. Is this the same thing being talked about here or is this something different?

 

My 11 JCW surges also

My 11 MCS I traded did not surge

I think some of this has to do with the gearing

 

JCW has different turbo and tuning, etc. from the MCS. I keep forgetting to pay attention when I drive.

 

My 09 had this too. I brought it in to the dealer several times. They said they could reproduce the problem. the fix for me was an AP tune. It's perfectly smooth now. My guess is the car was too lean with the stock tune.