Kingtal0n

There is a device called the Super-AFC (air flow converter) that alot of people use to correct airflow for their MAF or S/D computers. I hadn't ever even heard of it until I owned a Nissan, and substantially investigated aftermarket ECU "controllers".

Anyways, the main idea is airflow going into the unit (from the maf) and the unit corrects the output voltage, or % of airflow, and sends that to the ECU. you can dial in exactly how much airflow +/- % you want it to add or subtract. for instance, say your running lean around 4000RPM, you just tell the unit to add a bit of airflow around 4000RPM and it will richen up.

Thats oversimplified, the unit does a number of other things. Im just wondering if anyones used it on their chevy motor? It works with MAP too, but mainly people use it for a MAF. It would allow you to run a bigger maf or bigger injectors with the same maf, and correct the voltage without tuning the ECU, or better yet, it could theoretically "fix" the max maf limit in the 165 ECU. Think about it, using larger injectors and correcting the output voltage, if you double the size of your injectors and cut the airflow % to compensate (instead of retune) you can double your horsepower output before maxing the maf.

BigMike92Z

used it on an ls1 car before but never an older smallblock car or our ecu... theoretically i would think it should work, there really isn't anything car specific about it... you can remove them from car x, place them in car y and as long as you set them up correctly they'll work...

Kingtal0n

thats what im saying, yet i never even read the letters SAFC on this board, let alone heard about this item until I got interested in my 4-cylinder tuning dept. Its a shame because these little aftermarket items can make life simple, just because its designed with a 4-cylinder in mind doesnt mean it wont do wonders for a V8.

Steven89Iroc

I used one on my Talon before DSMlink for about 3 years, it did work well with the bigger injectors (650cc vs. stock 450cc). I still have it hooked up because I like all the monitoring functions.
It's not optimal, tricking your computer like that. You probably know this but it will be said anyway. When your ECU thinks there is a different airflow value coming in than there actually is, it affects more than just fuel, but that's simplified.
I have *heard* of people using them on MAF thirdgens, but I cannot verify.
Overall, it is a good semi-cheap easy way to get your car running better, but not best. That's my quick .02 on it, gotta run back to work now.

Kingtal0n

\


Yes yes, I have one on my Sr20 motor mainly for the dec-air function because of my open-atmosphere bypass valve...

but your right, you move the airflow you play with the timing as well. which is why I mentioned it in the first place, follow this scenario:

165ECM with a MAF on a thirdgen. you set it up for, say, 30Lb Injectors, but you install 45Lb injectors instead. You tune the ECM with the corrected value in the VE table, so when your SAFC pulls out airflow to correct for the injectors, your car is exactly tuned the way it should be.

For instance, Lets say at 2000RPM your car uses 50% VE. With the computer thinking 30Lb injectors, a programed A/F ratio of 12:1 would flood the motor with fuel because the injector constant is incorrect. So you have the SAFC pull out 20% of fuel from that cell, No problem thats what it was designed to do right?

But heres the trick. You know you will be pulling 20% of VE out, so in your EPROM you program that spot (30% VE) for the timing table you WOULD have programed at 50% VE. so your not doing anything except lowering the resolution of the maf, as if you instaled a bigger maf, and programming the ECU to compensate, except your not burning EPROM after EPROM, your just making while-you-drive changes to the SAFC. Its like a hand-held stand-alone option for $250.

1bdbrd

iTrader: (1)

i have thought about this many times and often wondered if it would work. i figured people here were so anti import they wouldnt know wtf i was talkin about.

now if you ran an SAFC why would you have to tune anything in your PROM? i was always under the understanding that these were to be used in favor of a standalone or tuned stock ecu?

BigMike92Z

this controls only fuel, not ignition timing.

1bdbrd

iTrader: (1)

damnit i knew that. then the obvious quesiton is this, aside from the datalogging type capabilities why run an SAFC? i mean if im gonna burn a prom or tune a standalone for timing i may as well do fuel also and not worry about another device.

Steven89Iroc

Pretty clever that is, re-adjust the timing in the EEPROM in conjunction with the AFC, it sounds like it might work well.

