Where the heck are the exhaust burbles?

[CaryTheLabelGuy]

Originally Posted by Blksnowflake

You are way serious dude, respect on your knowledge. We need that here....
but, I don't want facts or air in my injectormabobs spooling my gizmos in the retard divided by lift in the turbine thingies.... I just want pops and burbles man. The peoples want zee germans to give us
pops
and
burbles ya.

No explain, just do. lol

Lol. Ok, we at least agree on wanting more pops and burbles. I've been pretty vocal about this in this thread.

In regards to me being serious? People come to forums to learn things. I feel it's pretty important to present facts, I don't mean to ruffle feathers.

[CanAutM3]

Originally Posted by CaryTheLabelGuy

Lol. Ok, we at least agree on wanting more pops and burbles. I've been pretty vocal about this in this thread.

In regards to me being serious? People come to forums to learn things. I feel it's pretty important to present facts, I don't mean to ruffle feathers.

Please keep the technical stuff coming, some of us geeks feed on it .

[CanAutM3]

Originally Posted by CaryTheLabelGuy

The burble you're looking for is mostly from a more aggressive overrun on the 435i MPPK. The stock M4 doesn't have an aggressive overrun at all, unless you get a GTS or ZCP.

With that said, you will get some gurgles and pops and obviously when the ALS kicks in while in a decent amount of boost (aka the farts), but not as much as you were getting in the 435 MPPK.

Don't ask me why BMW did this, as the M2 has an aggressive overrun totally stock.

They kept it for the Competition Pack

[Blksnowflake]

Originally Posted by CaryTheLabelGuy

Lol. Ok, we at least agree on wanting more pops and burbles. I've been pretty vocal about this in this thread.

In regards to me being serious? People come to forums to learn things. I feel it's pretty important to present facts, I don't mean to ruffle feathers.

no feather fluffing here haha....keep that at home you freak.
I am picking up what you're putting down by the way, it's great info.

[M3Tooner]

I'm here to learn new stuff too, that's why I presented the facts that I found while researching the subject. Definitely not trying to ruffle any feathers.

So the pops and burble on non-turbo cars like the Cayman is truly only for the "Cool" factor then, since there is no need for ALS? I have found some articles online claiming that it could be used for exhaust valve cooling as well. Although that would mean you don't want to ignite the charge at all in the combustion chamber, instead you want it to cool the exhaust valves then after that it can self ignite in the exhaust manifold.

For the record, I love the pops and burbles. My first experience of it was on the Cayman GTS and 991 GT3 that I have driven. I'm so glad the new CP has it now too. I have one on order and can't wait.

[Boss330]

Originally Posted by M3Tooner

I'm here to learn new stuff too, that's why I presented the facts that I found while researching the subject. Definitely not trying to ruffle any feathers.

So the pops and burble on non-turbo cars like the Cayman is truly only for the "Cool" factor then, since there is no need for ALS? I have found some articles online claiming that it could be used for exhaust valve cooling as well. Although that would mean you don't want to ignite the charge at all in the combustion chamber, instead you want it to cool the exhaust valves then after that it can self ignite in the exhaust manifold.

For the record, I love the pops and burbles. My first experience of it was on the Cayman GTS and 991 GT3 that I have driven. I'm so glad the new CP has it now too. I have one on order and can't wait.

The burbles in the exhaust on non turbo cars, as well as many turbo cars, are there just for the cool factor. As you said, it can also be used to cool the exhaust valves. Since ignition timing is retarded, the combustion takes Place in the exhaust and not in the combustion chamber. Therefore it's a "cold" mixture of a small amount of air and some fuel that passes by the exhaust valves.

What wasn't quite clear perhaps in some of the previous posts is that if the burbles and pops are there as a result of anti lag (ALS), there also needs to be a decent amount of air going through the engine on the overrun. If the throttle/valvetronic is closed (as it usually is on the overrun/engine braking) there is very little air going to the cylinder and through to the exhaust manifold and turbo(s). Injecting fuel and retarding ignition won't create any high volume and high velocity exhaust gas to spool the turbo.

As far as I know, very few production turbo engines employ anti lag by using an open throttle and injecting fuel. The S55 and Porsche 991 Turbo S has at least "cold blowing". That is, keeping the throttle/valvetronic open on the overrun so that the engine continues to pump air and spool the turbo. The 991 Turbo S only introduced this technology on the facelifted version going on the market this year.

