I finally installed my Apexi SAFC2 this week and have a couple of questions for those who have them. I am hoping that this thread can serve as a knowledge base on the apexi for the MINI since nothing like this seems to exist that I have found. Thanks for your help!

My questions:

1) When setting it up, what throttle positions do you guys use for the "lo-throttle" and "hi-throttle" points? I'm going to be dialing in my part throttle and full throttle maps the best that I can, so who's done it?

2) Any tips or tricks when choosing settings?

My initial impressions:

The Apexi thing is really cool, but with all of the features it's pretty complicated at first! (I actually had to read the directions on how to operate it .)

 

You better know what you are doing with that thing...

Lean it out too much and kaboom

I know more than a few DSM guys who have blown up their toys playing with those...

 

Haha, yeah...you're totally right on ! I'm not going higher than 14.7 off boost, and I'm aiming for 11.5 on boost.

 

Did you get the pinouts with the instructions or did you use the pinouts that were posted on NAM a long time ago? I hope others will post there experiences (pics). Resist the urge, just use SMALL changes and do a lot of driving and logging!

 

I am logging various things with my plx r-300, and the apexi is soldered in using the spi diagram. The unit solders into various locations on the 'input' and 'output' plugs of the ecu harness. I didn't tap the knock sensor wire, because I talked with DrO and apparently it has a separate ground point, so it can't well be tapped in our cars. Perhaps he can explain further...

If I can find a scanner and SPI (Hubie) doesn't care, I could maybe post the pin diagram. Hope this helps!

 

Shamelessly stolen from Ryephile:

100% gasoline has an "ideal burn" ratio of 14.7:1. That means 14.7 parts of air for every 1 part of fuel. A lower number [like 13.0:1] means there is less air for that 1 part of fuel, which is also called "rich". Peak torque is about 12.8:1; however it is engine dependant, and the range is typically 12.8:1 to 13.2:1. The caveat for those figures is they are intended for naturally aspirated engines. Boosted engines [via either supercharging or turbocharging] require richer mixtures in order to cool down the very hot combustion temperatures due to the very high cylinder pressures versus naturally aspirated engines. The cooling effect of a richer mixture yields a greater detonation resistance, and thus keeps the engine from blowing up! A rule of thumb for boosted engines is that you want to run "one number" richer than peak torque, so your target should be 11.8:1 to 12.2:1. All of these figures are intended for full-throttle situations, not part throttle.

Of course there is another caveat. Most fuels today use 10% ethanol, which has a different "ideal burn" ratio of 14.2:1. This means your target full-throttle AFR's need to be from 11.3:1 to 11.7:1.

Part throttle situations are handled by the feedback loop from the O2 sensor to the ECU, and should always be 14.7:1, which is what the ECU is programmed for. This air/fuel ratio is perfectly acceptable for part throttle, and aids in correct catalytic converter function as well as good fuel economy.

So, to summarize:
Part throttle up to 3psi of boost: 14.7:1
Full Throttle on any MCS: 11.5:1


Good Stuff!! And please let us know how you are coming along with the APEXi. Right now, that is the leading contender for the turbo-only project

 

Haha...yeah, Ryan's the man! I had actually emailed him about that, and that was his reply to me (pms were full!). I'm shooting for exactly what he wrote, so I'll let ya know how it turns out! One thing, though....I'm gonna go conservative on the 14.7 at part throttle (more like 14.5) just to make sure I don't end up with spikes much higher than 14.7. (I'm personally unsure of how dangerous a spike of 15 at 10% throttle would be, for instance. Ryan, care to interject??) My wideband shows the afr jumping a lil on cold days until the ecu adapts.

PS: I can definately confirm that the ecu 'adapts' to environmental conditions. Even after it's "learned" itself with a week's driving, the afr will go leaner in cold weather and then return to normal after a few minutes of driving. Ahh gas law and smart machines !

 

Im available to answer any questions you may have on the Apexi. On your low & high threshold settings, you need to set them on how you drive your car. You can go into monitor mode and select the THR to view. This will show you your throttle pos in a percentage. From there you can monitor your A/F ratios and see where you need the different maps to kick in at. I intially had mine set at 20 & 70 % but since then have changed them to 10 & 50 which i do believe is the default setting.

 

Do you have a wide band installed in your car?

 

If you're asking me, yes I have the AEM wideband o2.

 

Of course....plx r-300....wideband with data logging . I just got done with a 5 hour highway trip, and this thing is super sweet!

Thanks, Trickle X, for the info. I'll be pming you. (and I'll post things that I learn here for the community as I get mine dialed in )

Isellem, have you got any advice or tips? I will be happy to pm you if you'd like to converse that way, but I think that posting ideas and info here would be the best for the community. There's so little info on the Apexi here... Thanks!

 

this is a little off topic, but where can i find the diagram to wire up the safc2? i cant find the diagram anywhere.....please maybe just PM me with that. thanks!!! (ok sorry to hi-jack the thread....continue haha)

 

If you don't mind, what are the main differences between the 300 and the 500? Just debating which route to go.

 

any MC's with the SAFC2?

 

It actually comes with the unit. Its in the manual, but I know there is a scan of it on one of this posts regarding apexi...just search apexi or afc.

 

ok thanks, i got mine from a friend and it didnt come with a book etc.