[Clap135]

Originally Posted by Litos

so we can all collectively agree that unless your car is running a V5 on autotune or a JB4 on autotune or meth (even on a stock car), you're more than likely running with an unhappy car.

that's all this really boils down to.

no because u need to be able to control both boost and ignition not rely on the knock sensor.

[techlogik]

Originally Posted by Clap135

no because u need to be able to control both boost and ignition not rely on the knock sensor.

Your sig and video FTW...haha...

[OpenFlash]

Originally Posted by InCityPhoto

Well someone agree's finally.

Make no mistake though... knock isn't desirable. Even "minor" knock is unwanted. And more serious knock is just bad news.

Shiv

[vasillalov]

Originally Posted by Clap135

no because u need to be able to control both boost and ignition not rely on the knock sensor.

Clap135,

I am catching a bit of a contradiction in your statements:

1. First you question my argument that timing drop does not necessarily mean engine knock.

2. Then you say that there is no direct way to capture the knock sensor output in a reliable fashion

3. Now you are saying that proper boost and ignition control are necessary, instead of relying on the knock sensor. (I agree with this BTW)

From all three, I don't see HOW you can accomplish all this given the restrictions above? I.O.W, how can a tuner company rewrite the timing tables, if they have no way of detecting knock events, since the knock sensor output is useless?

To turn this around a bit:

Say you are able to extrapolate a way to determine when knocking will occur with 100% certainty by the use of all other sensors EXCEPT the knock sensor. Say that's possible. Then wouldn't that mean that BMW would have already implemented an algorithm to pull timing when the conditions are approaching a knock threshold? :

[shifterboy45]

for those not aquainted with the operation of knock sensors or detection methods -- here is an patent article from 1994 explaining the princples of operation (not saying that Bosch or any other manufacturer uses this) --

from this article you can deduce what the manufacturers are looking for -- and some preventative (proactive) measure that were/are discussed when the components are built

but keep in mind these sensors directly correlate with the DME system logic.
breaking out of this envelope -- which is quick and dirty poses yet another challenge for tuners..

if i may -- you do not push a car to its limits (unless you have a full out race car) and ask it to live long and prosper.

http://www.patentstorm.us/patents/53...scription.html

[Dmacc]

The thought that keeps going through my head after reading 39 pages of posts is after all this obvious explanation of why knock is bad, even the slightest amount, people still want to stick with something unsafe?

All of you are BMW owners, you're all really too cheap to go with a tune that is going to save your engine for the longer run?

5/6 of this thread is a never ending facepalm

if you're going to tune, do it the right way, don't try to save a few bucks with a tune that isn't as superior to others, and in the long run will damage your engine more than another tune.

why have constant knock, which over time damages the engine, reguardless of how severe it is, when you can have the slightest occasional knock, or no knock at all?

This thread shows how little people care about their engine, and to what extent their retardation and thick-headedness will be the end of them.

come on now...

[Litos]

Originally Posted by BrianMN

In perfect conditions, things will likely be OK...it's when the conditions are poor that the danger comes into play.

well then THAT really sucks........

these damn cars are sensitive.......

[Dmacc]

Originally Posted by Litos

well then THAT really sucks........

these damn cars are sensitive.......

but as stated before, these aren't the only cars that knock stock.

[themyst]

The problem is many BMW owners lease their cars for 2-3 years so they really don't give a rats ass what damage they do.

Originally Posted by Dmacc

The thought that keeps going through my head after reading 39 pages of posts is after all this obvious explanation of why knock is bad, even the slightest amount, people still want to stick with something unsafe?

All of you are BMW owners, you're all really too cheap to go with a tune that is going to save your engine for the longer run?

5/6 of this thread is a never ending facepalm

if you're going to tune, do it the right way, don't try to save a few bucks with a tune that isn't as superior to others, and in the long run will damage your engine more than another tune.

why have constant knock, which over time damages the engine, reguardless of how severe it is, when you can have the slightest occasional knock, or no knock at all?

This thread shows how little people care about their engine, and to what extent their retardation and thick-headedness will be the end of them.

come on now...

[Clap135]

What are u talking about. You can tell if the car knocked by looking at the curve. That's all there is too it

Originally Posted by vasillalov

Clap135,

I am catching a bit of a contradiction in your statements:

1. First you question my argument that timing drop does not necessarily mean engine knock.

2. Then you say that there is no direct way to capture the knock sensor output in a reliable fashion

3. Now you are saying that proper boost and ignition control are necessary, instead of relying on the knock sensor. (I agree with this BTW)

From all three, I don't see HOW you can accomplish all this given the restrictions above? I.O.W, how can a tuner company rewrite the timing tables, if they have no way of detecting knock events, since the knock sensor output is useless?

