Stock MAF vs Ported MAF vs Granatelli
12-31-2003, 07:03 PM
#1
Banned
Thread Starter
Join Date: May 2002
Posts: 1,475
Stock MAF vs Ported MAF vs Granatelli
Well I finally got around to doing my OWN PERSONAL testing on the MAF sensor.. For awhile now this subject has been in debate. Some people say that it is ok to do while most say that it will only HURT your tuning... I decided to do my OWN testing and see what would happen with some REAL NUBMERS.
So first test that I did was with a STOCK Descreened MAF sensor. While viewing my BLM's and A/F on my wideband setup, at idle everything looks great. BLMS are at 128 +/- 2 numbers. Now in 4th gear at about 3k rpms I stomp on the gas going into PE MODE and log the data on my wideband. Numbers are in the high 12 low 13:1 AFR. So basically everything looks GREAT.
Now with that SAME SENSOR I put some PORTED MAF ends on it and re did all my testing. At idle my BLMS are pretty much LOCKED at 160 basically saying that the car is running LEAN and that the computer is adding the MOST amount of fuel it can to compensate... So then I head out to the freeway again and begin to test my WOT data above 3k again. Well my AFR showed reading in the HIGH 13's all the way to the low 15's (15:1 that is
)
So NOW with the same sensor AGAIN I removed it and put it back in the stock NON PORTED housing just to make sure that the sensor DIDN'T get fugged up somehow, and EVRYTHING went back to normal just as it did in the first test.
So this shows that the ONLY gains that people are seeing is from the car being DANGEROUSLY LEAN (15:1) in the upper RPMS. Porting the STOCK MAF DOES INDEED THROW THE CALIBRATION OFF! As much as I didn't wanna think that it could throw it off that bad, IT DOES!
My buddy is going to let me borrow his granatelli maf this coming week and I am going to do testing on that as well and see what happens as far as how it changes the AFR compared to the stock MAF.
Hope this helps
So first test that I did was with a STOCK Descreened MAF sensor. While viewing my BLM's and A/F on my wideband setup, at idle everything looks great. BLMS are at 128 +/- 2 numbers. Now in 4th gear at about 3k rpms I stomp on the gas going into PE MODE and log the data on my wideband. Numbers are in the high 12 low 13:1 AFR. So basically everything looks GREAT.
Now with that SAME SENSOR I put some PORTED MAF ends on it and re did all my testing. At idle my BLMS are pretty much LOCKED at 160 basically saying that the car is running LEAN and that the computer is adding the MOST amount of fuel it can to compensate... So then I head out to the freeway again and begin to test my WOT data above 3k again. Well my AFR showed reading in the HIGH 13's all the way to the low 15's (15:1 that is
)So NOW with the same sensor AGAIN I removed it and put it back in the stock NON PORTED housing just to make sure that the sensor DIDN'T get fugged up somehow, and EVRYTHING went back to normal just as it did in the first test.
So this shows that the ONLY gains that people are seeing is from the car being DANGEROUSLY LEAN (15:1) in the upper RPMS. Porting the STOCK MAF DOES INDEED THROW THE CALIBRATION OFF! As much as I didn't wanna think that it could throw it off that bad, IT DOES!
My buddy is going to let me borrow his granatelli maf this coming week and I am going to do testing on that as well and see what happens as far as how it changes the AFR compared to the stock MAF.
Hope this helps
01-01-2004, 04:01 AM
#2
Registered User
Join Date: Oct 2002
Location: Oklahoma
Posts: 441
Actually that helps a lot, because it does anwer the age old question. I will wait for your data on the granatelli to see if they are worth anything. I have heard the granatellis are great at first, then when the computer learns from them they dont do anything. you might want to take that into consideration when testing. -Michael
01-01-2004, 04:27 AM
#4
Registered User
Join Date: Oct 2003
Location: houston, texas
Posts: 1,220
yes that's very interesting I have a granatelli keep us posted I've been thinking of selling it on ebay for a while now and getting a LT4 MAF (unported) if you can find someone with one of those I'd be interested in those #'s also. I think the LT4 maf's can be easy tuned right guys?? 
-b
-b
01-01-2004, 10:55 AM
#5
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,824
Interesting, because your findings support what I have been telling people for years.
