Keith

I've also heard that the exhaust port should be polished so that carbon buildup in the little nooks and crannies is prevented.

1CAMWNDR

iTrader: (21)

MAC4264

Some of you are confusing port design, turns and angles with something else. Vortex generators change the direction the air goes, in simple terms. Do not confuse shape, turns etc. with a finish. To me a golf ball moving in the air with drag is different than air and fuel being vaccumed. Aerodynamics plays a role in the golf ball and has a small effect in the vaccumed sitiuation. Not saying you can not use some of the ideas but there is a difference. Air moves faster than fuel, therefore there is a separation between the two in the port at some point. The term is best descrbe as Limiting Port Velocity. IMHO I think there is nothing to be found in the texture of the intake ports. I have seen ports that are rough on one side and smooth as glass on the other side with puddy. Who cares how pretty it is when installed on the motor as long as it makes power. There are show cars and there are race cars.

TAQuickness

iTrader: (28)

I got to thinking about this thread right after I got done porting my Fast90...

Within a cylinder head, a rough (non-polished) finish in the intake runner will increase flow.

Does the same hold true in the intake manifold? Based on head flows, I would think there is some to be gained by texturing the intake runners in the manifold.

Richiec77

iTrader: (3)

And, would this follow true for a T.B. also? If the air is being directed like a cone, would there be less need for the increase in laminar flow? It is being directed unlike the golf ball.

Lasershop

iTrader: (2)

Next we all will be sanding down the body..... 80 grit... maybe the side windows.

1CAMWNDR

iTrader: (21)

I think the throttle body and intake manifold need as smooth a surface as possible since they do not have fuel in them. The slightly rough surface in the intake port is to cause a small amount of turbulence to keep the fuel suspended in the air stream.

FRANZ

I have always been under the impression that the air that hits the "ripples " in
the port tumbles, cousing a increase in velocity for the air flowing over it.

Kind of like a roler bearing affect.

FRANZ

This also aids in fuel atomization. Without texture in the port you would
have puddles of fuel running down the walls, not suspended in flow.

Richiec77

iTrader: (3)

Have you guy's read most of this thread? The Ripple as rough area's are meant to increase the flow of Laminar air.

matty169

I'm A Tech Inspector For Two Racing Associations. Heres The Scenario. End Of Season, Big Money Race, Using Spec Engines. One Car Is Obviousy Faster Than Everyone Else, While All Year He Was Slow. Upon Inspection It Is Revealed That The Entire Floor And Walls Of The Intake Are Dimpled, Much Like A Golfball. We Confiscated The Intake, Ran Back To Back Tests On Two Different Engines On Superflow Dyno Swapping Intakes Between Tests. Exact Same Intake, One Dimpled, One Not. Both Intakes Port Matched To The Heads. On These Two Engines The Dimpled Intake Made 23.9 And 23.2 Hp More. All Else Being Equal. Take It For What Its Worth. This Was Performed On Engines In The 650 Hp Range.

ronbros

AH! the heck with it, just pump 20 boost into the ports and you will forget about what they look like, try it you will believe it. I have been watching this port shape business for 50 yrs , all the cams, all the pistons, rods, cranks , heads, carbs, injectors,ignitions,exhausts, nothing feels more better, he-he, than pressure in the intake. RON

MAC4264

Matty169, if the intake was not supose to be modified in any way. Maybe it was ported and the acid dipped (looks stock). Does the two intakes hold the same volume. Next it would be interesting to know what the flowed.

TrendSetter

i ported those. they are a carbide finish...we do that on purpose on a lot of our intake ports. the exhaust side gets a full polish, but nothing like a mirror, more like the intake ports that most people do.
also to note that runner is NOT a full race port, it is from a budget head, very close to what most would call a 'stage 2.'

ronbros

HOW about direct chamber injection, would that change a lot of ideas on ports, but back to the old fashioned way , cnc grooves linear down the length of the inlet port then in the bowl the lines would start a swirl just below the seat so as to spin the air out of the valve area. that would also help swirl in the chamber. thats my thinking RON

Spinmonster

A golf ball uses the dimpled texture to increase air flow around it to make it go farther when its in the air. Makes you think that the smooth surface may not be the best for direct5ional airflow. Most heads only take into account airflow disruption from an obsticle.

TAQuickness

iTrader: (28)

CamTom12

iTrader: (1)

The argument for a textured surface has so far not involved suspending fuel... We're mainly talking about 'pulling' the air around corners.

Fluids (dry air, before fuel is introduced, is considered a fluid in the engineering world because it has the same flow properties as a fluid) want to flow straight, and fight towards tangents in a corner. Using the rough surface as a drag it helps pull the air around the corner quicker (like using the rear independent brakes on a tractor to help turn sharper). Who wants to borrow my old Fluid Dynamics textbook?

off topic - I like the new 'Practical Engineering' forum, NineBall!

1CAMWNDR

iTrader: (21)

I see. I see. So with the throttle body do we need a rough textured surface since there is no corner to turn? It is just straight into the intake manifold.
And the LS1 has a pretty straight intake port in the heads, so would it be of benefit to only have the textured surfafce at the short side radius, and smooth through the straight port?

matty169

no it was not acid dipped, this pattern was very obvious and looked like it was done with a 5/16 or so drill bit. Someone had alot of time involved. Engine builder tried to tell us that the intake was insalled by accident and he wanted us to sell it back to him. That didnt happen and they were fined. Inside of intake ports all micrometered the same and passed other tests. Casting marks inside intake were still visible and nearly identical.