To turn this around a bit:

Say you are able to extrapolate a way to determine when knocking will occur with 100% certainty by the use of all other sensors EXCEPT the knock sensor. Say that's possible. Then wouldn't that mean that BMW would have already implemented an algorithm to pull timing when the conditions are approaching a knock threshold? :

[Litos]

Originally Posted by BrianMN

In perfect conditions, things will likely be OK...it's when the conditions are poor that the danger comes into play.

so in poor conditions this iconic 3-series drives like a pig, loses power and knocks all over God's creation?

[Dmacc]

Originally Posted by themyst

The problem is many BMW owners lease their cars for 2-3 years so they really don't give a rats ass what damage they do.

If that's the case, they honestly should not be in this conversation at all. As for the people who are in this that plan on keeping the car for longer than a lease, and are arguing against the knock, well then they were simply dropped on their head repeatedly as a small child.

This thread is bookmarked for the "I told you so" link for down the road, when knock turned out to be the end of their engine...

[Litos]

Originally Posted by Dmacc

The thought that keeps going through my head after reading 39 pages of posts is after all this obvious explanation of why knock is bad, even the slightest amount, people still want to stick with something unsafe?

why did you spend $35k+ on a car that can't run safe when it gets a little hot outside?

[BeenieMan]

Originally Posted by Dmacc

The thought that keeps going through my head after reading 39 pages of posts is after all this obvious explanation of why knock is bad, even the slightest amount, people still want to stick with something unsafe?

All of you are BMW owners, you're all really too cheap to go with a tune that is going to save your engine for the longer run?

that's a contradiction in itself. if a stock car knocks as bad shown, the best tune would just retard the timing and leave the boost stock or drop it completely lol

and I have seen a log from all the tunes that showed timing drop. you just need to know how to increase boost and not knock to keep it safe

[fisherbln]

Originally Posted by Litos

why did you spend $35k+ on a car that can't run safe when it gets a little hot outside?

You still don't seem to hear what people are telling you repeatedly.

1. Many cars knock in their stock form in poor conditions, that is what the knock sensor is for.
2. While all knock is bad, a knock at low boost (stock) is not nearly as bad as a knock at high boost (tuned).

[shifterboy45]

this thread didnt start as a knock issue, but rather a timing discrepancy.

sensitivity to knock is important enough for most (if not all) manufacturers to list a minimum octane requirement.

what does this mean? well if run the car with enough ssubstandard fuel the knock events will sooner or later cause detriment to the engine operation.

this is important enough for BMW to develop a way to track the octane used in cars for the purpose of diagnostics.. feel free to ask any shop foreman at your local BMW dealer if they can check fuel quality on these current cars.

even though the boost is not raised via a tune, the effects of knock can be culmlative and ultimately destructive. can knock be prevented --no !! can it be held in check -- yes! if a car is tuned, its much MORE important to have control measure in place than wait for your stock logic to provide "life support" --

// im out --

cheers all

[vasillalov]

Originally Posted by Clap135

What are u talking about. You can tell if the car knocked by looking at the curve. That's all there is too it

That's ONLY in the case when you assume that timing drop = knock event 100% of the time all the time.

I guess I was not very clear what I was trying to ask here:

Say a brand new tuning company ABC decides to get into the N54 market. They would need to figure out how to modify the boost, timing, and a plethora of other tables in the ECU, correct? This means that at the early stages of the development the timing curve is UNKNOWN! They may have a general idea what it SHOULD look like, though. So how can this company use the ignition monitoring to determine what the timing curve is? They only way is to assume that timing drop = knock event 100% of the time and all the time! Now add to this the fact that no current tuner can make sense out of the knock sensor output, and you are stuck in a situation where the only way to properly define a timing table is through trial an error and guess work, correct?

I still maintain that there are other measurable variables that can be used to see when the engine is approaching knock threshold BEFORE engine knock actually occurs. I still maintain that BMW has an algorithm designed to handle most of those situations. If that is not the case, the they would not give you ANY powertrain warranty on that engine. The knock sensor is a "sledgehammer". If the ECU detects unfavorable conditions it may decide to drop timing before it starts knocking. When actual knock occurs, the timing MUST be pulled or damage can occur. If something is WAY TOO out of whack, then ECU enters limp mode.

What I am trying to say here is that the fact that no tuner has come up with a way to properly measure knock sensor output and make sense out of it, does not necessarily mean that such logic does not exist at all.

P.S.:
Do not forget, I am not defending or rooting for anyone here!

[Litos]

Originally Posted by fisherbln

You still don't seem to hear what people are telling you repeatedly.

