Would it be a bad idea to get a D16Z6 Intake manifold from a yard, and do a port and polish job on it?

I would be buying the manifold for 60$, and doing the job myself with a dremel tool.

Is it worth the $ or time?

 

correct me if im wrong but your only supposed to port the intake side. and port and polish the exhaust. polishing the intake has a negative effect if im not mistaken

 

definetely worth the time if you research it before doing it.

If not for the performance youll get some good experience out of it :thumbup:

 

You're not mistaken. The point and purpose of polishing is to reduce aerodynamic drag and turbulence. This is good for exhaust, and bad for intakes. The reason it's bad is that turbulence is NEEDED on the intake side to assist with atomizing the fuel. If there is no turbulence, the gas may not burn well in the combustion chamber. It's much harder to un-f**k it after you bolt it back on and your car runs like crap. Porting IS okay on intakes, though. Only polish exhaust stuff.

If you want to polish the outside of it to learn how to do that... you couldn't have picked a more difficult part. You'll be a pro at it by the time it's finished.

 

Ok, so then its worth it..?

How much do you think it would cost me to take my head to a machine shop and have them port it?

I want to increase the flow as much as possible.

 

:thumbup: cool i thought i had heard that before

 

I don't port. But I think that's old-school thinking, from back when there were carburetors (or throttle-body injection) that put fuel and air into the intake manifolds. Turbulent air would definitely help with fuel atomization then.

But our cars are fuel injected, with the injectors sitting practically on top of the intake valves. There's no fuel to try to "mix" with the air prior to the injectors, so turbulent air would be a moot point. The fuel is already atomized by the injectors.

Like I said, I don't port. I'm just applying logic and common sense, hoping I'm right.

 

It is true that injector design has more to do with fuel injected cars, but the same principles of aerodynamics apply. He said he wanted to port and polish a D16 intake manifold. The runners are long on that manifold, and begin long before the injectors in the path of the air... where the turbulence needs to occur.

It's true that it will make less of a difference in the bowls of the valves, but if it neither helps nor hurts at that point, why pay for the polishing or spend the time doing it? If you had ever polished aluminum, you'd know what a pain in the ass it is.

I can attest to porting being beneficial on imports. I ported my GSX's head, and I'm making 433chp on pump gas... 33hp more than I'm supposed to be able to make with a big16g turbo on race gas. There has been a substantial improvement on airflow by just grinding off the rough stuff.

I swear by porting and port matching all your parts on imports because many of them have parts that don't line up as well as they were cast to. It's not so bad on Hondas because 90% of the motor is made from aluminum so it's easier to keep the tolerances correct... but companies like Toyota and Mitsubishi that have tons of different materials and the thermal expansion/contraction rates are different on those parts during the cooling process. These parts are "close enough", but never line up perfectly.

Just a word of warning... too much added diameter to the intake ports will hurt you. You will reduce the intake velocity... which has just as even more to do with atomizing fuel on a fuel injected engine as the surface texture on the intakes of "old-school" engines.

 

I think you'd be wasting your time unless your head is already ported. Unless your a pro that has experience porting, and testing the airflow afterwards you risk losing power. Even an IM ported by a pro, or even Skunk2 IM will not net you much power on NA engine, with no head porting.

 

Meh... Its sounding like alost cause.. After all of that talk, I figure I wont do anything unless I go boost.. And in that case, I will prob get a skunk 2.