I bet if they could they would, no reason the laws of physics would be suspended just because it is a higher pressure than 14.7 PSI. I would be willing to be the reason has more to do with other things that make more power than good quench would that prevent quench from being an easily acomplished goal. Things like big valves and compression ratio are just bigger factors than quench, for example... if good quench adds 20 HP but but a bigger valve might be worth 50HP and make it impossible or very hard to get quench witch one are you going to choose?

Lets back up a second... and answer what the purpose of quench actually is...

Think of the fuel mixture as a series of fireworks, all connected by lines fuses. You light the fuse at one end and it slowly moves towards the first firework. Once it reaches the firework, it rapidly goes off. The fuse continues slowly to the next firework, and it goes off... on and on. When the burn is moving through the fuse, it moves slowly, but once it gets to the firework you have an enormous release in energy. Then it goes back to moving slow on the fuse again. This is an analogy of what's going on with fuel mixture. As you have lean spots from the mixture not being evenly distributed, the burn slows down as it moves across the chamber through the lean areas with no fuel (like the fuse). Once it gets to the pocket of fuel molecules again, it rapidly releases energy (like a firework).

Now this isn't exactly how it works, because we are talking about VERY high speed, and chemical reactions to create the heat release in chamber. But gives you an idea.

So you can see how pushing all of the fuel molecules together (essentially shortening the fuse length between each firework), would have a benefit to burn it all as quickly as possible. This is essentially what quench is doing.

As the piston gets to TDC, in the area of quench you get a localized "squeeze". The air/fuel mixture is then essentially "squirted" (for lack of a better term), towards the spark plug side of the chamber where the burn has started. This helps not only create turbulence and mix the fuel up for better even distribution, but also gets the molecules closer together to speed up the burn as described above. Faster burn means lower timing numbers. Remember any pressure created in chamber at TDC doesn't actaully rotate the crank, When the crank is at zero degree's, and the rod is straight in the cylinder... all it does is try to push the crank out the bottom of the block!!!

So why is quench less meaningful in a boosted engine then? If you think about it... the turbo/blower has already "packed" the molecules closer together to start with. This means there is less space for these "lean" pockets to hide like there would be on an N/A motor. The "fuse" length is essentially shorter between fuel molecules on the boosted motor, because the molecules of fuel are pushed closer together.

This is the primary reason why boosted motors run less timing. The burn speed in chamber is much faster, because everything is packed closer together. As boost goes up, timing comes out... its just a function of packing the fuel tighter together in chamber from shoving more air and fuel into the chamber.


So it's not that boosted motors don't "need" quench, it's just that effectively the boost pressure is already doing the same thing as the quench would.

Now I'm sure on some very high HP stuff with mega boost, we could debate if quench is detrimental to those motors... but for most of us living in normal HP land... it really doesn't matter.

Put the flat top in it that gets the compression right, and let it rip.

For reference... my boosted motor has the piston .050" in the hole with a .040" gasket... so doesn't have really any quench. It's been ran at 23psi non-intercooled on E85 with ~22 deg of timing. I am very confident it's not detonating, because if it were... the cast 360 crank would have been in many pieces years ago.


If this is true, why does the combustion chamber with the WORST quench only need 30-32 degrees total timing? Again, quench is a fix, not a need if everything else is correct.

Did you read what poly wrote right above your post?

Quench is a band aid for issues with the combustion chamber. It isn't voodoo or magic. It CAN help suppress detonation in a crap combo.

And yes, I've tested this enough that it became redundant and a waste of money.

I've run .150 to .030 quench and if everything else was correct, there was zero HP. Timing stayed the same...as in if an engine needed 42 degrees total timing it didn't matter where the quench was it still took the same timing.

I've been told that the blown alcohol Hemi motors need around 11.5 to 1 or higher mechanical compression to make good power with 30+ Lbs. of boost
I'm thinking of finding out on a wedge all aluminum street motor with a Pro Charger with EFI