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Wal
Dodge Dakota
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8/31/2004
15:20:15
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 Subject: porting TB
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Message:
what are you guys using to remove that "step" in each of the bores? I have been searching for a 2" dia. grinding stone to chuck into my drill press, but as it wears it won't stay true to size I guess. What else have you guys done? I could dremel it by hand but I was trying to keep it perfectly even.
Oh, almost forgot, I removed the upright pieces around the opening of the bores, and sanded the top smooth afterwards a couple weeks ago and the truck running GREAT. I even got better mileage on the highway :-)
Thanks in advance for any ideas or info. on this.
Wal
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prple-gaseatr
Dodge Dakota
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8/31/2004
23:13:50
| RE: porting TB
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what i used was a carbide tipped cutter for my die grinder, then, i used different sand paper to smooth it out finishing with 600 grit. when you use carbide cutters with a soft metal like aluminum, keep spraying the bit with alcohol to keep it from clogging
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Wal
Dodge Dakota
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9/01/2004
01:01:22
| RE: porting TB
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Hmm... alcohol. Do I use Thunderbird or Popov? What I pour the alcohol into me and then sweat on the bit? :-)
OK, I guess it is sounding easier to just use the die grinder instead of hunting down a big bit or stone.
As far as polishing to 600 grit, I thought you wanted a cross-hatch on the intake to get the air to tumble around a bit? I was going to use a brake hone on the bore when I was done. Thoughts?
Wal
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Bob Lincoln
Dodge Dakota
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9/01/2004
08:01:01
| RE: porting TB
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I think you want smooth, straight flow up to where the fuel is introduced, then swirl to mix well. So I would polish it up.
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Wal
Dodge Dakota
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9/01/2004
08:59:33
| RE: porting TB
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thanks, I knew it was beneficial but I didn't know at what stage of the game.
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TexasTodd
Dodge Dakota
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9/01/2004
13:13:31
|  RE: porting TB
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I used some dremel tool grinding bits,
you think that 'cross hatching' is going to do anything to the column of air, going thru whats usually a partially opened throttle body, or one that's opened full? I don't. Not when the 'cross hatching' is really just a mere what, 1/32?, if that?
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Tnjones
Dodge Dakota
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9/02/2004
16:55:44
| RE: porting TB
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Cross hatching or otherwise roughing the interior surface increases laminar flow (where the gas (air) flows against a surface). Polishing was discredited years ago through wind tunnel testing. If smooth and shiny gave better flow, Olympic swimmers would be wearing shiny latex suits instead of intentionally rough surfaced suits like they actually do wear.
The texture isn't just about improving mixture, it also improves flow. read http://www.winggrid.ch/ICAS_GROV.pdf
if you want a redicoulously technical explanation.
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Wal
Dodge Dakota
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9/02/2004
19:06:56
| RE: porting TB
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Wow, you confirmed what I believed to be true but that article is heavy. You should hand out No-Doze with your post ;)
TNX,
Wal
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N56629
Dodge Dakota
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9/03/2004
08:44:07
|  RE: porting TB
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That's an interesting article and it would be very applicable if we had carburators and trottle bodies that could fly. It would prevent stalls at high angles of attack.
I'm sure that under controlled conditions, there would be applications for this principle. However, I see no indication that random roughing of a surface would increase laminar flow.
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Tnjones
Dodge Dakota
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9/03/2004
16:10:20
| RE: porting TB
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Really? Ever seen the inside of a topfuel intake? What about the swimsuits? What's the difference between the flow over the outside of a wing and the inside of an intake?
Fluid dynamics are the same for a gas or a liquid and against an internal or external surface, bonehead. If you don't want to listen to those who have already done their research, then do your own or provide a credible source that contradicts.
Better yet, stay boneheaded so I can leave you in the dust.
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N56629
Dodge Dakota
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9/03/2004
18:50:42
| RE: porting TB
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Hey, dipstick, if you think rough surfaces are all the rage, in throttle bodies, I suggest you take a ballpeen hammer to yours. Maybe you can throw in a few vortex generators while you are at it. After all, they work great on airfoils. I bet you really go for those throttle body spacers with the fancy helical grooves. Same principle.
You offer absolute no proof that any old surface roughing will improve air flow in this particular application.
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slopehead
Dodge Dakota
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9/04/2004
10:15:03
| RE: porting TB
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I have two points:
1, alcohol is not recommended as a lubricate for machining anything due to its low flash point and invisable flames. Use kerosene, it has been a standard for over 50 years for machining Aluminum (but only aluminum) and is cheaper and easily available, even desiel fuel will workas it is very simular to kerosene.
2, roughing up a surface will not increase the amount of air flowing through a tube, but polishing will.
I own a machine shop and have built custom auto parts for certain "special" customers for over 20 years.
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prple-gaseatr
Dodge Dakota
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9/05/2004
07:51:40
| RE: porting TB
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-alcohol keeps the carbide tips from clogging with aluminum. its a hell of alot cleaner than kerosene. plus the alcohol evaporates rather quickly. it would suck to have kerosene all over you wouldnt it
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TexasTodd
Dodge Dakota
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9/05/2004
18:25:50
|  RE: porting TB
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If you crosshatched the entire intake, it may be something, you wouldn't notice it. HOw long is tha TB? 3 inches?
I sail a catamaran, and understand laminer flow, both on the sails and the hull.
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N56629
Dodge Dakota
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9/05/2004
19:24:51
| RE: porting TB
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"I sail a catamaran, and understand laminer flow, both on the sails and the hull."
The same is true with aircraft. Carbs and TB's, unlike these airfoils, never reach a critical angle of attack. Unless you can contruct a perfect airfoil, laminar air flow is of little consequence. If you can accomplish that, then a bicamber airfoil would provide more benefit than suface texture.
Bottom line, go ahead and polish the leading edge, but don't waste a great deal of time at it. Do your polishing in a lathe and don't attempt to do it free hand. You could make things worse than no polishing at all.
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clybon
Dodge Dakota
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9/06/2004
23:52:57
| RE: porting TB
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Olympics swimmers have BOTH slick surfaces and rough surfaces on there swim suits. When the ALL slick swim suits first came out swimmers complained that 1) could NOT feel the water 2) Could not PUSH off the water. SO.....swimsuit makers figured out that if you put the rough surfaces where it counts.... mostly on the bottom side of arms this gave the swimmers great push through the water and the slickness of scales on all other areas. Making the inside of the TB rough is a shi77y idea, you want less turbulance and you want the air to get to its destination with as little effort as possible.
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