I agree 'the hack' is not the way to go. That was sorted out pretty early in the thread. I do think that a normal AFC install is the right solution. As you can see from the A/F line in the dyno above, the changes needed in the fuel map are pretty minor. The shop I talked to that did an AFC install with this kit picked up 4-6 hp over most of the power band and cleaned up the fuel delivery pretty well. That is exactly what I had hoped it would do.

Thanks to everyone that posted something useful - consider the problem solved. Again, I will post before and after dynos in about a month, when the kit is installed and tuned.

 

ok people lets clear some things up

HE IS NOT RUNNING THE HACK!!!!

so stop posting about how the hack works or why it sucks because it doesn't apply here.

and yes i believe that the afc will allow you to adjust the a/f curve with it hooked up as designed and the kit hooked up with everything as well. if the afc is set to 0 across the board then your fuel curve would be the same as if it were not there. then you can adjust it accordingly. i don't see why it wouldnt work

my .02

 

My take on the subjects discussed so far:

The AFC hack this gentleman isn't running on his NSX would be a bad idea.

I believe the gentleman who owns an NSX, and had his injectors flow tested, that his injectors are 240cc units. 5.0 Mustang ran 180cc units. Most OEM injectors are smaller than you'd think.

There is nothing wrong with an FMU setup, if properly done. Use bigger injectors, a lower ratio FMU, and the AFC to tune the transitories... and amazingly an FMU works perfectly. All the high fuel pressure that make FMUs such a bad idea? They don't happen with bigger injectors and lower ratio FMUs. Any other complaints?

I'm not a big fan of a bunch of add-on controllers... are you or a friend handy with electronics in a kit form, and comfortable with setting up a standalone? Parts for a Megasquirt AVR run $170, it's a tune on the fly offshoot of the EFI332/diy-efi project. It offers full control of fuel, ignition, monitors wideband O2 sensors, and has motherfucking ION SENSE abilities. Can you say four digit pricetag fuel injection computers get fucked?

 

If you use the AFC with the voltage clamp, you will only be able to reduce the fuel curve, not add. the voltage clamp will prevent your ecu from seeing boost. during boost, your ecu thinks that it's just WOT and the injectors will be at peak duty cycle and the fmu will adjust fuel according to boost level. the afc will alow you to remove fuel, if you try to add fuel, the afc will change the map voltage to higher than at WOT and your ecu will read boost and through a code. so you can run a higher ratio fmu and use the afc to cut back fuel. that' my sugession. BTW, if i had an NSX, i would not be experimenting with any untested fuel setup. a used nsx engine is hard to come by.

as far as VAFC hack on boosted setup, I used it on my boosted b16 crx for 2 years and i was happy with it.

 

He wont gain much with AFC....

Why? Cause at 0psi (atmospheric pressure), MAP sensor reads almost 3V.
At 3.1V ECU goes into limp mode (at least on Civic's.. so NSX might be in same boat). Meaning, he still needs voltage clamp at 3V, but he could raise that 3V to almost 3.1V to gain that 3% more fuel. And that's it.

But.. seing as he leans out at higher rpm's.... maybe his fuel pump is starving injectors? Remember.. FMU....

So, I'd suggest also better fuel pump

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by khoalie &raquo;</TD></TR><TR><TD CLASS="quote">ok people lets clear some things up

HE IS NOT RUNNING THE HACK!!!!</TD></TR></TABLE>

True, but the thread is titled "AFC Hack on NSX"

 

Well, it looks like you have a solution, but here's two pennies anyway:

1. The AFC used in the traditional sense will do nothing for you under boost if you keep the voltage clamp. Try it, you will see.

2. I don't know why people jacked your thread here talking about the AFC hack. You didn't even want to know about that.

3. If you remove the clamp the car will go into limp mode after the MAp sees too much pressure so suing the afc without it is pretty much useless.

4. Hey, its your choice. I wish I had an NSX to play with.

Randy