Boost Manager Profile Analysis

July 3, 2015 Jeffrey Jones

With the Boost Manager operating and Aquamist’s Flow Sensor recording I logged my S4 to see how the pump duty cycle map that I had created worked out.

I’m attributing the jumpiness in the water/methanol flow to sensor noise which I hope to minimize in the future.

The water/methanol pump duty cycle map is based upon engine speed and manifold pressure (MAP). As is shown by the left line with arrows, activation of the pump takes place around 2000 rpm once MAP reaches about 6 psi of boost pressure.

At 10% duty cycle the pump is essentially still off with respect to the flow volume, this was first shown when I conducted a calibration session with the water/methanol injection system. I have the pump at such low duty cycle to get things moving in anticipation of the system injecting a measurable quantity of fluid shortly thereafter.

When engine rpm reaches 2500 and MAP passes 11 psi the pump duty cycle increases and the flow rate increases quickly. The flow rate tracks with the increasing rpm, though I have some refinement to do in order to match engine speed better.

A couple of other parameters that would be useful to look into are airflow, via the MAF reading, Fuel Injector Duty Cycle, and intake air temperature.

At the right side of the chart the flow rate drops, despite engine speed increasing, because the MAP is dropping and then lowers the pump duty cycle. This is another area of the chart that will get some attention to refine the pump duty cycle and better manage the fluid flow rate.

Flow Tests

Exhaust Manifold Velocity

June 17, 2015 Jeffrey Jones

What was done:

As a follow-on to the exhaust manifold pressure drop testing that was performed I decided to use a velocity probe to assess the airflow velocity out of the exhaust manifold at a fixed airflow rate.

Products:

I still had available the AWE Tuning, Silly Rabbit Motorsport, and Audi S4 stock exhaust manifolds.

awe-tuning, srm, Audi B5 S4 exhaust manifolds — (L-R) AWE-Tuning, Silly Rabbit Motorsport, Audi exhaust manifolds

Test Procedure:

The velocity probe was placed perpendicular to the plane of the exhaust manifold outlet approximately intersecting the plane across the outlet opening.

exhaust manifold velocity probe test — Velocity probe at outlet to exhaust manifold

Due to the interaction of the airflow with the probe the readings varied slightly. To try and minimize the affect of this variation 10 samples were taken for the AWE and SRM manifolds and averaged. The higher velocity from the stock exhaust manifold caused greater variation and therefore 20 samples were averaged.

Only the middle primary was tested.

Here is each product on the bench as the tests were being conducted.

audi b5 s4 exhaust manifold velocity probe test — Stock Audi B5 S4 exhaust manifold

awe tuning exhaust manifold velocity probe test — AWE-Tuning exhaust manifold

srm exhaust manifold velocity probe test — Silly Rabbit Motorsport exhaust manifold

The Results

exhaust manifold velocity probe test results — Airflow velocity test results

Based on the respective diameters of the primary runners and the outlet diameter of the manifolds the results are not surprising.

Turbo Selection

Project: B5 PB550

June 14, 2015 Jeffrey Jones

A few more months have passed and another option has popped up, this one from Project: B5 – a turbocharger called the PB550.

Looking at this offering and comparing it to the Project: B5 RS6-X it is not immediately clear what distinguishes these two products. I have tried contacting Project: B5 to find out what the differences are but have not had any reply back to my inquiries. Looking at the two product write-ups it seems that the two differ in the following ways:

PB550 uses a K04 style billet compressor wheel.
RS6-X uses a double stack RS6 style compressor wheel.
The RS6-X has a clipped turbine, the PB550 does not.

At this point I have never seen any data on an RS6-X turbocharger or the PB550. Based on the specs they are still in the region I consider a candidate system, but the lack of data and lack of communication from Project: B5 make it unlikely I would purchase one of these.

As for now the candidate list is:

BorgWarner K04 (great amount of data)
FrankenTurbo F21/MF (minimal amount of data)
ProjectB5 RS6-X/PB550 (no data)
SRM Billet K04 (no data)
TTE 550 (minimal data)

Audi B5 S4 Information and Testing