TB Porting?

[Camarowguy]

Here we go again. Everyone is entitled to their own opinion. But have of the opinions I just read are not fact. Just what someone thinks. Your an engineer? That means you know everything right? No. Your human. Just like doctors that misdiagnose people. Trust me, I know. Just because you have a title doesn't make it true. I was misdiagnosed several times last most and ended up having to be hospitalized because of it. Every doctor had their opinion and most of them were different. My point, just because you say it's so, doesn't mean it is. Your splitting hairs with this anyway. Your trying to say a polish tb makes more power. And then a spiral ported tb makes more power. I'll bet you money you could test three different tb's, polished, spiraled and hand ported with a semi smooth finish....won't be any difference as long as the shape and size are the same. Why? Get a velocity probe out and measure the airflow against the wall....you'll notice real quick there isn't much going on right next to the wall. It's called a boundry layer. Research it. Test it. Then post back. Fluid flow is a different ordeal and cannot be compared to airflow. Also, roughness on cylinder head intake ports is not for or against airflow. It's actually to keep fuel from sticking to the walls when the engine is cold.

[RX SS RACERX]

Not an engineer but last year I ordered a V-Max CNC from Pete. I could tell that he really enjoyed the challenge of improving the OEM TB. He gave me a lesson in airflow etc.-lost me about half way thru. At the time it was just going to be an inquiry but I was so impressed with the time he took and genuine interest that I purchased on the spot. I have no dyno numbers b/t smooth/hand or CNC or whatever but I can assure you the butt dyno and my ears noticed a 'change'. It didn't get slower! Definitely felt quicker thottle response. With the big dollars spent on my other mods I felt this was a bargain at $150. Just my 0.02.

[GTAHVIT]

I dont' think any one is disputing the benefits of a ported/polished TB.. I think we're debating the method... does one method really improve performance over another method?

from my perspective... as a non expert I can't imagine that it does at least not much.

But we all can agree that any ported TB will be an improvement over stock... yes?

[Nomad]

My issue is with someone coming on here, implying that the data provided by a manufacturer is faked ("make a dyno say whatever I want"), then stating that the same method will be used to prove how great his product is. So, I guess my question is, if one set of dyno numbers are faked, why would the second ones be valid?

[Camarowguy]

Originally Posted by White-2-SS

being the power gains are so small I think engine temp,air temp and humidity. Is the most important when comparing TB's to each other. Any one that has spent some time around a dyno should know this.

what he said^^^^

[SC2150]

Originally Posted by GTAHVIT

So let me see if I get what you are saying...

The "rougher" surface on the intake runners which causes the tumbling, helps to atomize the air/fuel mixture? Where the TB is only moving Air.. so since it is only moving air, to allow for max airfow, it should be smooth?

If that is what you are saying it makes sense to me.... Not that I'm qualifed to say right or wrong.


But I can follow your logic.

Tell you what. Call Darren Morgan at Reher Morrison (he will take your call). Involved in R&D from the first LS cylinder heads for GM before the release in 1997 and one of the most respected flow engineers on the planet. Author and involved in some of the highest HP per CI drag and pro stock motors in the world as well as everything up to IRL cars. He can show you ultra high speed wet flow bench video in slow mo to illustrate and it is all measured on their wet flow bench.


The texture breaks the surface tension allowing greater velocity thus greater volumetric efficiency. Mirror smooth actually causes turbulance and lower effiecency and slower velocity. I have been building race and performance engines for over 35 years and Pete Incaudo even longer. Ask Tony Mamo from AFR and every inch of the runners in intakes & cylinder heads as well as the anti-reversion spacers.

We went through all this misconception back in the 70's when we would spend hours after a port job polishing every inch of the flow surface to a mirror finish in the mistaken thought that it would help the flow, but it did just the opposite. It casue friction of the air mixture molecues and alonf the smooth surface the floww was slower than the center of the ports and the turbulence caused severly affected the power produced. The top cylinder head & intake manifold manufacturers today found this out by accident when thrashing to get ready for a race and leaving the ports rough....the HP increase was substantial and puzzeling at the same time. The less surface area for the molecues to touch and "stick" to the greater the velocity of the flow and thus more fuel/air entering the combustion chamber. On the short side radius we go even rougher.

