He is amazing! We need more episodes with Him. You know someone is an expert when they can transmit information in such a simple way that the listener says "duh".
This dude is actually incredibly knowledgeable in every aspect of these subjects. I subscirbed just from these clips because hes actually giving useful information
There are 2 types of knock - pre-ignition and detonation. What he describes as knock is detonation. Neither is good, but detonation leads to destruction.
Yes one is before the spark actually fires and the other one is after the combustion event. They both cause the same type of shockwave. It’s like hitting a piston with a hammer on its way up or down. Very devastating explosion when cylinder pressure goes up.
You are wrong. What is being described as knock in this video is knock. "Knock" is short for "end gas knock" as explained in the full version of this video. "Detonation" is something that CAN happen to gasoline engines as a result of pre-ignition. Pre-ignition is very different from knocking and can not be mitigated via ignition timing retard (obviously, since the spark plug is not the ignition source). Pre-ignition can sometimes lead to detonation when the spark plug fires and you get two colliding flames fronts.
"How quickly the mixture burns, is how fast its moving... charge motion." If I am understanding his principle, high velocity head ports would be less knock prone than higher flow, lazier head ports?
If you take off sprinting you need to get air in your lungs as quickly and controlled as possible or you’ll get winded. You don’t need to breath as hard walking, long controlled breaths. That’s how I think about it. A slow moving stream of air, not completely filling the chamber would cause some combustion issues.
Two categories of knock. 1. Pre-ignition occurs before the spark. 2. Detonation occurs after the spark. What he is describing as knock is detonation. More violent than pre-ignition.
@@BRENTHILL-eq4fb Yes, but most all modern automotive engines have knock sensors, and you can't audibly detect any type knock in most any performance application. Or looking at it another way, if a tree falls in the forest and you're not there, the tree still fell.
Wrong. It's not absorption of infrared radiation, it's compression heating. As the flame front propegates, the pressure builds and the compression increases the charge temperature until it ignites at other points in the unburnt charge. Hotspots can also serve as a point of pre-ignition.
I was going to say that cylinder pressures are increased as you advance. When cylinder pressure is higher, the fuel can spontaneously ignite hence similar to a diesel engine. The difference is that diesel engines can handle that sort of combustion whereas preignition can destroy a piston. You also can have hotspots like a sparkplug that's deeper inside the cylinder head or by running the engine hot. Adding oil squirters to the bottom of the pistons helps prevent knocking due to heat There is also the issue with the charge air being hot from a turbo compressor.
@@brarautorepairsRight so, the main reason for cooling the charge temp, is to get dense cool air into the combustion chamber. Less chance of pre-ignition or detonation. Water or Meth significantly cools the charge temp. There are guys that daily a 800hp car on 93, because they understand this concept.
@@JohnZornAscended Right. I had this argument with a guy that you don't need ethanol to make big power if you simply add water into the intake. I do not have access to E85 so I plan on running a water meth injection kit which is injected into the throat of the intake manifold which will cool the charger air significantly and allow for more timing.
@@JohnZornAscended right now I have problems with 93/94 octane and excessive timing corrections. I was able to run 93/94 with a less timing corrections before but it seems that the fuel stations aren't accurate with their octane rating. I suspect they have some 91 blended into. I can run a 91 tune with 93 without any timing corrections all day. The trap speed is actually better with the less aggressive timing. Weird is that I'm not getting any knock so the ECU might be retarding timing based on the AFR instead
@ The oil industry didn’t push that. The customers did. Like I said if it works for you, it does. It’s definitely not a one size fits all deal. Especially from companies that force features like auto stop start down their loyal customers throat. Big bag of cheaply made goodies from overseas, for 40,000$
He is amazing! We need more episodes with Him. You know someone is an expert when they can transmit information in such a simple way that the listener says "duh".
This dude is actually incredibly knowledgeable in every aspect of these subjects. I subscirbed just from these clips because hes actually giving useful information
You should listen to the whole episode it’s awesome
Bro just explained knock like a pro. Thank you
Great explanation of engine knock
Ill tell you right now this guy is the best youtube teacher for engine preformance
Good info to know explaisn why most newer cars have such high timing stock
I really like this guy
There are 2 types of knock - pre-ignition and detonation. What he describes as knock is detonation. Neither is good, but detonation leads to destruction.