But a question.... how long did you wait before testing each setup? In order for the BLM's to stabilize, particularly in Cell 15 where the PCM is going to get its PE mode BLM's from if the PCM is adding fuel, you have to have some "time" on the car, in which its been operated for a period of time in each Cell, particularly Cell 15. The ws6.com AFPR dyno test indicated his corrections took a period of "weeks". Sounds like way too long to me, but he was using a dyno. Point is though, you can't just switch MAF's and run the test... you have to build up operating time on each Cell. You may have done that..... just not clear from the writeup.
And, for people running stock tuning, and getting the typical 11.7:1 target A/F ratio that PE mode produces, the "leaning" might actually produce a noticable power gain, without leaning to the extent you got when starting with the more power friendly 13:1-ish A/F ratio. See what I'm getting at.... did you put enough operating time on the PCM to fully develop the BLM Cells?
Thanks for sharing, and PLEASE do not take my comments as criticisms.... I am just trying to make sure your "test" doesn't have any holes in the methodolgy
.
But a question.... how long did you wait before testing each setup? In order for the BLM's to stabilize, particularly in Cell 15 where the PCM is going to get its PE mode BLM's from if the PCM is adding fuel, you have to have some "time" on the car, in which its been operated for a period of time in each Cell, particularly Cell 15. The ws6.com AFPR dyno test indicated his corrections took a period of "weeks". Sounds like way too long to me, but he was using a dyno. Point is though, you can't just switch MAF's and run the test... you have to build up operating time on each Cell. You may have done that..... just not clear from the writeup.
And, for people running stock tuning, and getting the typical 11.7:1 target A/F ratio that PE mode produces, the "leaning" might actually produce a noticable power gain, without leaning to the extent you got when starting with the more power friendly 13:1-ish A/F ratio. See what I'm getting at.... did you put enough operating time on the PCM to fully develop the BLM Cells?
Thanks for sharing, and PLEASE do not take my comments as criticisms.... I am just trying to make sure your "test" doesn't have any holes in the methodolgy
.
01-01-2004, 02:50 PM
#8
Banned
Thread Starter
Join Date: May 2002
Posts: 1,475
Originally posted by Injuneer
Interesting, because your findings support what I have been telling people for years.
But a question.... how long did you wait before testing each setup? In order for the BLM's to stabilize, particularly in Cell 15 where the PCM is going to get its PE mode BLM's from if the PCM is adding fuel, you have to have some "time" on the car, in which its been operated for a period of time in each Cell, particularly Cell 15. The ws6.com AFPR dyno test indicated his corrections took a period of "weeks". Sounds like way too long to me, but he was using a dyno. Point is though, you can't just switch MAF's and run the test... you have to build up operating time on each Cell. You may have done that..... just not clear from the writeup.
And, for people running stock tuning, and getting the typical 11.7:1 target A/F ratio that PE mode produces, the "leaning" might actually produce a noticable power gain, without leaning to the extent you got when starting with the more power friendly 13:1-ish A/F ratio. See what I'm getting at.... did you put enough operating time on the PCM to fully develop the BLM Cells?
Thanks for sharing, and PLEASE do not take my comments as criticisms.... I am just trying to make sure your "test" doesn't have any holes in the methodolgy .
Interesting, because your findings support what I have been telling people for years.
But a question.... how long did you wait before testing each setup? In order for the BLM's to stabilize, particularly in Cell 15 where the PCM is going to get its PE mode BLM's from if the PCM is adding fuel, you have to have some "time" on the car, in which its been operated for a period of time in each Cell, particularly Cell 15. The ws6.com AFPR dyno test indicated his corrections took a period of "weeks". Sounds like way too long to me, but he was using a dyno. Point is though, you can't just switch MAF's and run the test... you have to build up operating time on each Cell. You may have done that..... just not clear from the writeup.
And, for people running stock tuning, and getting the typical 11.7:1 target A/F ratio that PE mode produces, the "leaning" might actually produce a noticable power gain, without leaning to the extent you got when starting with the more power friendly 13:1-ish A/F ratio. See what I'm getting at.... did you put enough operating time on the PCM to fully develop the BLM Cells?
