1slick7

I am going to get My FD Ported & Polished, and my only real question is how much?

Manolis_D

iTrader: (2)

OK dude, back up We need waaaayyy more info than that!

What exactly do you want ported? polished? ya know, little details like that

Rotortuner

Ya what you said doesnt realy make sense. We need to know who you want to do it and how big and what kind of port you want and also what is the car going to be used for? Those are all things that factor in cost and which port to go with cus there are only about a million different combos.

CJG

peejay

Polish = bad. Smooth surfaces flow worse than slightly rough ones.

Porting a rotary is much more than porting a piston engine... it's like porting the heads and changing the cam at the same time.

KraftDinner

It's more like porting the heads, but getting the same resuls as porting the heads, changing the cams at the same time

E6KT2

Maybe he means his whole FD. That's what it says. Does that include the windows? Can you port the windshield?

KraftDinner

A rock ported the windshield on our farm truck when I was younger. Didn't seem to affect performance much though...

Scrub

iTrader: (25)

LMFAO!!

Scrub

iTrader: (25)

I believe that you can port your hood with a pick, Homer Simpson did that once, but im not sure of the HP gains he got.

KraftDinner

LOL! I think that's the episode where he bought a gun, and then at that scene he told NED the holes in the car were "speed holes" to make it go faster.

Maybe he was making holes a cost effective way, so that hot air could be vented out of the top mount intercooler on their family sedan? :P

Zach McAfee

We used to take the governors off go karts and overrev them. The rod would break and port a hole into the side of the block, but it never ran any faster after that.

Why don't we answer this question as best as possible. I suggest a street port to maintain idle and get good performance gains. Price? Do it yourself for $50 (template) or pay labor $300-$600.

bcty

pay unless u are skilled and know what you are doing!

Scrub

iTrader: (25)

I still think he should port his whole car

SPOautos

Peejay - This is the first time I've ever heard anyone say polish = bad. I have however heard that polish = good many times.

I'm not saying anyone is right or wrong just looking for some more info. Why would smooth surfaces flow worse than rough ones?

STEPHEN

Zach McAfee

I'm with you on that one. I hope its not bad, I polished my intake ports!

fdracer

polishing is bad because a slightly rough surface will help in fuel atomization and combustion. if a surface is too highly polished any suspended liquid will tend to pool into droplets. you want your fuel to stay suspended in the a/f mixture as much as possible. also a little roughness adds a little turbulence to the incoming air and fuel. this aids in combustion and it slows down the air at the very end helping create a negative vacuum. that vacuum will allow you to actually suck in more air. think about the combustion as an explosion, the more turbulent and violent the environment the more powerful the explosion.

peejay

Kinda sorta maybe...

Don't forget that laminar flow isn't as efficient as turbulent flow. Having a rough surface helps break up the layers near the port walls and allows more of the port to work.

Zach McAfee

Well said. Makes sense to me.
So if I told you I polished the hell out of my intake ports (which I did), how much did I LOSE doing this? Is it neglegible? It seemed to me at the time that there would be enough turbulence created by the shape of the ports.

My engine builder for kart racing drills shallow holes at the end of the intake port just before the valves to create turbulence. Maybe an idea for us rotary engine builders?

peejay

Could be an idea... Could be.....

fdracer

How much horsepower are you making? If not that much then it's probably neglegible. You're biggest concern should be the fuel condesing back into liquid form at the port walls. They'll form droplets along the wall if it's too smooth. Just take fine grit sanpaper to it next time you open it up. Your cart builder's trick is done by quite a lot of people actually. I've seen shallow holes, slots on the port floor, dimples on piston crowns, etc. to try to help mixture conditioning and to help "guide" the flow of the intake charge. Today's builders have sort of gone away from that cause it does disrupt the laminar flow too much. It's prolly a better idea to just roughen up the intake walls w/ fine grit sandpaper.