[OpenFlash]

Drop outs are indeed knock. If anyone says otherwise, they are misleading you. The question should be how severe the knock is. Since each event registered as a knock, (be it mild, moderate or serious) results in 3 degrees of timing retard, you can't judge knock severity by the amount of timing pulled. Mild knock and more serious knock will result in the same amount of timing drop out.

But have no doubt, a timing drop is knock. You can prove this yourself by running high octane race gas and seeing these drop outs disappear. When the only thing you changed is octane, you can conclude WITHOUT A DOUBT, that knock was occurring before.

QED

[Proper Motion LLC]

Originally Posted by shiv@vishnu

Drop outs are indeed knock. If anyone says otherwise, they are misleading you.

Cobb has nothing to gain by telling me random drop outs of 3-6 degrees on a stock car are not knock.

[OpenFlash]

Originally Posted by Rysandro

Cobb has nothing to gain by telling me random drop outs of 3-6 degrees on a stock car are not knock.

If that is what they are saying, they are misleading you. I suspect they are saying that based upon the datalogs some of their customers are posting up. Along the same lines that throttle closure under boost is desirable. Yes, both throttle closures and drop outs are desirable given the alternatives (overboost/knock). But the proper solution is to address the cause of the problem, not argue about how appropriate the response is.

shiv

[Jeff@TopGearSolutions]

Originally Posted by Litos

so based on "any kind of knock being bad", why would it be so bad for a JB3/JB4 car to knock, when the car knocks in stock form ??

is there a level of knock to go by ??

car A knocks on 7psi this much
car A knocks on 13psi this much

.........AND, is there a chart that clearly says, if you knock that much your car is going to burn in a pile full of dead babies.......

And the viscous cycle repeats itself....

Cmon guys?

Cylinder pressures are exponentially higher at 2x more boost.

That means the THRESHOLD of "taking" any knock is lowered.

The stock DME is set up to run 7-8 PSi whatever it is.
The ignition tables are set up accordingly. Also Conservatively.

We know this because every manufacturer tunes their cars to be driven around the world. They also tune their cars for a minimum of 91 octane in our case.

Should grandma run 87 octane, the car wont kill itself? Why?

Cause of the knock sensor, it has the ability, to ward of knock incase grandma F*cks up.

Why does it work at 7-8 PSI, cause it maybe only has to reduce ignition 1 or 2 degrees, and keep in mind, its not like Grandma is hot lapping at laguna seca for 10 laps? Right?


Here is another scenario....

So.... you increase boost, 2x, 14 PSI, 93 octane...

Where should your ignition be? 5 degrees 6 degrees in the upper RPM?

Where does cobb place their stage 1 ignition? Why did they lower it?

Why didnt they just keep stock ignition? Let the stock DME figure it out?


Agian with increasing the boost 2x the ECU still thinks your only pushing stock boost so it Still thinks you want full timing advance for stock boost.

However, the knock sensors start going bananas and start pulling ignition.

They pull ignition until it stops knocking.

All good right?

WRONG...

The car will continue to try to increase ignition. Why?

Cause it thinks its still running stock boost, and is shooting for ignition timing preset for stock boost.

So that viscious cycle continues, constantly increasing ignition until it knocks, lowering it, and trying to increase it again till it knocks, and then lowers it. This pattern continues for quite sometime.

The cute thing is, and I use the word cute but I really mean pathetic, is that people refer to the initial runs of tunes as "adaptation"....

Oh its adaptating... what you mean is, the car went nuts when it saw those cylinders pressures, started knocking, and reduced ignition down to nothing.

Car felt like snot the first pull right?
But the 2nd pull felt better?
So did the 3rd right?

Thats cause you went from stock ignition, to 2x more boost with -2 degrees ignition, to maybe back 0 degrees ignition, and such and so forth, as you get your power back.

Now all of a sudden you get a day when its a little hot out, a little humid, and your racing that dodge neon srt-4 (man what a cool car).

You go for the 40 roll, and the car feels like sh*? Feels like its really down on power...

So you ask Mario, hey lets do another roll?

Car feels a lot better this run now.... interesting isnt it?

Want to know why?

Well during your adaptation period previously LOL your car found a happy medium for the conditions it was in. It got content with 5 to 6 degrees ignition whatever it was.

However, all of a sudden, since humid and hot air is less dense, car knocked, BAM, there goes your ignition, down to -2 or 0..

So it had to ramp back up for that 2nd pull against that SRT-4.

OK Cliff notes?

2x more boost

Car wants to run stock ignition but cant

Knock sensors lower ignition extremely.

Over time dme allows more ignition until it knocks again because it cant reach desired ignition.

Results in sitting on the threshold between grenading your engine for a long period of time.

Also results in INCONSISTENT day to day performance and driveability.
This is why the guys pushing 18-20+ psi, had no chance.

The DME is simply not quick enough to respond to knock when the timing tables arent designed for that 2x+ more boost.

Car could run a lot better, day to day, with no risk with PROPER ignition timing from the get-go... PERIOD.

