port and polished heads
#1
port and polished heads
are there any ball park price figures for port and polish on heads? trying to decide which way to go and just wanted to know how much it would be to have my heads P&P.
#4
Aftermarket heads are better but $800 who are you guy's going to? shop around here charge bout $400-500 a set depending on what you really want done, probly $500 for port match and pocket port on flow bench, maybe a little more if you raise and reangle the ports, like i did to mine, and these are good shops! but if you port them dont polish them. Have the shop run it rough, if the port is smooth the air sticks to the walls and causes drag, if its rough it creates air pockets along the walls that dont move, this is what us tuners call air push. This keeps the flowing air off the walls for better flow and volocity
#6
Never heard that before. Air flows better when the walls are smooth. Why would you want air pockets? Isnt that what happens when you remove the swirl dams which is bad. Its a bad way to increase air flow and makes the car hard to tune.
#8
You only want the exhaust ports polished this way carbon doesn't build up. The point of a rough intake tract is two fold:
1. The rough surface atomizes the fuel (more important to carb'ed engines).
2. It reduces friction between the air and surface. Remember, the greater the surface contact between surfaces, the greater the friction. Think of it as slicks vs. street tires. Slicks have a greater surface contact and therefore generates more friction w/ the ground.
1. The rough surface atomizes the fuel (more important to carb'ed engines).
2. It reduces friction between the air and surface. Remember, the greater the surface contact between surfaces, the greater the friction. Think of it as slicks vs. street tires. Slicks have a greater surface contact and therefore generates more friction w/ the ground.
#9
he is correct for race applications. On the intake side the polishing isn't terribly useful but you don't want to leave it rough cut. It needs only the slightest scratching of the walls to acheive the pressure differential that spawns the air-push effect. This is the reason golf ***** have liittle tiny dimples all over. It allows the air to form pockets of zero friction where moving air will just glide over without rubbing against the walls and lets the ball fly farther. Think of it as a bearing made of air.
All in all air doesn't behave intuitively. If you want it to turn you push it in the opposite direction you want it to go. It'll naturally resist that direction change and go the other way.
You pay what you pay. I paid almost nothing. My porter is a race head porter and charges 800-1000 bucks or more for a similar job as he's doing to mine. What I look for is someone with an innate understanding of how air reacts to attempts to channel it. I don't want a porter that just hogs it out as big as he can get it... I want one that knows what makes power. That's what I got from mine and he was still happy to see my suggestions and even incorporated a couple of them into his standard porting package.
All in all air doesn't behave intuitively. If you want it to turn you push it in the opposite direction you want it to go. It'll naturally resist that direction change and go the other way.
You pay what you pay. I paid almost nothing. My porter is a race head porter and charges 800-1000 bucks or more for a similar job as he's doing to mine. What I look for is someone with an innate understanding of how air reacts to attempts to channel it. I don't want a porter that just hogs it out as big as he can get it... I want one that knows what makes power. That's what I got from mine and he was still happy to see my suggestions and even incorporated a couple of them into his standard porting package.
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