Is BMW Burble actually good or bad?

[overlook637]

The factors leading up to a SCH are open for debate but it stands to reason that the more power you produce, the more stress on the engine, the more likely ANY negative outcome is to occur.[/QUOTE]

Engine power is downward on the piston, rods, crank into the transmission. Not into the valves.

https://qph.fs.quoracdn.net/main-qim...90be8b08dc39-c

[r0wr]

Originally Posted by overlook637

The factors leading up to a SCH are open for debate but it stands to reason that the more power you produce, the more stress on the engine, the more likely ANY negative outcome is to occur.

Engine power is downward on the piston, rods, crank into the transmission. Not into the valves.

https://qph.fs.quoracdn.net/main-qim...90be8b08dc39-c

[/QUOTE]
What does this have to do with burbles??

[Ian1973]

Originally Posted by r0wr

Engine power is downward on the piston, rods, crank into the transmission. Not into the valves.

https://qph.fs.quoracdn.net/main-qim...90be8b08dc39-c

What does this have to do with burbles??[/QUOTE]
The explosion forces are on all surfaces of a cylinder, valves included. Why would you think it's directional? I mean the burn starts at the spark plug obviously but then explodes outward all directions, the valves see the same forces as the piston face does. In many instances the valve isn't completely seated through a portion of the combustion stroke, so a bit leaves the cylinder.

[gatorfast]

Originally Posted by frankiebones

Nearly all confirmed SCH happened in the first 15-16 months of F8x production. Most were non comp pack.

The factors leading up to a SCH are open for debate but it stands to reason that the more power you produce, the more stress on the engine, the more likely ANY negative outcome is to occur. People have reported using the "kickdown" feature on DCT is something they wish to avoid.

If you wish to avoid Sport + because of the way power delivery occurs and you're THATworried about spinning your crank hub, that I can sorta understand, although its the most conservative approach to driving a race car I can imagine. However, it has nothing to do with burbles.

Where did you get the info that "most happened in the first 15-16 months of production"?

[frankiebones]

Originally Posted by gatorfast

Where did you get the info that "most happened in the first 15-16 months of production"?

There was a thread where the people with a confirmed SCH inputted their build month, tuned or stock, etc.

The late 2014 builds (MY2015) and the early 2016 builds (MY2016) had a few confirmed SCH compared to MY2017. However, it was still exceptionally rare when compared to the number of cars on the road.

I cant find the thread at the moment.

[Alan l.]

Theirs also at least a handful of 2018 ZCP cars that also report SCH here. From what i remember reading all of them were running a tune.

[frankiebones]

Originally Posted by Alan l.

Theirs also at least a handful of 2018 ZCP cars that also report SCH here. From what i remember reading all of them were running a tune.

Didn't see that...Interesting. The earlier MY's with confirmed SCH seemed to be 50/50 between tuned and stock.

[Jeff@TopGearSolutions]

Originally Posted by Alan l.

:begin rant:

I for one fucking hate burbles or whatever you want to call it on this car. Sounds artificial and whoever started this trend should be shot. I come from the days where a good exhaust system goes Vroom Vroom... not pop pop pop poppa poppa pop pop like i'm making fucking popcorn

:end rant:

AMG, Jaguar and a lot of exotics run them stock now.

[Alan l.]

Originally Posted by Jeff@TopGearSolutions

AMG, Jaguar and a lot of exotics run them stock now.

I hate on those cars as well and it doesn't make it "good" because they run it. Its the dumbest trend that even Hyundai's tunes incorporate now. Also there is a difference when a AMG GTR or a Lambo running having pops compared to a M3/3 series doing it. I wouldn't mind it as much if it only happened during a WOT pull/shift but having it do it while i'm decelerating going 20mph is sort of embarrassing.

[G35POPPEDMYCHERRY]

damn can somone actually answer OP question. I've been wondering too

[Soofy]

It's good, just send it

[gabriel.psd]

Dumbest thing to come to the M3/M4.

[overlook637]

Originally Posted by Ian1973

What does this have to do with burbles??

The explosion forces are on all surfaces of a cylinder, valves included. Why would you think it's directional? I mean the burn starts at the spark plug obviously but then explodes outward all directions, the valves see the same forces as the piston face does. In many instances the valve isn't completely seated through a portion of the combustion stroke, so a bit leaves the cylinder.[/QUOTE]

For older designed engines there can be some overlap. I had a huge camshaft in my Buell sportbike.

I doubt the modern BMW or EPA has any exhaust valve being open on combustion other than whats done in sport+ mode to keep turbo spooled up. OR burbles tuning which changes ignition, fuel, and perhaps valve VANOS to ensure the explosion/heat in the exhaust manifold.

[overlook637]

Originally Posted by G35POPPEDMYCHERRY

damn can somone actually answer OP question. I've been wondering too

did you watch the video?

[combivan]

The guys over at Protuningfreaks (bootmod3) say it is done via fuel cutoff delay and retard in timing.

So is this a bad thing on stock cat and O2 sensors?

[G4BR13L]

As far as I know when you lift off your foot of the throttle, there is still going to get a mixture of air and fuel in the combustion chamber but the ignition is retarded, this means that the fuel is ignited too late. The unburnt fuel is then detonated when it comes into the exhaust because of the heat. I guess that this is to maintain turbo boost pressure.

This is not good for the spark plugs, turbo’s nor for the cats.
About the O2 sensor: I am guessing that the ECU takes this into account since the lambda sensor (pre-cat) would signal and this would otherwise have an impact on the air/fuel ratio. A lambda probe does not like too very high temperatures obviously but the temp in the exhaust is imho low enough to not ‘fry’ the probe. Bosch LSU ADV sensor is used which can withstand temps to 980 degrees Celsius.

[pokerface]

I think the burbles on the ZCP are just right. The ones on the B58 MPPSK though are a bit excessive.

[Beemerm3]

i got a zcp and burbles when i let off gas. i rather listen to my exhaust then music. but traffic gets mad and speeds up next to me.

[M4newbie]

I am new as well. Have read pages of discussion on tuned burbles. What I want to know is: if the burble activity (whatever causes it technically) is bad, then why is it incorporated by BMW engineers in the stock competition M4? I have a new M4 with competition package. I like the exhaust sound burble and crackle to some extent, but all the discussions seem to point to potential problems. Why would BMW use it if it isn't good for the car?

[TrauCon]

Originally Posted by M4newbie

Why would BMW use it if it isn't good for the car?

1. Feel cool/good, be different. Not for me but for some people they like it.
2. As long as it can last through the warranty of 4 years .. all's good in BMW's point of view.

[Beemerm3]

Today my exhaust was going off again. This time I can feel a loud pop in my engine. Most times I would hear in the back of the exhaust. I probably downshift too early. This car is an animal.