1. Many cars knock in their stock form in poor conditions, that is what the knock sensor is for.
2. While all knock is bad, a knock at low boost (stock) is not nearly as bad as a knock at high boost (tuned).

my SRT8 doesn't knock
my SRT4 didn't knock
my STi didn't knock
my WS6 didn't knock
my OTHER SRT4 didn't knock

only car that has potential to knock in stock form from a car that i own or have previously owned is the 335.

what other $35-40K performance cars knock in stock form - i'd like to hear this

[BrianMN]

Originally Posted by Litos

my SRT8 doesn't knock
my SRT4 didn't knock
my STi didn't knock
my WS6 didn't knock
my OTHER SRT4 didn't knock

only car that has potential to knock in stock form from a car that i own or have previously owned is the 335.

what other $35-40K performance cars knock in stock form - i'd like to hear this

Remember we're mostly talking about very poor conditions, such as low octane or very hot weather. If you were to throw in some 87 into your cars, you'd likely see knock...

[SennaZ]

Originally Posted by JPSlick

edit- ^ Oh there you go, now you dont need to google.


We all have proof, its physics my friend.


Im sure you could sift through google and find the formula to calculate it, feel free. Again, its all physics, nothing hiding here.

Ask any engine builder or math wiz.

So it seems you and your buddies live in a vacuum? Me, I like my 1 atm of base pressure. And of course, you guys apparently relate manifold pressure to cylinder pressure not accounting for any volumetric losses.

But going back to your original claim: cylinder pressure does not jump exponentially with 2x boost pressure which is precisely why the JBx platform can compensate for 14psi boost situations. Now, if you want to talk 600hp engines running gobs of boost (a hell of alot more than 14psi), then it's a different ball game.

[Mike@N54Tuning.com]

Originally Posted by techlogik

Someone correct me if I am wrong on this summary.

Initially...yes. Procede does use the knock sensor. It has to come to some initial pre-determined method of knowing where to set timing to then start working algorithms and autotune the car and control timing to then further prevent the knock sensors and DME to jump in all the time. Whereas JB "rides" and relies on the knock sensor and stock DME timing settings entirely. Big difference riding the knock sensor (read, knock..knock..knock..not good, DME pull timing reactively ALL THE TIME.) Compared to testing and picking up on minor knock events then adjust timing to avoid it again.

You need to set some baseline with a piggy back, then set timing. JB does none of that. It just rides the knock sensor and DME stock settings stored in the DME...not good.

Cobb/GIAC do this by rewriting the tables after extensive dyno testing/tuning with specific hardware/octane and conditions to come to what those numbers should be, then hard code it in place. Thus, they have a pretty reliable/safe way to avoid knocking at specific boost, temp and a/f levels. It might knock depending on temp/octane based on variances they can't control obviously due to gas stations fuel quality, temp/humidity around the country etc...but for the most part, they have safe limits written into the tables for these scenarios for higher boost levels. Hence, you don't see GIAC ever blowing any FI engines, they got the system and tuning fundamentals down as well as anybody in the FI market to safely give good power gains using that method.

JB does not. JB is the only tune that doesn't do any of these things, by either auto tuning and controlling timing on its own, or pre-writing timing values into the DME directly.

JB just "rides" the knock sensor and pray the DME reacts to control timing.

Again, correct me if I am wrong on any of this anyone.

I hate to keep repeating myself but you're wrong. If the DME didn't learn the timing curve there could exist no JB4 log without dropouts. Yet many have been posting such logs in this thread already. So your theory is out the window. The truth is drop outs indicate the DME is having a hard time determining the proper timing curve because you are approaching the point at which your boost levels can no longer be supported with your octane. So you monitor drop outs and adjust the boost curve accordingly to avoid them. Once things are stable the DME optimizes the timing curve again and off you go with drop out free tuning.

Mike

[fisherbln]

Originally Posted by SennaZ

So it seems you and your buddies live in a vacuum? Me, I like my 1 atm of base pressure. And of course, you guys apparently relate manifold pressure to cylinder pressure not accounting for any volumetric losses.

But going back to your original claim: cylinder pressure does not jump exponentially with 2x boost pressure which is precisely why the JBx platform can compensate for 14psi boost situations. Now, if you want to talk 600hp engines running gobs of boost (a hell of alot more than 14psi), then it's a different ball game.

The air pressure from the turbo is not directly what is causing the increased cylinder pressure. The increased cylinder pressure is a result of more fuel being present in the combustion chamber because more air is in there. If there wasn't more fuel, you'd be running VERY lean. Because there is more air and fuel, the resulting explosion caused by the spark releases more energy. This energy increases pressure in the combustion chamber and (if timed correctly), pushes the piston down with said pressure.

This is why increased boost makes more power. More air + more fuel = greater pressure pushing the piston down with greater force. If timing isn't correct, that greater force is exerted at an inopportune time.