In your opinion, who has the best combustion chamber?

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Okay, how about this: if someone had a nice 440, stock stroke and went from 84cc rpm heads to victor heads ( both standard opening), what could you expect?

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Gen 3 Hemi

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The OP said big block and eliminated all the serious race stuff. He also just asked about combustion chambers, which is sort of odd, when there's other things much more pertinent to making power. The BS comes in about 65cc and when CNC'd about 75, which is about where you want to be with a flat top piston.

AFAIK, none of the common Mopar heads come with semi finished chambers so they can be properly CNC machined, as is SOP with serious stuff, but the BS is probably best suited to this, for the reasons I mentioned.

Would that be what I recommend? No, I have a set of Victors for the engine that's going to the step down from the B-1. That would be my suggestion at present. S/F....Ken M

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"modern" combustion chamber "design"

hmmmm

turbos are modern. oh wait they were designed in 1905. over 100 years ago lol.

get off the modern thing and think instead.

the shape of a combustion chamber is only going to change things minutely. what really matters is flow, velocity, compression ratio, etc. quench/squish/all that crap comes into play if you are not using race gas. if it's a street engine then you are limited by fuel.

if you have lots of E85 available local to you then you can go 12.5:1 compression.

that being said, the heads with raised ports will outperform the stock sized port heads every time.

so W9's and Victors and some others with raised ports will eat up the other ones, especially at higher rpms. combustion chamber design has little to do with this. but if you are on the street you are not going to be runnin around at 7200 rpms and stuff.

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run at 11:1 on pump gas and make power without a huge cam to vent cylinder pressure out the exhaust at lower engine speed.

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inform this

"variable cam timing" in the gen3

I wonder what that does?

and the LS7 "Variable valve timing (VVT) is a standard feature on 6.0L and 6.2L engines"




it's pretty much standard on 11:1 pump gas engines

it has nothing to do with production of power, it's rather for the prevention of knock.

the thread starter will probably not find a variable timing camshaft for his BB mopar. that being said he should probably go with raised ports if he wants all out power. combustion chamber design and flame travel has very little to do with power. they are to prevent knock/detonation.

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A technique used to prevent the onset of knock is the high "swirl" engine that forces the intake charge to adopt a very fast circular rotation in the cylinder during compression that provides quicker and more complete combustion. It is possible to manufacture gasoline engines with compression ratios of over 11:1 that can use 87 (MON + RON)/2 (octane rating) fuel with the addition of variable valve timing and knock sensors to delay ignition timing. Such engines may not produce their full rated power using 87 octane gasoline under all circumstances, due to the delayed ignition timing. Direct fuel injection, which can inject fuel only at the time of fuel ignition (similar to a diesel engine), is another recent development which also allows for higher compression ratios on gasoline engines.

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run at 11:1 on pump gas and make power without a huge cam to vent cylinder pressure out the exhaust at lower engine speed.

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inform this

"variable cam timing" in the gen3

I wonder what that does?

and the LS7 "Variable valve timing (VVT) is a standard feature on 6.0L and 6.2L engines"




it's pretty much standard on 11:1 pump gas engines

it has nothing to do with production of power, it's rather for the prevention of knock.

the thread starter will probably not find a variable timing camshaft for his BB mopar. that being said he should probably go with raised ports if he wants all out power. combustion chamber design and flame travel has very little to do with power. they are to prevent knock/detonation.

Quote:

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A technique used to prevent the onset of knock is the high "swirl" engine that forces the intake charge to adopt a very fast circular rotation in the cylinder during compression that provides quicker and more complete combustion. It is possible to manufacture gasoline engines with compression ratios of over 11:1 that can use 87 (MON + RON)/2 (octane rating) fuel with the addition of variable valve timing and knock sensors to delay ignition timing. Such engines may not produce their full rated power using 87 octane gasoline under all circumstances, due to the delayed ignition timing. Direct fuel injection, which can inject fuel only at the time of fuel ignition (similar to a diesel engine), is another recent development which also allows for higher compression ratios on gasoline engines.

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