2

R

1 - RPML 1

2 - RPML 2

4 - RETARD 1

5 - RETARD 2

6 - RETARD 3

50 RPM

STEPS

7 - RPM SWITCH

P/N

3 - RPML 3

D - DEG / PSI

E - MAP SELECT

8 - HSA SLOPE

9 - HSA CUT-IN

A - HSA MAX

B - TRIGGER

C - CYLINDER

676M

BTR

UP

DOWN

VALUE

MODE

+50

RPM

CONTROL CENTER

®

MODE

FIGURE 1

Push this button to change the mode.

Push either of these buttons to change

the value of the mode.

NOTE: If any button is held down for more

than 1/2 second, the displayed value will

change automatically.

Additional Functions:

installation and setup work better. One of these is the high speed

advance function. This lets you put small amounts of timing in the

engine after the torque peak to pick up a bit of horsepower. There are

three things that need to be set up for this: the cut-in RPM (Mode 9),

the maximum advance (Mode A), and the slope (Mode 8). The cut-

in RPM is the RPM where you want the curve to start working. The

slope is how much the timing will advance every 1000 RPM after the

cut-in RPM. The maximum advance is the highest amount of ad-

vance you want the system to reach.

For example, say that your engine has the torque peak at 6500 RPM,

and you want to add some timing after this. You might want to start

adding timing after 7000 RPM, so this becomes your cut-in speed. If

you then want 2 degrees additional timing at 8000 RPM, then the

slope would be set for 2 degrees per 1000 RPM. However, let’s say

that you don’t want more than 2 degrees of advance, so you would set

the maximum advance at 2 degrees. See Example 7 for more detail.

The other similar mode available is trigger compensation, which is

set when the mode indicator is “b”. This lets you compensate for the

various delays in ignition timing caused by both electronic and me-

chanical changes. To set the trigger compensation, set mode 9 to

5000 RPM, and mode 8 to zero. What this does is tell the system to

start the high-speed advance at 5000 RPM, but with a slope of zero,

there should be no advance. Once the system is set up this way,

watch the timing as the engine revs past 5000 RPM. If the timing

does not stay at a steady value (once the 5000 RPM point is reached)

then adjust the compensation value until it is as flat as possible. For

example, if the timing retards slightly as the RPM goes up, increase

the compensation value. If the timing advances slightly as the RPM

goes up, decrease the compensation value.

NOTE: This function is only valid for RPM above the high-

speed advance cut-in RPM. If you have the high-speed ad-

vance cut-in set above the normal operational range of the

motor, the compensation function does nothing.

Once the compensation is set, then the high speed advance set-

tings will be accurate. The factory setting should be correct for

most types of flying magnet type crank trigger systems, and should

not normally need to be adjusted unless you are using a different

trigger type.

Number of cylinders selection

Number of cylinders selection

Number of cylinders selection

Number of cylinders selection

Number of cylinders selection

The next mode that can be set is mode “C”. This allows you to

select 4 through 12 cylinder operation. This ensures that the RPML

and the timing are proper for the engine. Mode 6F is special—this

is for odd-fire V6 engines ONLY! The cylinder firing spacing should

be 45/75 (at the distributor) or 90/150 at the crank.

MAP Sensor Functions:

The 676M has two modes for use with a MAP (manifold absolute

pressure) sensor. Mode “d” lets you select the number of degrees of

retard per pound of boost, from .1 to 4 degrees. Mode “E” lets you

select the type of MAP device. Typical MAP sensors used in turbo/

supercharged engines are either 2 or 3 bar range, and these

correspond to “2” and “3” in mode “E”. Selection “1” is different. This

is not made for a 1 bar MAP sensor. Instead, selection 1 lets you use

an external 0-5 volt signal to control a 0-20 degree retard. This signal

could be from an external dash-mount control, such as the Mallory

29784, or from an external proportional nitrous controller.

MAP sensor and extension harness are not supplied with 676M.

Part numbers are:

716

2 bar MAP Sensor

717

3 bar MAP Sensor

29785 Extension Harness

NOTE: The 3 bar MAP Sensor (PN 717) and Extension Harness

(PN 29785) are included when a complete Mallory 667BTR

Ignition System is purchased.