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Granatelli MAF question...help!

3K views 31 replies 15 participants last post by  cowboy 
#1 ·
i am ordering the granatelli Mass Air Flow Sensor from stylinconcepts.com, and i need to know if i should get the one that goes with a cold air intake. I have the Airaid intake....but its just a box and bigger filter, in the same place as the stock airbox. so does that count for a "cold air" intake? i told the duesch on the phone but i dont even know if he was aware of his own name he was so stupid. is this even a big deal? the whole point of this MAF is that it is bigger and that it reads the air/temp to determine the mixture of air/fuel right? so if i get one meant to be w/ cold air intake...then my readings will be wrong right? sorry to ramble on, just not sure how to ask the question, I'm a little new. thanks for the help.
:banghead:
 
#3 ·
thank bro, the MAF is a christmas presant, i just need to tell my mom which one to order. it seems like a waste but i barely talked her into it so oh well. maybe ill get the pulleys next, did you install them yourself? hey did your hypertech help out your horsepower any? my friends tell me its only for telling your computer if you have changed gears, wheels size, and stuff like that....
 
#5 ·
Yeah, I installed the pullies, it isn't too bad as long as you have a Impact Gun. and for the HPP3, I like it alot, but I noticed you have a 5-speed, so your only gonna benefit w/the top speed adjustment, and the octane upgrade, which I believe throws a little more timing and fuel. ( I maybe wrong on that). but I do like what it did for the shifting (automatic).
 
#6 ·
Gonna put my .02 cents in here. Hypertech is a big waste of money as far as power increase goes. If you need to change gears and tire size they are fine. If you are after power they are a waste. The Grannatelli is pretty cool. It doesnt get hot. After you have been driving around for awhile go touch your stock MAF and it will burn you its so hot. The Grannatelli will only be warm. I had Mach Perfomance reprogram my computer and since I had the Grannatelli Cold air unit he said he could enable the computer to recognize lower temps and more air flow. Cooler air is better air and the way the Grannatelli is about not getting so hot I would say get it. The HPP3 is crap as far as HP increase goes.
 
#8 ·
The fact that the stock MAF get hot will make no difference! Just like with the 'intake material plastic Vs. Metal' debates.
The temp of the pipe (or MAF) doesn't matter b/c air travels through it so fast, it doesn't have time to absorb more than 1-2 degrees of heat.
1-2 degrees is NOT going to affect performance.
 
#9 ·
prostreetgmc said:
Nice times 98esten, just wondering what mods you have , I went to your website and seen some of the things you have done, but I didn't see anything that could get you in the 13's
I have a Comp cam 510 lift port and polished heads 3200 stall trans go shift kit Mach performance reflash MSD digital 6 March 3 piece pulley set STOCK y pipe and Stock exhaudt no Catalytic converter. Those times were on stock internals and stock pistons. Over Thanksgiving I put in A new 4.3 bored 30 over with forged pistons and compression is 10:1 . It has more power now with the new engine I hope to get to the track this weekend and get some new best times. Oh and those times were made in the Hot humid nights of June.
 
#10 ·
So if I have the K&N FIPK2 then I should order the CAI one? If so why because if the K&N works with the stock maf why order the other one?
 
#13 ·
The GMS normal non "C" model will make you run lean worse than a descreened and ported stock one. The "C" model can see more GPS air flow than the stock one, but doesnt do anygood for 2 reasons. One you wont have entering any more air flow than the stock one, and then it still will read lean. 2nd it takes over 275 flywheel before you've outflowed what the stock can read, plus the fact without a reflash to tell the OBD what to do with the new air flow numbers, its futile to use it. The only guys to actually need the GMS units are forced inducted, even then if the reflash could be done right, your better of using a 3 1/2 MAF like the LS-1's use. Reads more accurately and PRO-M no longer makes the GMS units for GMS cause they were selling ported stocks with overiszed ends on them, so who's making them now??? Its your $300+!!
 
#14 ·
964pt3 said:
The GMS normal non "C" model will make you run lean worse than a descreened and ported stock one. The "C" model can see more GPS air flow than the stock one, but doesnt do anygood for 2 reasons. One you wont have entering any more air flow than the stock one, and then it still will read lean. 2nd it takes over 275 flywheel before you've outflowed what the stock can read, plus the fact without a reflash to tell the OBD what to do with the new air flow numbers, its futile to use it. The only guys to actually need the GMS units are forced inducted, even then if the reflash could be done right, your better of using a 3 1/2 MAF like the LS-1's use. Reads more accurately and PRO-M no longer makes the GMS units for GMS cause they were selling ported stocks with overiszed ends on them, so who's making them now??? Its your $300+!!
Like I said I like mine and I have the reflash from Mach. I had to send it back To Grannatelli one time and put the stock one back on and I could definately tell a difference. I would spend money on the Grannatelli before I would a HPP3
 
#15 ·
GMS unit wont do the normal S10 owner a thing, not even with a Bill Mach reflash, it cant!!! Oh I know some non S/C owners will say it does but the butt dyno ideal comes to mind very fast.

