Ported Edelbrock versus W2 out of the box !

[PRH]

Where does the trend towards aluminum fit in with the quench issue.

Aluminum is a better thermal conductor than iron, so the “quench” portion of the quench/squish process is just more effective since more heat is pulled from the chamber into the cooling system.

In most racing situations, the lighter weight of the aluminum is just another added bonus.

I added another link in that earlier post that discusses the differences in quench/squish.

 

[Duane]

Quench dome piston for use with open chamber style heads:
The little dome fits into the open quench pad area of the heads.

So, there needs to be some planning involved so you end up with the little dome being within .040-.045 from the quench area of the head at tdc when assembled.
Getting the quench area of the heads equalized, and the correct depth, with the chambers at the correct finished volume for the desired final CR is usually the biggest challenge when going about it this way.

Much simpler with flat tops or inverted domes and closed chamber heads.

View attachment 1715269632

Thanks I missed that second link. That was a much better explanation.

 

[PRH]

For street stuff in particular...... quench is your friend.

 

[rumblefish360]

To anybody posting on this thread, and others...... the guy posting as PRH on here is one of the sharpest Mopar head guys in the country. Believe me
I hope nobody runs him off this board. His info is spot on and very helpful. Glad you showed up here Dwayne.

Carry on..... lol

LMAO! Yuip, I knew who I was talking to. I'll echo the above, glad your here. I hope you stay.

Rather than typing out a loooong response.......

What Is The Ideal Quench Height? - Hot Rod Magazine

Quench vs Squish:

Quench

The short version:



As I mentioned earlier, it can be done with open chamber heads, I’ve done it myself several times.
It’s just easier ....... and generally less expensive to achieve ..... with closed chamber heads.

OOOO, good read. Very good!

For street stuff in particular...... quench is your friend.

No doubt no doubt! Run it every time! This is how I can get away with what I did.

 

[Duane]

For street stuff in particular...... quench is your friend.

Thanks for the edumacation lol

 

[SS Lancer]

The valvetrain cost has always been a barrier to the w2 especially the long valve version.
I stayed with it because I made the investment to all the other needed specialty parts 20 years ago lol. Sort off all your eggs in one basket.
But if starting from scratch the edelbrock cost versus performance
Does look very attractive. The thing to remember is that the w2 was designed from the beginning as an all out race head and its original goal was to get the pushrods out of the way to make the ports bigger which required a dedicated valvetrain.
Having said that, I too am surprised at the performance levels some guys are getting with the edelbrock, especially Pittsburgh racer, getting high 9,s. Low 10.00s being very common with a stroker build.
Not sure how much benefit to the closed chamber in a stroker build.
Some closed chamber designs are shrouding the intake airflow.

Thank you Im kinda building a bastard motor # because of weight per cubic inch rules within my gasser group and wanted a small block of course so thats why Im doing this unusual build
90 over ( 4") bore 1968 318 block
NOS ( Bob Glidden ) 3.20 stroke crank
6.200 small journal rods
12.1 compression with Professionally ported rpm 340 heads
Tunnel ram 2-4 set up
It should be a nice motor with plenty of power for my Henry J with a Jerico.

 

[Duane]

For street stuff in particular...... quench is your friend.

So just to add to this, I was reading David Vizards how to build horsepower, and it explains that the benefit of a flat top piston is the rapid ignition of the flame front. For absolute best torque and horsepower (assuming good fuel) compression is still good, but not with a high dome piston that has edges at the top of the dome.
Apparently this high dome blocks the spread of the flame front and costs horsepower.
So barring octane requirements, a high compression motor (over 12:1) with a flat piston dome give best performance.
What I was saying before, is that achieving that ideal is easier to do on a stroker build because of increased swept volume(longer stroke).
Part of that ideal would be not to big of a combustion chamber as well. Interesting stuff.
He also said that a fuel mixture inside the quench/squish area cannot ignite until the piston is .100 away from the head. That explains why the ideal quench distance is .040- .060 depending on rod material.
and it's resistance to detonation on lower octane fuel.

 

[Wyrmrider]

I helped design and dyno the KB quench dome pistons
much easier than welding up the chambers
Quench- two parts
two cold surfaces
not enough space left for enough molecules to support combustion
push chamber closer to plug
SQUISH
turbulence and tumble and swirl
but you can have too much- blow out the fire
you can have less with high octane fuel or alky
goal is to get chamber - all points -as near the spark plug and the exhaust valve as possible
Tougher with a Big block except with the 413 Truck heads where the spark plugs come in from the top like a small block
as others have said you can get race high hp with an open chamber and high octane
Those comments on dome pistons are correct- we learned that with the 413 wedge- fire slots were a band aid
for the street quench and Squish rule

 

[Garrett Ellison]

I helped design and dyno the KB quench dome pistons
much easier than welding up the chambers
Quench- two parts
two cold surfaces
not enough space left for enough molecules to support combustion
push chamber closer to plug
SQUISH

 

[SwingerMan]

My W2 headed 408 made 532 hp / 540 tq on Mike @ Muscle Motors engine dyno. Only thing done to the heads was some bowl work. They are open chambered final compression is 10.75:1 running a solid flat tappet comp cam .597/.585 lift and 259/264 @ .050.

My Dart is a powder puff local cruiser all steel parts and a 3:55 rear gear. It went 11.20 @ 119 weighing just over 3600 lbs with me in it. Stock suspension on Springs n Things HD rear springs and a set of 235/60/15 Mickey ET streets. Car has more in it I just don't track it, only made 4 passes in the 8 years the motor has been together.