Multi-Stage Wastegate Control Valve Using The EEPC
Description
This page describes how to install a multi-stage wastegate control valves
(WCVs) setup using the Electronic Engine Performance
Controller (EEPC). To read more about WCVs, see the Increasing
Boost With Wastegate Control Valves page. This setup gives you
multiple stages of boost, depending on throttle position. It also
has an output for the Quick Pressure Feature, which uses the MAP sensor
to measure pressure. The particular example implements 3 stages of
boost.
Building The EEPC
In order for this system to work, you need to build the Electronic Engine
Performance Controller for it. The following page contains all the
information you need to do this:
EEPC: TPS-Based WCV Controller With
Quick Pressure Release
Be sure to read all of the information on that page and to follow all
the testing and calibration procedures before installation. In addition
to the parts needed by the EEPC, you will also need the following parts
for the 3-stage setup:
-
(3) adjustable
modified pop-off valves - see the Increasing
Boost With Wastegate Control Valves page
-
(3) vacuum solenoids - best place to these is a salvage yard
-
some 5/32" I.D. vacuum hose, length depends on your application
-
some 18 guage or thicker wire - length depends on installation, multi-color
is always helpful
-
(3) plastic "T" fittings for 3/16" I.D. hose
-
(1) 0.010" - 0.020" restrictor or a needle valve
-
maybe - (1) 3/16" to 1/4" vacuum hose adapter with a short piece of 1/4"
(7/32") vacuum hose if needed for your wastegate actuator
Installation
How you physically install the solenoids and pop-off valves is entirely
up to you. The most important thing to remember is that the pop-off
valve that is to be set to the highest boost should have the shortest vacuum
line path. As you will see in the diagram below, the high boost valve
goes through the shortest part of only one solenoid, while the low boost
valve goes through the long parts of two solenoids. It is important
to remember this if you want a system that has good response. If
you are going to add more stages, just make sure the valve stages are lower
and lower as you go down the chain of solenoids.
The EEPC circuit provides the ground to the solenoids, so each solenoid
needs a common 12V source. It's always a good idea to put a small
fuse on this line, close to the power source. About a 3A fuse should
work well. It is best to install the EEPC inside the passenger compartment,
rather than under the hood. Even if you seal up the case well with
RTV, the extreme temperatures under the hood can cause the circuit to not
behave properly. Here is the diagram for the valve and solenoid setup:
This EEPC needs the output signal from the TPS
and MAP sensor. Please use your
vehicle wiring diagram to locate these wires. I highly recommend
soldering into these wires, rather than using wire splices. A reliable
connection is very important. If you have an 1987 or earlier vehicle,
these wires are already available in the passenger compartment in the harness
to the logic module (see your wiring diagram). For 1988 and later
vehicles, the wires go right from the engine to the 60-way connector on
the SMEC or SBEC (see your wiring diagram). You will have to run
two wires from under the hood back into the passenger compartment.
The EEPC will be wired like this:
Calibration
To calibrate this system, you need to think about how you want your system
to respond. The following procedure is a starting point and can be
used as an example if you wish to change your caliration later. The
EEPC for this setup actually has three TPS-controlled outputs for three
solenoids. This can potentially be used for 4 stages of boost, but
this example has been using 3 stages, so the 3rd output of the EEPC will
not be used in this setup.
As far as I know the TPS for all of
these engines has an output voltage range of about 0V at closed throttle
to 2.60V - 3.00V at wide-open throttle (WOT). You can verify this
by measuring the voltage on the output of the sensor (the center wire)
with the ignition key in the "on" position. You must remember that
the computer treats WOT as a special condition. If you are not familiar
with this, please read the 2.2L/2.5L Turbo Engine
Important Upgrade Information page. Now you must choose the throttle
positions at which you want each stage to turn on. Below is a table
showing throttle position in degrees and the corresponding approximate
TPS output voltage:
|
Throttle Position
|
TPS Output
|
|
Closed Throttle - 10 degrees
|
0V
|
|
20 degrees
|
0.38V
|
|
30 degrees
|
0.75V
|
|
Half Throttle - 45 degrees
|
1.31V
|
|
60 degrees
|
1.86V
|
|
Computer sees WOT - 79.3 degrees
|
2.60V
|
|
Actual WOT (floored) - 90 degrees
|
3.00V
|
-
Set reference voltage 1 of the EEPC (R1) to the point at which you want
to go from low to medium boost. Try about 1.30V (measure at pin 4
of U1), which is about half throttle.
-
Set reference voltage 2 (R2) to the point that you want to go from medium
to high boost. Try about 2.60V (measure at pin 6 of U1), which
just at the beginning of the WOT zone.
All MAP sensors for our engines have an output voltage range of near 0V
at full vacuum to about 5V. The stock Chrysler MAP sensor for turbocharged
engines is a 2 bar sensor. Below is a table showing the manifold
pressure and its corresponding output voltage for the 2 bar MAP sensor.
The range shown is the reliable voltage output range of the sensor.
It can go higher than 4.90V, but the sensor manufacturer does not gauruntee
anything about it's output.
Manifold Pressure
(relative sea level / absolute)
|
2 Bar
MAP Output
|
|
14.31psi / 29.01psi
|
4.90V
|
|
14.00psi / 28.70psi
|
4.84V
|
|
13.00psi / 27.70psi
|
4.67V
|
|
12.00psi / 26.70psi
|
4.50V
|
|
11.00psi / 25.70psi
|
4.33V
|
|
10.00psi / 24.70psi
|
4.16V
|
|
9.00psi / 23.70psi
|
3.99V
|
|
8.00psi / 22.70psi
|
3.82V
|
|
6.00psi / 20.70psi
|
3.47V
|
|
4.00psi / 18.70psi
|
3.13V
|
|
2.00psi / 16.70psi
|
2.79V
|
|
0.00psi / 14.70psi
|
2.45V
|
|
5.00inHg / 12.24psi
|
2.03V
|
|
10.00inHg / 9.78psi
|
1.61V
|
|
15.00inHg / 7.33psi
|
1.19V
|
|
20.00inHg / 4.87psi
|
0.77V
|
|
25.00inHg / 2.41psi
|
0.35V
|
|
29.10inHg / 0.40psi
|
0.02V
|
-
Set reference voltage 4 (R4) to no greater than 2-3psi below the setting
of the low boost pop-off valve. If you have problems with boost peaking,
you can drop this voltage even more. It is generally easier just
to set it to 0psi (2.45V).
Once you have the unit installed and calibrated, take it out for a spin.
You can tweak your boost pressures and the boost stage references as you
see fit. Enjoy!
This page is maintained by Russell W. Knize and was last updated 04/20/99.
Comments? Questions? Email
minimopar@myrealbox.com.
Copyright © 1996-2003 Russ W. Knize
