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Just wondering,

what are the pro's and con's of using the Apexi SAFC if all you want to do is adjust air fuel ratios?

how difficult are they to wire in for the DIY'ers.

I assume you still need to get the car on a dyno to tune them correctly?

If that is all you want, they are great. Pros - you can get as much as 10rwkw just with that. cons - they are more expensive than things like the Jaycar Digital fuel adjuster and it does the same thing.

Yes you still need to get it dynoed, but they are pretty simple to install I think. Especially if you are a competant DIYer.

Brand new Apexi III on eBay are about $480, Apexi II new is about $350, Jaycar DFA $79 + $59 for the hand controller.

The apexi might do timing aswell, i'm not sure, I don't think so though.

Boags

No, Apexi only does fuel.

Easy to install, only 6 wires to connect, instructions as follows:
http://www.apexi-usa.com/pdfInstallation/15.pdf

On my NA8 I got 6rwkw when I got it tuned and like Boags says you HAVE to get it tuned on the dyno. Please ignore the US forums which say that you can tune it by ear (eg \"lean it off until it pings then richen it a notch)

Cons are that the work by fudging the airflow signal, so the more you lean off, the more ignition advance you will get, which may not be what you want, but in my experience, you only have to make small adjustments to the stock fuelling, so the ignition shouldn't be that far off.

I've never tried the Jaycar one, but the APexi does work well. Also has some limited data logging capability too.

PDF doesn't seem to be working Babs

JBT wrote:PDF doesn't seem to be working Babs

That's funny...just go to www.apexi-usa.com and click on "support". You'll see the links to the instructions...

Thanks Babs. First link was looking for updates and then just gave blank pages. Worked with your suggestion to go via the website.

Question:

The S-AFC II info says: ....Features for the S-AFC II include:
Newly designed case and user interface, single button menu navigation, 12 point fuel correction in 200 RPM increments.....

The Jaycar DFA info: ......It gives you the power to completely tune the air/fuel ratio throughout the entire load range, at 128 load points, providing incredible mapping resolution and brilliant drivability......

What does this mean? The DFA is more accurate when set up than the S-AFC II?

JBT wrote:Thanks Babs. First link was looking for updates and then just gave blank pages. Worked with your suggestion to go via the website.

Question:

The S-AFC II info says: ....Features for the S-AFC II include:
Newly designed case and user interface, single button menu navigation, 12 point fuel correction in 200 RPM increments.....

The Jaycar DFA info: ......It gives you the power to completely tune the air/fuel ratio throughout the entire load range, at 128 load points, providing incredible mapping resolution and brilliant drivability......

What does this mean? The DFA is more accurate when set up than the S-AFC II?

What it means is that the Jaycar thingy has more points where you can program in the lean/rich value. The SAFC has 12 points thruout the rev range and between those points it averages out the values.

The Jaycar thingy has a lot more resolution...question you should ask is...do you need it? Ie, if you're just plotting a straight line, does it matter that you have 128 points to do it with or 12?...and which is gonna be cheaper to tune on the dyno?

One of the limitations of the SAFC is that if you have to go lean here, rich there then lean again here, rich there, then it starts to "fight" the stock ecu, and gets an inconsistent result. This is where the Jaycar one will work better. But if you're just leaning off 12% after 4500rpm, then that issue won't rear its head...Decisions, decisions

Babalouie wrote:...Decisions, decisions

You ain't kidding . Thanks to everyone here though, I'm slowly starting to get my head around all this stuff. A couple of Autospeed articles on the DFA are helping too. Thanks for persevering with me everyone .

You could also run a MegaSquirt wired to control the fuel only.

JBT wrote:

Babalouie wrote:...Decisions, decisions

You ain't kidding . Thanks to everyone here though, I'm slowly starting to get my head around all this stuff. A couple of Autospeed articles on the DFA are helping too. Thanks for persevering with me everyone .

Yeah, don't forget ease of tuning as one of the things you should take into consideration. SAFC has only a small number of adjustments so 15mins on the dyno is more than enough and then you're on your way (and it's fun to sit in the passenger seat and make the adjustments yourself). That's a much cheaper exercise compared to a car which has to spend half a day on the dyno...it also is a piss easy install, I struggle with stereo installs (took me a week to do the Luce) but I had the SAFC going in 20mins.

saboteur wrote:You could also run a MegaSquirt wired to control the fuel only.

I might have to use yours on a long term trial .

Babalouie wrote:don't forget ease of tuning as one of the things you should take into consideration

Very good point. I suppose one thing that puts me off the SAFC II is that screen thingy. Don't like the idea of that sticking up on the dash or something. Where have you got yours mounted? Photo?

JBT wrote:Very good point. I suppose one thing that puts me off the SAFC II is that screen thingy. Don't like the idea of that sticking up on the dash or something. Where have you got yours mounted? Photo?

Mine is mounted below the single-DIN stereo. Rather than have a pocket like most, I screwed in an alloy plate, which I was at some point going to put gauges in. The SAFC is velcroed there, and when I part in dodgy places, I unattach it and slide it under the mat...it's worthwhile having the SAFC in an accessible place, since you can toggle it to the peak readings, which you tend to do to see how close you got to redline, max airflow, etc.