2000Audis4

I dont see to many options for aftermarket intake manifolds, actually the only one i ever saw was inline pro's. Is there better ones out there? or should I port and Polish the oem one, and if so where is a good place to have it done. thanks

SBIT

You cannot find aftermarket options because you are searching for a part that is almost perfect from the factory.
All companies that specialised in the car they don’t spend money or time to improve this part for some reason. Its perfect!!
Concerning your idea to port and Polish it i think is not a good one!!!! You need to have in the intake the lower temperature as possible. If you polish the intake you will achieve the opposite because with polish the temperature goes up. So the air will be hotter and this means power loss.
In crease in temperature is the reason that many owners stopped polish the cover head also.
My opinion is to leave the intake as it is!!! Put only an intake gasket (Hondata) in order to have lower temperature to the intake.

yamahaSHO

A port and polish isn't going to heat up your charge air.

SBIT

We made the test with polished cover head and the oem cover head and the difference was 8c degrees. Polishing is a good conductor of heat and you don't want that. The choice is yours

Garrett_si

that true because polishing reduce the area size of the aluminum, and there is less area to exchange temp between aluminum and air but inside the intake this is minimal lost.

Polishing the outside, paint the outside of the manifold will affect more.

to reduce the intake manifold temp you could add more aluminum surface to the outside of the inside (heat sink)

4forall

Basically what he is saying is because they have a texture to them from the factory that increases the surface area as well as makes high and low points to allow head to disappate. If you poslish the outside you are reducing this effect.

How ever i dont think polishing the inside would matter as much as the heat has nowhere to really go anyway.

liquid_helix136

Also, from I've seen around here is that the intake manifold is far from perfect. Someone noted that the size of our intake manifold is ideal for an engine with 1.6l in displacement, and so a 2.0 or 2.2 like ours should have a bigger IM. Why no one has made a good aftermarket replacement is anyones guess.

yamahaSHO

I'd like to know more about your testing conditions.

As for the charge air in the intake; I do not want it conducting any heat. A smooth surface will transfer less heat. In addition, laminar, not turbulant flow will also conduct less heat.

As for the exterior absorbing engine bay heat, coatings and heat management would likely provide the most benefit.

Breaking Point

Our intake manifolds are garbage! Plenum to small.runner I,d, to small.doesn't come close to supporting laminar air flow as far as air travel and is also very turbulent which is also a no go. A big factor for us however is space in our cars.I've been welding up some different designs at work for my s that support laminar air flow with equal and longer runner length but a rather small "Plenum" if it could even be called that.once I get a few more made up I'm going to be testing the lot of them.and I'm a firm supporter or polishing the inside of intake manifolds.polishing a valve cover or external of any part is going to heat soak worse.but to smooth out air travel works great for our high revving engines. Personally if it were a lower revving engine I'd leave it just ported and not polished so the inner pipe would act like a golf ball and help the air travel faster for that type of application. And furthermore your intake is only as weak as it's smallest part.so upsize without overdoing.

starchland

Is throttle response,part throttle drivability an issue? Can this be seen on a dyno? I'm sure the stock I'm is a bit of a sacrifice