Ok, so on this car I recently got the previous owner had a vafc2 on the car. The mods are b16a pisons, short ram, 4-1 header, test pipe, msd blaster 2 coil, stock injectors and 60mm catback.
I noticed that on the vafc, throughout the entire rpm range it only had a correction of +1% at partial and full throttle. I was just playing around and added up to 7% in above 4000 rpms and at WOT. The car runs much better now up top. So this peaked my interest. Does anyone have any recommendations on ballpark figures (i know it wont be exact without wideband) on how much fuel I should be adding in up top?

And yes I know it will be a lot better with a chipped ecu instead of the VAFC.

Thanks in advance for the help!

 

Honestly, you need you read your A/F with a wideband. Only then will you be certain you are making beneficial changes. Anything else is just a guessing game. If it seems to run better adding some fuel, go ahead for now though, it won't hurt anything.

 

Yeah I'm figuring the same. I was kinda hoping some other high comp b18 guy would come in and tell me if he had to add fuel or not with boltons. Thanks for replying though.

 

Most High Comp guys over 11.8:1 don't use V-AFC anymore, now that more sophisticated management has dropped in price and is easier to get a hold of.

 

Yeah, i wouldn't be using it either if it wasn't already on the car when I got it lol.

 

Also to note, this is just my daily driver. Not really wanting to put much money into it right now. But I might invest in a good burnt chip and a dyno tune if I could gain some MPG.

 

sell the vafc on ebay , get crome and a chip burner

 

To adjust the fuel correction setting on VAFC II, the best way is to tune in on dyno in few runs and see the graph... U might need to monitor the excess O2 at the exhaust to know whether its rich or lean air-fuel-mixture.