Wyrmrider
Well-Known Member
Quench: Unlocking Performance Squished Between the Piston and Head
somewhat self serving but ok to start a discussion
somewhat self serving but ok to start a discussion
I've known people who run .020 quench. I've never read one single time about .035 being minimum, but I have read that .035 is OPTIMUM in just about every article.
That said, Plenty of engines run without quench and make plenty of power.
Yes but it is also a matter of the cams size in order to reduce the dynamic compression ratio down to a pump gas level. Otherwise, you can run ether a mix of race fuel with it or E-85 as the octane rating is high.Can you run pump gas with quench @ that high of a compression?
I still don't get why Chrysler bothered to use closed-chamber heads on engines where the pistons are .050"+ down in the hole. Even the Magnums are .050" below deck, no quench to speak of in those. I bet if the pistons were at or close to zero-deck those engines could handle a full extra point of compression, heck the 5.9s had occasional pinging issues on low-grade gas and they were only 8.8:1.
I was complaining about that to friend of mine up the street who is a serious Ford guy and builds engines with his dad, he told me Fords don't really have that problem. They all came with essentially zero-deck pistons and compression ratio was determined by head chamber volume. It's not fair!! lol
I think it was Pontiac also did that, cylinder head cc thing.I still don't get why Chrysler bothered to use closed-chamber heads on engines where the pistons are .050"+ down in the hole. Even the Magnums are .050" below deck, no quench to speak of in those. I bet if the pistons were at or close to zero-deck those engines could handle a full extra point of compression, heck the 5.9s had occasional pinging issues on low-grade gas and they were only 8.8:1.
I was complaining about that to friend of mine up the street who is a serious Ford guy and builds engines with his dad, he told me Fords don't really have that problem. They all came with essentially zero-deck pistons and compression ratio was determined by head chamber volume. It's not fair!! lol
no one is saying you can't make hp with an open chamber head
In fact you might may make more top end than with a closed head
but the closed head will run much better when not rowing the gears
All I'm sayin is, quench ain't the end all be all that all the magazines and forum heroes make it out to be. Everybody reads all these articles in these magazines that have sponsors throwin expensive parts at them push. There's your clue. Those editors will say anything their sponsors want them too.
People go runnin out and spend all kinda money on a quench engine so they can push the boundaries of what pump gas will run on for what? 20 more HP? Ok, let's say everything is a great match and say 50 HP. Then, if they make one tiny mistake guess what? they have a big heavy expensive pile of metal that has to be spiked with race gas.
The bottom line is, you want to be safe on pump gas? Keep static no more than 9:1 and dynamic no more than 7.5.
There's a LOT more at play than "JUST" SCR and DCR. There's load, temperature, humidity, traffic, how good the cooling system is, how many fat women you're haulin around.......all that stuff can make an otherwise pump gas friendly not so pump gas friendly......and at the WORST possible time is when it WILL happen.
This right here is why we keep seein threads like "my engine is runnin hot" over and over and over and over again.
Boundaries are just that. With a 100% street car, they should be adhered to. Want that 9:1 motor to haul butt? Put good heads on it.
All true , but I like to quench them all. I ran a 426 hemi for 14 yrs with the pistons kissing the heads just enough to keep the carbon cleaned off at 6500 rpm, Tom Hoover said it was just right . Works for me , I have .039 on my 505, and have been running 91 octane , but have since found 93 , 3 miles from my house.
Strangely enough the new "kum and go" convenience store is right beside a new dodge dealer ship that sells hellcats, wondering if the dealership had anything to do with the 93 being sold there. First 93 I`ve ran across around here .
I had 160 thou quench Bob. Zero deck, .120" deep combustion chamber on the 906 heads and a .040" gasket. 160 thou.I believe Jim Laroy's made 700 plus HP without quench so it must not be real important.
All I'm sayin is, quench ain't the end all be all that all the magazines and forum heroes make it out to be. Everybody reads all these articles in these magazines that have sponsors throwin expensive parts at them push. There's your clue. Those editors will say anything their sponsors want them too.
People go runnin out and spend all kinda money on a quench engine so they can push the boundaries of what pump gas will run on for what? 20 more HP? Ok, let's say everything is a great match and say 50 HP. Then, if they make one tiny mistake guess what? they have a big heavy expensive pile of metal that has to be spiked with race gas.
I'm glad you could put in print what my jumbled mind thinks. How many projects are never completed or sold for pennies on the dollar because it has to be built a certain way and no other will work. Or so they are told. Not saying the other way is wrong, maybe just not right for the majority of people. I'd love to have a zero deck, flat top piston 360 with Edelbrock Magnums with all sorts of neat valvetrain pieces. But the stock 360 short block with pocket ported 587's and stamped steel rockers arms would get the engine in the car a bunch quicker and a whole lot of more smiles per dollar. IF the beater 360 could run 13's and the sophisticated quench engine ran 12's, which would be a bigger surprise to people? Thanks for letting me rant. No rights, no wrongs, just what the $$$ will allow.
I had 160 thou quench Bob. Zero deck, .120" deep combustion chamber on the 906 heads and a .040" gasket. 160 thou.