Don't "baby" the M3 during break-in

[Superfly_M3]

Hi Guys,

So I know the manual says to keep the RPM below 5,500 and not to floor the car during break in period (2000km). But a friend of mine told me that if you baby the car during the break in, you might not get the full potential (power) from the engine down the road. He also said that there might be carbon build up in the cylinders. I know this topic has been discussed to death, is there any merit to all of this? How much throttle did you use when breaking it in?

[THE TECH]

[mdosu]

ooo popcorn!

[E90///M3`]

Originally Posted by THE TECH

let me just pull up a chair and join you...

[M3PO]

Who is your friend? One of the BMW engineers that designed the S65?

[///M Ryder]

Originally Posted by E90///M3`

let me just pull up a chair and join you...

I'm in as well......I got the beer for this one fellas ................Phil

[JCtx]

Do you believe everything your friends tell you ? Didn't think so. A little search would have avoided you public embarrassment .

And no, your engine is not going to blow up if you don't follow break-in recommendations, evidenced by the many demos beaten to death since mile 1. But it's not best for the engine either. Remember it's not a racing engine; you want it to last 100K+ miles, not 1K. Good luck.

[disapr]

You see, what no one tells you is that the best way to break-in in a new engine is with Nitrous. That's right, Nitrous. You need at least a 150 shot dry kit. Make 4 to 5 WOT runs on spray until you bounce off the limiter in each gear while the engine is stone cold. Once at operating temperature, let the engine cool overnight and repeat.

A few sessions of this will ensure the MOST HP from your engine with zero carbon build-up!

[HT1000]

Originally Posted by Superfly_M3

Hi Guys,

So I know the manual says to keep the RPM below 5,500 and not to floor the car during break in period (2000km). But a friend of mine told me that if you baby the car during the break in, you might not get the full potential (power) from the engine down the road. He also said that there might be carbon build up in the cylinders. I know this topic has been discussed to death, is there any merit to all of this? How much throttle did you use when breaking it in?

Is your friend a BMW engineer? Did he design, build and test your engine? Is he providing warranty coverage on your engine?

Why would anyone believe any other source but the BMW factory engineers?

To answer your questions:

1. The way to get full potential is to break your engine in by the OM as this allows the new, tight fitting parts to burnish in properly without causing hot spots and scuffing, which occurs with high rpm and high loads - WOT.

2. There won't be any excessive carbon build-up as the engine runs very clean so there isn't excessive carbon to start with.

3. Driving it like you stole it is a great way to lose 15 hp from scuffed cylinders, piston rings and pistons. It will also reduce the service life of the piston rings considerably.

Some folks seem confused. Driving according to the OM is not "babying" the engine. It's normal driving, not WOT spirited driving. "babying" the engine is not good either.

If you want the best performance and service from your engine, just drive your car according to the OM until it's properly broken in then use gradually more throttle as the mileage increases and the engine frees up. If you don't care about the engine then drive it any way you like. Beating it will only cost you power, not increase it.

[abbar]

newb question but what does WOT mean?
i can provide the popcorn for this question ... haha

[Iplayedmyself]

I heard a rumor like this back in the day when i was into mustangs, I was told by a certified Ford tech that the motor has noticeably less output, but thats still no reason to beat the crap out of the motor in the first 1k. He told me that the ecu takes a less aggressive stance so the fuel and air ratio isnt "up to par". (i'm not saying i believe it) He then told me after 1k just unplug the ecu for 10 mins so it does like a reset of sorts, then drive it like you stole it so it take a more aggressive stance, once again im not a tech nor engineer but that is what i was told. if anyone else has heard of this chime in.

[M3PO]

Originally Posted by Iplayedmyself

I heard a rumor like this back in the day when i was into mustangs, I was told by a certified Ford tech that the motor has noticeably less output, but thats still no reason to beat the crap out of the motor in the first 1k. He told me that the ecu takes a less aggressive stance so the fuel and air ratio isnt "up to par". (i'm not saying i believe it) He then told me after 1k just unplug the ecu for 10 mins so it does like a reset of sorts, then drive it like you stole it so it take a more aggressive stance, once again im not a tech nor engineer but that is what i was told. if anyone else has heard of this chime in.

