Smoooth Manifold

[02silverpathy]

I have taken my 2 upper mannifolds off my VQ a total of 3 times...everytime I note how rough the inside of the manifolds and runners are (and how much PCV blow-by opil collects here)...this leaves air just tumbling around inside, not sliding right in. I suspect that the roughness, smoothed out would deliver some added benefit, and not be too expensive. After all if a K&N adds a 14.46 dyno WHP due to less pipe restriction and open element, then smoothing the inside of the intake manifolds m-u-s-t provide something huh?

 

My first thought was to have it powder coated inside and out....but that won't really smooth the inside, just fill some nooks...so I am seeking real answers here! Honing? Polishing? Sanding? Mail it out to a pro? Hook me up!

 

I would love to think that defeating the variable runner gizmo might help, but that may also reduce some torq/MPG, as that is what it is supposedly there for. Lol, that would also entail removing those power valve screws ...eliminating any problem there huh?

[GhostPath]

I have taken my 2 upper mannifolds off my VQ a total of 3 times...everytime I note how rough the inside of the manifolds and runners are (and how much PCV blow-by opil collects here)...this leaves air just tumbling around inside, not sliding right in. I suspect that the roughness, smoothed out would deliver some added benefit, and not be too expensive. After all if a K&N adds a 14.46 dyno WHP due to less pipe restriction and open element, then smoothing the inside of the intake manifolds m-u-s-t provide something huh?

 

My first thought was to have it powder coated inside and out....but that won't really smooth the inside, just fill some nooks...so I am seeking real answers here! Honing? Polishing? Sanding? Mail it out to a pro? Hook me up!

 

I would love to think that defeating the variable runner gizmo might help, but that may also reduce some torq/MPG, as that is what it is supposedly there for. Lol, that would also entail removing those power valve screws ...eliminating any problem there huh?

 

The variable length manifold trick, if defeated, will destroy your low end torque.

 

Contrary to what the old hotrodders thought, smoothing or polishing the intake runners will actually HURT power production. As computer flow modelling has shown, you need turbulence in the incoming air stream to help create the swirl in the combustion chamber. To do that, you need some roughness in the intake runners.

 

In this era of tight emissions standards and tighter fuel economy standards, if polishing the runners was going to provide any benefits, you'd see makers doing it. Not even Ferrari polishes the inside of their intake manifolds.

 

Do try to keep up with the latest in engine tech and research will you? :D

Edited March 25, 2008 by GhostPath

[STOMPER]

The variable length manifold trick, if defeated, will destroy your low end torque.

 

Contrary to what the old hotrodders thought, smoothing or polishing the intake runners will actually HURT power production. As computer flow modelling has shown, you need turbulence in the incoming air stream to help create the swirl in the combustion chamber. To do that, you need some roughness in the intake runners.

 

In this era of tight emissions standards and tighter fuel economy standards, if polishing the runners was going to provide any benefits, you'd see makers doing it. Not even Ferrari polishes the inside of their intake manifolds.

 

Do try to keep up with the latest in engine tech and research will you? :D

 

 

 

^^^^^^^^What he said^^^^^^^

[02silverpathy]

So...do you think that it is just purely the path that the air takes that makes the K&N so responsive? That is, without the ribs in the intake boot.

[jj big shoe]

Yup. When porting heads or intakes, you leave a rough-to-the-touch surface on the incoming and mirror polish the exhaust to minimize carbon deposits.

If you want to help your engine breathe better, you'll want to port match the heads and intake to the size of the opening in the gasket. There's a bunch of how-to info on the web, but here's the post of my progress. I ran out of time to do the intake, but same principle.

[02silverpathy]

How about a P&P betwen the 2 manifolds and at the bottome leading into the true "lower intake manifold"?

[GhostPath]

How about a P&P betwen the 2 manifolds and at the bottome leading into the true "lower intake manifold"?

 

 

Port yes, polish no.

 

The intake tract MUST be rough.

 

 

The reason the K&N does better is because it's not stuffed in the restrictive airbox that came from the factory and can therefore flow more air.