Now to answer you 1bdbrd, first, if you're thinking about it for your '91 T/A, it won't work because you don't have a MAF to intercept the signal from.
The reason you want to use it with a '165 ECU is because the MAF max's out at a lower airflow level than some people care for (255 gm/sec), meaning you can't adjust the ECU to compensate higher than that limit. The AFC can trick the computer into thinking there is less airflow coming in so you can tune fuel delivery around that (or get bigger injectors) and still have a 'higher' measurable limit.
The AFC also affects timing because it tricks the ECU, it'll have more timing at lower airflow levels. If you tune the timing curve like he said, you won't need to worry about it.
Basically, you're just making an adjustable MAF that you can tune around to get the desired results.

The common use of it is to avoid the ECU tuning like you said so you can add larger injectors and tune the fuel curve, but that's where it has shortcomings when dealing with timing and such.

Either way it's still a piggyback, but I think it might do some good to get more out of the stock '165 MAF setup.

Kingtal0n

Exactly my point. One thing though,<b> "Now to answer you 1bdbrd, first, if you're thinking about it for your '91 T/A, it won't work because you don't have a MAF to intercept the signal from."</b>

If im not mistaken the SAFC can work with a MAP signal as well... Its labelled KARMAN PRESSURE SENSOR in the booklet. not sure how it works, though.

Why use it instead of just a ROM tune? how many times do you rom tune your car? How good are you at rom tuning? I have a friend on Rom tune #105 and hes about to load back to #45 because its running worse now than back then.

With the SAFC and some ballpark timing tuning, you can tune your ROM on the fly in the driver seat while you drive around. It really is THAT simple.

Steven89Iroc

Maybe you can intercept the MAP signal, hmm, not sure about that one.
What I am sure about though is that it's not the Karmann option, as that is the type of MAF my Talon uses stock. It's based on the Karmann vortices which are created in those type MAF by placing basically a flat bar in the path of airflow then counting the blips of the signal that happen due to the swirls of air (Karmann vortices) directly behind the flat bar. It's not pressure based at all.
Now I'm running a more efficient and accurate GM hotwire MAF with a translator.
This is probably more than you all cared to know, heh.

At any rate, I'm not sure about the MAP signal but you might be right.

As for the on the fly tuning, that would definitely make it easier once you get the proper base changes done inside the ECU.

CrazyHawaiian

Yeah the SAFC will definately work with our types of cars. You're talking about the Apexi unit right? I didnt find much info on these forums either, but I did find some experiences on the Sy/Ty boards (guys running 749 ECM's). I dont plan to run a SAFC after my 749 swap, but I do plan to use one of the HKS/Apexi/etc electronic boost controllers once I get my turbo setup complete (with electronic wastegates). I messed with the older version SAFC with my old Mustang SVO. The SAFC will work with both MAF and MAP, and even other types of systems. My old SVO used a VAM, and althought I didnt get it working 100%, I'm sure I could have with more time. Alot of guys I know with the boosted import motors (SR20, 2JZ, 4G, etc) run the SAFC instead of standalone ECM. My friend with the 649rwhp auto supra (2JZ and SP67 single turbo) is running the SAFC and I believe his system is MAP. Hes pretty much maxxed out the capabilities of the SAFC (big injectors), might have to swap to standalone soon. SAFC works great but it does have its limits.

Steven89Iroc

Yeah, the Apex-i S-AFC (the newer versions of course).
Cool, nice information to know, I stand 100% corrected.

88iroc-Z

iTrader: (1)

I am about to install an Safc-II on my car, which has the 1227165 ecm which is Maf based so it should work, and yes it does also work on MAP cars but I do not think that it will work on your '91T/A for the fact that the SAFC-II does just as stated befor eadjust MAF and/or MAP signals in whick case it can only alter one of thse signals at a time and not both, so if a car has MAF and MAP one will be contradicting what the other is saying.

And also it DOES affect timing as well, it is not a gigantic difference but when you affect how much air and/or vacuum your car is seeing coming in it also affects your timing.

which I have noticed on my Toyota that when you add % more you advance timing, which is not good in a forced induction or nitrous car, but you can as said before run bigger injectors or a higher bar map sensor(by changing "in" & "out" setting on MAP/MAF) so that you are subtracting % of fuel.At least these are my findins with my toyota, nissan, and hondas I have used the SAFC-II on.

-Daniel

junkcltr

iTrader: (1)

Anything that fools the ECM is a krutch for not having the ECM tune right. I only play with the GM SD and I know there is no need for any converters if you know how the ECM code & tables work. Lots of GM MAF people krutch the MAF tables.

