[MAKH 5]

Originally Posted by charern

Thats awesome!
Is there any functionality for it? Or is it just for fun noises?

Just fun noises lol.

[xnick101]

Any updates on this?

[Insane435]

Not sure if this has been figured out yet but i have something to add.

I have both an ewg n55 in my 2014 435 and then i have an 2018 x4m40i. The x4 behaves exactly like the m2 with n55. When you rev it at idle, it bangs off the limiter much differently than my 435 which has bm3 and xhp stage 3. Ive also noticed in the m40i when you left off the throttle you get thrown forward where in the 435 nothing happens. After owning the m40i, the 435 seems pedestrian at times.

Can you get the 435 to behave like the m2 when revving, upshifting and letting off the throttle?

[Thomas590]

Originally Posted by charern

Thats awesome!
Is there any functionality for it? Or is it just for fun noises?

In theory it should add some lifespan to your turbo.

Originally Posted by Insane435

Can you get the 435 to behave like the m2 when revving, upshifting and letting off the throttle?

Yeah, you can get it to work just like it is in N55 M2.

[Insane435]

Originally Posted by Thomas590

In theory it should add some lifespan to your turbo.


Yeah, you can get it to work just like it is in N55 M2.

And this requires a custom tune through bm3?

[thejeremyman9]

Originally Posted by Thomas590

In theory it should add some lifespan to your turbo.


Yeah, you can get it to work just like it is in N55 M2.

I would like to hear why you think this is going to add lifespan to your turbo.

[Thomas590]

Originally Posted by thejeremyman9

I would like to hear why you think this is going to add lifespan to your turbo.

I think it's related to this:

Originally Posted by Boss330

With valvetronic, you can have better control of valves (I guess?). For instance creating a "blow through" situation where the injected fuel is ignited but the combustion pressure isn't trapped inside the combustion chamber but released through the exhaust valves (intake valves must be closed during this stage to avoid the pressure escaping to the intake manifold) and thereby spinning the turbos. Sort of like igniting fuel in a container with a small opening, creating a "jet stream" of hot air (exhaust). That "jet stream" will keep the turbos spinning at a high rpm (stated to be around 100.000rpm!!!). Since the combustion pressure is bled out through the exhaust valves, engine braking shouldn't be adversely affected perhaps?

And I also believe that this "jet stream" will be able to sustain a certain boost pressure even under deceleration. At least that would be beneficial in reducing lag, as otherwise the turbos will need time to raise pressure. With a "anti lag base pressure" of say 0.5bar, the engine would feel much more responsive and lag will be virtually non-existent.

For the cylinders that "participate" in the anti lag function this is how I imagine the system works:

Stage 1: Air enters combustion chamber (intake valves open, exhaust valves closed - intake stroke)
Stage 2: Air is compressed (intake and exhaust valves closed, creating engine braking - compression stroke)
Stage 3: Fuel is injected and spark is introduced (both intake and exhaust valves closed, or possibly starting to open exhaust valves here - combustion stroke)
Stage 4: Combustion starts and exhaust valves are opened to vent exhaust (intake valves closed, exhaust valves open - "exhaust stroke")

Stage 1-3 is equal to a normal 4-stroke combustion cycle
Stage 4 is different because the combustion energy isn't used to push down the piston, but to create a "jet stream" of exhaust gases to the turbos and spinning them.

Fuel injected in this "anti-lag" process is measured to create a combustion needed to spin the turbos, not the same amount of fuel needed to push down the piston in a normal 4-stroke cycle.


I'm pretty sure that emission and mileage data is at the normal settings for all cars on sale today.

Originally Posted by CanAutM3

Good analysis .

I agree that, with this feature, it is possible to keep the car "on boost" with "closed throttles". To achieve this, the intake valves would need to open as little as possible on a few cylinders (while remaining closed on others) to just sustain the exhaust "jet stream" you mention. With the intake valves mostly closed there is very little air flow into the engine and the turbos do not need to produce much work to maintain boost. By precisely adjusting the bleed off valve and Valvtronic, the turbo speed and boost pressure can be maintained.

It is very similar to an old driving technique I learned in rally school. Left foot brake to slow the car down but keep the right foot on the throttle to keep the turbo spinning and on boost (I know, there are other reasons to left foot brake but this is also one of them )

Originally Posted by CanAutM3

When abruptly lifting the throttle on the S55, "farting" noises can be heard. There is some wizardry happening in the engine system to keep the turbos spooled. It is most probably a combination of the waste-gates, Vanos and fuel injection that come into play to maintain high energy gases in the exhaust.

Originally Posted by Boss330

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.

Originally Posted by julienjj

The shift ''farts'' are caused by the torque reduction during shift. Give the transmission a break to execute the upshift faster.

The throttle lift-off cylinder blanking last 2 seconds to keep the turbos spooled.

Since I discovered the eeprom is different I'm waiting to find a local M2 to read it from.

What i hope now is that the DSC in a non-M car can "talk" to the M dme program... since the M2 N55 use the same DSC unit as the M3&M4 and not like the M235i

Also that the automatic transmission in my car works the same (almost a given, since BMW tend to design their engine software to match virtually all transmission they make, DCT, 6MT, ZF...) but still a risk

Has anyone figure it out yet? Bob from Stage FP got the beta file if you are interested. You still need MHD to load this.

[thejeremyman9]

Originally Posted by Thomas590

I think it's related to this:

Has anyone figure it out yet? Bob from Stage FP got the beta file if you are interested. You still need MHD to load this.

