[G80indy]

It's great that the N55 based M2 is getting great reviews however I am bugged that with mileage the performance is sapped with gradual carbon buildup in the intake.
I'm not convinced that by using Shell 93 it won't build up.
(I have yet to transition to direct injection / still have port inj. NA BMWs.)

Thoughts ?
Not sure the B58 design resolved the issue found in the N54/5, but still wondering about this.

[Verbiage]

Walnut blasting every 40K miles should do the trick. I prefer it to seafoam.

[G80indy]

Originally Posted by Verbiage

Walnut blasting every 40K miles should do the trick. I prefer it to seafoam.

Yeah I know about that. That's the "fix"--
It's extreme IMO.
I'm more interested in prevention and the engine design

[PrematureApex]

Originally Posted by 330indy

It's great that the N55 based M2 is getting great reviews however I am bugged that with mileage the performance is sapped with gradual carbon buildup in the intake.
I'm not convinced that by using Shell 93 it won't build up.
(I have yet to transition to direct injection / still have port inj. NA BMWs.)

Thoughts ?
Not sure the B58 design resolved the issue found in the N54/5, but still wondering about this.

Why would gas help? It's a DI engine. That's the point, the fuel never touches the valves.

There is no solution.

Originally Posted by 330indy

Yeah I know about that. That's the "fix"--
It's extreme IMO.
I'm more interested in prevention and the engine design

Extreme? It's no big deal.

A few hours to do yourself, or a few hundred to get it done by an indy. Hardly a big deal every 3-5 years.

[OG///M]

Originally Posted by 330indy

It's great that the N55 based M2 is getting great reviews however I am bugged that with mileage the performance is sapped with gradual carbon buildup in the intake.
I'm not convinced that by using Shell 93 it won't build up.
(I have yet to transition to direct injection / still have port inj. NA BMWs.)

Thoughts ?
Not sure the B58 design resolved the issue found in the N54/5, but still wondering about this.

What others already said in addition to redlining the beast at least once everyday as you get on the on ramp.

[PrematureApex]

Originally Posted by Francis///M

What others already said in addition to redlining the beast at least once everyday as you get on the on ramp.

Unfortunately, it doesn't do a damn thing. That's more for exhaust side buildup some other cars have (E39 M5, for example IIRC).

There are track-only N54/55s out there that still have buildup.

That being said, anecdotally, the N55 is less prone.

[Verbiage]

Originally Posted by 330indy

Yeah I know about that. That's the "fix"--
It's extreme IMO.
I'm more interested in prevention and the engine design

Is there another way that is more "simple"?

[PackPride85]

I believe Porsche recommends their own DI cleaning service every 60k miles where they actually remove the head and hand clean it. Not cheap, but it does the trick.

I've had a BG DI service done on my mazdaspeed 3 where they suck in some cleaning agent through a vacuum line similar to seafoam. Never had it scoped to see if it worked but my gas mileage is still solid after 8 years and 110k miles. https://www.bgprod.com/catalog/gasol...ction-cleaner/

Or you buy a BRZ that has both DI and port injection and not worry about it.

[paradoxical3]

This won't be an issue. I visually inspected my valves at 70k miles of hard use and there was no point to clean them; they were so clean that the shop said that I wouldn't even be able to tell a difference if we blasted them. The PCV system is way better on the N55 than it is on the N54. The shop walnut blasts many N54s (several a week) and have never come across a N55 that was worth doing it under 100k miles.

[PrematureApex]

Originally Posted by paradoxical3

This won't be an issue. I visually inspected my valves at 70k miles of hard use and there was no point to clean them; they were so clean that the shop said that I wouldn't even be able to tell a difference if we blasted them. The PCV system is way better on the N55 than it is on the N54. The shop walnut blasts many N54s (several a week) and have never come across a N55 that was worth doing it under 100k miles.

So the rumors are true. Thanks!

[LDSM]

Originally Posted by paradoxical3

This won't be an issue. I visually inspected my valves at 70k miles of hard use and there was no point to clean them; they were so clean that the shop said that I wouldn't even be able to tell a difference if we blasted them. The PCV system is way better on the N55 than it is on the N54. The shop walnut blasts many N54s (several a week) and have never come across a N55 that was worth doing it under 100k miles.

thanks for the info, I've read a few other N55 owners saying the same thing.

[JohnNC-M2CS]

What about using a can of BG44K in the fuel tank every 3 - 6K? I've been using it for years on my cars, that average 75 - 85K before I sell them, and never had a performance issue that I could detect.

[PrematureApex]

Originally Posted by JohnVa1M

What about using a can of BG44K in the fuel tank every 3 - 6K? I've been using it for years on my cars, that average 75 - 85K before I sell them, and never had a performance issue that I could detect.

Again, it's a DI engine. The fuel doesn't touch the intake valves. Hence the buildup problem.

Nothing about fuel, in the fuel, etc. has any bearing on the issue.

[craina]

Regular WOT is known to slow the buildup.

[JohnNC-M2CS]

Bah, I should have know that, thanks.

[Nine Lives]

Originally Posted by craina

Regular WOT is known to slow the buildup.

Yep,
The ' Italian tune up ',still the original and best way to cure all known engine problems

[goodboy1451]

Originally Posted by Verbiage

Is there another way that is more "simple"?

Yes there is. Keep it in the garage and don't drive it.

[ORIGIN M.]

You drink walnut puree.

[PrematureApex]

Originally Posted by craina

Regular WOT is known to slow the buildup.

Known to? Again, that's for preventing/slowing exhaust side build up, not intake side which we're talking about. Track only N54s (and even N55s) have the issue.

[Verbiage]

Originally Posted by PrematureApex

Know to? Again, that's for preventing/slowing exhaust side build up, not intake side which we're talking about. Track only N54s (and even N55s) have the issue.

Just stop answering...people don't read the responses anyway.

[PrematureApex]

Originally Posted by Verbiage

Just stop answering...people don't read the responses anyway.

It's brutal. They read something on the internet, then re post it, without any attempt to understand the problem, etc.

[Verbiage]

Originally Posted by goodboy1451

Yes there is. Keep it in the garage and don't drive it.

Ummmm. Right.

Originally Posted by PrematureApex

It's brutal. They read something on the internet, then re post it, without any attempt to understand the problem, etc.

Well, that, and the answers to the questions are usually right in the thread. I technically answered it theoretically because I understood it to be similar to my N54 notwithstanding combustion characteristics, and then I was given more information not 3 posts down.

Reading is fundamental, folks. Fundamental.