I was wondering if a Apex-i AFC II controller is worth getting for a NA maxima. I figured I would ask you guys in this forum cause you would know more about them.

 

A NA Maxima would need at most only minor changes to the afr, which would have to be done on a dyno. So you're looking at spending $300+ for the s-afc II plus a couple of hundred for the dyno time for only a few hp gain. Not worth it. It would be better to spend your money on a JWT ECU upgrade.

 

JWT don't have a ECU upgrade for a 2000 maxima.

 

many SC/TC'ed maximas were running super rich to begin with. in that case, you can fine-tune the car by using the S-AFC. That way, you will adjust the air-fuel ratio to the lean side a little bit. For instance, maxxboost00's car was running less than 10:1 AFR and dynoed at 270whp. With SAFC, Kevin was able to bring the AFR back to 11.5:1 and the car then dynoed at 301whp.

 

Not worth it, even if you do gain 1-2hp at the wheel, you won't be able to tell because your dyno runs won't all come out with the exact same hp #'s.

Use only if you have forced air induction.

 

Doesn't the ECU learn that the AFC is in the system and eventually compensate back to factory settings? Wouldn't this make AFCs (Fields, Apexi, etc.) useless? I think you can reset the ECU every now and then and get around this though.

 

This is true for the low throttle settings. The high throttle settings when the ECU is in open loop mode are not corrected by the ECU.

 

So the AFC can change the open loop operation of the system??

 

Yes. This is also why we can run rising-rate fmus to lower the afr when boosting. The ecu doesn't try to correct anything at high throttle or WOT settings. It just thinks everything is going according to premapped air-fuel curves based on a 43 psi fuel pressure and is happily oblivious to the massive amounts of air and fuel being dumped into the engine.

 

I see

It seems like a new ECU program would be the only way to perminently remap the a/f curves for increased power below WOT. It would be really nice to feel the increases in power at all times, not just with the pedal to the floor.

 

That would be nice, but it would probably be too expensive for getting more efficiency out of the engine at partial throttle.

Also how often do you race at partial throttle
-hype

 

A partial throttle race is when the guy next to you is racing you and you don't realize it. Probably happens more than we realize.

Air-fuel mapping at partial throttle is optimized to give as close to a stoichiometric afr as possible. It doesn't serve any purpose to change that, your gas mileage would suffer and you would pollute more. (And we're really concerned about pollution in this forum, wink-wink nudge-nudge.)

 

Isn't a JWT ECU upgrade similar in price to a Vortec Super FMU and an Apexi Super AFCII?

 

Yes, it is. $595 for the jwt upgrade, $279 for the sfmu and I've seen s-afcII's for about $330.