Not that the unit is a bad thing. It is useful for a lot of people. It is a work around for not knowing how the ECM deals / controls fuel and spark according to the stock input sensors.

junkcltr

iTrader: (1)

A stock 165 ECM GM MAF will read a max of 255 GM/SEC at 5 volts output. So lets say this "smart" thing knocks the voltage down to 2.5 volts........now the ECM thinks it is seeing 255/2 = 127.5 GM/SEC. Suppose the real engine airflow increases to 230 GM/SEC........the MAF still puts out 5 volts (nothing more). So the ECM still thinks it has 127.5 GM/SEC.

Overall, with a stock GM 165 ECM MAF, these things are useless. The only way to get more airflow GM/SEC with stock MAFs is to run two MAFs in parallel. At that point, it is easier and cheaper to get a LS1 or LT1 MAF and tune with that. If you are burning a chip for timing, you might as well use the LT1/LS1 and use that for fueling.

The "fooler" thing for 165 GM ECM is a waste of money. I am not aiming this directly at you Steven89Iroc. Just trying to save all involved in this thread some time & money.


EDIT: This also applies to the 1bar 730 ECM people with boost. A stock 1bar will not read boost and you can't "fool" it into reading boost.

Overall, if you are MAF and see more than 255GM/SEC you need a new MAF or need to "fatten" your WOT tables. If you are boosted MAP, then you need a 2bar or higher MAP sensor and the proper code. In both respects, an FMU and tuning is better than the "airflow tricker" thing.

Steven89Iroc

Wow, old thread. The last thing I want to do is misinform anybody, but here's my take on it.
You need to use bigger injectors for it to work that way. The way I understand it is that the 8-bit ECU's inability to read higher than 255gm/sec is the problem. (11111111 binary = 255 = maxed out). Simply using an LT1 or LS1 MAF and tuning isn't going to correct the airflow limit of the '165.
Say you install 44lb/hr injectors (for simplicity's sake), which is 2x stock L98. Also say that with your engine combo you need stock fueling at idle (again for simplicity's sake). You'd need to decrease the correction % by 50 to make up for 2x the fuel. Do that at all RPM and throttle points to compensate for 2x the fuel. Okay, simple so far.
Now say the real engine airflow reaches 255gm/sec at WOT at 4000rpm, but the ECU only sees 2.5 volts (127.5gm/sec). At this point you're still at -50%, so you have room to increase fueling by tricking the ECU. By 6000 rpm say your engine is now flowing a real 510 gm/sec, but the ECU is still only seeing 2.5V (127.5gm/sec) because you're still pulling 50% even though your MAF is still putting out 5V (maxed). . Now you increase the airflow tricker to 0%, and the ECU sees the full 5V (255gm/sec), and effectively gives the engine twice the fuel it thinks it's giving because the injectors are twice as big as stock (and you haven't changed anything inside the ECU). Adjust all RPM and throttle points accordingly.
As I said earlier this has definite drawbacks and limits, but can work OK (given real world circumstances and not my example), some of which but not all were mentioned in the thread.

I could be understanding some things incorrectly, but this is to the best of my knowledge. Someone can correct me further if need be.

junkcltr

iTrader: (1)

You can play games with it like that, but you are still messing with the chip to get the fuel tables right. The "tricker" is simply adding one more level of complexity and confusion to get the fuel tables right. It is more simple and cheaper to do like most people do with a maxed out MAF and that is to increase the WOT PE tables (using a WBO2) to get the fuel right. It is tuning without regard to actual airflow just like one would do with the "tricker" installed. The "tricker" simply tricks the user in which fuel table to adjust.

An LT1 MAF will read more GM/SEC at 5 volts than a TPI MAF. So, when the ECM sees 5 volts (1111_1111 binary) the GM/SEC can be more for the TPI MAF. Yes, it requires a fuel table re-curve.

TPI MAF @ 255 GM/SEC = 5 volts
LT1 MAF @ greater than 255 GM/SEC = 5 volts

The MAF airflow works like MAP pressure vs. voltage. As you increase the range of a MAP from 1bar to 2bar, you lose 2x the resolution. A 1bar at 104KPA will read 5 volts, a 2bar map at 208 KPA will read 5 volts. Now looking at the MAFs.........a TPI MAF is like the 1bar map, and the LT1 MAF is like the 2bar map. It isn't about the ECM only being 8 bit. It is about the sensor maxing out a certain GM/SEC or KPA. This is why people install the 2bar with boost instead of trying to "trick" the ECM using a 1bar sensor. This is why TPI guys move onto a LT1 frequency based MAF. BTW, the 165 ECM has an input for a frequency MAF like the LT1 MAF.

