WHATS THE TRUTH??? AFC/450cc's???
 

OK, I've been reading these posts for over a year now and still don't know if this is a safe setup....AFC DSM 450cc's 7psi D16Y7 MSD BTM . People say that the AFC hack will advance your timing too much at lower boost levels and possibly break something. Can't I retard the timing only under boost and be safe? I mean just let the ECU control things normally (except the pulsewidth of course) off boost then retard the timing only while under boost? That sounds right to me.. or do I have to retard the timing all the time(on/off boost) to get it back to factory timing off boost? please help guys I'm getting less and less attracted to the AFC hack every day but with reason? or do people just not know what the hell they're talking about? THANKS!!!

Re:WHATS THE TRUTH??? AFC/450cc's???
 

This is how I see it.
The AFC is to control the bigger injectors.
The BTM is to control your timing.
The BTM will only change your timing per pound of boost. So if your just cruising it won't retard your timing untill it see's boost. Plus everyone says that you don't need a BTM for 7psi anyways.

Re:WHATS THE TRUTH??? AFC/450cc's???
 

woah! slow down a bit! first of all the afc has nothing to do with your timing. thats just for your injectors. the btm is only to retard your timing under boost. ;D im using the afc hack with 8-9psi and no timing retard just 91 octane gas, and everything is runing smooth. so freaking smooth i dont have a clutch any more! my new one is in the mail as we speak!

Re:WHATS THE TRUTH??? AFC/450cc's???
 

i just thought of something...i dunno if it's the THC but do our cars....or my car D16Y7...even change their timing? I mean I have no knock sensor so my ECU can't retard timing right? I mean it wouldn't have a reason to not that it can't. nevermind I think this is a dumb question. I was trying to compare our cars to distributor-less cars but I forgot what I was trying to say...thank you please drive through

Re:WHATS THE TRUTH??? AFC/450cc's???
 

Honda ECU maps are in RPM vs MAP format for fuel as well as ignition. You better believe that it changes your ignition timing.

An AFC hack alters the nature of the stock ignition map in a way that an MSD-BTM cannot entirely address; for the lower part of the boost event you are running more total advance than the same ECU on a stock vehicle at WOT... about 10 degrees more on average.

The solution for OBD0/OBD1 is to chip your ECU with the correct ignition map. :>

Re:WHATS THE TRUTH??? AFC/450cc's???
 

well you know what i mean dam it, theres no settings on the afc to change the timing, byaltering what the ecu sees it will change the timing like joseph says but you wont have control of that like you would with a btm. make sense or am i just discerboblelated?

Re:WHATS THE TRUTH??? AFC/450cc's???
 

exactly, I know the AFC cannot directly change timing but the ECU will see a lower MAP voltage and advance timing....Can this be fixed with a BTM? probably not because it only works under boost. Damn so this AFC hack isn't as good as I thought. ----. Ok so it sounds like standalone is the only way to go to have a safe setup. OK one more question....what If I was to use smaller injectors like say 310ccs, wouldn't that keep the MAP voltage closer to where it should be by not having to go as far negative on the AFC? but then the ECU would see boost later in the rev range huh? dammit this sucks am I crazy?

Re:WHATS THE TRUTH??? AFC/450cc's???
 

The AFC hack is better than it appears. An MSD BTM, which costs $$$, can't cope with the nature in which the ignition curve has been altered. It can't take timing out where you most need it taken out.

For OBD0/OBD1 Hondas the solution is as simple as a chip with altered ignition profile to reflect the AFC hack. If you care to DIY, it costs as much as a Batronix chip burner ($75-100 depending) to implement. You also now have the backbone of a limited standalone, like Zdyne or Hondata.

Re:WHATS THE TRUTH??? AFC/450cc's???
 

thanks JD your info has really helped me and I appreciate it. Now one last question then I'll quit buggin you, I have a 99 DX with the D16Y7, what would be the downfalls of converting to OBD1? I mean are all the sensors interchangeable, I think that they probably are, seeing how Honda likes to use the same parts on as many cars as it can. I mean will i get weird CEL's because of the conversion? I would like to be able to use my existing wiring harness too is that possible? I should use a 92-95 DX ECU correct? THANKS!!!

Re:WHATS THE TRUTH??? AFC/450cc's???
 

If you run the wrong code in the OBD1 ECU your idle ends up a little unstable. It's cosmetic, but the earlier IACVs had a different duty cycle and code that suited them, the same can be said for the later IACV and code. You won't damage anything, the idle just hunts a bit.

And I do recommend the P06 Civic DX ECU since it's cheap and the same thing as most of the non-VTEC ECUs.

Re:WHATS THE TRUTH??? AFC/450cc's???
 

How much does the idle hunt? like jump around from 500-2000 or like 500-700? that I can deal with....Can I adjust the (injector) pulsewidth at idle to correct this or am I SOL? thanks!

Re:WHATS THE TRUTH??? AFC/450cc's???
 

Try 1000-1200 when you're supposed to idle at 850.

If you want a standalone type setup, get a P06, and OBD2 to OBD1 adapter harness, and the new Uberchips tuner app. Under $500 for everything - if you were already OBD1 the estimated price quote is $318, which includes your chip burner and all accessories except a laptop.

Re:WHATS THE TRUTH??? AFC/450cc's???
 

Is this even with altering the throttle screw thing? At its minimum/maximum? Just impossible to get around?

Re:WHATS THE TRUTH??? AFC/450cc's???
 

everything that i have heard is that base timing witht he hack and btm works just fine on obd2. however, if it isn't wouldn't just backing base timing at the distributor back a little and then using a btm work just as well? this would also give you a safety margin to use btm to adjust timing/tune safety if you got bad gas, had extreme temp/weather change (heat/humidity), or drove from fla to the mountains? please don't flame if i'm totally off base, just trying to get the 411.

Re:WHATS THE TRUTH??? AFC/450cc's???
 

People make the AFC + BTM setup work, yeah. Your ignition is still much more advanced when compared to FMU + BTM or the usual standalone settings. If you do not run lean, you won't have any problems. If you retard timing you will affect low end power and start up.

At the cost of AFC and BTM, you could have a better setup on an OBD2 car. My $0.02. If you are comfortable with an AFC + BTM setup and uncomfortable with the possible complexity of something I'd propose, go for the AFC + BTM... they do work, just be careful and get your fuel dialed in. It's not a safe starting point to tune from, so beware *shrug*

Re:WHATS THE TRUTH??? AFC/450cc's???
 

Thing is I already have the AFC from my last car....and 450cc would be cheap to get. I will get them from a yard then send them to RC to get cleaned /balanced before installing them. RC said it's about $20 per injector to clean and balance. The only thing I'm worried about is the ignition timing. I mean the ECU will advance it too much and i'm worried I won't hear the ping and then it'll all be over before I can lift off the throttle. Anyone have any idea what the timing will be at say 4000RPM with 450's set at -%35? I just want a ballpark figure to see how unsafe this setup really is. (stock ECU) D16Y7 thanks!!! one more thing, does the ECU base timing off of TPS voltage too? or just map voltage vs. RPM?

Re:WHATS THE TRUTH??? AFC/450cc's???
 

is uberchips vertigo?

Re:WHATS THE TRUTH??? AFC/450cc's???
 

The guy that got booted from this board for being a royal prick, yes.

Re:WHATS THE TRUTH??? AFC/450cc's???
 

jd by chance are you a moderator on the aem ems forum?