Getting the most out of your Apexi S-AFC= Stock MAF honeycomb removal

[Multiades]

Originally posted by BAdAzZV8
When you remove a restriction in the MAS(combs) you are letting more air in, but not all of it is being metered. That is why it leans out your car, b/c more air is getting in and not being metered. That is why he can richen his AFC and get timing retard.

The vette guys gut their MAFs to run a little leaner b/c factory settings are a bit rich.

So multiades, he is correct when he says that you can richen the AFC when gutting the MAS. You see, not all the air is being metered, so there is no correction at the MAS as you stated, there is only the AFC correction.

I understand that you can richen the AFC when gutting the MAS, and I understand WHY you can richen the AFC when gutting the MAS.

Let me phrase it differently for you: not metering all of the airflow coming into the engine is EXACTLY THE SAME AS applying a negative correction on an AFC.

That's really all that's going on here -- you use less negative correction at the AFC, because the MAS itself is already misrepresenting the amount of air moving through it. The AFC is designed and installed for the purpose of misrepresenting airflow, but it does it by modifying the signal directly, not by bypassing the metering element.

I'll draw a diagram later if need be.

-Chris Wood

[BlackStealth]

Your AFC setting seem very rich. I have a similar setup, and with the FJO, I'm closer to -30 LO across the board, and -30 from 1K to 4K, and -39-39

My car at the time didn't have a fuel rewire mod and ran great with those settings. Now that I did the Erik Gross fuel rewire mod, I'm running very rich. So yeah, my settings will be going more negative just as soon as I retune it tonight/tomorrow.

Removing honeycombs from the MAF isn't new to me. The absence of the honeycombs allows more unmetered air. This alone is responsible for the biggest gain more so than what overall air flow restrictions the honeycombs imposed. Some people reported problems when doing this mod on their Talons, but mine worked fine. Once I got a SAFC for the Talon, I had to add alot of postive correction at idle to get the O2s to cycle again. Somewhere in the neighbourhood of +43% correction, and close to 0% correction on the other RPM bands. My car still had stock injectors, and the purpose of the mod was to avoid fuel cut. The hacked MAF reported less Hz (airflow) to the ECU and never reached the critical fuel cut Hz flow number.

After reading the success of Innovator's mod I'm a little torn. Stick with the MAFT+LS6 MAF mod and live with high timing or mod the stock MAF & have reasonable timing numbers.

[Innovator]

Chris.

Doing it mechanically as opposed to electrically, yields different results.

The AFC is entering an altered signal, where as the modded maf is actually allowing more to enter in addition to fooling the ECU. Some how the AFC in line is altering more than just the MAF signal.

I know you understand this from an engineering standpoint, but there are other factors than neither you or I are aware of. The results I've experienced are factual, and it appears the explanation goes beyond the obvious.


In the end, it really doesn't matter why it works, because the end result is that it does.

Perhaps you can figure out *exactly* why it works, but this thread isn't being aided by arguing.

[Import Power]

Some get odd results gutting the maf. Thier cars start acting wierd and driveability goes out the window. If it works for you go for it. But it's not a 100% of the time reliable tuning/setup method.

Guess try it for a while and see what happens.

[Turbodrvn]

Originally posted by antero


After reading the success of Innovator's mod I'm a little torn. Stick with the MAFT+LS6 MAF mod and live with high timing or mod the stock MAF & have reasonable timing numbers.

Me too, antero........I'm torn and awaiting more feedback/results from both mods......

Innovator: we appreciate your research and development....please keep it coming......much thanks..


Peace,

Ahmed.

[Innovator]

Originally posted by Imp Pwr Online
Some get odd results gutting the maf. Thier cars start acting wierd and driveability goes out the window. If it works for you go for it. But it's not a 100% of the time reliable tuning/setup method.

Guess try it for a while and see what happens.

I still can't think of a single reason why this would cause runability issues"after a while". If the fuel trims are good (closed loop when cruising), there is absolutly no reason why the ECU would get spooked.

If the LTFT is in the window, and the car stay in closed loop when it should be, the ECU is happy, end of story. It should not change.

The only thing I have to add to my original post , is that the correction has to be positive (like +15 at idle )because of the reduced metered air flow at idle. Idle is much more affected by this modification than any other RPM point... I found with my 550cc injectors that other than at idle, Low settings of-15- 20 is perfect...

Low settings are not that critical, as long as you get the car in closed loop. The ECU will do the rest of the work for you while idling, at partial throttle, and cruising. Itf the low settings are to wacked, you will get a CEL that will point you in the right direction ( to go leaner or richer) WOT needs the real fine tuning, but that's not rocket science either. The wideband O is the best way. I think it's one of the most important things you can buy. I've tuned 100's of cars, and I'd be lost without a wideband. I'm just pissed I waited so long to tune my own car with one. Ehh, the customer always come first ....

Save your money that you would spend on a different metering system, mod your current MAF and get a FJO. See what HP you've been leaving on the table by running by having to to rich because your timing was to high.

[Bluv69k]

Originally posted by Bluv69k
so let me get this right.
You removed the sides and top and bottom of the mas honeycomb. You then had to richen you high and low, lets say roughly 10%. What is you low/high % set at? What is you base timing set at? any thing special? And thats all I have to do? just adjust the s-afc to compensate for the "missing air flow"? How easy are they to reinstall if this dosn't work well?

Can someone explain in some detail what open and closed loop is?

anybody?

[Innovator]

Originally posted by Bluv69k
anybody?

Closed loop is a mode that the ECU goes in to when at idle, partial throttle and at cruising speeds.

In this mode, it uses the O2 sensors to maintain a A/F ratio of 14.7:1 (Stoich), which is the chemically correct mixture for the lowest emissions and fuel economy.


If you have the setting to far off, the ECU can't achieve closed loop.

At WOT, the ECU comes out of closed loop, disregards the O2's completley, and uses the MAF to regulate fuel. THat is why it's so important to have the WOT A/F setting correct.

In closed loop, the ECU is very adaptable, and it has a big range it can work within...

[Bluv69k]

well how do you know it is in closed loop? How can you tune with a regular 02 sensor? any instructions on hacking the mas?

[Innovator]

When in closed loop, the O2 voltages will cycle rapidly from .1-.8 volts .

If you have a A/F gauge, you will be able to tell with ease. If not, you can use a DVOM hooked up to the signal wire of either upsteam 02. Really though, you need to have at least a basic A/F gauge, or you should just leave it alone...

To mod the MAF, you just need to remove the four screws on the MAF the hold the honeycombs in, and gently tap out the two side and one lower HC out. You leave in the large center HC.

Use the smooth back of the screwdriver to tap the HC's out. Don't hit them hard. A gentle tap will work without damaging them.