Commpressor inlet porting

[project94tsi]

Im fully porting my 14b i just bought and was wandering can I port the compressor inlet to somewhat make it look like the inlet on the big 16g just as long as i only port about and inch deep into the inlet. there is an attachment of a pic of the big 16g for referance. I figured it would be ok cause turbos like the FP Red have a huge funnel shape to them, but i just wanted to get your guys thinking on it. Thanks

 

[pneumo]

Go for it. I did it to my 14b when I rebuilt it. The housing is thick enough to remove quite a bit of material. I shaped the inlet into a smooth bell shape, or velocity stack. I also used a Scotchbrite scouring pad and some polishing compound to polish the inlet. It looked awesome! In theory it should help reduce turbulence of the air going into the turbo.

 

[nine5raptor]

If you can get the angle on the intake to be no more than 7 deg or so along the intake, you will have the least amount of loss going into the turbine.

btw, turbulence is a good thing.

 

[Eagle 5]

Originally posted by nine5raptor
btw, turbulence is a good thing.

not always though...

 

[nine5raptor]

If you want more efficient flow it is. Laminar flow gives you too much loss from shear stress.

 

[pneumo]

Are you talking about the state of the boundary layer? I can see how a turbulent layer adjacent to the wall might reduce drag, but IMHO the remainder of the airflow should be laminar. I'm curious to hear any new info.

 

[nine5raptor]

If you don't have turbulent flow, then it eventually all becomes a boundary layer (both sides converge in the center). The layer next to the wall will always be static (assuming subsonic flow) so you want the flow immediately inside that to be turbulent to minimize loss (drag).

 

[Defiant]

Maybe a Tornado on the inlet would help.


or, maybe not.

 

[pneumo]

Indeed.

Obviously there shouldn't be any extra restrictions in the intake, so where's the break even point between low restriction and high turbulence? There are plenty of turbulators along the intake path; MAF, the accordian ridges in the rubber intake pipe, BOV return line, the small machining remnants in the turbo inlet, the curve of the intake pipe, even the junctions of all those separate parts. They all induce turbulence to some degree.

Maybe we could have a definition of just how turbulent the flow needs to be?

Does the velocity of airflow make a difference when looking for the point at which laminar airflow eventually becomes 100% boundary layer?

 

[project94tsi]

yeah so yes or no on the inlet porting?

 

[nine5raptor]

Originally posted by pneumo
Indeed.

Obviously there shouldn't be any extra restrictions in the intake, so where's the break even point between low restriction and high turbulence? There are plenty of turbulators along the intake path; MAF, the accordian ridges in the rubber intake pipe, BOV return line, the small machining remnants in the turbo inlet, the curve of the intake pipe, even the junctions of all those separate parts. They all induce turbulence to some degree.

Maybe we could have a definition of just how turbulent the flow needs to be?

Does the velocity of airflow make a difference when looking for the point at which laminar airflow eventually becomes 100% boundary layer?

I wouldn't rely on restrictions to produce the turbulence at all. Wholly turbulent (internal) flow is a function of density, velocity, piping diameter, and fluid viscosity. Basically, you want to maximize your piping size without it going so big that the air slows down and runs over itself. This is the idea behind exhaust flow and whether a pipe is too big. You want as much flow as you can, but if the air velocity drops too much, you get a traffic jam and actually lose flow.

Before a turbo, I would try to minimize restrictions. For a given airflow, generally a lower pressure ratio will give you a better efficiency if you look at flow maps. 2 ways to lower the pressure ratio: 1. turn the boost down 2. minimize the pressure drop in the intake. We don't want to lower the boost because that lowers the air entering the motor, so instead we want #2. Make your intake as unrestrictive as possible to get the most out of your turbo.

 

[nine5raptor]

Originally posted by project94tsi
yeah so yes or no on the inlet porting?

If you can, do what was suggested and mimic a velocity stack. The very edge of the inlet is the most important. Smooth off that 90 degree edge.

 

[DSMJim]

What ever you do, don't take any material away from the area where the blades are. If you increase the clearance between the housing and compressor blades it will dramitically effect how your turbo operates. The opening to the turbo your almost free to do what you want with it, within reason of course.

 

[nine5raptor]

Good call. Stay away from the blades. Just round off the very beginning of the inlet.