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22750 Views 49 Replies 10 Participants Last post by  Revhead Kev
Ok it is finally here:
Here is my humble "how to" for the installation of A'PEXi SAFC II on X-Trail 2005 QR25DE engine (Canadian Edition):

** This write-up does not cover the initial set up configuration and tuning of the SAFC II. This should be done by a knowledgable tech.
** Also take note that once your SAFC is installed and powered you should immediately do initial set-up before starting the engine.

** Warning:
- Not for the faint at heart.
- Knowledgeable and at ease with wiring & soldering is a must.
- Not responsible for "screw ups".

I can't say it enough: Read, Re-Read, and PLEASE Read again ALL documents supplied by A'PEXi with the unit.

Find a suitable location for mounting the unit.
I located mine in the hidden double door compartment below the climate controls. (see below)

Take off some side panelling to find a suitable route for the cable.

Access the ECM location by:
- removing the "lower panel" (part 27 in picture) snaps in only
- removing the "glove box" (part 31 in picture) by removing two holding pins (part 32 in picture)
- removing the "glove box cover" (part 36 in picture) held in place by a quantity of 6 screws (part 3 in picture)
(While taking this last part be careful not to pull apart the air bag connector)

So far these steps are the same as what is needed to access the "cabin air filter" (models equipped).

You should now be able to see the ECM as per below:

WARNING: Before disconnecting any ECM harness connector: YOU MUST Disconnect the batterie negative terminal.
(unfortunately this will screw up radio settings and clock :( )

Disconnect harness connectors as per pic below and carefully remove the protector covering the connectors.

Also carefully pull away some the black plastic wire covering; you should now be able to see clearly the pin connector and each wire.

Start identifying each wire color and confirm the terminal point number:

Terminal----car ECM--------------sensor------------------A'PEXi SAFC II
number----wire color---------------------------------------wire color

# 15---(wire color white)-------Knock sensor---------------color purple
# 50---(wire color white)-----Throttle position--------------color grey
# 51---(wire color orange)---Mass Air Flow sensor--------color white & color yellow

# 116--(wire color black)----------Ground------------color brown & color black
# 120--(wire color grey)-------Power Supply----------------color red
# 103--(---no wire----)--------Tach RPM-------------------color green

All SAFC wires tap onto ECM wires except for the MAF sensor;
MAF sensor wire is to be cut:
SAFC's yellow wire connects to ECM side of #51 orange wire
SAFC's white wire connects to car's MAF sensor side of orange wire

In the case of the car ECM RPM signal:
Some model years (in this case 2005) do not have a wire attached to the terminal # 103;
you therefore have to get inventive on how to insert a wire into the terminal # 103 and get a good connection. Some report heating wire end covered with solder and inserting it into the terminal socket, but I would prefer some other method; I have not figured that one out yet but as soon as I do I will write a follow up.
In the case of the SAFC ground wire: there are two wires (brown & black) that need to be connected to the same car ECM ground wire with only a small space between them (no less than 1 cm). Also note that the SAFC brown wire should be the one closer to the ECM side.

- The above wire color codes correspond to my 2005 X-trail with QR25DE Canadian Edition.
- Color codes for your particular car should be doubled check in your applicable service manual since they may not necessarily match.

Once all connections are done, soldered and secured, tidy up the harness, put back the insulation, button the harness back to the ECM and close up the area in the reverse order.

(I will be seeing my tuner/technician/chemist this coming thursday for proper tuning, and will report back on the improvements)

If you are interested in accessing my SAFC II on my page, here is the direct link:

There you go, I'm done. I hope this helps and is not too confusing...
Comments welcomed.
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ValBoo said:
Here's how A'PEXi SAFC works:
You can have it set with two different metering maps:

Map 1 which is applied at 35% wot or below
Map 2 which is applied at 75% wot or above

When you are in-between 35% and 75% wot the unit will proportionally interpolate settings between Map 1 and Map 2.

Hope this helps.

Marc, from what I've read on the Spec-V forums, we should just set the high map since the QR just reads on closed loops when not under aceleration or when the accelerator is not fully depressed. I just set the high map and have it kicking in at 35%.
Thanks Valboo. hope we can share more experience. did u dyno ur xttail after install safc II ?how many hp add?tnx.
Hi Wilson,
No dyno before or after any of my mods unfortunately.
But depending how bad (rich) your air fuel map is you may expect 6 to 7% improvement in power with a good map adjsutment.
Hi Valboo,
Glad to hear ur feed back.can u teach me how to tune my safc2 ? bec i just installed it 2wks ago,but until now stil not tune .thanks.
ValBoo said:
Hi Wilson,
No dyno before or after any of my mods unfortunately.
But depending how bad (rich) your air fuel map is you may expect 6 to 7% improvement in power with a good map adjsutment.

Hi Wilson,

Since you asked about this...
I was browsing on an another forum and found this dyno graph relating to the addition & tuning with an SAFC...this is really good info:

This is based on a QR25DE engine out of Spec V but the air fuel ratio numbers look alot like mine were:
You can see that prior to tuning this graph shows a rich air fuel mixture at 11.5 to 12.0.
After tuning it is leaner at 13 to 13.5.

The horsepower numbers are represented at the wheels and show a peak increase from around 150 to 165. This translates to an increase of 10%... a little more than I mentioned in my earlier post :).
Hope this helps.
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Hi Valboo,
Thanks so much of the picture n teach.hope i can tune it like the picture. hehehe
Marc, I am now looking at getting the Apexi for my exy (that sounded good LOL) to correct the running rich problem I am having, but when I started to look for to aqcuire one I noticed that there is a new release product that was released after the Apexi SAFC II, called the APEXI AFC NEO which seems to do everything the SAFCII did and offer more.

Do you know anything about it and if it can be hooked-up to the exy in the same way the SAFCII?

Also, I have been getting conflicting recommendations about the use of the Apexi due to the fact that it doesn't offer timing advance capabilities which other similar devices (like eManage and others) can offer.

Is timing advance capability really needed, considering that the TA can be done as a one off setting or do I need to look to have the TA value adjusted for all RPM ranges?

I have looked over the AFC NEO... looks good and wiring seems to be the same.
see link for manual and wiring (PDF):
APEXi - Super AFC NEO - Manuals and Documentation - Nengun Performance

I cannot answer your question about the need to control timing advance: I just don't know enough on it (yet). :)
Thanks Marc. I have decided to go with the Unichip that controls both timing and fuel:air ratios. Will update you guys when it is all fitted and dyno tuned.
The documentation only shows Nissan Xtrail QR20DE.
How different would the ECU be for the QR25DE we have ?
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