The Secrets to Breaking in an M Car (or any BMW)

 Does the way you break in a car really matter? We ‘ve been asked that question many times over the years by readers. There are two popular schools of thought. The first is that you strictly follow the manufacturers guidelines and go easy. The idea is that this allows for the various mechanicals to be properly ‘bedded in ‘ and for wear to happen gradually.

The second is that you simply drive the car how you would normally from day one. Here the idea is that you ‘re breaking in the car by treating to a heavy does of normalcy.

For us the answer has always been easy. If German engineers suggest you go easy on a car they ‘ve engineered, we suggest you follow their advice. But what about M cars? We know that M cars demand a 1,200 miles service at the close of break-in. But what else is specific to M models? We talked to a BMW about to see if there were some specifics that, while not in the manual, are good guidelines to follow. What they told us expanded on the manual and gave us a lot of the reasoning behind the rules (along with a few new ones to follow). You can see the entire list after the break.

BMW 1M Launch

Tires: these need 200 miles of wear before they have the full intended grip. Until then avoid unnecessary wear or heavy cornering.

Gearbox: you should always treat a manual box with respect. But none more than the first 400 miles. During that time be extra clean with your shifts and for God ‘s sake don ‘t grind anything but your teeth. Once the 400 miles are up, feel free to have at it.

The M Differential: The M Diff is a complex and special piece of mechanical goodness that requires some serious respect. That means no full acceleration – ie slamming your foot the floor. But what if you accidentally do 5-6 times? While it doesn ‘t mean expensive repairs down the road it will cause the M Diff to be noisier as it racks up the miles. So how can you feel the brunt of an M car while in the break-in period? During the first 1,200 miles M recommends that you ease on the throttle rather than slam it to the floor.

BMW 1M Launch

The Engine: The official line by BMW on the 1M is to keep it below 4,500 rpms until 1,200 miles. In reality, we ‘ve heard that you only need to keep it below 4,500 until it gets closer to 1,000 miles. At that point you can start to gradually increase your self-imposed redline until that magic 1,200 miles mark when you can also touch redline now and again.

The other requirement is to vary the RPMs through the range while not reaching over 100 mph. The thought here is that this will allow you to vary the load on the rings which allows them to seat properly.

Breaking in my 1M has been a test of patience given the ability of the twin-turbo inline six to generate enormous torque from the lowest depths of the rpms. With only 800 miles to go until that 1,200 mark, I may just make it without laying down black marks.

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  • Adam

    Great write up Gabe!

    While Ive not owned a new M model yet I’ve always wondered what all was involved with the “break in period”. I although with my commutes 1200 miles would be done with in just over a month so I could probably resist mashing it.

  • iNomis

    Given the power, sophistication and need to break the engine in, why doesn’t a 50k car provide an automated or fixed way to do so? If it were a slow or cheap car I could understand, but I can’t think of a good reason here.

    • Guest

      When you’re about to get t-boned by a garbage truck and mash the go pedal, you expect the car to respond. If it didn’t, because of an automated break in rev limiter, I would imagine (at least in the US) litigation would follow.

      • Andrew Popoola

        Maybe the cars should come already broken in?

        • arcsinice

          Ya…, for an additional $5K increase in price. Idiot.

  • RKCA1

    I followed the recommended BMW break in procedure for my 2000 Z3 M Coupe with S52. with over 45K miles it still dynoes at 221hp, which is within 2hp of what it dynoed when it had 5000 miles on it. Yes it was same dyno at the same shop, but obviously different times/conditions 🙂

    +1 goes to BMW Mgineers 🙂

  • josh

    In the supplemental manual there are special instructions for breaking in the 1 M.  It directs you to keep it under 5,500 RPMs rather than 4,500..  Wonder what the reasoning behind that it… 

    • The info we have here comes from sources inside BMW… and it’s not 4500 until 1200 but 4500 and then a gradual increase until you hit 1200.

