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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Dyno #'s vs Break-in Procedure



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      08-17-2007, 09:25 AM   #23
Max_!
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> Is that how you justify that?

It's how all companies justify everything nowadays, especially in the US.

It also doesn't make sense for BMW to put a complicated break-in procedure in the manual like the one used for race engines. "Take it easy the first few 1200 miles" works well enough.

Trashing your car off the lot is not a good way to break it in, but it's also very unlikely you can break it in really hard in normal traffic.

I'd call a break-in hard if it's driven under track conditions.

> None of these can be machined so perfectly, especially in mass production, not to require a break in period.

But they're also not so imperfect that there is continued metal-to-metal contact during normal operation, any such contact would cause rapid wear regardless of how you operate the engine.

> I would rather observe a reasonable break in than wilfully damage a brand new car.

No argument there. An engine needs breaking in. But if you drive it too gently you're also damaging it.

> I'll go engine brake down a long hill. Thats the way I was taught to do motocross bikes.

That pulls the rings away from the cylinder wall. It's also not in the manual.

> I broke my car in hard (lots of up and down the rev range accellerating and engine braking down hills, but not over 5k rpms very often), and I have had zero oil consumption so far

That's pretty much what it says in the manual you should do. You're probably close to the perfect break-in.
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      08-17-2007, 06:02 PM   #24
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Quote:
Originally Posted by Max_! View Post
> Is that how you justify that?
>But they're also not so imperfect that there is continued metal-to-metal contact during normal operation, any such contact would cause rapid wear regardless of how you operate the engine.
Its not necessarily metal to metal contact, its just that the load bearing surfaces of the engine aren't using thier full surface area to support the loads. In extreme cases it could lead to metal to metal contact, which would likey gall and ruin the component. Thats unlikely, but still possible in a new engine.
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>> I would rather observe a reasonable break in than wilfully damage a brand new car.

>No argument there. An engine needs breaking in. But if you drive it too gently you're also damaging it.
How is a very gentle break in harmful? Enlighten me.
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>> I'll go engine brake down a long hill. Thats the way I was taught to do motocross bikes.

>That pulls the rings away from the cylinder wall. It's also not in the manual.
Oh really? Prove it.
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>> I broke my car in hard (lots of up and down the rev range accellerating and engine braking down hills, but not over 5k rpms very often), and I have had zero oil consumption so far

>That's pretty much what it says in the manual you should do. You're probably close to the perfect break-in.
I have to disagree here too. Applying full torque to the driveline during break in is not a good idea.
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      08-31-2007, 01:00 AM   #25
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What is the real definition of running it in hard ? Will it really do damage in the long term if i hit it twice to redline in the longterm ?
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      08-31-2007, 01:11 AM   #26
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I did European delivery.

Risk = breaking it in hard with 150 MPH autobahn runs at 5200 RPM in 6th gear.

Benefit = 150 MPH autobahn runs and not getting arrested!

Obviously the benefits outweigh the risks
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      08-31-2007, 05:35 AM   #27
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Quote:
Originally Posted by e36jakeo View Post
I did European delivery.

Risk = breaking it in hard with 150 MPH autobahn runs at 5200 RPM in 6th gear.

Benefit = 150 MPH autobahn runs and not getting arrested!

Obviously the benefits outweigh the risks
:rocks::rocks:
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      08-31-2007, 12:02 PM   #28
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Same here

Quote:
Originally Posted by e36jakeo View Post
I did European delivery.

Risk = breaking it in hard with 150 MPH autobahn runs at 5200 RPM in 6th gear.

Benefit = 150 MPH autobahn runs and not getting arrested!

Obviously the benefits outweigh the risks

+1


Same, I was good until around 500-600 miles, but yeah going to Germany and not having some fun at high speeds would be a shame.
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