Interesting thread, but...

My priority is to create a car that will last as long as the last car i had - 13 years. Coming from a 94 Nissan Altima, the MCS is an outrageous combination of performance, fun and good gas mileage. (Don't laugh, one of the key reasons I am now waiting for an 07 instead of buying an 06 off the lot is because the 07 is much greener.)

Given this is an enthusiasts' forum, I have not seen a lot of posts about Mini being green, but I digress.

The reason I am posting here is to ask, what is the recommended break-in procedure for those of us who think the car is fast enough as is, and just want to increase gas mileage and reliability?

 

The regular break-in procedure. Just keep driving that way after the break-in period is over.

 

I will definitely argue that following the MINI break-in guidelines is increasing the risk of long term damage and inefficiency due to improperly seated piston rings. Not properly breaking in your rings means they are not sealing as much as possible against the cylinder walls and the piston ring lands. This non-optimal seal will cause greater oil consumption and reduced fuel economy on top of less power. It's not magic; there's no reason to feel threatened in deviating from MINI's guidelines, or fear catastrophic damage from following logical guidelines based on mechanical engineering experience.

 

How does following MINI's recommendation not allow piston rings to seat? I would not advocate to anyone to risk losing their warranty.

 

Ryephile, I would have to argue that following Mini's guidelines, while conservative, should not result in any issue with ring seating.

With 11:1, or better, compression ratios, there is little need to push the engine hard at all to have satisfactory ring seating. I would argue if you push them too hard you could collapse the ring. I think the latter is more of an issue with high compression engines than the former.

But, this is a topic ripe with opinion. I see no harm in following Mini's guidelines. If the engine compression ratio was 9:1, I might favor your point Ryephile. I just cannot see it being an issue with a high compression engine.

 

Moreover, the break-in period is for a relatively short time and is intended to recognize the extreme tightness of a new engine. Although I am skeptical of the claim that MINI's recommendation will preclude proper seating of the piston rings, the suggested more aggresive treatment of the engine can easily take place after 1500 miles.

 

With the MINI's fairly high chamber pressures (high compression + turbo) wouldn't the rings be more likely to seat well without having to take it to red line? Shouldn't just putting your foot in it at low revs in the first tank full accomplish this sufficiently?

 

I should think so Robin.

When I was racing rails (dragsters), we used to seat the rings by starting the engine without the water pump connected, blip the throttle twice, shut it down, change the oil and be ready to go.

Always had to be careful not to put too much crosshatch on the cylinder walls as the pressure from the compression ratios would be more than enough to seat the rings with little heat needed from friction with the cylinder walls.

Back then we were running 12.5:1 compression ratios. High for the time.

 

No wonder why you are so impatient about getting your MINI.

 

That's just the kid in me LynnEl.

Hmnm,..course, I guess it was just the kid in me whe I used to race. LOL!

 

So, any update on your car? Doesn't MINI call you first by now?

 

Just waiting for it to get built right now. It's in the queue. I figure it is on schedule for a 5/10 delivery.

 

I didn't say they wouldn't seat at all. I said they wouldn't seal as best as they possibly could. There is definitely a difference! Furthermore, if MINI chose to be that strict about their warranty coverage, they'd do the same thing that buffdigits said happened with his Mustang Cobra and put break-in code in the ECU so rebels like me couldn't violate MINI's guidelines no matter what.

The MCS's static compression ratio is 10.5:1. Under peak stock [over]boost of 15.3 PSIg, the "effective" compression ratio is 20.6:1 This means that when you drive your MCS and floor it, you're running 20.6:1 from about 2200 RPM to 5000 RPM. That's a lot of cylinder pressure. MINI knows this, and they also know that their piston design and their direct injection quenches and squishes the charge very effectively and efficiently. If MINI knew there was a reliability issue at early stages they would NOT let you hit overboost and subject the engine to those pressures. FYI, the effective CR is actually lower at redline because the boost is reduced up there.

I understand this topic has long been ripe with misinformation and hot-headed opinion. Most of us, me included, aren't willing to do scientific testing to conclude anything useful. All we can rant about is our scientific deductions or emotional feelings on the subject. Regarding the warranty risk; that's up to you and how much you let the dealership bully you around. The issue there is, first you'd have to blow up your engine. So far the Prince engine isn't getting a BMW E46 //M3 reputation for instant engine grenades, nor would I expect it.