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Quench: parallel or tapered squish area? #3009610
01/27/22 02:34 PM
01/27/22 02:34 PM
Joined: Mar 2007
Posts: 3,275
West Coast, USA
jbc426 Offline OP
master
jbc426  Offline OP
master

Joined: Mar 2007
Posts: 3,275
West Coast, USA
My current Indy EZ heads were a flat surface outside the chamber area, which made the flat quench pad on the piston have a parallel surface in relation to the head surface. My engine builder is recommending what he referred to as having the heads/chamber "softened" to enhance the combustion chamber and to further reduce the incidence of detonation when running north of 10 to 1 compression on California pump swill.

I haven't read much about that concept. Does anyone out here know of this concept?


1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
Re: Quench: parallel or tapered squish area? [Re: jbc426] #3009613
01/27/22 02:39 PM
01/27/22 02:39 PM
Joined: Dec 2021
Posts: 1,072
Loudoun County, VA
Brad_Haak Offline
super stock
Brad_Haak  Offline
super stock

Joined: Dec 2021
Posts: 1,072
Loudoun County, VA


2021 Challenger 6.4L Scat Pack 1320 (2022)
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
wheels, tires, air filter: 1.714, 11.833 at 115.80 (DA 310 ft)

1973 Challenger 452 ci street/strip (2008)
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
Re: Quench: parallel or tapered squish area? [Re: Brad_Haak] #3009705
01/27/22 07:06 PM
01/27/22 07:06 PM
Joined: Mar 2006
Posts: 9,791
MI, usa
dvw Offline
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dvw  Offline
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Joined: Mar 2006
Posts: 9,791
MI, usa
It appears that not many, if any have verified this concept. There's a difference between softening the chamber and tapered quench. Both done for different applications. Pretty high end stuff. That being said if you want to learn from one of the best. De-atomization of air fuel mixture in intake tract of IC racing engines. Here's part 1 there are 3.
https://www.youtube.com/watch?v=f8XG9T8v-ng
Doug

Re: Quench: parallel or tapered squish area? [Re: jbc426] #3009767
01/27/22 09:16 PM
01/27/22 09:16 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 43,007
Bend,OR USA
10.0 to 1 compression ratio with aluminum heads on a BB or SB Mopar V8 I wouldn't be the least bit concern with Detonation or Pre-Ignition as long as you run a cooler spark plug and not more than 36 degrees total timing twocents
What elevation are you at and what octane gas are you planning on running in the motor?


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Quench: parallel or tapered squish area? [Re: jbc426] #3009837
01/27/22 11:57 PM
01/27/22 11:57 PM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
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polyspheric  Offline
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Joined: Oct 2007
Posts: 4,205
New York
The quench surfaces need not be flat, parallel, or horizontal.
Most common use of matching tapers: aims the extruded charge mass toward the spark plug.
My 2-stroke H2 Kawasaki had 2 tapers (2 degrees different) opening as they move towards the bore center.
Actual hemi (geometric shape) may have domes contoured to match the chamber radius - the quench distance (plus some safety for rock-over @ TDC).


Boffin Emeritus
Re: Quench: parallel or tapered squish area? [Re: Cab_Burge] #3009849
01/28/22 01:28 AM
01/28/22 01:28 AM
Joined: Mar 2007
Posts: 3,275
West Coast, USA
jbc426 Offline OP
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jbc426  Offline OP
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Joined: Mar 2007
Posts: 3,275
West Coast, USA
I appreciate the input from you kind Mopartarians. Thank you.

Cab, I'm pretty much at sea level and I'm thinking of running California pump premium @ 91 octane and spraying 100 % methanol using a tuned Alkycontrol set-up metered by the Holley HP computer with the water injection add-on. I thought about going to E-85, but it is still not widely available as you get away from major urban areas. I like road trips.

https://www.alkycontrol.com/

By spraying Methanol, I'm thinking I can get away with 11 to 1 or a touch more with aluminum heads. The Holley HP will allow the use of knock sensors, but I still have a learning curve on adapting them to an RB. I never use heavy throttle below 3000 rpm, and that straight methanol makes a significant drop in air intake temperatures and bumps the octane pretty good too.

Is anyone running a similar set-up out there in this low octane world?


1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
Re: Quench: parallel or tapered squish area? [Re: jbc426] #3009897
01/28/22 11:29 AM
01/28/22 11:29 AM
Joined: Mar 2010
Posts: 1,060
Atlanta, GA
M
mgoblue9798 Offline
super stock
mgoblue9798  Offline
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Joined: Mar 2010
Posts: 1,060
Atlanta, GA
David Vizard has a Youtube video of him porting an old school small block chevy closed chambered iron head. He sloped the closed chamber part toward the intake valve on the intake side of the chamber. Left the exhaust side flat and claimed there was no benefit to sloping that area.







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