The car is continually monitoring and changing the AFR based on multiple parameters (throttle position being a major one). It can produce a wide range of AFRs at all times. It's ability to produce certain AFRs (namely the best AFRs to produce peak power at that particular RPM) is limited by programming rather than break-in. That said, cars have learning ECUs these days. They will adjust to driving style changes (and to some degree breathing mods) on their own over time. The break in period is purely for mechanical break in of sliding surfaces. Resetting the ECU will speed up the learning process but it's not a requirement to get full power. The ECU will not "learn away" its potential to produce full power if you start driving like an old woman.

[Iplayedmyself]

Originally Posted by M3PO

The car is continually monitoring and changing the AFR based on multiple parameters (throttle position being a major one). It can produce a wide range of AFRs at all times. It's ability to produce certain AFRs (namely the best AFRs to produce peak power at that particular RPM) is limited by programming rather than break-in. That said, cars have learning ECUs these days. They will adjust to driving style changes (and to some degree breathing mods) on their own over time. The break in period is purely for mechanical break in of sliding surfaces. Resetting the ECU will speed up the learning process but it's not a requirement to get full power. The ECU will not "learn away" its potential to produce full power if you start driving like an old woman.

thanks for setting that to rest, for me at least i was not aware of that, and is very very helpful and knowledgable.

[BLACK OPS]

**e92 m3 manual states <5500 rpm and <105mph. I just broke mine in and it didn't feel as though I was babying the car when I hit these upper limits. Certainly tempting at times to go beyond 5500 but I'm not sure this 1200mile session is that difficult to accept.

Other things thrown around were not keeping your speed or rpm constant (ie. cruise control) and to mix up your gears frequently. Even past the 1200 mile mark the manual states to progressively work the engine harder but not balls out! quantity vs quality

[M_GmbH]

Originally Posted by abbar

newb question but what does WOT mean?
i can provide the popcorn for this question ... haha

Wide Open Throttle

[M_GmbH]

Originally Posted by BLACK OPS

**e92 m3 manual states <5500 rpm and <105mph. I just broke mine in and it didn't feel as though I was babying the car when I hit these upper limits. Certainly tempting at times to go beyond 5500 but I'm not sure this 1200mile session is that difficult to accept.

Other things thrown around were not keeping your speed or rpm constant (ie. cruise control) and to mix up your gears frequently. Even past the 1200 mile mark the manual states to progressively work the engine harder but not balls out! quantity vs quality

During my run in period I would go out every second or third night and run the car through all gears accelerating from 20kph to 120kph several times. Also using all the power programs. No WOT though - just progressive urgent acceleration.

Bedding in the brakes correctly is also important - make sure you do some big decelerations from about 120kph down to walking pace, don't come to a complete stop and do not brake so hard as to engage ABS.

[S65V8]

Originally Posted by ///M Ryder

I'm in as well......I got the beer for this one fellas ................Phil

Looks like I'm not too late...just missed the previews...

[Templar]

I had a friend tell me to jump out of the window of my second story home once. Now I have pins and a screw in my ankle.

Not really, but come on, your friend is an expert on the S65 huh?

[Gearhead999s]

100% throttle & full RPM for short periods when fully warmed up and 1st trackday after the 1st service at 1900 kms.Did the same thing to my 02 E46 M3 and my 08 E92 M3 with no engine issues on them or any other vehicles that I have driven in the last 41 years.The engine needs full load to seat the rings as soon as possable.By the time you get the car from the dealer the engine has already had ample running time to worry about the initial break in.These break in instruction are more for liability concerns than any mechanical reason.I have always had very low oil consumption on all the M's that I have owned.

[BMW Fanatic]

Can I join?

[M3PO]

Originally Posted by Gearhead999s

The engine needs full load to seat the rings as soon as possable.

Can you explain to me why the rings would not seat without full load during break in?

[Gearhead999s]

Originally Posted by M3PO

Can you explain to me why the rings would not seat without full load during break in?

They will seat under partial load but it will take a longer period to accomplish the task.When I worked in a race engine shop many years ago you could watch the blow bye diminish in volume as you loaded the engine on the dyno in the 1st 20 minutes of running.If the rings did not seat in this period you usually had a problem to deal with later on.The rings are the only item that needs to brake in on a modern engine.Every other rotating item runs in an oil film and should never touch anything else if it is assembled & engineered properly.

http://www.mototuneusa.com/break_in_secrets.htm