Steven89Iroc

You don't have to mess with fuel tables in the ECU to get the tricker to work that way, you mess with the tricker's "fuel tables" instead. You just have to know what AFR is coming out of the engine to do that accurately. It's not paying games, it's what it's designed to do. That's the advantage to the tricker like you said, you don't have to mess with ECU anything. It's for people who don't know how or don't want to mess with/spend more money on chip tuning equipment. That way it has real limitations, you can only go so far with the fuel, and the timing gets more jacked up the further you go. I was thinking there was no real way around the ECU's 255 limit other than that, and that's why I thought tuning timing in the ECU in combination with the tricker was the best way. But there is another way, sort of, as you said.

The 255 limit is still in the ECU. Whatever you trick it with externally (a different MAF or an airflow tricker) is going to be a crutch. With a MAF that will read more airflow per volts you have to scale the ECU differently, that decreases the resolution. Of course that's what you just explained. However, I don't see how this is better than using a tricker. They're both bandaids to get around an inherent 8-bit limit, if used for increasing a 255 gm/sec measurement.

I've never heard of an input in the '165 to read the (unusually high?) frequency of the newer MAF's, but you would know a lot better than me. Would you not have to scale that differently as well, causing the same problem?

In short, what are the simplest options for most people?
1) Install a tricker and a WB and go to (the edges of) town. Limited
2) Install all the chip stuff, a tricker MAF and scale accordingly, and a WB and go to town. Limited
3) Install all the chip stuff and a WB, increase the WOT PE tables and go to town. Limited?
4) Reprogram the code in the ECU everywhere to interpret each byte as more airflow than 1 gm/sec. (Same as rescaling MAF values?)

I dunno. The AFC has it's uses, and works for them. I used it and tuned with it in the black car for quite some time, with surprising success.
My head hurts. I'm dumping all this 80's GM crap and going with an LS1. :P (j/k)
Did you ever get the "BAUJP" working right? I want to take the "easy" way out and use boostable $8D instead of trying to get the headache-prone $58 working right, but I wouldn't want to benefit from all of your hard work for free.

junkcltr

iTrader: (1)

I agree that the "tricker" is fine if you don't want to buy PROM burning equipment and learn prom burning. BUT, if the ECM spark is going to be messed with then you might as well ditch the "tricker" and do the trick with the ECM fuel tables.

One more time, it is NOT an ECM problem. It is a MAF problem. Just like the 1bar MAP problem with boost. You can install a 2bar or higher for boost with the so-called 1bar 730 ECM. You can install a bigger MAF for more than 255GM/SEC. You are missing the point that the TPI MAF is 5 volts at 255 GM/SEC. The MAF can't put out more than 5 volts so an A/D with more resolution (more bits) or more dynamic range will not help (more volts). The TPI MAF will only go to 5 volts at 255 GM/SEC

The 165 ECM was designed to be able to handle a frequency MAF also. The freq. inputs have a programmable divide counter input.

Yes, it is good if someone doesn't want to get into anything else in the chip.

It is working right. The problem is that it has a lot of other non-boost stuff in it. Stuff that someone justing wanting to run a 2bar MAP would be confused by. I need to strip out that stuff if I release it. It will take some time to do that and I have been busy playing with welding machines (I get bored with doing the same old thing) and finishing my truck turbo install (going on 1.5 years now). I will get back to cleaning up the BAUJP once I get the truck finished. In the mean time, check out the DIY PROM board. The $59 code has just been released for testing and they are looking for V8 testers. It is a smart group that developed the $59 code.

Guest

You dont need 2 MAF's to run more than 255 gm/sec, thats inexperience talking right there. With the OBDII swap theres not much point in fiddling around with that nonsense anymore though.

junkcltr

iTrader: (1)

No one said it had to be two MAFs. It needs something that divides the airflow in a known ratio so the tables can be adjusted accordingly. Inexperience as to?

Sure, go with the LT1 MAF. It can be used with an older ECM. You have to learn how to code and understand the equations first. Got any disassemblies of the OBDII code? Understand how it really works with the MAP and the MAF?

305q_ta86

iTrader: (1)

My opinion: It's crap. All it does it mess with the maf signal. It cant control timing or anything else. Lots of guys in my 240sx club use them because they're slightly easier to install/use than something else. But think about this. It costs MORE than a fully assembled megasquirt, and MS does everyhting the safc2 does and waaaaaaaaaaaaay more.

junkcltr

iTrader: (1)

That pretty much say it all. It is hard to believe that someone would pay more for it than a MS-II.

