Porting/Dremel question
...94% correct.
Joined: Oct 2002
Posts: 1,283
Likes: 2
From: High Texas
Originally posted by andrew lohaus
this is realy only true of carb'd engines where the fuel/air mixture travels the entire intake track. on our cars there is only fuel in in the secondary runners of the lower manifold (below the secondary injectors). and while a mirror polish might be over kill and could possibly cuas a little fuel drop-out, you certainly dont want it rough. it should be atleast smooth to the touch.
and dont kid yourself that a rough surface keeps the fuel in the air. pop of your lower intake and look in the secondary runners. they are pretty rough from the casting and most likely slimmed with the varnish of accumated feul.
this is realy only true of carb'd engines where the fuel/air mixture travels the entire intake track. on our cars there is only fuel in in the secondary runners of the lower manifold (below the secondary injectors). and while a mirror polish might be over kill and could possibly cuas a little fuel drop-out, you certainly dont want it rough. it should be atleast smooth to the touch.
and dont kid yourself that a rough surface keeps the fuel in the air. pop of your lower intake and look in the secondary runners. they are pretty rough from the casting and most likely slimmed with the varnish of accumated feul.
A good portion of the intake tract does have fuel/air flowing through it.
Rotary Enthusiast
Joined: Jan 2003
Posts: 1,255
Likes: 0
From: fl
as i stated before, the primary runers (the middle 2) have no fuel in them until IN THE MIDDLE HOUSING right before the ports oppen up to the rotors. this is no more than the last inch of runner before it oppens.
the secondaries (outer 2 runners) have no fuel until the secondary injectors right at the end of the middle manifold (essentialy the beging of the lower mani) this only makes up the last 1/4 or so of the intake track (after the tb).
im am refering specificaly to n/a's tiis are possibly different.
while it may be overkill, a mirror polish will have NO EFFECT on the fuel mixture/atomization if it is done before the injectors, and its effect after them is debatable. this is why the manifolds were designed with bleed sockets and plastic diffuers. those are far more responsible for atomization (and at less detriment to flow) than casting imperfections.
the secondaries (outer 2 runners) have no fuel until the secondary injectors right at the end of the middle manifold (essentialy the beging of the lower mani) this only makes up the last 1/4 or so of the intake track (after the tb).
im am refering specificaly to n/a's tiis are possibly different.
while it may be overkill, a mirror polish will have NO EFFECT on the fuel mixture/atomization if it is done before the injectors, and its effect after them is debatable. this is why the manifolds were designed with bleed sockets and plastic diffuers. those are far more responsible for atomization (and at less detriment to flow) than casting imperfections.
...94% correct.
Joined: Oct 2002
Posts: 1,283
Likes: 2
From: High Texas
Originally posted by andrew lohaus
...this is no more than the last inch of runner before it oppens.
...this is no more than the last inch of runner before it oppens.
According to the "put a string through it, hold it tight, and measure it" method....6.25" of intake tract has fuel flowing through it.
Rotary Enthusiast
Joined: May 2004
Posts: 1,088
Likes: 0
From: OC
Originally posted by Falcoms
Hey, guys, you are not going for smooth when porting the intake ports on the engine, you want it rough to keep the F/A mix disturbed and mixed when it goes into the chamber. The exhaust, on the other hand, you want as smooth as can be so that there is as little back pressure to slow the rotor as possible.
Hey, guys, you are not going for smooth when porting the intake ports on the engine, you want it rough to keep the F/A mix disturbed and mixed when it goes into the chamber. The exhaust, on the other hand, you want as smooth as can be so that there is as little back pressure to slow the rotor as possible.
actually on carbd motors.. its reccomended that you DONT have glassy smooth manifold parts. the a/f mixture will condense and create loss of power
having a slightly rough surface creates microturbulence, which acts as a buffer between the metal and the fast moving air stream in the intake manifold, if you can imagine it, like wheels on a car, the car rolls by while the wheels are going every which direction, and the ground never moves.
Windsor, Ont
Joined: Sep 2002
Posts: 1,175
Likes: 0
From: Windsor, Ont
Originally posted by razorback
got the bits today. here is a photo with a quarter. not as big as i thought they were. but they will work. cant complain for 10$
got the bits today. here is a photo with a quarter. not as big as i thought they were. but they will work. cant complain for 10$
Thread
Thread Starter
Forum
Replies
Last Post
Adaptronic S5 Turbo PNP Unit questions
_Tones_
Adaptronic Engine Mgmt - AUS
10
May 25, 2021 05:37 AM
Nosferatu
2nd Generation Specific (1986-1992)
7
Sep 5, 2015 02:13 PM