Yes one is before the spark actually fires and the other one is after the combustion event. They both cause the same type of shockwave. It’s like hitting a piston with a hammer on its way up or down. Very devastating explosion when cylinder pressure goes up.
You are wrong. What is being described as knock in this video is knock. "Knock" is short for "end gas knock" as explained in the full version of this video.
"Detonation" is something that CAN happen to gasoline engines as a result of pre-ignition. Pre-ignition is very different from knocking and can not be mitigated via ignition timing retard (obviously, since the spark plug is not the ignition source). Pre-ignition can sometimes lead to detonation when the spark plug fires and you get two colliding flames fronts.
So great! Thank you!!
"How quickly the mixture burns, is how fast its moving... charge motion."
If I am understanding his principle, high velocity head ports would be less knock prone than higher flow, lazier head ports?
If you take off sprinting you need to get air in your lungs as quickly and controlled as possible or you’ll get winded. You don’t need to breath as hard walking, long controlled breaths. That’s how I think about it. A slow moving stream of air, not completely filling the chamber would cause some combustion issues.
HCCI and TJI mitigate both of these things and aren't dominant in the market yet.
Knock occurs when the fuel ignites before the plug sparks not the other way around.
Two categories of knock. 1. Pre-ignition occurs before the spark. 2. Detonation occurs after the spark.
What he is describing as knock is detonation. More violent than pre-ignition.
Not always. That's just one mode of knock. There are others. Video is correct.
@mback12000 this type of knock is not normally audible to the naked ear as fuel ignites when piston has passed tdc.
@@BRENTHILL-eq4fb Yes, but most all modern automotive engines have knock sensors, and you can't audibly detect any type knock in most any performance application. Or looking at it another way, if a tree falls in the forest and you're not there, the tree still fell.
@mback12000 very true. That's the reason for knock sensors.
Wrong. It's not absorption of infrared radiation, it's compression heating. As the flame front propegates, the pressure builds and the compression increases the charge temperature until it ignites at other points in the unburnt charge. Hotspots can also serve as a point of pre-ignition.
I was going to say that cylinder pressures are increased as you advance. When cylinder pressure is higher, the fuel can spontaneously ignite hence similar to a diesel engine. The difference is that diesel engines can handle that sort of combustion whereas preignition can destroy a piston.
You also can have hotspots like a sparkplug that's deeper inside the cylinder head or by running the engine hot. Adding oil squirters to the bottom of the pistons helps prevent knocking due to heat
There is also the issue with the charge air being hot from a turbo compressor.
@@brarautorepairsRight so, the main reason for cooling the charge temp, is to get dense cool air into the combustion chamber. Less chance of pre-ignition or detonation. Water or Meth significantly cools the charge temp. There are guys that daily a 800hp car on 93, because they understand this concept.
@@JohnZornAscended Right. I had this argument with a guy that you don't need ethanol to make big power if you simply add water into the intake. I do not have access to E85 so I plan on running a water meth injection kit which is injected into the throat of the intake manifold which will cool the charger air significantly and allow for more timing.
@ I think if you can easily get to e85 fine. But water meth allows you to get fuel where you want, like a street driven vehicle should.
@@JohnZornAscended right now I have problems with 93/94 octane and excessive timing corrections. I was able to run 93/94 with a less timing corrections before but it seems that the fuel stations aren't accurate with their octane rating. I suspect they have some 91 blended into.
I can run a 91 tune with 93 without any timing corrections all day. The trap speed is actually better with the less aggressive timing.
Weird is that I'm not getting any knock so the ECU might be retarding timing based on the AFR instead
And all that can be mitigated with water?
Knock isnt bad, unless used in abundance😅
You just talked me into an EV
If you would like to shell out 20,000$ for a huge heavy battery that won’t charge good enough in the winter. It may be for you.
@@JohnZornAscended I don't blindly believe oil industry FUD. I've been shopping around, and if my Focus dies tomorrow (possible) I'll get a used Bolt.
@ The oil industry didn’t push that. The customers did. Like I said if it works for you, it does. It’s definitely not a one size fits all deal. Especially from companies that force features like auto stop start down their loyal customers throat. Big bag of cheaply made goodies from overseas, for 40,000$