EDIT: It actually isn't that bad in one sense. It is a decent work-around when compared to buying prom burning tools or a new ECM.

Guest

Thats what I was referring to. Thats not true. As for your other thoughts on how the system works, I can see a bunch of mistakes.

junkcltr

iTrader: (1)

It doesn't have to be another MAF. It can be anything actually that leaks air past the MAF. My thoughts on how a MAF works are incorrect? Please correct them with actually MAF flow facts and/or the actual mask/bin & ECM you are referring to. Seeing a bunch of mistakes doesn't really mean anything without facts to show they are mistakes.

Guest

Ok, we'll start right there. Untrue.
I'm not going to post anything to prove anything, I'm going to leave the proof to yourself. If you think the 255 limit is in the MAF, post why, with proof. Otherwise you're wrong.

junkcltr

iTrader: (1)

Nah, it is true. I see you are one to believe what you read on the web and not do any actual testing and code reading.

Already proved it to myself. So you are wrong. I love posters who just guess at stuff or listen to the "the experts" without actually testing out anything.

EDIT: I just did a search to see if you had any posts with info regarding engine sensors and/or ECMs. It turns out that you don't. So my guess is right that you don't test sensors or know how to read code. Also, I see you don't know about MAFs and airflow. I gained that knowledge by reading your "dyno results" thread with your listing of "screenless and finless MAF". You performed the worst operations on a MAF possible......basically you junked a good MAF. That sums up that you don't understand how a MAF or airflow works. Ever hear of turbulent flow?

Guest

I see you still arent posting proof... Too busy assuming that previous posts of my own (or lack of) somehow link my knowledge of subjects. Again, post up proof. You say you've proved it to yourself, what did you test? What was your procedure? What was the output that lead you to believe the 86-89 MAF airflow curve isnt variable with respect to voltage? Like... it can read something more than 255gm/sec at less than 5V.

Junked a MAF. Thats funny. Why dont you go ahead and explain turbulent flow and screens.

junkcltr

iTrader: (1)

The proof is because it is true.

Tested: MAF, ECM
Procedure: Install googles, Install Ozzy CD, blow air through MAF, record voltage on O'scope.


Huh, the curve is variable. It is a MAF......it meters air and varies an output voltage.

The only funny part is that I don't own that junk MAF. Turbulent flow is non-smooth flow. Screens keep out the mosquitos.

Guest

Because its true? LOL.

The MAF output to the ECM is voltage based. The voltage relation to airflow through the thirdgen MAF can be changed from stock to read higher than a 255gm/sec flowrate at a 5V output from the MAF, or 4.5, or 4, or whatever you want it to read. I dont know why you would think otherwise other than lack of knowledge. The 255 limit IS in the ECM. Visit $32/$32B/$6E Table 6 sometime.

As for removing the screens, nothing wrong with that. I have no bends before the MAF so I'm sure have a nicely centered flow so I dont need the turbulent restriction they cause. The air filter will take care of any debris. The fins arent there for airflow, they are there to cool the electronics package. Maybe if I drove on a daily basis in Death Valley in the heat of the summer I'd be worried.

junkcltr

iTrader: (1)

You really don't understand how the MAF or the ECM or the code works, do you? I really don't think there is any saving this one.

Some are analog voltage based. Some are frequency based.

Finally, you actual say it (what you said was untrue when I said it). That is, the stock TPI MAF flows 255 gm/sec at 5v. Yeah sure, you can hack a MAF so that it flows more air at max flow and reads 5v. But doing that shows that you don't understand how an intake track works and why the screens are there. Quit scratching the surface of the bin only looking at the tables. They won't give you the info you need to understand how it works. Referring to table 6 in the 165 based code is pointless. You need to know how the ECM actually uses the numbers......not just what the file editor labels say.

Ummm, you actually need bends. Re-read the part about turbulent flow. Ummm, the screens are there for flow, not filtering. Again, read the part about turbulent flow. Hacking a MAF like you did will make it work at WOT better, but every where else in terms of flow it is now a POS. So yeah, you junked it. When I say TPI MAF, I mean a stock un-hacked one. Heck, if you are into hacking MAFs then quit fooling around with the dinky screens & fins airflow gain. Pull the sensing element and install it in a 4" pipe and have all the flow in the world at 5v out. This is not a TPI MAF any longer but will flow much more gm/sec at 5v than a TPI MAF USING a TPI MAF sensing element. Have fun trying to CAL it. I guess the CAL wouldn't be much worse than the TPI MAF you hacked already.