So, while it's true that ALS create pops and burbles in the exhaust, it's more likely that the pops and burbles we hear on cars like the 335i with MPP, Focus RS etc is just a fuel and ignition timing excercise to create a cool sound Not an air, fuel and ignition strategy to be used as ALS.

AFAIK the sounds of a ALS system is also more aggressive and "explosive" than the burbles of the likes of the Focus RS and 335i MPP

At least BMW explains it as just a "cool" feature (just like Ford does for the Focus RS):

http://www.bmwusa.com/standard/conte...35i-Sedan.aspx

More Power. More Dynamic. More Emotion.
Once the Power Kit is installed, the vehicle's rated horsepower is increased from 300 to 320 on all models. Automatic transmission-equipped models enjoy a 32 lb-ft peak torque increase (to 332 lb-ft), while manual transmission-equipped models benefit from a 17 lb-ft peak torque increase (to 317 lb-ft). All models receive a re-mapped accelerator pedal calibration for more dynamic throttle response, and the Power Kit produces a signature, highly-emotional "exhaust burble" sound during engine overrun conditions. 0–60mph acceleration is improved 0.2 seconds compared to standard 335i models, while 50–75mph times drop by a full half-second.

[x.shell]

Originally Posted by Boss330

The burbles in the exhaust on non turbo cars, as well as many turbo cars, are there just for the cool factor. As you said, it can also be used to cool the exhaust valves. Since ignition timing is retarded, the combustion takes Place in the exhaust and not in the combustion chamber. Therefore it's a "cool" mixture of a small amount of air and some fuel that passes by the exhaust valves.

What wasn't quite clear perhaps in some of the previous posts is that if the burbles and pops are there as a result of anti lag (ALS), there also needs to be a decent amount of air going through the engine on the overrun. If the throttle/valvetronic is closed (as it usually is on the overrun/engine braking) there is very little air going to the cylinder and through to the exhaust manifold and turbo(s). Injecting fuel and retarding ignition won't create any high volume and high velocity exhaust gas to spool the turbo.

As far as I know, very few production turbo engines employ anti lag by using an open throttle and injecting fuel. The S55 and Porsche 991 Turbo S has at least "cold blowing". That is, keeping the throttle/valvetronic open on the overrun so that the engine continues to pump air and spool the turbo. The 991 Turbo S only introduced this technology on the facelifted version going on the market this year.

So, while it's true that ALS create pops and burbles in the exhaust, it's more likely that the pops and burbles we hear on cars like the 335i with MPP, Focus RS etc is just a fuel and ignition timing excercise to create a cool sound Not an air, fuel and ignition strategy to be used as ALS.

AFAIK the sounds of a ALS system is also more aggressive and "explosive" than the burbles of the likes of the Focus RS and 335i MPP

At least BMW explains it as just a "cool" feature (just like Ford does for the Focus RS):

http://www.bmwusa.com/standard/conte...35i-Sedan.aspx

Just a side note... don't need MPP for the burbles. My 335i just had the MPE and it burbled all the time.

[danniexi]

get a quesalupa from taco bell.. dat shiet will make you burble all day long.

[CanAutM3]

Originally Posted by Boss330

TInjecting fuel and retarding ignition won't create any high volume and high velocity exhaust gas to spool the turbo.

Not sure why you would say that . At my work, we make turbine engines that produce several thousand horsepower on that very concept .

IMO, injecting fuel is a much more potent method to keep the turbos spooled compared to "cold blowing".

[Boss330]

Originally Posted by CanAutM3

Not sure why you would say that. At my work, we make turbine engines that produce several thousand horsepower on that very concept .

Perhaps you should read it in the context it was written

there also needs to be a decent amount of air going through the engine on the overrun. If the throttle/valvetronic is closed (as it usually is on the overrun/engine braking) there is very little air going to the cylinder and through to the exhaust manifold and turbo(s). Injecting fuel and retarding ignition won't create any high volume and high velocity exhaust gas to spool the turbo.

Unless you make turbines that produce several thousand horsepower without adding air to the injected fuel, I still think my statement is true...

As I tried to explain, to have ALS you need more than just fuel and retarded ignition. You also need AIR... When the throttle is closed you have very little air so not really any ALS effect. Open the throttle increases air flow and then the fuel injected and retarded timing can create ALS

[M3Tooner]

Originally Posted by CanAutM3

Not sure why you would say that . At my work, we make turbine engines that produce several thousand horsepower on that very concept .

