Yet another break in question

[ZoinksM3]

My M-DCT M3 should be in next week. I was planning on driving it down to Houston from Dallas, about 250 miles each way.

I didn't see anything in the documentation saying that long distance drives are bad for the break in period. Just need to keep it under 5500 RPM/105mph and vary the speed.

This kosher? Should I bring some oil along-with?

[TLud]

You'll be fine as long as you vary the load on your engine (varying speed is not important, varying your RPMs is).

[UltimateBMW]

I've argued in the past that part of the break-in may of been the heating up and cooling of the engine (thermal expansion) as well. But this is purely just my own speculation, and completely unfounded.

The drive to Houston isn't too bad, you should be fine. Just change it up while you drive like you already know about.

[jm1234]

Originally Posted by TLud

You'll be fine as long as you vary the load on your engine (varying speed is not important, varying your RPMs is).

Aren't you breaking in the transmission and differential too? If so, he might want to vary his speed as well as RPMs.

[TLud]

Originally Posted by jm1234

Aren't you breaking in the transmission and differential too? If so, he might want to vary his speed as well as RPMs.

You just made my point. You can change gears, RPMs, and load on the highway without varying your speed.

[Davinhci]

you'll be find just change speed from 55 to 75 to 110 and back to 60 and you'll be ok.

[ZoinksM3]

Originally Posted by Davinhci

you'll be find just change speed from 55 to 75 to 110 and back to 60 and you'll be ok.

105 max

Based on traffic on I45, alternating load should not be a problem

Thanks folks

[TLud]

Originally Posted by ZoinksM3

105 max

Based on traffic on I45, alternating load should not be a problem

Thanks folks

No doubt. Coming into Conroe on a Friday afternoon will take the problem right out of your hands.

[ZoinksM3]

Originally Posted by UltimateBMW

I've argued in the past that part of the break-in may of been the heating up and cooling of the engine (thermal expansion) as well. But this is purely just my own speculation, and completely unfounded.

That is interesting from a metallurgical perspective, although I don't think there is much going on. I would hope that no parts, save the headers, would become hot enough to complete some type of deferred annealing/hardening process. The crystalline structure, and thereby strength, of the metal parts should be pretty much set after fabrication. Normal heat-based expansion/contraction is usually addressed with gaskets and tollerances.

I think the break-in is to familiarize the parts with each other. Cylinders with cylinder walls, clutch with plate, etc. Heat may play a card here as well.

[Patricius]

When I broke in my M-DCT coupe from the Performance Center (about 850mi), I alternated speeds, gears, and naturally RPM every 10 minutes or so. I also did runs from 1st through 7th @ 105mph under varying throttle inputs.