What I learned here is that you don't understand airflow (hacked MAF), you don't understand code (calling out a table only), and you don't understand electronics (thinking the ECM 8_bits is the problem). If you really want to learn about this stuff, set up a flow bench, get a logic analyzer, O-scope, disassembler/assembler, etc. Maybe then you will understand this stuff. Otherwise, you will just spread false info. with your lack of knowledge.

Guest

I dont understand? Thats a laugh. You dont understand, typical SD guy.

Guest

Wrong. This will not get past the limitation in the ECM. Read the code sometime, the voltage is converted within the ECM to counts, 0-255. Its assigned gm/sec. You can make the MAF flow 512 gm/sec at 5V out if you want, and the ECM will still think its only flowing 255gm/sec.

Sure. And what are you using to convert the output so the 165 can understand it? And then after that, what good is it? The ECM still only understands 255gm/sec as the maximum value reported from the MAF.

Probably only the good piece of advice you've given.


Yes it is. The MAF is easily recalibrated from an electronic standpoint. Once you do that, you are still limited because the ECM limits it. If you think otherwise, show me where in the code the readings from volts to counts go above 255. Better yet, post up a code where someone can run a MAF reading 512 gm/sec @5V and report 512 gm/sec to any data logger of your choice. You claim to know all about the code and say the ECM isnt a problem, so post it up. I'm sure many people would love to have that.

Pointless. I gave up posting information years ago when I was constantly met by uninformed people telling me HP limits, fuel limits, limits in general that could never be overcome and to swap to a SD because there was no way otherwise. Whatever. I've done left them behind and done things that arent possible and never bothered to post about it so people like yourself could tell me I was wrong. Keep telling yourself that, and being in the dark. Better yet stop giving out advice about how the 32 or 6e works, you dont know. If you did, you would have already run or coded a car with a MAF capable of output past 255 gm/sec, with an ECM capable of using that information and providing correct fueling based on that information.

Excuse me? I wont even try to make sense of that nonsense, aside that removing screens and fins had nothing to do with 'hacking' the MAF to read something other than 255 gm/sec @ 5V. There happen to be electronic components under the cover, if you've ever looked at one.

Sure. So stay on point. The original post from over 2 years ago was referring to the 165, so from that he's running 32 or 6e. That'd be analog voltage. He wasnt talking about TTA's, V6's, or 85's.

Re-read what? Why in the world would I want to introduce turbulence and reduce airflow by leaving the screens in when I have control over the reported data? So the CAL is off when the screens are removed, big deal. Thats what the ECM code is for. Translate read flow to provide a correct fuel curve. If you think it cant be fixed, good thing you arent trying to do so. You'd fail. The MAF itself is a calibrated device. Plot the V vs GM/SEC sometime in excel, its not linear. Being a calibrated device you can do whatever you want to and recal accordingly.

Do me a favor, stop providing bad advice about the thirdgen MAF and stick to what you know.

Guest

Oh, and here's the "useless" table 6 (from the $32 bua Y-car hack):

;----------------------------------------
; Mass Air Flow TABLE 6
;
; TBL = 1.00 * gms/SEC
;
;----------------------------------------
LC6D4: FCB 255 ; TBL SCALAR
LC6D5: FCB 16 ; 16 LINE TBL
;----------------------------------------
; gms/SeC BIN VDC #/HR
;----------------------------------------
FCB 207 ; 206.2 1536 4.39 1591
FCB 213 ; 212.2 1552 4.43 1637
FCB 219 ; 218.1 1568 4.48 1684
FCB 226 ; 225.1 1584 4.53 1737
FCB 233 ; 232.1 1600 4.57 1791
FCB 240 ; 239.1 1616 4.62 1845
FCB 248 ; 247.0 1632 4.66 1906
FCB 255 ; 254.0 1648 4.71 1960
FCB 255 ; 254.0 1664 4.75 1960
FCB 255 ; 254.0 1680 4.80 1960
FCB 255 ; 254.0 1696 4.85 1960
FCB 255 ; 254.0 1712 4.89 1960
FCB 255 ; 254.0 1728 4.94 1960
FCB 255 ; 254.0 1744 4.98 1960
FCB 255 ; 254.0 1760 5.03 1960
FCB 255 ; 254.0 1776 5.07 1960
FCB 255 ; 254.0 1792 5.12 1960

Looky there, max reading @ 4.71V
So much for this quote:

junkcltr

iTrader: (1)

Actually, that proves my quote to be correct. The table shows 255gm/sec at 5.03v.