IMO, injecting fuel is a much more potent method to keep the turbos spooled compared to "cold blowing".

Not if you put a giant throttle plate in front of your turbine engine and close it.

[CanAutM3]

Originally Posted by M3Tooner

Not if you put a giant throttle plate in front of your turbine engine and close it.

My point is that by igniting a small amount of fuel in a relatively small amount of air and you get a rather significant expansion.

When you add fuel and ignite it, you need much less air to obtain the same energy as blown air alone.

[CanAutM3]

Originally Posted by Boss330

Perhaps you should read it in the context it was written



Unless you make turbines that produce several thousand horsepower without adding air to the injected fuel, I still think my statement is true...

As I tried to explain, to have ALS you need more than just fuel and retarded ignition. You also need AIR... When the throttle is closed you have very little air so not really any ALS effect. Open the throttle increases air flow and then the fuel injected and retarded timing can create ALS

See post above.

Even with the throttle closed (which does not mean it is completely closed), there is still a decent amount of air that is pumped through the engine, it is not zero.

[Boss330]

Originally Posted by CanAutM3

See post above.

Even with the throttle closed (which does not mean it is completely closed), there is still a decent amount of air that is pumped through the engine, it is not zero.

So are you saying that a turbine engine can make thousands of horsepower with a very limited amount of air flow???

And that you can have a efficient ALS with the throttle valves closed???

Of course there is a small amount of air when the throttle is closed, I even said so in my first post on this. Without that air there wouldn't be any burbles in the exhaust, just fuel fumes coming out of the tail pipe. But I haven't heard of any ALS operating efficiently on a closed throttle yet. Your view also renders the whole F1 strategy of cold and hot blowing by employing an open throttle meaningless. They could apparently have created the same effect on a closed throttle... (I hope you don't mean that). After all, if all known ALS systems rely on more air than what can be drawn through a closed throttle and F1 used open throttle to create sufficient gas flow, I think it would be the same here... At least both Ford and BMW say it's just for show and claim no advantage from creating the overrun burble... Quite the contrary, Ford says it burns more fuel and isn't an effective engineering solution. It's just a show off.

My first post on this simply said that without introducing more air flow than the small amount of air under a closed throttle situation, no effective ALS would take place. I'm not sure why you seem to disagree with that?

[CanAutM3]

Originally Posted by Boss330

So are you saying that a turbine engine can make thousands of horsepower with a very limited amount of air flow???

And that you can have a efficient ALS with the throttle valves closed???

Of course there is a small amount of air when the throttle is closed, I even said so in my first post on this. Without that air there wouldn't be any burbles in the exhaust, just fuel fumes coming out of the tail pipe. But I haven't heard of any ALS operating efficiently on a closed throttle yet. Your view also renders the whole F1 strategy of cold and hot blowing by employing an open throttle meaningless. They could apparently have created the same effect on a closed throttle... (I know you don't mean that).

My first post on this simply said that without introducing more air flow than the small amount of air under a closed throttle situation, no effective ALS would take place. I'm not sure why you seem to disagree with that?

You wrote:

"Injecting fuel and retarding ignition won't create any high volume and high velocity exhaust gas to spool the turbo."

I just wanted to point out that if you add a little fuel to a relatively small amount of air and ignite it, you will get a significant expansion and hence higher velocity gases (volume is fixed, hence the higher velocity from the increased pressure). That is the operating principle of reaction engines. For sure, the more air you add, the more fuel can be added and hence the greater the power produced. But the principle remains, you can significantly increase the energy level by igniting fuel in the air.

I guess my main point is that you need much less input air to get the same benefit from "hot blowing" than you would from "cold blowing".

My understanding of F-1 hot/cold blowing is simply about maintaining the air flow around the rear aerodynamics to sustain downforce on the engine overrun. It is not quite the same thing as the need for high energy gases to keep a turbine spinning. You need enthalpy to generate work.

[AIRPOWER]

Originally Posted by Blksnowflake

You are way serious dude, respect on your knowledge. We need that here....
but, I don't want facts or air in my injectormabobs spooling my gizmos in the retard divided by lift in the turbine thingies.... I just want pops and burbles man. The peoples want zee germans to give us
pops
and
burbles ya.

No explain, just do. lol

Yo Blksnowflake you are hilarious, I love your sense of humor. But you forgot to add in how many gigawatts of ionized nanoids you need injected into your gleecion hydro flanger to get the maximum burble

[Boss330]

Originally Posted by CanAutM3

You wrote:

"Injecting fuel and retarding ignition won't create any high volume and high velocity exhaust gas to spool the turbo."

