IonNinja

the way it appears to be done on the AEM forums is that the majority of the tuning is done via o2 feedback and then cleaned up afterwards with the fuel map. guess it doesn't really matter though as long as you get the correct result.

so in reality, you really should only be reading 14.7:1 at idle and/or vacum right? i don't have a wideband so not sure how it all reads under partial throttle and coast down...

o3nisoaso3

those are what i got now

i have cams and full exhaust along with an intake soon, thats what i am tuning for. what kinds of power would i be looking at?


what are the names of some of the best books you read? i read a few and want more cant find any that i think are good

xCobalt05x

ok, im going to have to look in how to do that. im not quite clear on how the AEM is going to mask the computer from seeing the AFR real time. from the install instructions the narrow band o2 signal is only tapped and not intercepted so it could send a "clamped" signal to factory computer (dont know how else to describe it). tapping a signal wont modify or alter the singal that will go back to the factory computer. only and interception of the signal will allow for you to send an altered signal back tot he factory computer

Sw4y1313

At cruise and idle you will read about 14.7:1. During load for FI you want to be around 11.5 - 12:1. Im going to stick it around 11.8:1 max to be safe and then jump on a dyno to see what the car likes the most.

o2 feedback is alterning the o2 signal so the car will add or remove fuel. But what you really want to do is make it so the computer thinks its still at 14.7:1 and not at 11.5:1 like you want to be(on an FI car). Your doing this because if the car sees your running too rich, it will pull fuel on its own, which you dont want it to do. And thats where fuel trim comes into play. If you alter the cars fuel trim too much, it will throw a CEL and i believe go into limp mode.

o3nisoaso3, i just searched on the forums and on google for each part of the car. Once i grasped the functions of each part of the car, i went on to turbo systems, and read about each part of that. Take it one step at a time. Your curiosity(sp?) will lead the way, or at least mine did. Try this: every time you read a post about something your unsure of, go to google and search it. Find out as much about that topic as you can. Then come back to the forums and do it all over again.

slindborg

A good site for boosted early 1990's 2.0L 16V GM engines is www.max-boost.co.uk

Cobalt4Life

so a clamped signal meaning it tricks the ECM for a certain AFR?? bascially locked on to a certain number so that the ecm believes its that certain number.. sorry confused a tad and confusing myself lol..

IonNinja

i have this book, which is fairly good from what I've read so far:

http://www.amazon.com/Modify-Managem...048231-2957245


i also have this one but it doesn't really address tuning:
http://www.amazon.com/Street-Turboch...pd_sim_b_img_2


but pretty informative...

Witt

Not only does it clamp it, it offers a signal "skew" in which you can alter the feedback signal from the o2 to the PCM in order to pull your fuel trims back to near 0.

BTW, Ionninja those are two of the most informative books out there. The How to Tune and Modify EMS gives a very good explanation on how EMS and all the supporting components work in terms anyone can understand.

IonNinja

with the AEM you aren't clamping the o2 signal you are intercepting it...

with what I have read so far, you can simply alter the voltage being sent to the ECU by the o2 sensor and the ECU will then pull or add fuel (to an extent) to get you to the AFR you are looking for...

so for instance, if you need additional fuel at a certain point on the map (the one I saw was MAP vs voltage)...you decrease the voltage being sent to the ECU so it will think its running lean and add additional fuel. this is the basics of it from what I understand...

you can also adjust fuel trims and clamp the MAF as well...

I got it for Christmas

still have alot more to read though...

Witt

This I don't think can happen. AEM states their software only works with analog MAFs. Someone wrote a write up on intercepting MAF that Zinner and I questioned. Neither the software or hardware appears to have digital MAF capabilities. AEM support has also stated on their forum that they don't support digital MAFs.

Even if they did, you really wouldn't want to mess with it too much with an electronic throttle. If you skew MAF too far from MAP or TPS you'll end up with limp mode quickly.