Thanks for sharing, and PLEASE do not take my comments as criticisms.... I am just trying to make sure your "test" doesn't have any holes in the methodolgy
.
ONE I don't have STOCK TUNING, my car is tuned BY ME PERSONALLY to run at 13:1 in WOT. So I know that with my STOCK MAF it runs at 13:1 in WOT. So then when I put the SAME SENSOR at which I was using in my stock MAF in a PORTED HOUSING and then I turn the car on... IMMEDIATELY the BLMS have already seen that something is wrong and they shoot to 160 on each side... Where's before they were at 128, 127 etc. Then when my WOT AFR is normally at 13:1 it is NOW at in the HIGH 14's LOW 15's AFR. So there's no needing to wait like a week or whatever before the computer catches on because it already caught on to something being wrong right off the bat. So then, when I took that SAME SENSOR that just made the car run at like 160 BLM's at idle and part throttle, and put it in a STOCK NON PORTED HOUSING, fire the car up and BOOM the car is at like 160 BLMS for like 10 seconds before it realizes that everything is ok now. Then of course at WOT everything goes back to my normal 13:1
So the numbers don't lie, and I don't belive that it takes no friggin WEEK to learn cause my car shows it learning RIGHT AWAY
Oh and everything is a go for the granatelli this week, I will be getting to do testing on a 350111-C which is the granatelli MAF for the LT1 w/ Cold Air Tuning... I will keep you guys posted.
01-01-2004, 05:50 PM
#9
Registered User
Join Date: Oct 2000
Location: Groton, CT - Moving to Jax, FL in 2004
Posts: 47
Been running my second Granatelli (this one tuned after a post a couple years back on this board) and no problems from it. The first one I had bought though, was a different story altogether...
Good luck & keep us posted!
Good luck & keep us posted!
01-01-2004, 06:01 PM
#10
Registered User
Join Date: Jul 2003
Location: (SHOWING U MY TAILIGHTS)FaiRFieLD CaLiFoRNiA
Posts: 2,006
great thanks alot for the info on your testing . . .let us know about the gms . . .i have one and id love to know if its actually bad for my car . . .thank you keep us updated
01-01-2004, 08:02 PM
#12
Registered User
Join Date: Mar 2002
Location: Baton Rouge, LA, USA
Posts: 2,743
Based on the general design of MAF's your car did exactly what I would expect.
However, in my case, I believed the stock MAF to be a restriction. So, I cut the air-foil out of it and bored it 1/16". I installed it and the BLM's were on the high side (140 ish) as expected. So, to remedy this, I reduced the injector constant by a factor of 128/140. Now, the BLM's stay around 128, the MAF doesn't max out as early (~4,800 rpm in my case), the A/F ratio at full throttle is the same as before, and I have a less restrictive MAF.
Mike
However, in my case, I believed the stock MAF to be a restriction. So, I cut the air-foil out of it and bored it 1/16". I installed it and the BLM's were on the high side (140 ish) as expected. So, to remedy this, I reduced the injector constant by a factor of 128/140. Now, the BLM's stay around 128, the MAF doesn't max out as early (~4,800 rpm in my case), the A/F ratio at full throttle is the same as before, and I have a less restrictive MAF.
Mike
01-01-2004, 08:55 PM
#14
Registered User
Join Date: Mar 2002
Location: Baton Rouge, LA, USA
Posts: 2,743
Originally posted by JDMZ28
engineermike- if properly tuned, could a ported MAF "hurt"performance?
engineermike- if properly tuned, could a ported MAF "hurt"performance?
Keep in mind that, for over a decade, Mustangers have matched large MAF sensors with large injectors without touching the program in the computer. This is essentially the same as tuning for a larger MAF, but by increasing the injector size instead of decreasing the injector constant.
Mike
01-01-2004, 09:40 PM
#15
Registered User
Join Date: Sep 2000
Location: Novi MI
Posts: 491
engineermike - I plan on having my computer tuned again by MADZ28 because I think my car is running a little on the rich side. I have a laptop, a cable, and I can get tuning software. Is it possible for me to record what my car is doing with the laptop, send the file over the internet, have it modified and then sent back to me? I know he can't tune for optimum power because of the lack of a dyno, but he can get the A/F, timing damn close, by looking at the numbers right?