Porting Heads

The 1UZFE EGR Delete Kit is available for sale here.
same reason they still burn petrol...

its cheap, and it works. plenty of other designs around, but they still wont have a great effect on the problems introduced to the intake port wave character and subsequent harmonics as demonstrated with the poppet
 
thanks...

v-eight is a bit nerdy, but i enjoy researching and reading all the higher-end tech/engineering stuff :) its nice to draw it together in an applied way there. slowly watching the site grow, its pretty satisfying

cheers
ed
 
poppet valves dont make any sense. no matter what lift you run, they are always in the way.
 
that doesnt make any sense either. i dont get it, how do you lose flow if you run more lift?
 
A simple way to illustrate is an aircraft wing, beyond a certain angle of attack the airflow can not stay attached to the curved upper surface, massive turbulence, no lift, aircraft falls from sky.

The port, valve shape and combustion chamber behave in a similar fashion, once the airflow detaches from the surfaces you get massive turbulence and less flow.
On a high velocity flow bench you don't have to read the gauges, you can hear the turbulence!
 
I joined V-Eight.com.au a couple of days ago and I expext to learn a lot.

I don't care how old you are you can always learn more.
 
A simple way to illustrate is an aircraft wing, beyond a certain angle of attack the airflow can not stay attached to the curved upper surface, massive turbulence, no lift, aircraft falls from sky.

The port, valve shape and combustion chamber behave in a similar fashion, once the airflow detaches from the surfaces you get massive turbulence and less flow.
On a high velocity flow bench you don't have to read the gauges, you can hear the turbulence!

now its starting to make sense. does all that apply to forced induction, knowing that the charged air in the intake will always try to escape to a lower pressure area should reduce the effects you talk about wouldnt it?
 
Top stuff that. I got into a barney last week with a guy who reckoned knife edge on valve stems was more efficient than blunt and that polished runners were better than slightly roughened. Even after trying to use the golf ball analogy I couldnt convince him... now Ive got proof!
 
the thing with forced induction is that you can be an inefficient chump of an engine designer, and whatever ineffeciencies exist can simply be overcome with a few more psi of pressure differenetial.

the flow character remains the same (or worse) but you you 'dumb' your way through it so to speak. interestingly its an uphill battle as the harder you push it, the more inefficient things will become, but some folks must try!

and your phrasing of 'charged air' in the intake is a bit wrong. what pushes the air into the cyls in an NA engine? 14.7psi of atmospheric pressure ;)
 
by charged air i refer to greater-than atmospheric absolute pressure. say 24.7 aPSI (absolute PSI).

the reason i ask that, is top fuel dragsters use much more than half an inch(around an inch i think) of lift. now i know those engines arent made for the street, but a setup like that would never produce any amount of power if they werent pushing a big air charge into the engine. my little theory is that high boost pressures overcome the turbulence because the law of pressure. simply forcing the air into straighter paths because the boost pressure.
 
Just bear in mind a Fuel Dragster engine would be hard pressed to do more than 2,000rpm in it's life.

In a normal 5 second run it will do around 650prm.

Think about it our engines will do that in 30seconds cruising down the freeway.

Another interesting thing with AA Dragsters is the cam is ground out of phase to allow for the twist it gets from the lift and tension of the valve springs.
 
Another interesting thing with AA Dragsters is the cam is ground out of phase to allow for the twist it gets from the lift and tension of the valve springs.

... and not just the cam!

Cranks are machined out of time end to end so what at full power the engine actually optimises the timings by twisting the crank straight!

How cool is that!
 


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