I just bought a vafc2 for my CT SCed s2k. I only got it because when I brought my s2k to have the FPR adjusted (and a few other things) they recommended that I get something better to adjust the AFR. I know the vafc isn't the best outthere but I only really wanted it so I don't foul the plugs and have to fill up twice a week. The car needed to be set really rich to offset the leanest point.

Anyway the shop was just going to street tune it so I didn't have to spend money on the dyno and they said the dyno wasn't necessary with just the vafc and my wideband. My friend street tuned his turbod car with a neo and has been telling me just to do it myself.

So what I am wondering is should I just do it myself? I'm guessing I just drive around at WOT and try to get all the AFRs as close to 12.5 without going over.

Also would I just leave the FPR where it is at and the map clamp in? I'm guessing since it is a piggy back i would still get a check engine light without the clamp and that what the FPR is at wouldn't effect anything as long as it isn't adjusted after the tune.

 

Been running this set up for years man, its a decent working system if you get it right. Your right in aiming for 12-12.5. You may find that right at vtec it will lean out momentarily at close to 13. as long as its a quick spike its fine. Just street tune it man, use 2nd and 3rd gear. 4th gear for pre vtec tune. Lower vtec to 5k -5.5k. There is allot of people that don't understand the vafc and are scared of it. But for your situation it fits the bill nicely. Just use it for WOT/wide tune and vtec control

Yes you need to leave the map clamp in.

 

I'm worried about the fuel correction factor when lowering vtec though. I just threw it on and have it at the stock settings for now. I might mess with it tomorrow if I have time. I have heard that the ecu relearns it's self so changing the narrow settings is useless.

 

Incorrect. The only settings that the ecu "re learns" is the narrow/closed loop fuel corrections. Vtec settings are not re learned and have no cause for concerns when lowering. The only thing you need to realize is that the vafc vtec control overrides the ecu's ability to control vtec by throttle position, so no matter what, your vtec will come on at the selected setting on the vafc. 5k rpm is about the lowest you what to go, other wise vtec will come on at partial throttle... if you shift high normally, or cruise at a rpm at 5k or above. Make sense?

 

I ment narrow not low cam. I got confused and fixed it right away after I posted.

But as I said I was worried about the correction factors when changing the engagement point because when reading the manual it looked tricky.

 

Nothing tricky about it. The directions are more confusing then actually making the adjustments Just set the high cam for 5k and the low cam for 4.9. This will let vtec come in at 5k on acc ...and then come off when lifting the throttle at 4.9k. You can move these points around anywhere you like with no issues. Set it for 5.5k on... and 4.3k off if you want for example. The purpose of this on/off engagement setting is to let you custom tailor your power curve for your driving habits. If you accelerate into a turn and let off you will fall out of vtec in oem mode sometimes. Adjusting the off vetc lower will let you stay in vtec to power out of the turn smoothly and quickly for example.