GrimmSpeed Mazdaspeed Electronic Boost Controller User Manual

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GrimmSpeed 3 Port Boost Control Solenoid

Installation Instructions

MazdaSpeed3/MazdaSpeed6

***Picture above is MS6 BCS***

All GrimmSpeed products are intended for Off-Road use only.

Park your vehicle on a level surface. Fully engage the parking brake and put wheel stops on
the front and rear wheels to keep the vehicle from rolling.

Warning (read before installing):

Before moving forward with the setups outlined below, insure that you have the experience
and confidence to properly tune your car. If not, please consult a tuning professional.
Without a proper tune you can overboost and damage your engine.

Under no circumstances is the GrimmSpeed Solenoid to be used in any applications where
failure of the valve to operate as intended could jeopardize the safety of the operator or any
other person or property.

Note! You must tune for this hardware in 3 port mode! Using stock or off-the-shelf EM with a

3-port solenoid installed in interrupt mode will result in overboosting!

Items Included:
MS6 MS3
(1) GrimmSpeed BCS (1) GrimmSpeed BCS
(1) Rubber Grommet (2) M6 Bolts
(1) Rubber Washer (2) M6 Lock Nuts
(2) M6 Lock Nuts (1) Hose Connector
(1) Hose Connector (1) Rubber Cap
(1) Rubber Cap

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A. Purpose

The benefits of this upgrade are faster spool, ability to hold higher boost, and better control
over boost. A side benefit of the improved boost control is the ability to reach higher target
boost levels in the low (1st and 2nd) gears.

B. Technical Background

A BCS is a binary device – i.e. it is either on (energized), or off. In the context of the
MazdaSpeed device, when the BCS is energized, air is allowed to pass through the device,
while it is off, the air flow is cut.

There are two modes of boost controller operation, at least in this context: “bleed” 2 port
mode, which is the mode that the stock BCS operates in, and “interrupt” mode, which is the
mode that a 3-port BCS can operate in. Note that a 3-port BCS can also operate in “bleed”
mode, depending on how it is connected.

Despite being digital in nature, these devices perform a very analog-like task, which is to
control the boost level. In order to do so, the ECU opens and closes the solenoid at varying
speeds, from 0 Hz (closed) to (effectively) ∞ Hz (open).

C. 2-Port Operation (Stock) Review

The stock solenoid is part of the stock bleed-based boost control system. When the solenoid is
off (closed), pressurized air from the compressor is fed straight into the wastegate control.
Any increase in compressor pressure beyond the rated pressure of the wastegate control
results in the wastegate being opened, preventing buildup of boost.

When energized (opened), air is allowed to bleed off the compressor-to-wastegate line by way
of the dual waste gate hose fittings (in stock vehicles, this air is vented back into the intake
post-MAF). This prevents the wastegate from seeing the full compressor pressure, allowing
boost to build.

While the stock system operates adequately, it can lead to problems at higher-than-stock
boost levels. Since the bleed system is sized for the stock turbo at stock boost levels, it is
typically incapable of correctly metering air at higher boost, allowing the wastegate to see
pressure and open before intended. Additionally, since the wastegate is never completely cut
off from seeing compressor pressure, it can open at low boost levels and inhibit boost buildup.
Ideally, the wastegate should remain entirely closed for fastest boost buildup (as all exhaust
is then forced through the turbine).

Installing the GrimmSpeed BCS in 2 port mode does not require tuning.

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D. 2-Port Installation

Installation for MazdaSpeed3:

1. Remove air box top.

2. Remove top battery cover.

3. Remove front battery cover.

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4. Line up the left grommet hole with the existing front battery cover hole near the top of
the cover. The bracket grommets should be parallel with the top of the front battery cover.

5. Drill the left side mounting hole using a 1/4" drill bit.

6. Using provided Grimmspeed bolts and nuts, mount the solenoid on the battery cover.
Reinstall battery front cover and top cover.

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