Virgin KA-T tuning question/problem

[gunluvS14]

Hey guys,

First time KA-T here, so please be gentle with me.
Well, my setup is typical bottom mount T2 manifold, front mount, walbro fuel pump; running N62 MAF, 550cc injectors, and yes, I tune it with S-afc2 and AEM WB UEGO.

Before you tell me to throw that S-AFC into the trash can, which I will in 6 months, I would like to give it a try first.

The problem I'm having at this moment is, the transient response and occasional hesitation/hi-cup.

I'm running low boost right now, pump gas, and my base timing is set to around 16-18* BTDC. I'm running NGK BKR7E copper plug, gapped to 0.032". No sign of detonation on the plugs yet.

During cruising under partial throttle, 3k, 3.5k rpm, not building boost yet, my AFR is around 14.7 to 15.8, that's normal right?

Under boost, I have a pretty flat 10.8:1 AFR from 3k to 6,600rpm, pretty rich, I might trim it out a bit later on. No problem there, the car pulls fine and smooth.

NOW, it only works when I roll in my throttle slowly, but if I am cruising, around 2,500rpm, still have vacuum, then I jab open the throttle suddenly, my AFR will go dead lean, the car will buck, and it will take a full second before the car generate power again or having the AFR falls back down to where it supposed to be.

At first I thought it was my MAF sensor, but i pulled the code, it didn't say anything about my MAF. That scenario only happend when I have WOT in a hurry, if I be smooth and roll it in slowly, i wouldn't have that problem.

I would like to have it fix before my next autoX event, if the car being retarded like this, I won't be having any fun.

Can someone help me out and give me some suggestions?

Thanks in advance :)

[gunluvS14]

no input or comment from you guys?

[smelly240]

you wont be able to fix this problem without a daughterboard... the a-afc is actually dramatically increasing the timing yor computer is giving since its telling th eecu theres much less load than there is -

if u get a daughterboard - i can give you an extremely good base to start with, but an afc will get you nowhere.

you probably have 25deg of timing at wot bc of that stupid thing.

theres nothing you can do to make the safc work better

[gunluvS14]

Hmm, that's a shame.
if its timing related, how come it only happens when I have a quick throttle opening.

The car drives fine and make decent power under WOT if I roll in the throttle smoothly.
someone suggested i have a bad FPR which react too slow from vacuum to boost.

[awesomenick]

If you'd like another piggyback thing to help the SAFC, you could use an MSD BTM.

I have one for sale.

But in all honesty, I would get a daughterboard.

[Exas Spec D]

Try KA-T.org. They answered my questions pretty damn quick and fixed my issues with my set-up.

[S14DB]

SAFC only does RPM trim. It has no load map. You are only going to get it spot on for one throttle position, WOT.

Time to get some real tuning.