Ok, I found out the local dyno is $80 for baseline, with unlimited runs afterwards.

Tuning the AFC, what percentage of throttle should I have it come on at?

What is the best A/F to shoot for with N/A mods?

About how much does 1% on the AFC change the A/F?
What I mean is my A/F is at 13.9 and I change my AFC to -1%, what will the change be on my A/F?

 

You will find out on a dyno what percentage does what. Every car is different.

all the tuning is usually done with WOT, but I'm pretty sure you could try different throttle positions.

 

Right now I have the AFC set to start correcting at 95% throttle. I read on HP.com that if you do that then the ECU will most likely not adjust itself to correct the AFC. Most driving from what I have notice is between 12 and 20 percent throttle. I could probably adjust it down to about 60% and not harm anything.

 

Very possible. You could always go and adjust even those low throttle settings for better gas milage or something.

 

if he goes back and try to lean/richen in the lower mid range to save fuel the ECU will relearn everything and "cancel" after a while what he's doing with the SAFC
reason is simple, the ECU reads the O2 sensor and "see" what's coming out of the engine

To modify the A/F ration under closed loop (90%) of most street driving with the SAFC you'll have to hook it up the the front O2 sensor wire so this way you'll lie to the computer telling him you're running too rich, the computer will in turn lean the engine via the short and long term fuel trims

the idea with the SAFC hooked up to the MAF wire is to use it only for WOT (open loop) conditions,that way the ECU won't "relearn" the corrections made by the SAFC

shoot for a A/F of 13.5 to 1 at WOT

 

I don't know who started that shitty rumor about mods affecting the a/f ratio because it "brings in more air". The ECU via MAF, Knock, and O2, is going to read whatever has been done and put the AFR where it wants. A CAI isn't gonna run the car lean/rich/whatever. This is only applicable to old school carbs, where they don't have an ECU to correct for this. So getout.gif old schoolers!!! mad.gif

lmao.gif

Java:
You want your WOT to be around 13.5:1
So set your low throttle point at 20%, and your high throttle at 80%. (The stock ECU converts to Open/Closed Loop Map around 60% IIRC.)
Leave your SAFC LOW map at 0% all the way across. (The ECU is going to cancel out these numbers no matter what you put in. Unless of course you do something more than 20% out of the ECU's correcting range. Then it'll throw a CEL.)

Now, go out on a *large open/empty highway* and start running in 4th gear. Then do a WOT run taking note of your AFR's and correct them in the SAFC High Map as needed, until you get roughly 13.5:1 across the board.


And you're done tuning.......for now.

 

Thanks JonGTR, that's what I needed to know. And that rumor about mods affecting A/F isn't just here, there is a local site that I post on and they tried telling me I am good to go cause the CAI and BBTB have adjusted my A/F already. smile.gif

 

Yea, probably started by carburated people. They don't have ECU's to correct it for them.

 

carbs in fact add fuel based on the air flow but can't see the denser charge (cold air)
MAP sensor system (rd and most honda) won't see the added air flow they'll see the denser (colder) charge with the IAT so to an extent they will compensate for the CAI but not by 100% see yes.. map car will run a bit leaner with a CAI

 

We don't have MAP's. Our MAF see's the extra airflow, and the AIT sees the colder temps. Everything gets figured.