I am sure you can do better than that. Use your imagination when you look at the tables. Imagine an 8_bit value at 0x255 is for 512gm/sec and go from there working things backwards...that is a hint for you about using other MAFs with the 165 ECM and thirdgen V8 bins.

EDIT: BTW, where do you think the 4.7v to 5.1v saturated output comes from? Ever think it is the voltage variation from fully saturated transistors (0.3v) in the MAF. Ya know, the electronic thingy-do-dads that you said are under the cover of the MAF. Could it be? Nah, it must be some inherent ECM problem forcing that to happen, huh?

injdinjn

junkcltr;
Trust me, you will loose this argument.

junkcltr

iTrader: (1)

Public forums aren't about winning or losing arguments. They are to give info. to people so they can make their own decisions. As much as he likes saying "you are wrong", he still doesn't show that he is "right".

Simply using that table from the ECM shows how non-linear the output becomes near the rails (think OP AMP / transistor leaving the linear region). Every sensor has a dynamic range. The ECM A/D and code provides the resolution over that dynamic range. This is true for all sensors and sampling devices including MAFs.

If someone really wanted to increase the airflow limit using only TPI MAFs then another A/D input could be used for the second MAF. The A/D values are then summed to create a 16 bit value. Fuel eqn. is then adjusted / re-written accordingly. Yup, in order to do it right you need to change the ECM code to 16 bits.......because the dynamic range increased by a factor of 2.

Hogging out a MAF so it is no longer CALed and playing with the tables will get you a decent running engine. But in terms of true airflow.....it has been lost. The sensor needs to be CALed on a flowbench with an electronic measuring device (O-scope, A/D sampling, etc).

Have you guys actually measured the output of a MAF, understand how the output electronics work, understand how to change the fuel eqn. to 16 bits? It doesn't sound like it. That is not a dig or anything, but that is the only reason that you think it is an ECM problem.

Guest

And still, you have posted zero proof. Post up a working 165 with any other MAF and the computer reading, calculating, and reporting something more than 255 gm/sec. You've said more than once in the ECM is not the limit and its not an issue. If thats the case, and you've tested all these electronics, post it up. Without proof, your opinion is as worthless as the words you've used to state it.

As for your arguments, start at the top.

You said in reply #16:
"The only way to get more airflow GM/SEC with stock MAFs is to run two MAFs in parallel."

Then you said in reply #22 and #26:
"No one said it had to be two MAFs."
"It doesn't have to be another MAF."

And you want to argue? You cant even make correct statements from one minute to the next. I'd hate to see what a computer program written by you looks like. One second it'd be going left, the other it would be going right... and in the end it would go nowhere.

"Actually, that proves my quote to be correct. The table shows 255gm/sec at 5.03v."

Great, reading comprehension. And I thought you said the table was pointless?

"Referring to table 6 in the 165 based code is pointless."

Right there.

How about you explain what you think the purpose of the screens is, in detail.

Guest

"But in terms of true airflow.....it has been lost. The sensor needs to be CALed on a flowbench with an electronic measuring device (O-scope, A/D sampling, etc)."

That must be why there are so many variations in the MAF tables from one broadcast code to the next, because the sensor is so perfectly calibrated.

junkcltr

iTrader: (1)

True, I have posted zero proof. Neither of us have given any proof. Ha ha, no I am not giving my code away publicly. Besides, it would be all zig-zag and go nowhere. With a stock TPI MAF, the ECM is not the limit. The ECM is the limit when you go to other MAFs and want good resolution. That is when the code needs to be converted to 16 bit for the fuel eqn.

To do it right, you need two stock MAFs and another A/D input for the second MAF and convert to 16 bit fuel. That is the "right" way to to it using TPI MAFs. I figured you could catch on to that but you didn't. You can put a pipe in parallel with the stock MAF and re-CAL the 8 bit fuel table and use the stock 8 bit fuel eqn. You didn't catch on to that either. That is why you think things changed. If you use a bigger MAF that flows more than 255gm/sec and max. of 5v analog out then you lose resolution. Best bet is to use a larger freq. MAF and one of the parallel timer counter inputs. You need to re-code of course.
Circular programming, you are correct that I code that way. It fools the untrained eye and some disassemblers.

