ZE build thread

[93GT speeding]

http://forums.probetalk.com/showthread.php?t=1701149655

Just incase you don't see it in the Pic forum. There is a link to 3 pages of pictures of my ze build, and a small list of mods.

~chris

[diablovt6o]

I hate you......

[ddrop]

im curious to why you polished the intake side of the head as well as the intake runners...

[FWP!]

im curious to why you polished the intake side of the head as well as the intake runners...

I was wondering the same thing.

[93GT speeding]

They are ported a little then i polished them, and i did so because a smooth wider port is always gonna flow better then a one thats like 40 grit sand paper.

Anytime you buy aftermarket heads... the ports are machined, so they are smooth, it would be much cheaper just to cast them like a oem head.
Every little bit helps.....

[FWP!]

actually... smooth ports aren't good for mixture. It's good to have turbulance from rough walled ports to cause more tumbling of the air as it enters the chamber... the combustion chamber ITSELF can benifit from it tho.

[93GT speeding]

That might be true if your running a carb. but with fuel injection, as soon as the fuel gets sprayed into the air thats as mixed as its gets. Besides once it all gets in the combustion chamber, it really doesnt' matter, there is only a certain amount of fuel thats going to burn.
Infact look at Interprep pictures,
http://www.interpreptuning.com/images/DCP_0198.jpg
http://www.interpreptuning.com/IMAGES/DCP_0199.jpg
http://www.interpreptuning.com/IMAGES/DCP_0209.jpg

You will never find a race engine that has a rough intake,cumbustion chamber,or exhaust. Think of it like an airplane wing, a 1/32" of rough ice can make enough turbulance to cause a stall, when the wing is perfectly smooth, the air flows perfectly.

[FWP!]

A rough walled intake manifold and intake ports is going to be better than one with a polish on it. Interprep does leave theirs rough, like in the pictures, and from what I saw, you really polished yours up. Injected gas in an intake stream isn't as mixed as it gets. Even the new direct injection technology relies on swirls from the air coming around the intake valves to create an optimum charge when it mixes with the gas injected right into the cylinder. A rough edge on the incoming paths create a tumbling effect of the air, creating turbulance, which better mixes the gas and air for an even charge before it enters the combustion chamber.

Just my $.02

[JOSEPH PIERCE]

[ddrop]

A rough walled intake manifold and intake ports is going to be better than one with a polish on it. Interprep does leave theirs rough, like in the pictures, and from what I saw, you really polished yours up

There is a thing called a boundry layer. As you all know...fluid velocity at the walls is always 0. As you move from the wall the fluid velocity picks up until a maximum average velocity is reached. The distance from the wall to when the maximum average velocity is reached is the boundary layer.
In other words its a thickness layer that is effected by the friction of the wall. The thinner that boundry layer is, the more fluid is flowing through a port. A rough surface finish helps minimize this boundry layer. (This also explains why golfballs have them dimples in them )

[93GT speeding]

By no means am i trying to get an argument going, but if a rough surface in a head helps flow better, why would any aftermarket heads have a smooth or CNC'd finish. I mean look at any racing heads, and you will not find any with a rough finish. Just do a google search for performance heads, and you will see what I'm saying. If you look at Edelbrock, Trickflow, Dart, Ford Racing, whatever you want .. even the heads on a stock Ferrari have a smooth intake and exhaust port.

[Shawn93GT]

nice work

but can i ask who that posted in this thread actually has experience in the field of fluid mechanics?

[ddrop]

It depends of what you mean by experience.

I certainly have been at a professional machineshop enough to know of this effect. (ive been going there since i was a lil kid and have practically been living my winter weekends there...ask jay ). Flowbench tests have proven this boundry layer theory correct. When i recently had my headwork done, i did plenty of research on this topic. A polished intake will decrease ur velocity and be worse for fuel atomization(yes even on a fuel injected car such as ours).

I mean look at any racing heads, and you will not find any with a rough finish. Just do a google search for performance heads, and you will see what I'm saying. If you look at Edelbrock, Trickflow, Dart, Ford Racing, whatever you want

Alittle SMOOTHER...maybe...POLISHED ....NO. i have yet to see any of these heads or intakes you described with polished runners like you have on ur intake.


Here are some sites that may help you out a bit;

Intake and exhaust port surfaces are polished using different techniques. Intakes are finished with rotary stone in the die grinder which leaves a surface that is noticeably dull and rougher. In pre-flow bench times, everything was near-mirror finish. Flow testing done in the '60s and early '70s discovered that with intake ports, this finish was detrimental. A very smooth port wall causes much turbulence restricting flow in the main part of the air stream.

source:
http://www.idavette.net/hib/bbfh2.htm

http://forums.probetalk.com/showthread.php?t=1700954829

http://forums.probetalk.com/showthre...=boundry+layer

very nice article:
http://www.team-integra.net/sections...sp?ArticleID=9

http://forums.probetalk.com/showthread.php?t=1701140523 -theres a head archive i made a few months back after doing all my research.

[Shawn93GT]

<--- Mechanical Engineer i also have my PE and EIT licenses

[93GT speeding]

i have yet to see any of these heads or intakes you described with polished runners like you have on ur intake.

First of all .. look at the links i posted before from interprep, they look exactly like my heads. DPR Racing 6 cylinder toyota head Look at any other performace head, a cnc'd head has just as smooth of a port as what i made mine. Besides, you guys are just looking at one picture, i know how smooth it is, and you apparantly think its like a mirror and its not.

2nd... I never said I didn't understand or know about what your talking about because I do. Besides my father was the one advising me on what I should be doing, and since he designed performance fuel injection systems for GM and holds a few patents on them, and has more experince building racing motors then all of us combine im not to worried about what I did.

3rd... This is not why I started this thread, my intention was not to debate what I did, just to show some of the stuff I had done.
If you dont agree with what I did thats fine with me.