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#21
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dude, its all the same shit no matter if its done across the other side of the world.
The formulas and flow physics do not change coz some yank has calculated them. where its for a buick. subaru or a daewoo |
#22
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FYI This is what they are talking about and what the calculations are made for.
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[DBR] |
#23
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instead of getting all arty farty and devo about everything..
lets see some results cause i am honestly interested in seeing what this sorta of porting will achieve. Be cool if it made a difference and would also serve as a good "don't" for others thinking of the same route. mush i say |
#24
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Remember that comparing cross section areas only tells you a very limited picture.
(and for those playing at home all you need to do is d1^2/d2^2 - all that pi stuff cancels out... mmm pie) As you change cross sectional area you are changing the volume of the pipe (doubt there are any infinitesimally small pipes in an engine to stuff that statement up.). When volume is changes you must still fall true to combined gas law where: PV/T = constant, or simply P1V1/T1 = P2V2/T2. since the volume increases (i.e. V2 becomes larger) and temperature would stay constant in the 2 pipes, the pressure in the pipe will have to decrease. Now is a lower pressure in the pipe a good or a bad thing? I'll leave that one alone. My thoughts on porting and polishing are to remove any edges, roughness and irregularities in the pipe. Roughness increases fluid friction (bad), step changes form turbulent flows (badish - all depends on the scale of bad) and irregularities are bad too. Essentially in a perfect fit, there would be no flanges, just seamless joins to eliminate all these bad things. At the end of the day they would add up to very small gains, but sometimes those small gains are worthwhile. A back to back plot of ported vs unported would be awesome if anyone wants to do that
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[COLOR="Gray"]550Nm off a 2L... Just wish it was in the dak dak...[/COLOR] |
#25
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i understand exactly what a restrictor is, in turn - available flow in a given diameter of a pipe, restrictor or your pvc reticulation is the same, professor metro-testicle. Its why iv copied what they said on the thread as they applied the same calc. obviously ur gonna get a shit load more of losses.
I wouldnt of ported the turbo inlet if i hadnt already ported the standard up pipe. The larger cross-pipe has already proved itself for me, i gained more top-end with my previous tune with the vf-34 @ 20 psi- albiet slightly more lag becuase of the larger diameter in the x-pipe. |
#26
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Quote:
http://forums.nasioc.com/forums/show...unported+graph Last edited by waxdass; 26-05-2008 at 12:44 PM. |
#27
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Also, I hope you removed the roughness in the pictures you posted. The idea is to get it as smooth as glass.
Roughness increases the friction factor which is what you are trying to eliminate. You can see from a Moody diagram how roughness affects flow in pipes.
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[COLOR="Gray"]550Nm off a 2L... Just wish it was in the dak dak...[/COLOR] |
#28
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laminar flow is slower than turbulent flow. < increasing reynolds number.
This is because with laminar flow - there is more friction on the edges to the pipe. Last edited by waxdass; 26-05-2008 at 02:14 PM. |
#29
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Quote:
Turbulent flow only happens because the boundary layer friction increases. In piping up to Reynold's number of 2000 is usually laminar. As the velocity increases to greater than a Re of 4000 you have fully turbulent flow. Everything in an engine should just be considered turbulent flow. Leaving a rough surface just increases the wall friction making the flow more turbulent.
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[COLOR="Gray"]550Nm off a 2L... Just wish it was in the dak dak...[/COLOR] |
#30
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LOL I love this..
Tode is a Qualified Engineer, but John is a Doctor in Physics....CRIPPLE FIGHT!!! Here I've got a flow chart for you guys.. Port Up-pipe -> ???? -> Profit |
Tags |
job, port, rails, split |
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