[butters1234]

Originally Posted by shiv@vishnu

Along the same lines that throttle closure under boost is desirable. shiv

Dont have those either on any of my logs

[Jeff@TopGearSolutions]

Does anyone know why in this calibration of ignition.

(Low load Left, High boost right)
(Red to orange)
AS boost increases (and load), Ignition lowers?


Can anyone here tell me why increasing boost 2x and relying on the knock sensor is the ideal way of tuning? When all you need to do is lower ignition from the get-go and everything works peachy?

[Slops]

Originally Posted by Litos

my SRT4 began knocking somewhere @ 19psi. anything under 18 would be fine. that was on pump gas with basic boltons.

Nice pics, I see Carlos did those for ya. My SRT4 did the same thing

[Litos]

i AM Carlos

[Mike@N54Tuning.com]

Originally Posted by Litos

so based on "any kind of knock being bad", why would it be so bad for a JB3/JB4 car to knock, when the car knocks in stock form ??

is there a level of knock to go by ??

car A knocks on 7psi this much
car A knocks on 13psi this much

.........AND, is there a chart that clearly says, if you knock that much your car is going to burn in a pile full of dead babies.......

They are leaving out their dirty little secret. How do you think the "autotuning" maps that everyone runs here from a certain piggyback work? They raise boost and advance until light knock is detected, back off, rinse, repeat. The same basic algorithm the JB4 uses on map 5.

Mike

[Jeff@TopGearSolutions]

Mikey, you know as well as anyone else I'm not sleeping on the verge of knock running methanol, which is why I run it.

Ideally a Cobb ATR tune would fit my bill, but its simply not available to the market yet.

Ive been saying this since day 1;

All the tunes out are sub par at BEST.

This is not about picking tunes. You can purchase whatever tune you guys want. Please feel free. I can even help you install it.

The point is, teaching people the right way.

If you want to say that all the tunes ride the knock sensor, say it Mike...

Just realize, that is NOT the right way to tune a car. Period.

The goal of these threads atleast partially by CLAP is to educate and push the tuning platform of the N54 community in the right direction.

[SennaZ]

Originally Posted by JPSlick

Cmon guys?

Cylinder pressures are exponentially higher at 2x more boost.

So let me get this straight, you have some sort (any sort) of proof that the average cylinder pressure goes from say 300 psi to what, 600 or 1200 psi when boost is raised from 7 or so, to 14 psi?

[fisherbln]

Originally Posted by SennaZ

So let me get this straight, you have some sort (any sort) of proof that the average cylinder pressure goes from say 300 psi to what, 600 or 1200 psi when boost is raised from 7 or so, to 14 psi?

Yes, PV=nRT. Simply put, more air means more fuel which means a bigger explosion when the knock occurs.

[Jeff@TopGearSolutions]

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

Originally Posted by SennaZ

So let me get this straight, you have some sort (any sort) of proof that the average cylinder pressure goes from say 300 psi to what, 600 or 1200 psi when boost is raised from 7 or so, to 14 psi?

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.

In the meantime, you guys enjoy your day, I got work to do

[Litos]

Originally Posted by Mike@N54Tuning.com

raise boost and advance until light knock is detected, back off, rinse, repeat. The same basic algorithm the JB4 uses on map 5.

Mike

patiently waiting for Map 5

[Clap135]

Yes its called physics and backed by common sense. If cylinder pressures wouldn't increase neither would power.....think logically

Originally Posted by SennaZ

So let me get this straight, you have some sort (any sort) of proof that the average cylinder pressure goes from say 300 psi to what, 600 or 1200 psi when boost is raised from 7 or so, to 14 psi?

[Clap135]

All this shit has been already stated by me multiple times. Yet the same people who simply don't understand the answer continue post. Get a clue already.

[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.

[InCityPhoto]

Originally Posted by shiv@vishnu

Drop outs are indeed knock. If anyone says otherwise, they are misleading you. The question should be how severe the knock is. Since each event registered as a knock, (be it mild, moderate or serious) results in 3 degrees of timing retard, you can't judge knock severity by the amount of timing pulled. Mild knock and more serious knock will result in the same amount of timing drop out.

But have no doubt, a timing drop is knock. You can prove this yourself by running high octane race gas and seeing these drop outs disappear. When the only thing you changed is octane, you can conclude WITHOUT A DOUBT, that knock was occurring before.

QED

Well someone agree's finally.

[BrianMN]

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.

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

[techlogik]

Originally Posted by Mike@N54Tuning.com

They are leaving out their dirty little secret. How do you think the "autotuning" maps that everyone runs here from a certain piggyback work? They raise boost and advance until light knock is detected, back off, rinse, repeat. The same basic algorithm the JB4 uses on map 5.

Mike

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.

[vasillalov]

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.

Looked from a different perspective:

Don't go driving like maniac (WOT party at the drag strip) when its 100F and you know you put crap fuel in the car.

[vasillalov]

Originally Posted by techlogik

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.

Amen brother!