IonNinja

I don't even know the diff between analog and digital MAF so I can't argue that

I do know they support some form of MAF adjustments but I guess if the above is true we can assume its referring to analog MAFs.

that kinda raises a concern though because in the thread I posted in the tuning forum, I remember reading that if I could make adjustments to the MAF when tuning for mild cams then everything would sort of "fall into place." well if I can't tune the MAF then what? stuck with tuning via o2 feedback?

Witt

You shouldn't need to tune the MAF really. Tuning the o2 will tune the MAF and MAP at the same time which is optimal in a 2.2L cobalt imo.

The signal that each reports to the PCM. Digital ones report back a frequency analog report a voltage 0-5v.

IonNinja

ohhhh okay actually I remember this being mentioned on the AEM forums somewhere...

sort of off topic but why would an MAF clamp be needed anyway, IIRC the Hahn kit on the LSJ does not max out the MAF so why would this be necessary on 2.2 power levels?

MAP clamp I can understand but not MAF...

Witt

GM MAFs can reach about 13,000hz before clipping occurs. Because the stock DTCs are setup to trigger a MIL anytime something could no longer be emissions compliant the normal operating frequency may not ever exceed 10,000hz or so as anything above that on a stock engine would be abnormal. There the failure point of the MAF would be coded into the software, something an SCT reflash can fix.

IonNinja

okay so essentially they're just raising the failure point whereas its not something 2.2 guys can do so we essentially would just clamp it before that point.

makes sense i just didn't think it would be necessary...

xCobalt05x

the AEM install instructions shows a Tap to the o2 and not an interseption of the wires.

tru2nrtt777

iTrader: (1)

Simply put:
analog=rolling hills of signal (~~~~~)
digital=cliffs and walls (_-_-_-_-)

lightinbalt

Ok, I have a quick question, I know that you have to look at your afr when tuning with the piggyback. if i where to put a afr gauge on my tri pod would that work instead of getting the widebrand?

Cobalt4Life

no, you need to get a wideband as the wideband is a AFR gauge.. what your thinking of is the narrowband afr gauge which will do nothing for reading AFRs for our cars.. you need a wideband

IonNinja

yes I know that

sorry, just different terminology...i was thinking of an addtional wire tapping into the o2 sensor and intercepting or skewing the signal.

not having the o2 sensor go directly to the AEM and then to the ECU

poor choice of words, my bad.

thanks that clears it right up for me

are you an electrician by chance?

analog > volts
digital > frequency

makes more sense to me this way

Sw4y1313

Also ion, think of analog as 0 - 255 and digital being 1's and 0's.

Oh Witt, the FIC software has a clamp section that requires you put a max voltage you want the ECM to read from the MAF. So it has to be digital because its 0 - 5. Even in the FIC's help guide it tells you how to clamp it.

Cobalt05, yes you are tapping into the o2 sensor but its still skewing the numbers. It doesnt HAVE to intercept it to do it.

tru2nrtt777

iTrader: (1)

Nope, I have been into car audio(and the racing scene) since 2k1ish and am going to school to be an A.S.E. Master Tech. Already got done with one of my electrical classes hence me actually being remotely knowledgable about this stuff.

Witt

If its 0-5 its analog. I'm quite certain it can't clamp a GM MAF.

A work around is to build a larger diameter custom intake pipe. More airflow will go by at a lower frequency.

http://forum.aempower.com/forum/inde...c,20963.0.html
http://forum.aempower.com/forum/inde...c,21284.0.html
http://forum.aempower.com/forum/inde...c,20502.0.html
I could go on but I think you guys get the idea. If MAF reports back a frequency, AEM FIC can't touch it. Go for the o2 imo.

zinner

There are devices out there that can modify and clamp the GM style MAF.

HunterKiller89

iTrader: (1)

i gotta agree with ionninja in that i specifically remember seeing the field where you input your MAF clamp voltage