I just wanted to point out that if you add a little fuel to a relatively small amount of air and ignite it, you will get a significant expansion and hence higher velocity gases (volume is fixed, hence the higher velocity from the increased pressure). That is the operating principle of reaction engines. For sure, the more air you add, the more fuel can be added and hence the greater the power produced. But the principle remains, you can significantly increase the energy level by igniting fuel in the air.

I guess my main point is that you need much less input air to get the same benefit from "hot blowing" than you would from "cold blowing".

My understanding of F-1 hot/cold blowing is about maintaining the mass air flow around the rear aerodynamics to sustain downforce on the engine overrun. It is not quite the same thing as the need for high energy gases to keep a turbine spinning.

I don't understand why you keep quoting that out of context

It's quite clear (I thought) from the context that I am talking about ALS and that the amount of air needed to have any effective ALS needs more air than a closed throttle provides. That was the whole point there. I referenced previous posts talking about the burbles in the exhaust and said that from those posts it possibly hadn't been quite clear that you also needed to add air to have any effective ALS function. Just adding fuel and retard timing (under a closed throttle situation with very limited air flow) wouldn't create any noticeable ALS effect. I'm pretty sure that if it did, both BMW and Ford would have mentioned it in their PR material... As I said, Ford actually said that the burbles was bad from an engineering and efficiency standpoint but that sometimes you had to make sacrifices for emotional gains...

I still believe that what Ford said is true. Just adding a bit of fuel and retarding the timing on the overrun doesn't create any meaningful or noticeable ALS effect. Unless you also introduce air by opening the throttle/valvetronic or inject air directly into the exhaust manifold (ala WRC anti lag)

[TR930]

High performance race cars can pop and burble on decel, I hardly doubt they do that for show?? My old 930 turbo would pop, burble, throw flames on hard shifts.... it was glorious.

[M3Tooner]

Good discussion guys. As far as the pops and burbles go, I think my conclusion is that although After-run fuel dumping together with retarded ignition can have the potential to act as ALS, maybe it does to a very small amount that is not worth mentioning, it is probably not the primary goal for BMW for the CP. Otherwise they would have claimed so in their press release, but instead they just say that the sound is more "Emotional" or more "Powerful". They could have said "Improved Throttle Response" or something along those lines. Same thing for Ford Focus RS, just for the Cool factor.

What I do know is that the REAL deal ALS that I have heard on the Global Rally Cross cars is extremely loud on closed throttle, like gun shots. It was also mentioned earlier by our SME that they have dedicated air injection plumbing pre-turbo to inject more air to help make a larger BANG. There is no way they can open the throttle enough to flow air though the engine during decel, they would loose too much engine braking. It was also mentioned that the stress put on these systems while running closed throttle ALS is probably much higher than what the typical OEM's are willing to cope with.

[shadowyman]

Originally Posted by M3Tooner

Good discussion guys. As far as the pops and burbles go, I think my conclusion is that although After-run fuel dumping together with retarded ignition can have the potential to act as ALS, maybe it does to a very small amount that is not worth mentioning, it is probably not the primary goal for BMW for the CP. Otherwise they would have claimed so in their press release, but instead they just say that the sound is more "Emotional" or more "Powerful". They could have said "Improved Throttle Response" or something along those lines. Same thing for Ford Focus RS, just for the Cool factor.

What I do know is that the REAL deal ALS that I have heard on the Global Rally Cross cars is extremely loud on closed throttle, like gun shots. It was also mentioned earlier by our SME that they have dedicated air injection plumbing pre-turbo to inject more air to help make a larger BANG. There is no way they can open the throttle enough to flow air though the engine during decel, they would loose too much engine braking. It was also mentioned that the stress put on these systems while running closed throttle ALS is probably much higher than what the typical OEM's are willing to cope with.

MPE makes those "gunshot" noises everytime exhaust flaps are closed and at a higher rpm, the flap's opened while upshifting momentarily. It's extremely loud.

[x.shell]

Alright. Can someone make this mod for the F80? I don't need burbles if I can have this...

[M3Tooner]

Originally Posted by exo-shell

Alright. Can someone make this mod for the F80? I don't need burbles if I can have this...

Whoever dubbed those F1 sounds in there have some skillz! Especially when it came to a stop at the cross road, perfect sync!