AFC tuning how to? "properly" and "on your own"
 

My car has CAI, catback exhaust, and VAFC-II installed. I am wondering how I should tune my AFC.

I am not interested in messing with VTEC... just the A/F ratio. I've played around the settings and know that there's some power to be extraced, but I can't get it right.

So I guess my question is two-fold:

1. If I am to spend money and take it to a shop, what are the procedure and equipment involved?

2. If I am to do it on my own, with "butt dyno", or possibly a dyno software running in a laptop which plugs into OBD (forgot what the software is called), what's the procedure involved? And what's the goal? I realize most likely with #2 I can't get as much as #1, but I am asking given what I have in #2, what can I do the get the most out of it.

With #2, I've played around with A/F corrections at various RPM, and the throttle points (narrow/wide throttle percentage). I can't get it quite right - my main problems are that a) there's a "power dip" at around 3-3.5k RPM, and b) the throttle response is not linear... i.e. when I step on it, there's power, but when I step further, the power is flat. I recently disabled the settings, and find the stock settings nice and smooth and linear...so I know my procedure is wrong and want to start from scratch.

I am trying to use #1 as the last resort as much as possible, simply because it's costly and #2 is more fun and rewarding. Any help is appreciated. Thanks in Advance.

I'm assuming your running this on a Honda but the year and model of car would help out.

VAFC are not very reliable for actual tuning and if your wanting to actually do some real tuning you will need datalogging and a wideband as well as a chipped ECU.

Berz out.

Car is 99 Honda Prelude SH.

After some research it seems that if I want to go for standalone ECU, then I have to give up ATTS. So this isn't desirable for me.

VAFC can't be completely worthless... can it? :) There must be some ways that it's a useful tuning tool... (is there?)