TIP PCV Port Test 2


A few weeks ago I made some initial measurements of the vacuum generated at the inlet elbow PCV port with the stock turbo inlet elbow, an aftermarket elbow, and a prototype I was working on.

Stock TIP PCV Port Vacuum Check
Stock TIP PCV Port Vacuum Check

I had an idea to try and increase the vacuum inside the prototype elbow by building a raised area on the inside of the elbow.

Elbow Modification:

I stayed with the existing prototype elbow design and leveraged a high-lift airfoil shape to create the raised area.

Airfoil v1
Airfoil v1

The upper half of the airfoil was added to the elbow:

Inlet Elbow with Airfoil Insert
Inlet Elbow with Airfoil Insert

The update printed well which setup conducting a second flow test.

Inlet Elbow Prototype 2
Inlet Elbow Prototype 2

Flow Test:

This second prototype included a change that moved the measurement port to the center of the elbow. The goal of this change was to try and take advantage of what should be a local high-velocity area.

TIP Airflow Velocity Model
TIP Airflow Velocity Model

Since this meant two changes were being made a second hole was made in prototype one (1) to measure the vacuum at the center of the elbow, shown below:

Prototype 1 - Test 2
Prototype 1 – Test 2

Prototype 1 was then retested:

Prototype 1 - Flow Test 2
Prototype 1 – Flow Test 2

The new location showed a slightly greater vacuum at 22.5 inches of water at an airflow rate of 350 CFM.

The other port location measured 14″ of H2O @ 350 CFM.

Next, the second prototype was configured for the flow test:

Prototype 2 - Flow Test
Prototype 2 – Flow Test

An improvement was recorded with the vacuum increasing to an average of 33.5 in of H2O @ 350 CFM:

Prototype 2 - Vacuum Measurement
Prototype 2 – Vacuum Measurement

Note: The picture shows a reading of 32″ of H2O because turbulence causes pressure fluctuations and the moment the picture was captured the reading was down from the average.

Results Comparison:

A summary of all test results to date is shown on the chart below:

PCV Port Vacuum Test 2
PCV Port Vacuum Test 2


A prototype turbo inlet elbow was made with an internal raised area to determine the effect on the vacuum at the raised area.

A flow test showed an increase in the vacuum level from 14″ of H2O @ 350 CFM at the OEM port location with a prototype elbow up to 33.5″ of H2O @ 350 CFM at a center location with a raised area inside the inlet elbow.


5 thoughts on “TIP PCV Port Test 2”

    1. I’ve measured two aftermarket TIPs and have two others I could measure in the future. The two I measured created a similar amount of vacuum. I don’t recall any that I tested in the past having a design feature that would promote high vacuum at the PCV port.

  1. Could this actually add a strain on the pcv? Been thinking about deleting the whole thing using the racing line plate or the 034.

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