Reher Morrison is perhaps the most respected race engine builder in the US, at least right there with amoung the top ten.

The website is: www.rehermorrison.com Call. David Reher is the owner and Darrin Morgan the porting genius. Or call Tony Mamo...another greatly respected port & flow engineer.

It is a waste of time to argue here and confuse everyone with assumtions when all this is available for anyone that wants to take the time to do a little research.

My background?

Over 35 years of building race and performance engines.

Engineer and machinest by trade.

Owner of one of the winningest big $ bracket teams in the Eastern US for over 7 years.

Multiple Divisional, National, and World championships in both NHRA & IHRA in numerous classes.

Featured in multiple mainstream performance magazines over the years with several cover features of street builds up to 1200hp & above before many were anywhere near that HP.

So, if you want to debate this please list your qualifications and the facts and references to back it up or we are just wasting everyones time with this crap.

Here are some excerpts from publications on modern porting:

Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve the quality and quantity of the air flow. Cylinder heads, as manufactured, are usually suboptimal due to design and manufacturing constraints. Porting the heads provides the finely detailed attention required to bring the engine to the highest level of efficiency. More than any other single factor, the porting process is responsible for the high power output of modern engines.
This process can be applied to a standard racing engine to optimize its power output as well as to a production engine to turn it into a racing engine, to enhance its power output for daily use or to alter its power output characteristics to suit a particular application.
Daily human experience with air gives the impression that air is light and nearly non-existent as we move slowly through it. However, an engine running at high speed experiences a totally different substance. In that context, air can be thought of as thick, sticky, elastic, gooey and heavy (see viscosity). Pumping it is a major problem for engines running at speed so head porting helps to alleviate this.

The "Porting and Polishing" myth
It is popularly held that enlarging the ports to the maximum possible size and applying a mirror finish is what porting is. However that is not so. Some ports may be enlarged to their maximum possible size (in keeping with the highest level of aerodynamic efficiency) but those engines are highly developed very high speed units where the actual size of the ports has become a restriction. Larger ports flow more fuel/air at higher RPM's but sacrifice torque at lower RPM's due to lower fuel/air velocity. A mirror finish of the port does not provide the increase that intuition suggests. In fact, within intake systems, the surface is usually deliberately textured to a degree of uniform roughness to encourage fuel deposited on the port walls to evaporate quickly. A rough surface on selected areas of the port may also alter flow by energizing the boundary layer, which can alter the flow path noticeably, possibly increasing flow. This is similar to what the dimples on a golf ball do. Flow bench testing shows that the difference between a mirror finished intake port and a rough textured port is typically less than 1%. The difference between a smooth to the touch port and an optically mirrored surface is not measurable by ordinary means. Exhaust ports may be smooth finished because of the dry gas flow and in the interest of minimizing exhaust by-product build-up. A 300 - 400 Grit finish followed by a light buff is generally accepted to be representative of a near optimal finish for exhaust gas ports.
The reason that polished ports are not advantageous from a flow standpoint is that at the interface between the metal wall and the air, the air speed is ZERO (see boundary layer and laminar flow). This is due to the wetting action of the air and indeed all fluids. The first layer of molecules adheres to the wall and does not move significantly. The rest of the flow field must shear past, which develops a velocity profile (or gradient) across the duct. For surface roughness to impact flow appreciably, the high spots must be high enough to protrude into the faster moving air toward the center. Only a very rough surface does this.
A developed velocity profile in a duct that shows why polished surfaces have little effect on flow. The air speed at the wall interface is zero regardless of how smooth it is.



MethodsThe die grinder is the stock in trade of the head porter and are used with a variety of carbide cutters, grinding wheels and abrasive cartridges. The complex and sensitive shapes required in porting necessitate a good degree of artistic skill with a hand tool.
Until recently, CNC machining was used only to provide the basic shape of the port but hand finishing was usually still required because some areas of the port were not accessible to a CNC tool. New developments in CNC machining now allow this process to be fully automated with the assistance of CAD/CAM software. 5-Axis CNC controls using specialized fixtures like tilting rotary tables allow the cutting tool full access to the entire port. The combination of CNC and CAM software give the porter full control over the port shape and surface finish.
Measurement of the interior of the ports is difficult but must be done accurately. Sheet metal templates are made up, taking the shape from an experimental port, for both cross-sectional and lengthwise shape. Inserted in the port these templates are then used as a guide for shaping the final port. Even a slight error might cause a loss in flow so measurement must be as accurate as possible. Confirmation of the final port shape and automated replication of the port is now done using digitizing. Digitizing is where a probe scans the entire shape of the port collecting data that can then be used by CNC machine tools and CAD/CAM software programs to model and cut the desired port shape. This replication process usually produces ports that flow within 1% of each other. This kind of accuracy, repeatability, time has never before been possible. What used to take 18hrs. or more now takes less than 3hrs.
Valves and valve seats are ground with special equipment designed for this purpose.
[edit] Summary

