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Time for change
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I'll admit I don't know everything about engines, but I know... A lot.
However one of the areas ive never been able to come across other than stories and heresay regards "quench" area.

The stories I've heard reflect changes in compression by adding a thicker headgasket or by stacking stock ones etc. Ive heard stories that suggest by changing the quench, or "squish" area you can actually increase knock propensity even though the compression has dropped. Reason being erratic flame fronts due to changing squish or quench, which alters swirl, mixture etc... At least those are the only reasons I can think of that could cause more knock with less compression.

I know there can be truth to this, but how many have experienced it. I probably should ask this in the NA forums, but its important for me to get good exposure to this question so I can parse through the BS answers from the correct ones.

Thanks in advance, I haven't read any good articles on this subject.
There are a couple of good motors out there I would consider turbocharging but do not want to swap pistons, and I was thinking about having custom HGs made.
I.E. Gms 3.6 Liter V6. Sleeved block, Forged crank, rods, and pistons, but the compression is high stock.
 

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I'd be interested in hearing experts opinions as well... Like you, I've also heard about there being nice gains to be had by setting up a proper quench area and problems caused by having too much or too little.. I have been researching it for my own build, but information seems to be few and far between and no hard data to back it up.
 

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I'm not an expert but would also like to hear more interesting expert thoughts on this. I have no personal experience with it, but it's been discussed in many publications over the last 45 years of me reading about engines.

I think it pretty much says this in your linked article, but a simple picture is that one reason those areas are called "quench" areas is that they are quenched/run cooler than the rest of the combustion area ...and one of the main reasons why they are cooler is that the flat area on the piston top comes close to the flat area in the head combustion chamber and squeezes or squishes the combustion charge out of that area prior to ignition, so it runs cooler in that area; the piston being closer to the head in that area also helps draw heat out of that area. So if you add a thicker head gasket, you open up that space between the top of the piston and the head, so the combustion gases stay in there and when they ignite, there is also less capability to pull heat out into the head so that area is hotter than it would have been before and it can easier lead to detonation. Of course part of this effect is offset by the lower compression of running a thicker head gasket, so like most things, it's a balancing act.

There are a couple guys here who are experienced combustion engineers, maybe they'll chime in if somebody wakes them up.
 

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2jz powered
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What has been posted is my understanding of "quench" or "squish" area but i'd love to heard from some of the experts on here about stacking headgaskets. I am very curious about this since i've seen this concept brought up many times.
 
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