OK, the car is brand new and only has 150 miles on the clock, but it just doesn't feel right (my point of reference is my wife's stock 2005 MCS with 12,000 miles on the clock). The dealer assures me that the performance will improve significantly once the car is broken in.

I'm adhering strictly to the break-in recommendations so I'm not really reaping the performance benefits of the JCW kit, which appears to come on "strong" above 4000 RPM. But, it seems to have no urgency to throttle input; in fact just the opposite. I seem to have a bad case of "hesitation" under mild acceleration conditions. For example, if I'm cruising at ~2800 RPM in 6th gear and apply the throttle, it seems like something is holding the car back; not quite a misfire, but it feels like it's pulling timing? Same thing, if I try to accelerate smoothly in 3rd gear through the 2500-3500 RPM range. I'm on my first tank of gas and I'm hoping they cheaped-out and put a lower octane in.

The car is a 2006, but the JCW kit was installed by the dealer (they've done plenty before mine). I checked with my MA and they definitely installed the JCW software onto the ECU after installing the hardware, so I'm at a loss what the problem could be. Obviously I can't dyno it with so few miles on the clock. Maybe it's just me?

Anybody else here think their JCW performance was underwhelming during the break-in period?

 

ouch...sorry to hear this is all happening.....could be a lot of things, but try checking to see if an 0-ring is leaking or something.....does it feel like its losing back pressure anywhere?...i had a problem similar and thats what it was..so check it out

 

No experiance with the JCW but this does sound like maybe you are on a low octane. But even with my 05 MCS I feel the car really didn't kick in until ~3200 as you do need a few more revs to get the most of the torque curve, plus your intake wont really open up until 4500RPM. I'd stay with the break-in proceedures and then if its an issue 1250 miles down the road go talk to the dealer.

 

Its called sixth gear and the lack of cubic inches.

Your not going to feel that thing pull until between 4500 and redline ... Guess you got to wait.

 

2800 in 6th? Mine pulls, but not hard . . . Let it break in, run a tank of good gas through it, so it's not pulling the timing back and if it still feels "puny" at 1250 miles, take it back.

Wifey put regular in mine about a year ago and it REALLY didn't like it. I'll bet you have cheap gas . . .

 

I'd bet gas as well... but gas QUALITY, not particularly OCTANE...

I would hope that the dealer is putting in 92 or 93 octane, but my MCS was sluggish until I almost ran out of gas one day and had to stop at a Chevron instead of my regular Fina station. The car suddenly woke up... throttle response was much more rapid and there was better pull across all rev ranges. With the Fina gas, I'd put the clutch in and punch the accelerator from idle and there was a 1-3 second delay before the engine would respond...

After some experimentation, Shell and Chevron seem to run the best for me here in TX (butt dyno... no real numbers)

Run your next tank of gas down to 'E'mpty and fill up with a better brand. A friend of mine also likes BP in his '04 MCS.

 

I'm not expecting it to pull like a train, but torque & power increases relative to a stock MCS should be noticeable, even below 4500 RPM. The hesitation I'm feeling under "mild" acceleration is disconcerting.

I've never driven a car before that feels like the ECU is badly mapped and full of flatspots (that includes my wife's stock MCS). I had read posts here stating that the JCW software smoothed these out?

 

I guess I'm not insane. I only run shell in the car.

 

That's why I think bad or low octane fuel. Once the computer starts retarding the timing, they run like, well you know, crap!

 

There isnt THAT much of a difference b/w a stock MCS and a JCW S

The power is different, but the power band is still about the same.

ANY car in 6th gear wont pull hard, I highly doubt the small difference in torque b/w the JCW and the standard S would make for a noticable difference in 6th gear.

 

I don't want to be-labour the point. It doesn't matter what gear I'm in.

If I'm in 3rd and I try to accelerate smoothly and progressively (i.e not pedal to the metal) through the 2800-4000 RPM range there's significant hesitation as if something's holding the car back. I'm certainly not "lugging" the engine i.e. being in too high a gear for the revs. I'm certainly not expecting warp-speed pick-up but my wife's MCS doesn't behave like this and is noticeably smoother and quicker with the same throttle inputs through the same RPM range.

 

Must be that factory limiter kicking in so you dont damage the car to reduce warranty claims.

 

Maybe I'll just have to mate my JCW with my wife's MCS and hope the offspring turns out right

 

Or maybe you will get some wierd offspring, since Factory JCW cars and Standard MCS's shouldnt be interbred.


You might get like a VW Diesel Rabbit or something.

 

I bet your wife has filled up at a decent gas station and your dealer (at 150 miles, you are probably still on the dealer's gas) has crap.

Give it another hundred until you are near empty, fill up at Shell and let us know how it turns out.

All of your symptoms sound like my MCS until I got some decent gas.

 

maybe they forgot to install the jcw supercharger w/ the smaller pulley.

there's definitely a difference w/ even just a 15% pulley noticeable by
the butt meter @ 2800 rpm

 

I've got about 350 miles on my 06 JCW (factory). I hope for your sake that it is bad gas, because my car experiences absolutely NO hesitation. It is extremely smooth in it's power delivery. In fact, I think the car pulls pretty hard from 2500-4500 even at part throttle! So much so that when I pulled off the lot, I gave it about 1/3 pedal and the car freakin' took off!! I'm on my second tank of gas (the dealer put the first tank in, BP I think), I used Shell.

 

.

 

. . . a proper running JCW should only do one thing . . . IMPRESS YOU!

Otherwise, you've got a problem. Seek out another JCW owner in your area and try to get a comparison test drive.

 

Good idea. Actually my dealer had a fully kitted-out JCW for sale on the lot.....but he wouldn't let me test drive it.

 

I went out this morning paying close attention to how my JCW responds (remember less than 400 miles on it). and after the engine warmed up, I got on it wot....WOW, instant response and pulled hard from 2000-4500.

If your next tank of gas doesn't clear up your problem, I would take it back to the dealer. If they can't figure it out, try another dealer.

 

"flat spot"! No known cure, other than putting your foot down farther!

Matt

 

Mystery solved (hopefully).

My MA admitted that it's the dealership's policy to gas-up all new MINIs and BMWs with regular gas

 

And they cripple the performance. Don't they read the manual?

Matt

 

no surprise here........