Montezuma

I second

Injuneer

Not sure why you feel you have to get so defensive.... I know you have your own tuning in the car, and I know you have it properly tuned for WOT. That is not relevant to my question.

My question is.... did you operate the car for even 30 or 40 seconds within the Cell boundaries (RPM and MAP) for Cell 15 BEFORE you ran your retest?

I know the BLM's will start to change immediately.... but since there are 16 different cells defined by MAP and RPM, the BLM's within a Cell can change ONLY when you are actualy operating within the MAP and RPM boundaries for that Cell. And.. you may have altered the Cell boundaries with your custom tuning, but you still have to operate the engine within those boundaries for EACH Cell. When you start it in idle, you are only looking at Cell 16... and yes, the Cell 16 BLM's will start to respond immediately. But Cell 15.... the Cell used for PE mode BLM's when the PCM is adding fuel... will not start to change until you operate the engine above 2,000RPM, and with an engine load corresponding to 80kPa MAP. And yes... I know with your own personal, custom tuning you can alter those boundaries, but you still need to operate the engine under those conditions to change the BLM's.

What say you?

InjectedSS

Oh, No I know what your saying. Sorry if I came off defensive, but I just wanted to make it clear that I did go thru some EXTENSIVE testing to make sure that I would get some RELIABLE results for everyone to learn from and put an END to this Porting the MAF debate that has been going on for the longest time.

What I decided to do in my testing was to use the BLMS as a guide of what was going on in PART THROTTLE & IDLE since using the wideband was kinda inacurate since the computer is always trying to shoot for 14.7:1 and using the BLMS would show me if the computer was trying to ADD or SUBTRACT fuel. For my WOT tuning I decided to use the WIDEBAND since the computer runs in PE MODE and the BLMS are ignored and not used. This way I can get an accurate reading of what was going on in WOT..

When testing first I RESET my computer by pulling the ECM fuse, then I logged my car with the STOCK MAF and noted my BLM's and AFR etc. The results were that the BLMS were around 128 at idle and crusing, and at WOT the AFR was at 13:1 Then I reset the car again and then put in the PORTED ENDS with the same sensor of course, that way there would be NO QUESTION about using a different sensor etc. Then I drove around and I logged with the PORTED ENDS and that's where I noticed that the BLMS did go up to 160 and the AFR did get thrown off as well causing the car to run LEAN LEAN LEAN 15:1 at WOT.

THEN to satisfy my own thinking, I put the STOCK sensor in AGAIN with the NON PORTED ends, then I reset the computer ONE LAST TIME and then drove around the car for a little while and noted that the BLMS were at like 128 crusing and at idle. Not Dead ON 128 but up and down between like 126-128 as normal... Then WITHOUT RESETTING the ECM this time I installed the PORTED ENDS and the started the car and the same thing happens, BLM's go shooting up to 160 at idle and at crusing, and the AFR ran LEAN as heck 15:1 at WOT in the upper RPMS, and running lean at idle as well. But with the computer TRYING to compensate for the lean condition the AFR was around like low 15's high 14's.. BUT the BLMS WERE MAXED at 160, basically PROVING that the MAF readings WERE being thrown off....

Hope this explains thing's a little better Fred

predator

do you think that the z06 maf would do the same thing because i have that on my car and was wondering if mine was screwing up too i think i may put the stocker back on

InjectedSS

Hmm that's an intresting question. It very well may. But here's what I am HOPING that I will achieve when I check the granatelli MAF.

I am HOPING that granatelli has calibrated their MAF's so that they are ONLY CALIBRATED for the MAF being PORTED, as apposed to the the STOCK MAF's only being calibrated for NOT being ported. Meaning that when GM designed our stock maf's they knew that it would have the dividers in the middle and a screen.. So in turn GM made all their calculations to account for all that... Well HOPEFULLY granatelli has ONLY calibrated their MAF's for being PORTED and NOT having a screen and dividers in the middle.

What I don't want to see is that granatelli MAF's just TRICK the computer to make the car run LEAN, meaning that even though the granatelli mafs are ported out, the reason people are getting more power from them is beacuse granatelli TRICKS the ecm into running leaner, where's with a stock maf you could just do the SAME THING by going into the MAF table's and make the car run leaner even with a stock maf. Im hoping that the power that people gain from granatelli MAF's is simply from the extra air coming in from the maf being ported. So basically the granatelli mafs are

As far as the ZO6 MAF, if someone want's to send me their's I can test it out and send it back no charge of course. Other than that I have no idea.. Maybe I will run into someone locally that has one and I will eventually be able to test it as well... I can't see the ZO6 MAF being a very good mod because doesn't the ZO6 MAF still have the dividers in the middle? Where's a granatelli MAF doesn't have ANYTHING in the middle except the little sensor.

bunker

I have a MAF table for a Z06 maf somewhere on my computer

predator

HEY I COULD PROBABLY SEND MINE

engineermike

In order to tune the WOT A/F ratio, he would need some WB O2 data. The O2 millivolts isn't enough.

Other than that, what you're suggesting is possible.