First off, PRO-M had made what GMS called the "C" units , which were calibrated to give the same reading for the same air flow numbers as stock did. They knew air was gonna pass beyond the wires unseen so they flow tested them to then match the stock reading per flow. GMS took it upon themselves to get a bunch of A/C Delco stock units, cut the plastic center bar supporting the wires and then add oversized ends to them which PRO-M had also made. They called the calibrated true MAF a "C" and the modified overpriced stock ones NON. The got caught by Pro-M and Pro-M pulled there making and support to GMS forever. WHo makes them for GMS now??? GOod question since there arent that many out there who make them. So on that fact alone I would avoid GMS's all together, track record shows they like to run on false premises. Thisat one time was posted on Pro-M's web site.
Now Pro-M still makes and sells the real units. But your stock one can handle everything you can throw at it correctly till around 250-275 flywheel. You can bolt on every mod out there NA and not hit those numbers. Add a cam , head work etc and you may just hit it. Pro-M makes these units for those who can get beyond the 275 barrier where CFM flow rates are over what the stock one can handle.
You want to know another thing. You know why all the aftermarket CAI kits have elbows in the front? K&N knows , but I bet to guess the other dont and are copycating. It does 2 things, one is it puts the larger filter area near the headlight bucket hole for cooler air. Second when air travles in the tube, air changes speed, the inside turn will go faster than the outside turn, air will tend to travel the shortest path. Well when it enters the MAF , most of the air passes under the wire, unseen. Well when the MAF reports lower air flows it adds timing. The gain you get is not all from more air flow, its part due to more timing. What helps it further is the cone shape, a cone shape causes a vortex to be created, larger volumes of air in a tighter space, thats why the cone narrows towards the very front edge, if it didnt, no vortex. Now GM made the stock air box to flow straight into the MAF so it could see most all the air and not have this imbalance, the screen and center bar are there to correct problems in flow, not restrict even though it will.
Save your money!!! The CAI is adding timing for you, helping aid in the motor getting all the air it can, having a larger MAF area when the throttle body is smaller, and think about that, the throttle body bore almost dead matches the stock MAF size, the throttle bore becomes the restriction point, what do you do then??? Bore it out and slow the velocity of air entering!!!
 
#16 ·
Just to add.

From GM-Trucks.com

hcvone-<<Screen name
We dyno tested 4 GMS MAF sensors on an 02' Z06, we lost power with 2 of the sensors, and gained less than 2 rwhp with the other 2 sensors, these were "special" tuned sensors from GMS , we then tested 2 GMS MAF sensors on a 1500 pickup, both lost over 5 rwhp on the dyno. Sport Truck magizine also reported similar finidings in their test last fall.

Fullsize forums-
vortec stroker
Curved ducting creates turbulence which distorts maf readings.

Best explanation I ever saw posted about MAF workings.
Fullsize forums
James B.

Do you know how a Mass Air Flow sensor works? Basically you have wires that are being sent pulses of current at a frequency which varies to maintain a given resistance. Utilizing the principle that the resistance of a conductor changes with temperature, the computer is able very precisely determine the correct amount of frequency compensation across those filaments as air flow changes. The temperature of the intake air is a critical variable of the algorithm used to calculate the Air Flow value. Falsifying this value completely throws off the air/fuel calibrations which must be relearned by the computer once it goes into closed loop. Long Term Fuel Trim will be skewed in the positive direction due to the lean condition just as Boosted-Z71 said.

So, where does the power increase come from then if it's making it lean? The power increase comes from timing advance. The IAT and Timing Advance relationship is intended to PREVENT detonation as intake temperatures rise. Tricking the computer into believing it's breathing cooler air will advance the timing but probably enough to cause detonation which is picked up by the knock sensors and retarded again, but maybe not as much. The problem with this is that knock sensors respond to detonation which means that if you're getting knock retard (which anyone who's doing this IAT falsification would) the engine-damaging condition has already occurred and the transducer picked it up.

It's just a bad idea. I could go on, but it's your choice. I would encourage you not to do it, so would your truck if it could send you e-mail.

BTW - another "modification" high up on the list of common ignorant things done to vehicles in the name of performance is the "descreening" of the MAF sensor. Again - BAD. That screen is there for a reason, to stabilize and polarize airflow over the sensor elements. At minimum the MAF would have to be recalibrated for the change in air handling characteristics - something aftermarket companies (not mentioning names) have not succeeded in doing with any sort of consistency or quality whatsoever. That's why the informed supercharger guys don't run those things. The bottom line is that removal of the screen is also sabotage to your own vehicle. It's funny, this is often called a "free upgrade." I don't see how destroying a $210 MAF sensor is free, OR an "upgrade." Oh well...