I follow the logic in the quotes you posted, but i don't see how that's going to improve turbo lifespan... they are talking about reducing turbo lag, and keeping the turbo spooled, and presumably increasing/maintaining high EGTs. None of that seems "better" for the turbo lifespan.

[Thomas590]

Originally Posted by thejeremyman9

I follow the logic in the quotes you posted, but i don't see how that's going to improve turbo lifespan... they are talking about reducing turbo lag, and keeping the turbo spooled, and presumably increasing/maintaining high EGTs. None of that seems "better" for the turbo lifespan.

In this case you are right. In regular ALS looks like this = dump a bunch of fuel into the engine to keep the turbos spinning. Due to the constant explosions in front of the turbo wheel, the lifespan is rapidly declining. That’s a fact, no one denies it. You can’t add any lifespan to your turbo with that.
But here we have a different type of ALS, similar to Porsche’s solution. It doesn't dump extra fuel into the engine to keep the turbos spooling.

Lifting off the throttle pedal shuts off the fuel injectors, but leaves the throttle partially open. This allows more air to pass through the engine, keeping exhaust flowing and spinning the turbos even during deceleration. If you compare it now to people willing to have ALS, this solution adds lifespan compared to regular ALS.

The only downside I see is engine braking effect is reduced by this ALS. But you should only feel it when you aggressive drive your car.
Everything we have here are are just guesses. We don’t know yet how exactly work this system.
Please don’t get me wrong, we are all here to find the solution how to get it to work on regular 35i cars.

[Thomas590]

Originally Posted by nioh_lbbm2

Like in my last post, the "BRAAAP" isn't anti lag. It's simply the result of boost release into the exhaust.

Anyone can confirm it?

[harkes]

Originally Posted by Thomas590

In this case you are right. In regular ALS looks like this = dump a bunch of fuel into the engine to keep the turbos spinning. Due to the constant explosions in front of the turbo wheel, the lifespan is rapidly declining. That’s a fact, no one denies it. You can’t add any lifespan to your turbo with that.
But here we have a different type of ALS, similar to Porsche’s solution. It doesn't dump extra fuel into the engine to keep the turbos spooling.

Lifting off the throttle pedal shuts off the fuel injectors, but leaves the throttle partially open. This allows more air to pass through the engine, keeping exhaust flowing and spinning the turbos even during deceleration. If you compare it now to people willing to have ALS, this solution adds lifespan compared to regular ALS.

The only downside I see is engine braking effect is reduced by this ALS. But you should only feel it when you aggressive drive your car.
Everything we have here are are just guesses. We don’t know yet how exactly work this system.
Please don’t get me wrong, we are all here to find the solution how to get it to work on regular 35i cars.

This sound really cool. Hope it will make its way into MHD as an option to tick off

[Thomas590]

Originally Posted by harkes

This sound really cool. Hope it will make its way into MHD as an option to tick off

One day maybe

[F20_M135i]

Response from a custom MHD card tuner: This sound is not reproducible on an N55B30 PWG

[LA1Z24]

My 435i makes a very similar burble as it is shifting. Sounds like an aggressive fart. This is the sound we're discussing? I have a FBO N55 EWG

[thejeremyman9]

Originally Posted by LA1Z24

My 435i makes a very similar burble as it is shifting. Sounds like an aggressive fart. This is the sound we're discussing? I have a FBO N55 EWG

No. This is a lift off sound. Check the earlier videos.

[Thomas590]

Originally Posted by thejeremyman9

No. This is a lift off sound. Check the earlier videos.

Yup

Originally Posted by F20_M135i

Response from a custom MHD card tuner: This sound is not reproducible on an N55B30 PWG

Time to change a tuner I guess.

[fortythirtyfive]

MHD just released an anti-lag option for S55/N55 engines and the demo video replicates this sound..

I'm going to try flash it in the morning

[LA1Z24]

Originally Posted by thejeremyman9

No. This is a lift off sound. Check the earlier videos.

Upon shifting, throttle is closed briefly. I think that is considered "lift-off", no?

I still stand by my statement. My car makes this almost exact noise when on the gas hard, and it shifts.
I'll take a video in the next few days if I can figure out a way to mount the gopro back there

[XxThe_RemedyXx]

Originally Posted by LA1Z24

Upon shifting, throttle is closed briefly. I think that is considered "lift-off"

I still stand by my statement. My car makes this almost exact noise when on the gas hard, and it shifts.
I'll take a video in the next few days if I can figure out a way to mount the gopro back there

I know whatcha mean bud. My 335 does the same thing when shifting between gears hard. I think what people are trying to achieve is this sound when letting OFF throttle from a hard acceleration.

[thejeremyman9]

Originally Posted by LA1Z24

Upon shifting, throttle is closed briefly. I think that is considered "lift-off", no?

I still stand by my statement. My car makes this almost exact noise when on the gas hard, and it shifts.
I'll take a video in the next few days if I can figure out a way to mount the gopro back there

Yes, we know exactly what you are talking about. All of our cars do that from the factor. The classic "fart" on shift. Here's one of my older exhaust videos:

This thread is about something different and if you go back to some of the OPs there was this same exact discussion. This thread is about the sound when you let off the throttle without shifting. Its like a overrun sound. Has nothing to do with changing gears.

[F20_M135i]

Originally Posted by Thomas590

Yup

Time to change a tuner I guess.

it's my fault, I misinterpreted what I heard here.

good luck getting your "braap" sound back

[Insane435]

Its not just a sound either, the entire car “bucks” when you let off. My m40i does this.