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See also: General Notes - Performance Data - Potential Risks
Notes:
This article assumes that
the user is familiar with the rewards and risks of a
boost controller. Furthermore, it merely represents my
experience and opinions, and should not be taken as a
definitive work.
The work described here
was undertaken by Graydon Stuckey, with erratic assistance and more frequent
interruptions from me. All errors contained in this
article, however, are mine, not his.
There are two major
components to an HKS EVC-IV boost controller:
- The controller unit
- The valve actuator
This page will deal
primarily with the installation and setup of the actuator,
as the actual operation of the controller unit is fairly
well covered in the manual HKS supplies.
ACTUATOR
INSTALLATION
The only components which
were not supplied by HKS were a couple of hoseclamps and
brass T-joints for the air hoses. These are readily
available at any decent hardware store.
- Remove the airbox,
and then remove the airbox housing (note: in the
process, you'll have to remove a couple of large
clamped air hoses and the MAF leads). The housing
itself is attached by a single bolt at the top,
and slots in via two pins in its base. This gives
you easy access to the turbo and wastegate.
- Disconnect the hoses
to the wastegate frequency valve (WGFV, Checkered arrow above). With both
hoses and the electric plug to the WGFV removed,
the WGFV will be sealed.
Remove the large U-shaped plastic duct shown
above. It connects to the airbox, the turbo cold-side,
the intake manifold and the bypass valve.
- Mount the EVC valve
actuator to a firm surface, preferably not hot,
as close as possible to the wastegate (WG). For
our purposes, we mounted it to the front of the
airbox housing, as shown above. Note the
following hoses:
Orange: HKS signal line, with filter, will
be T'd to the bypass valve line
Yellow: HKS output line, will go to the top
of the WG.
Blue: HKS input line, with filter. Will be
T'd to Green and Red hoses.
Green: Audi hose, will go to a tap on the
cold-side of the turbo.
Red: Audi hose, will go to the tap on the
lower part of the WG.
Gray: HKS power and signal leads. See
step 6.Note: the T for the Blue, Red and Green hoses is not from HKS.
- Choose a location for
the input hose (Green). We have now tried two locations (see
above). The stock location (2) offers, in my
opinion, a good overall balance of low- and high-end
boost. An alternative (1) on the outlet of the
cold-side spool generated better low-end boost,
but restricted the high-end quite severely.
- Reinstall (loosely)
the airbox housing. Connect the Gray wires from the actuator (see
step 3) to the HKS wiring harness, and route them
behind the airbox housing.
Connect the Red, Yellow and Green hoses. The Green hose will go to whichever
tap you chose in step 4 above. The Red hose will go to the stock
tap on the lower part of the WG. The Yellow hose will go to the top of
the WG. It's probably best to unscrew (carefully)
and rotate the upper WG so as to minimize the
length of the Yellow hose (which will in turn
increase the rapidity of the EVC's effect).
- Connect the Orange hose to the (HKS) T and
insert it into the approach to the bypass valve,
as above.
- You can now
reassemble the air filter, clip it into the
housing and then re-bolt the housing to the car.
Re-attach the MAF lead. Re-install the U-shaped
pipe, and re-attach it to the airbox, turbo,
manifold and bypass valve. Check that all clamps,
hoses etc. are secure.
The actuator installation is now complete.
CONTROLLER
INSTALLATION
All that's left now is to
hook up the controller unit and calibrate it. The
location of the controller is entirely arbitrary, the
only restriction being the length of the wiring harness.
It should be accessible within the cockpit, at least for
the passenger. Suggestions:
(Simplest) Drill a hole
through the firewall in the vicinity of the glove
compartment and route the cable through it (then seal the
hole back up). Hook the controller unit up to the harness,
and power it from the (switched) wire for the glove
compartment light. The EVC head unit can then sit out of
sight in the glovebox. In any event, calibration is most
easily accomplished with a driver and a calibrator in the
car simultaneously.
(Better) Again, route the
cable through the firewall, but mount the controller unit
in the space beneath the ashtray. Note, you cannot use
the ashtray light as a power-source because it is
activated by the lighting system, not the ignition.
Installation
on my S4, with my Davtron digital
intercooler gauge to the right of the EVC head unit.
CALIBRATION
In general, the
calibration instructions HKS supplies are quite
straightforward. A couple of notes, however:
- Unless you own a drag
strip, performing all the tests in 3rd gear will
be hard. Second gear works fine. Likewise, "up
and down" the same stretch of flat road is
acceptable, rather than having to circle back,
off-boost, before starting again.
- Initial tests
indicated that the setup described here is good
for boost of up to +1.45 bar. I would suggest
carefully reading the boost and performance
sections of Scott Mockry's website before deciding what level
of boost you wish to run. Personally, I have high-boost
set to +1.25 bar and low boost set to +0.80 bar.
- Performance improves
rapidly as the EVC "learns" the boost
curve. After 10 or 15 runs, it will have
assimilated most of the info it needs.
- Carry out the
calibration as close to "normal conditions"
as possible (i.e. if you live in Arizona, don't
calibrate it in Alaska).
- During
calibration, back off at redline. You don't want
to "teach" it bad behavior.
- In my experience, not
much (i.e. <10-15%) "offset" is
required on an S4/S6 AAN motor with a K24 turbo.
If the EVC seems unable to reach the boost level
you want, check everything else before cranking
max boost to +1.8 and the offset to +150%.
- What if it all goes
wrong during calibration? Brilliantly, the method
of setting the unit up from scratch is covered in
a "note" on the second page (great
place to start). Power the unit down. Wait (cursing
under your breath) for a few seconds, then press
and hold the Mod button. Still holding it, press
and hold the Alt button. Still holding both of
them, press the Sbc button. The unit should beep
and then get ready to start learning again.
- Sometimes, during
initial calibration (specifically, the first two
runs, "-L-" and "-H-"
respectively), the unit will record a run that
you'd rather forget about (e.g. you're at 5,000
rpm when you see a cat in the road, and back off,
but the unit just "learns" that your
turbo runs out of oomph after 5k). You can't
always use the resetting technique described
above. Don't get mad at the unit (I did). Power
it down, turn off the ignition, wait a minute,
turn back on the ignition, and then use the reset
procedure described in the bullet above.
Other Modifications:
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