Aussie heads?
Freshman User
Joined: Mar 2002
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Aussie heads?
>but in the end its the reduction of the head volume and the
>shape that allows the higher cr to work with lower octane.
The quench design helps in as far as a cooler, smoother flame front that allows the mixture to be burned in a more controlled manner. Also with the quench on the chamber it causes turbulence in the cylinder as the piston closes the gap. This swirls and mixes the mixture and keeps it from detonating.
I'm sure that an engineer could explain this better and give you scientific reasons/formulas for why this works. But the simple fact is that a quench chamber can always run more compression and will burn more efficiently than an open chamber making more power. But for some reason it is harder to get a quench chamber to pass the smog requirements, at least in the distant past is was.
>shape that allows the higher cr to work with lower octane.
The quench design helps in as far as a cooler, smoother flame front that allows the mixture to be burned in a more controlled manner. Also with the quench on the chamber it causes turbulence in the cylinder as the piston closes the gap. This swirls and mixes the mixture and keeps it from detonating.
I'm sure that an engineer could explain this better and give you scientific reasons/formulas for why this works. But the simple fact is that a quench chamber can always run more compression and will burn more efficiently than an open chamber making more power. But for some reason it is harder to get a quench chamber to pass the smog requirements, at least in the distant past is was.
Senior User
Joined: Jan 2002
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Aussie heads?
The reason why quench heads have trouble passing emmissions is because as the flame front gets cooled down it leaves fuel unburned. Hence, there will always be unburnt fuel coming out the tailpipe of a car running quench heads (at least I'm pretty SURE that's why)
Tuned
Joined: Jun 2001
Posts: 266
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Aussie heads?
>Christian...LoL...we are disgussing this on 2 differant
>topics. But with Quench heads, and flat top pistons, you
>are going to get, 11:1 compression, (Or atleast VERY CLOSE)
>You can use 91 octane. Trust me I do it. I know it does
>not matter over the internet, becuase there is no way to
>prove it, but it can be done. I do it everytime I fill up.
>I am in the US, and I use 91 Chevron. no pinging...trust
>me...trust me...
>
>Jeff
What cam do you run?
>topics. But with Quench heads, and flat top pistons, you
>are going to get, 11:1 compression, (Or atleast VERY CLOSE)
>You can use 91 octane. Trust me I do it. I know it does
>not matter over the internet, becuase there is no way to
>prove it, but it can be done. I do it everytime I fill up.
>I am in the US, and I use 91 Chevron. no pinging...trust
>me...trust me...
>
>Jeff
What cam do you run?
Lead Driver
Joined: Nov 2000
Posts: 6,636
Likes: 349
From: Albuquerque
Aussie heads?
Might Mach, do you know what your static compression is? I'm running early 2v Cleveland head with custon dish pistons and get about 168 to 170psi. I think I'm around 10:1. Also running fine on 91 octane.
Bear Tracks
Bear Tracks
Senior User
Joined: Oct 2001
Posts: 268
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From: North Texas
Aussie heads?
Harder to get "quench" chambers to pass emissions because of what they do: they "Quench" the charge, causing unburned hydrocarbons because of the cooler chamber surfaces.
Correspondingly, they prevent detonation, by means of induced swirl as mentioned previously, thus allowing higher compression ratios with lower octance fuel.
But if someone REALLY had to have aussie heads, why not get some shipped from Aussie-land? The exchange rate is great (for us) and shipping by water ought to be reasonable.
Correspondingly, they prevent detonation, by means of induced swirl as mentioned previously, thus allowing higher compression ratios with lower octance fuel.
But if someone REALLY had to have aussie heads, why not get some shipped from Aussie-land? The exchange rate is great (for us) and shipping by water ought to be reasonable.
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Aussie heads?
I know cast iron is not the easiest metal to weld but has anyone ever tried to add metal to an open chamber head and re-machine it to the quench chamber shape? Maybe the added thickness would keep the cooling passages from absorbing heat properly. Just an idea.
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2v, 302, 302c, 91, aussie, australian, camresearchcorpcom, chamber, closed, closedchamber, ford, heads, octane, sale, wwwcamresearchcorpcom
