Techno Torque 2

[ppbon]

Originally Posted by Lil bastard

How are you determining that you have established laminar flow? At what velocities?

... is not the correct term, but rather "less turbulent flow".
I'll be posting a video later this week where you'll be able to see the increased efficiency of the TechnoTorque.
Also, the piece is designed for the lower RPMs, where additional torque is needed.
At high RPMs, let's say at 6000 RPM, a 2.5L engine will be sucking in 7,500 liters of air per minute so at this speed, efficiency is out the window. It really doesn't matter that much if the inside of the Tee is smooth or not.
But at idle (800 RPM) it's only sucking in 1,000 liters of air, or 7.5 times less air. Here the smoother the walls are the more efficient the flow will be from the low RPMs.
That's why we see an increase in Torque at lower RPMs and no change basically in the HP curve.
Happy Boxstering,
Pedro

[blue2000s]

Attached is a picture of a CFD (fluid dynamic modeling) model that I ran to illustrate what's actually going on in the "T". No offense to Pedro at all with the following description, I'd just like to help clear things up a bit.

The center of the air channel from the throttle body will enter the "T" and stagnate (stop) as it hits the back wall. This builds a "wedge" of high pressure air at the center of the "T". This essentially does automatically what the little plastic wedge of the technotorque does.

The shape of the wedge created by the air itself isn't necessarily ideal and will change with flow and time, so the shape of the technotorque may help to slightly improve flow, but without analysis and testing of several iterations (like CFD or a flow bench), it's lucky if it does. It can just as easily impede the airflow and hurt power.

I believe that the polishing of the runner probably has as much (if not more) to do with the power improvement than the wedge itself.

Now notice that the flow as it goes sideways entering the horizontal tube, flattens out. Leaving more than half the tube to useless recirculation. The flow at the "top" of the horizontal tube in the picture actually just flows in a big circle! We call that recirculation. This increases the air velocity, leading to pressure losses in the junction.

The big benefit to the IPD plenum isn't the wedge at the base of the "T", it's the fact that the vertical tube in my picture gradually gets wider before opening into the T and has nice, rounded edges as it transitions to the horizontal. This helps the air to make the 90 degree turn while better sicking to the walls of the tube. This makes MUCH better use of the horizontal tube volume and significantly lowers the overall pressure drop through the "T".

BTW - The plenum is the shape it is for manufacturing simplicity and cost. There isn't enough of a benefit to power or drive-ability to justify the extra cost of optimizing the part from a manufacturer's perspective. Porsche went as far as they saw prudent with cost for performance in mind. So don't think everything's perfect with this car, it's as good as Porsche decided to make it considering the costs of manufacture.

[Samson]

Interesting... thanks for posting!

[ppbon]

Originally Posted by blue2000s

No offense to Pedro at all with the following description, I'd just like to help clear things up a bit.

... as a matter of fact I applaud and welcome these discussions, since they help to enlighten us all.

Your fluid dynamic model of the plenum's Tee is very impressive and most likely correct, if there was no throttle body and butterfly valve controlling the airflow.

Because we have a throttle body with a butterfly valve, the flow of air into the Tee does not come from the center of the air channel, but through two crescent moon-shaped opening on the sides of the air channel. These variable openings, whose area is dictated by the position of the accelerator pedal, create all sorts of turbulence within the Tee.

When I started with my experiments I took a tee and made a clear porthole on its top so that I could see what was happening inside. Inside the Tee I had attached small streamers (much like those on the sails of a sailboat) which allowed me to see the airflow through the Tee from idle to wide-open throttle.
I also ran other visual experiments which I will document shortly with a short video showing the improved performance of the airflow.

Happy Boxstering,
Pedro

[blue2000s]

Originally Posted by ppbon

... as a matter of fact I applaud and welcome these discussions, since they help to enlighten us all.

Your fluid dynamic model of the plenum's Tee is very impressive and most likely correct, if there was no throttle body and butterfly valve controlling the airflow.

Because we have a throttle body with a butterfly valve, the flow of air into the Tee does not come from the center of the air channel, but through two crescent moon-shaped opening on the sides of the air channel. These variable openings, whose area is dictated by the position of the accelerator pedal, create all sorts of turbulence within the Tee.

When I started with my experiments I took a tee and made a clear porthole on its top so that I could see what was happening inside. Inside the Tee I had attached small streamers (much like those on the sails of a sailboat) which allowed me to see the airflow through the Tee from idle to wide-open throttle.
I also ran other visual experiments which I will document shortly with a short video showing the improved performance of the airflow.

Happy Boxstering,
Pedro

The stagnation and separation will still be present, even with the throttle plate there.

[sb01box]

Originally Posted by blue2000s

Attached is a picture of a CFD (fluid dynamic modeling) model that I ran to illustrate what's actually going on in the "T". No offense to Pedro at all with the following description, I'd just like to help clear things up a bit.

The center of the air channel from the throttle body will enter the "T" and stagnate (stop) as it hits the back wall. This builds a "wedge" of high pressure air at the center of the "T". This essentially does automatically what the little plastic wedge of the technotorque does.

The shape of the wedge created by the air itself isn't necessarily ideal and will change with flow and time, so the shape of the technotorque may help to slightly improve flow, but without analysis and testing of several iterations (like CFD or a flow bench), it's lucky if it does. It can just as easily impede the airflow and hurt power.

I believe that the polishing of the runner probably has as much (if not more) to do with the power improvement than the wedge itself.

Now notice that the flow as it goes sideways entering the horizontal tube, flattens out. Leaving more than half the tube to useless recirculation. The flow at the "top" of the horizontal tube in the picture actually just flows in a big circle! We call that recirculation. This increases the air velocity, leading to pressure losses in the junction.

The big benefit to the IPD plenum isn't the wedge at the base of the "T", it's the fact that the vertical tube in my picture gradually gets wider before opening into the T and has nice, rounded edges as it transitions to the horizontal. This helps the air to make the 90 degree turn while better sicking to the walls of the tube. This makes MUCH better use of the horizontal tube volume and significantly lowers the overall pressure drop through the "T".

BTW - The plenum is the shape it is for manufacturing simplicity and cost. There isn't enough of a benefit to power or drive-ability to justify the extra cost of optimizing the part from a manufacturer's perspective. Porsche went as far as they saw prudent with cost for performance in mind. So don't think everything's perfect with this car, it's as good as Porsche decided to make it considering the costs of manufacture.

I'm not good at fluid dynamics - but would the analysis paint a different picture for pressure versus suction?

[blue2000s]

Originally Posted by sb01box

I'm not good at fluid dynamics - but would the analysis paint a different picture for pressure versus suction?

Nope, same thing as far as fluids is concerned.

[sb01box]

Originally Posted by blue2000s

Nope, same thing as far as fluids is concerned.

reason for the question is that with suction, cavitation can occur whereas with push stagnation maybe but no cavitation.

[blue2000s]

Originally Posted by sb01box

reason for the question is that with suction, cavitation can occur whereas with push stagnation maybe but no cavitation.

It's more complicated than that, technically.

Cavitation refers to the phenomenon in which a liquid flow experiences local low pressure such that it changes phase to a gas. In this case, we are already talking about a gas, so there's no possibility for cavitation to occur.

[sb01box]

Is TechnoTorque wedge providing the necessary solid feature to maintain low Cg and assist air flow?