The internal aerodynamics involved in porting is counter-intuitive and complex. Successfully optimizing ports requires an air flow bench, a thorough knowledge of the principles involved, and engine simulation software.
Although a large portion of porting knowledge has been accumulated by individuals using "cut and try" methods over time, the tools and knowledge now exist to develop a porting design with a measure of certainty. Porting by inexperienced individuals without a full understanding of the fluid dynamics of the process still continues but the results are spotty and the process is expensive and time consuming with many more failures than successes[citation needed].
[edit] References

1. ^ [Bamsey, Ian. "Grand Adventure." Race Engine Technology Issue 035: 16. ..I guess ferrari and mclaren will be begging at twr's door hat in hand for the super secret to 265 bmep? I won't hold my breath because its pure garbage! No shitbox rally car with all its air filters will ever achieve those numbers and any decent RPM -motorhead ]
2. ^ Superflow flow bench manual

[edit] External links

• Free demo engine simulator used to generate graph above
• Cylinder head porting techniques
• The Brzezinski "UnderCover" Cast Iron Cylinder Head Porting Technique
• A 5-axis CNC cylinder head porting machine in action.
• An Overview of Power Sport Cylinder and Head Port and Polish.
• A number of articles about porting.
• Kinematic Models for Design Digital Library (KMODDL) - Movies and photos of hundreds of working mechanical-systems models at Cornell University. Also includes an e-book library of classic texts on mechanical design and engineering.

[CC Performance]

Originally Posted by GTAHVIT

I dont' think any one is disputing the benefits of a ported/polished TB.. I think we're debating the method... does one method really improve performance over another method?

from my perspective... as a non expert I can't imagine that it does at least not much.

But we all can agree that any ported TB will be an improvement over stock... yes?

the biggest difference in numbers will be a result of the different dynos used

[SC2150]

I also wanted to add that any that have visited my shop have seen the dgrees, certifications, and accomplishments on display in the lounge. I have been doing this my whole life and am in my mid 50's. Pete Incaudo has several years on me and a far more impressive resume. Remeber. We had been hand porting the LS TB's and intakes since 1997 when they were first released and sold a ton of them. It was Pete that came along with the idea of using the same textured porting on the TB's. We spent months on our enclosed, climate controlled dyno duplicating run conditions as closely as possible and tons of trial and error before he perfected the LS1/6 design and it was amazing. Greg lovell and Mike Norris were the hands on testers in working with pete to develope the LS2/7 and LS3 versions we have today. If it wasn't science we would still be porting by hand.

More reading:

A recent porting improvement is turning
the grinding over to a CNC robot.
Such computer numerically controlled
machining offers several porting advantages,
but the main ideas are the CNC
machine is extremely accurate, able to
replicate the same port every time, precisely
place the port relative to the valve
no matter how variable the cylinder casting
and via its accuracy and repeatability
can generate textures a human cannot.
Thanks to its accuracy and surface
texture, a CNC ported cylinder head
slightly outperforms the same level of
hand porting, according to Ly-Con. The
improvement is mainly in the intake
port, where the CNC machine leaves a
series of visible steps that act like golfball

dimples, breaking and bending the

boundary layer more sharply than the
smoother texture of hand porting.
On the exhaust side, Ly-Con polishes
the CNC-generated steps out because
they give exhaust residue a perfect toehold.
Thus, the reduction in carbon
buildup trumps the airflow improvement
from the steps.
About the only disadvantage to CNC
porting is extra cost. It takes a machine
capable of cutting in at least four axes,
and it’s better to have a five-axis CNC
machining center to replicate human
arm and wrist motion. Such machines
represent an investment far in excess of
six figures, so the payback has to come
from somewhere.
In fact, the high cost of CNC head
porting has severely limited its migration
from the relatively high-volume hot

rod automotive universe.

