Fuel / Air Mixing Methodology

[Tobias Funke]

so some engines use special geometry at the top of cylinders, around the intake ports, to help mix fuel and air more efficiently

for example, please see this interesting article ( there's many like it that you can read online ) :

https://www.motortrend.com/how-to/cy...irl-and-tumble

i've saved an image attachment in case the link breaks

my question is, why isnt this just done in the manifold or carburettor ? it would seem easier ...

and if the answer is ' no difference ' then can we build our own for engines that dont already have it ?

[squirrelman]

" the time has come, the walrus said, to talk of many things.......

......of shoes and ships and sealing wax, of cabbages and kings."

[Tobias Funke]

Id have to guess that your interpretation of that story is different to mine lol

[6]

so some engines use special geometry at the top of cylinders, around the intake ports, to help mix fuel and air more efficiently

for example, please see this interesting article ( there's many like it that you can read online ) :

https://www.motortrend.com/how-to/cy...irl-and-tumble

i've saved an image attachment in case the link breaks

my question is, why isnt this just done in the manifold or carburettor ? it would seem easier ...

and if the answer is ' no difference ' then can we build our own for engines that dont already have it ?

JD would be the man on here to most accurately and with the most detail answer that question. But I would doubt he is going to, So, as a simple answer,

If you did that in the carb or intake port you would slow down/lessen the air getting into the combustion chamber. You want as much air as you can get in there (thus why you don't want T junctions, ribbed small diameter flexie hose, and the like between your smaller single carb and the intake port).


JD sells heads that he has designed that are ported to different degrees and with different valve sizes for different applications. They have been flow tested, dyno tested and are well proven..

If you are looking to make more power his heads are a good way to go. There are also his cams, cams, again, different cams for different uses, but they all get more air into that chamber..

Back to swirl.. the hawk has two spark plugs in each head.. Now, before you tell me that's so that if one goes bad you can still drive home (like carbs), that is to help burn faster and burn any un burnt fuel in that combustion chamber. Flam burns faster when you ignitie it at two points, which as you may have read is one of the goals of designing the "swirl" in there.


There have been many books written on cylinder head design. Probably not the best starting spot, but you don't seem to have much faith in learning things in the proper order

[Tobias Funke]

you've raised a lot bro ! i need to revisit as time permits in coming days to address it properly