And about the ZO6 MAF, the ZO6 MAF tables in the ZO6 computer are different than our LT1 tables, so it IS calibrated differently.

Mike

Injuneer

Have you specifically programmed the PCM to ignore the BLM's at WOT/PE mode? If not, is DOES use the Cell 15 BLM's, under certain condition. If the PCM is "adding" fuel in that cell (BLM above 130), it uses the BLM's from Cell 15 to do the fuel calculations in PE mode. It only ignores Cell 15, and defaults to Cell 18, with the BLM's locked at 128 IF the PCM was "subtracting" fuel.

I get countless DataMaster and AutoTap logs to look at to try and help people, and its pretty easyu to tell when the PCM was reset before the log was done, because each time the PCM moves to another Cell, it will be at 128, and it will start to respond by adjusting to the O2 sensor feedback. But there are some Cells that don't happen to get used during that particular logging period, and they will stay at 128 because the engine never operated in the range defined by the RPM and MAP. And even if the engine operated in a particular Cell for a few seconds, that is not enough to fully develop the correction when you start getting up to 140 or down to 115.... it takes a while for the PCM to make a small adjustment, watch the short terms (INT's), then make the required next small step on the BLM's. It is not instantaneous. It takes time.

Please read my original post.... I am not faulting what you have done. I noted that your conclusions were predictable. But I was only trying to make sure you used the correct method to produce those results. It appears there is some confusion on hopw the PCM operates in PE mode.... just trying to make sure your method reflected the way it actually works. I'd like to try what you have done myself, but my stock PCM, my MAF sensor and my O2 sensors are long gone.

Brent94Z

Also, take a look at the GPS air flow. Stock is around 230 at redline in 2nd gear. With ported MAF ends (with non calibrated/adjusted sensor) you'll most likely find that number dropping down to below 200 for the same conditions.

I did some testing with the Granatelli and found that the gps flow number went up about 5 or stayed the same so that was good. It'll be interesting to see if you get similar results when you test the Granatelli.

InjectedSS

HA, that's soo funny that you mentioned that Brent cause I forgot to bring that up as well. At idle with my STOCK sensor being NON PORTED the gms per/sec were at like 10-11 and then with the PORTED ENDS it was at like 7-8 gms per/sec. Once again PROVING that porting the MAF DOES screw the calibration up

Well send me a PM and we can work something out.

MentalCaseOne

Sorry for butting in but, My stock computer (never been programed) with my stock MAF (original from factory)
are reporting:

6 grms per second
650 RPMs
194.90 coolant temp
injector pulse 2.80 milliseconds
Barometric presure 4.90 (pretty much Sea Level)
Vacum 20 hg (measured with mechanical vacum gage)

So my point being here is.... It all depends at what RPMs your 10 - 11 grms per/sec are happening. Every car is different and it should be way better to use just one stock test mule and then swap all the MAF sensors and see the results.



Per your post
It sounds like My non-ported all stock MAF is screwing the calibration just like Ported MAF is.... What if its not? what if its the other way around? what if my A4 Idles slower than your M6? see my point? and why would two cars with identical "stock" camshafts will be made to idle at diff speeds?

Lets just get one test mule car perfectly dialed in.... then swap the MAFs on it to see what effect to then have. As for the Stock Ported MAFs my logic dictates that GM calibrated them for the Airflow/temp/air speed/MAF inside Diameter. Anything we do to them will throw the calibration off.

I found out that even for Oxygen sensors they do use the Tubing inner diameter into their calculations.... use the same Oxygen sensor on a "larger diameter tube" and you throw your oxygen sensors readings off calibration. Dont get me wrong the oxygen readings will be still the same but it will detect a less amount of everything due to less velocity in the exhaust tubing.

Check this out:

http://www.uscar.org/consortia&teams...htm#Parameter1

Grab some aspirins before you go in there.... trust me.

Marvin

InjectedSS

DUDE, I was using MY OWN CAR for all these test's. So the car was idling EXACTLY the same RPMS for ALL TESTS. What are you talking about? Your confused but I can see what you trying to get at.

M6's are set to idle higher from the factory than the auto's. I think it has something to do with the torque converter or something like that. Whatever is going on with your car doesnt sound right though.. You sound like you could use a tune that's for sure Especially with that 194 TEMP Yikes dude, sounds like STOCK tuning to me.

MentalCaseOne

AHHHHHHHHHHHHHGHHH! DUDE!! you got me on that one... I swear I thought I was answering to some other dude replying to your post!.. and I was like wait a minute.. we can't compare across cars for this testing just yet!!! So fair is fair, you got me dude but then I got you too.... read on =)

I was about to say "You think I am an idiot for no reading your asnwer carefully dont you??"


But then I realised you said.... At that moment I was like NO! REALLY? (grin)


I'll let ya figure out the rest.


The way I see it we are even

Marvin

Ok Ok I am not 100 percent stock. I have the 160* thermo but for this test purpos, I did let the girl --warm up to the ocassion-- if you know what I mean

InjectedSS

LOL ok Im lost but it's all good

Either way, anyone with even a STOCK car can benefit from a tune. I don't know if that's what you were getting at....