  • Dylan Bland

    A little frustrated you sat on this information until now as many including myself have taken delivery of their 1M when this information comes a little too late! That said, I think the only part I screwed up was not flooring it a handful of times below 4,500. I never took stability control off (no black lines for me during break in!) but I may have accelerated quickly enough to have made the diff noisy later in life? 

    I wonder why M didn’t include this information in the manual. Seems really easy to do. Annoying. Also – I agree with a previous comment and think with a car as powerful as the 1M they could programme into the ECU (or whatever) limits on the engine to protect the car during break in. If this were clearly documented it would not pose any danger pulling out of intersections etc…M cars would still perform better than regular street car at full RPM.

    As an aside, I did a BMW training day this week and the instructor did many hot laps in an M3 with only 800kms on the clock. So in NZ at least clearly BMW don’t care too much about the break in…another reason why I’d never buy an ex-demo car.

    • Michael

      I don’t think we sat on this info but it recently came to the surface after some recent discussions with M engineers.

      I believe I had a similar post a few years back for the M3, only real difference are the RPMs.

      -M

      BTW- hard accelerating a few times is no big deal, the main importance is varying the RPM and not always hard acceleration with the diff. It is also less of an issue now as BMW is using heavier fluids in the rear from the start (impacts fuel economy slightly).

      • Dylan Bland

        I understand Michael – sorry didn’t mean to be too negative. I would have loved to have known this that’s all. M should publish this info! Love the blog and both your work!

    • 03beastcharmer

      I don’t think the no WOT/hard acceleration is a new statement. I assume the clear break-in sticker at the top of the windshield is similar to other M-cars. On my 07 M Coupe, the 1st thing it says is “No full throttle” and the 2nd item is the RPM limit, then the speed limit is 3rd.

      To me, no full throttle and an RPM limit means don’t do hard accelerations or fo high into the rev range.

      • Dylan Bland

        My 1M didn’t have a sticker.

  • Dr Obnxs

    There is a third school of thought and it’s covered here: http://www.mototuneusa.com/break_in_secrets.htm The idea is that you need a high load to get the rings against the cylinder wall while the hone pattern is fresh to really seat the rings to make a good seal. 

    Personally, I do agree that the engineers that design and build something know their technology better than most, but I just don’t buy the idea that what’s in the manual, or distilled here, is the one and only way to skin this particular cat. (remember, one of the goals of the manufacturer is to minimize warranty repairs, not necessarily to maximize power over the long run or whatever…) Break-in procedures have been debated for decades, and will still be debated for decades. Also, pretty much all of us won’t be breaking in or rebuilding enough engines ourselves to really know for sure what really is the best way to go.

    I’ve had cars broken in according to “manufacturers recommendations” that have sucked down oil like crazy, and had them that have been pretty tight as well.

    Anyway, do what you want and listen to whomever you want to. I just thought I’d point out that there are more perspectives in breaking in engines than the two listed at the beginning of this post.

  • Dgszweda

    How does this jive with the fact that when the BMW cars come off the line during their electronics inspection that they rev them to redline and hold that for a little bit of time, while the computer checks everything out?  I have been to about 5 BMW plants and every single one of them do this and I never saw them skip a car.

    • Dr Obnxs

      A rev to red line with no load isn’t really the stress that actually having the car launch under load would be. So it’s not as out of place as it may first seem…

  • arcsinice

    If in the market for ANY high performance car never even remotely consider the vehicle if it has more than four to seven miles on the odometer. I can assure anyone who is looking at such vehicles that an odometer with forty, fifty, sixty, seventy plus miles on the odometer has been trashed by some pot bellied, bearded scumbag fluffer who bs’d his way at the dealership claiming he was in the market which he never was and just wanted to joyride the car, always slamming thegears, going beyond redline. I blow fuses at a dealership when I see this shit and believe me, I’ve seen it. No excuse for the dealership they know better but don’t give a damn. Actuallyit works in their favor with warranty work which is income for them.