[CC Performance]

Well we're going to put one of TB's on the OP's car and have it dyno-ed at a very well respected shop. Wongs Performance Engineering.. Tommy is very well respected in the Corvette community and will provide the before and after for us. He has a mustang dyno and should have a few different vehicles to test it on for us from a Camaro to a C6 Z06 show we should get a good cross section of results from modded to stock. We will of course post up the results. I've been turning a wrench since 1974, this isn't my first rodeo...LOL We will put it to the test and see what we get, thats the best way I know. The TB is on the way to me as I type and the OP and I have already talked and Tom is ready to go as well. Hand porting is an art, some of the most desired porters in the world hand port their heads. Cnc is a production process that ensure the same results each time provided there is no core shift. Its as good as the person who designs the program and there are people very good at it as well. Tony Mamo hand ports heads for people who want more out them. He takes it beyond what the cnc machine does from AFR. Tony and I have spoken many many times, he has done work for me personally and my customers as well. Richard from WCCH uses the cnc and cad cams his designs and does very well.. I have some of his heads on my car as well. Both methods are proven to be very good, it comes down to the person doing the work/designing the program.

Just a reminder here we're talking about a throttle body.

[Scruffage]

Originally Posted by SC2150

The texture breaks the surface tension allowing greater velocity thus greater volumetric efficiency. Mirror smooth actually causes turbulance and lower effiecency and slower velocity.

The less surface area for the molecues to touch and "stick" to the greater the velocity of the flow and thus more fuel/air entering the combustion chamber. On the short side radius we go even rougher.

[SC2150]

TIP #8 ALTERNATIVE TO POLISHING, THE TEXTURED FINISH


THE TEXTURED FINISH ARGUMENT
It is often thought that enlarging the ports to the maximum possible size and applying a mirror finish is what porting is. This in not always the best aproach. A few ports may be enlarged to their maximum possible size (in keeping with the highest level of aerodynamic efficiency) but those engines are usually only found in the higher echelons of racing and world record setting, where the actual size of the ports has become a restriction. Larger ports flow more fuel/air at higher RPM's but sacrifice torque at lower RPM's due to lower fuel/air velocity, so it is critical to bear in mind the "end results" you wish to work towards. A polished finish on the port does not provide the increase that one might assume. In fact, often within certain intake systems, the surface is intentionally textured to a degree of uniform roughness to allow for fuel deposited on the port walls to evaporate quickly, due to the increase in surface area. A rough surface on particular areas of the port may also alter flow by energizing the air boundry layer, which can alter the flow path to a large degree, theoretically increasing flow. This is similar to the way dimples on golf ball are inteded to work. Flow bench results shows that the difference between a mirror finished intake port and a rough textured port is typically less than 1%, which can be argued is negligeable. There is no difference between a port finish that is smooth to the touch and one that is mirror finished as far as CFM flow, but it is velocity of that flow that makes power. Exhaust ports can be a different subject and it may be useful to give them a smooth finish because it will reduce the dry gas flow and exhaust by-product build-up. Medium grit cartridge rolls across the surface with a light buffing works quite well on the exhaust port side.
PORTING " HOW TO " for intakes and cylinder heads

ANY surface or component that air and air/fuel mixture travels through the principal applies to.

This is all proven science and I can keep listing all the reference material and actual facts vs opinons and "because I did it" opinions.

[edog]

Where is the other guys #2 post?

[TAG UR IT]

Originally Posted by White-2-SS

^^^ Must have got nuked. It happens around here. Why is it that all of the aftermarket cold air intakes have a smooth tube if a textured surface breaks tension and is so much better. That 3inches of surface change is not gonna make that big of a difference. I can not wait for TSP to post up the results.

Oh? You sure about that?...

You know...it seems as though someone likes to complain quite a bit about how this board is run....

For the record, the only post that's been "nuked" in here was done by Bonemaro to his own post. No other posts have been "nuked" by anyone...mods or members. ....And you know what they say about people who make assumptions...

[Scourage]

boundary layer

Like airflow over an aircraft wing,