Correct, it proved your point and it proved my point. That is a null.......in other words pointless.

Sorry, it is secret dynamics info. and I can't give it out. Any Physics book will give you the basic understanding.
----------
Yes.

Guest

"Not giving code away"... so still no proof. Please refer back to when you chastised me for supposedly knowing nothing because you didnt see any posts, and watch your stones from that glass house.

"Sorry, it is secret dynamics info."
lol.
Most people dont understand the definition of turbulence, and that the screens just introduce more turbulence.

"To do it right, you need two stock MAFs and another A/D input for the second MAF and convert to 16 bit fuel. That is the "right" way to to it using TPI MAFs. I figured you could catch on to that but you didn't. You can put a pipe in parallel with the stock MAF and re-CAL the 8 bit fuel table and use the stock 8 bit fuel eqn. You didn't catch on to that either. That is why you think things changed."

Actually I read fine, thanks. You changed from one statement to another, its in plain english. You need 2, then you dont. I guess if you arent going to admit that mistake, I'll just stop wasting my time with someone that doesnt know what they are doing and wont post up supposed proof as if it were common knowledge.

"As much as he likes saying "you are wrong", he still doesn't show that he is "right"."

Neither are you, for that matter.

junkcltr

iTrader: (1)

Sounds good. I don't see that either of us are getting anywhere with giving anyone useful information. I will stop posting to this to.

injdinjn

Correct english is "I will stop posting to this too" .

If you are gonna throw rocks don't live in a glass house,

Nitpickers will get nitpicked

junkcltr

iTrader: (1)

I said I wouldn't post to this, but this is a non-technical post so it doesn't really count. I see you have little understanding of the topic so you just throw in Peanut Gallery comments because you have nothing better to do.

I let the "loose" thing go when I read it yesterday.......but since you bring things up......I don't think I can "loose" this argument. I guess this means you don't understand tech stuff and you do not know how to use the English language. Your comments trying to help out the other poster almost seems like you have some secret love for him.

I normally don't post things like this but your posts added zero value to the topic.

Steven89Iroc

Come on guys, everyone needs to act a little more mature. It's hard for anyone to decipher what's true and what's untrue with all the bickering going on, so take it to PM's if it must continue.

I think people now have enough information about the why and how of the S-AFC to make their own decisions on whether or not they should use one. If not, then keep the discussion technical if someone asks about it.

Kingtal0n

Guys this MAF thing is a "BANNED TOPIC" As in its already been discussed YEARS ago, and STICKIED.

here:
https://www.thirdgen.org/forums/tpi/...nce-again.html

Also:

This was all right in front of your faces, stickied to the top of the TPI board. And I remembered it from 2003! Say NO to Drugs!

Guest

And it was fixed when? Sure, 2003... and still people are running around with stock MAFs and stock codes. Fixing any issue the MAF may have doesnt get around limitations on the ECM side. To say the ECM (and code within, hell thats how it works ya know) is NOT a problem is... being sorely mistaken. Sure, you can use the 2 register stacking just like GM did, and change everything related to the 0-255 stacks used to translate the MAF data, but why? The amount of time involved isnt worth it unless you just gotta do something to kill time. It would be easier to rewrite the entire thing. May as well get rid of the 8 bit right then and there instead of fussing around with adding registers.

Banned topic from 2003, your original post date up there is 2005. But thanks for bringing this back up to offer absolutely no help.

Kingtal0n

What the hell are you talking about? I didnt say anything about fixing anything, or limitations from the ECM, or rewriting code. I Was just pointing out the simple Fact that this had already been discusses in 2003, and stickied. thats.... it. What the hell are you going on about?
And my post in 2005 about this "SAFC" device was only offered as a response to the post in 2003 when I found out about the limitations of the ECM.

If you re-read my next to last post, you will find quotes. Quotes that only agree with what you've been saying for the last 20 days in this thread! Where does it say I disagree with you, MADMAX? Where does it say ANYTHING about me refuting your claims? It doesn't! I Agree! I Was helping you by supporting you! SAY NO TO DRUGS!!!

bensbaby

I have a 88 GTA tpi
I hooked up a apexi sfac to it yesterday to be able to tune it
Did any of you ever get it working
I don't know how to set it to flap or pressure or hotwire? If so what numbers
Not karmen