A reply later
The elements in the MAF are heated. As an example, asume the actual intake air temperature is 100 degrees. The engine is at 2000RPM cruising down the highway with an intake airflow of about 60gm/sec. This amount of airflow through the MAF at 100 degrees is drawing an amount of heat from the MAF elements requiring a current compensation frequency of X amount.
If the air temperature was actually 50 degrees cooler, a greater amount of heat would be lost from the elements at the same 60gm/sec. requiring a greater amount of frequency compensation to maintain the right resistance.
So, MAF freq cruising @ 2000 rpm in 50 degree air is much greater than MAF freq cruising @ 2000 rpm in 100 degree air. The only way the computer knows they're both 60gm/sec is IAT input.

Consider a scenario where the IAT is falsified 50 degrees negative. Cruising at 2000rpm with 100-degree intake air is invoking a MAF frequency the same as X above, but the computer thinks air temperature is 50 degrees lower which means the the resulting calculated Mass Air Flow will be a lot less grams per second. The computer would believe there is less air going into the engine than there really is. Less air gets less fuel. The computer will see the problem in closed loop and finds O2s lean. It will eventually compensate with long term fuel trim. That's all fine for cruising, but at wide open throttle the system goes open loop and provides fuel based solely on the fuel map. LTRIMs should always be as close to Zero as possible - it means that the preprogrammed fuel map matches what the engine actually needs.

I hope this helps. Knowledge saves money.
 
#17 ·
964pt3 said:
GMS unit wont do the normal S10 owner a thing, not even with a Bill Mach reflash, it cant!!! Oh I know some non S/C owners will say it does but the butt dyno ideal comes to mind very fast.

First off, PRO-M had made what GMS called the "C" units , which were calibrated to give the same reading for the same air flow numbers as stock did. They knew air was gonna pass beyond the wires unseen so they flow tested them to then match the stock reading per flow. GMS took it upon themselves to get a bunch of A/C Delco stock units, cut the plastic center bar supporting the wires and then add oversized ends to them which PRO-M had also made. They called the calibrated true MAF a "C" and the modified overpriced stock ones NON. The got caught by Pro-M and Pro-M pulled there making and support to GMS forever. WHo makes them for GMS now??? GOod question since there arent that many out there who make them. So on that fact alone I would avoid GMS's all together, track record shows they like to run on false premises. Thisat one time was posted on Pro-M's web site.
Now Pro-M still makes and sells the real units. But your stock one can handle everything you can throw at it correctly till around 250-275 flywheel. You can bolt on every mod out there NA and not hit those numbers. Add a cam , head work etc and you may just hit it. Pro-M makes these units for those who can get beyond the 275 barrier where CFM flow rates are over what the stock one can handle.
You want to know another thing. You know why all the aftermarket CAI kits have elbows in the front? K&N knows , but I bet to guess the other dont and are copycating. It does 2 things, one is it puts the larger filter area near the headlight bucket hole for cooler air. Second when air travles in the tube, air changes speed, the inside turn will go faster than the outside turn, air will tend to travel the shortest path. Well when it enters the MAF , most of the air passes under the wire, unseen. Well when the MAF reports lower air flows it adds timing. The gain you get is not all from more air flow, its part due to more timing. What helps it further is the cone shape, a cone shape causes a vortex to be created, larger volumes of air in a tighter space, thats why the cone narrows towards the very front edge, if it didnt, no vortex. Now GM made the stock air box to flow straight into the MAF so it could see most all the air and not have this imbalance, the screen and center bar are there to correct problems in flow, not restrict even though it will.
Save your money!!! The CAI is adding timing for you, helping aid in the motor getting all the air it can, having a larger MAF area when the throttle body is smaller, and think about that, the throttle body bore almost dead matches the stock MAF size, the throttle bore becomes the restriction point, what do you do then??? Bore it out and slow the velocity of air entering!!!
Well before the cam when I went to the Dyno it made a 14 HP difference. You have alot of book smarts sounds like but no real experience to back it up. Say what you want but I still say the fact that I am the Fastest N/A truck on the boards tells me my combination works good and part of that combination is a Grannatelli MAF.


Also Are you Sonoma 96 on SSf?
 
#18 ·
The stock MAF can only recognize 175gm/sec. And if you send your computer off to have it reprogrammed and you have the Grannatelli the computer can be set to recognize more than 175gm/sec. And with the stock MAF it gets very hot so that has to have some affect on the needles inside and how they read.
 
#19 ·
Your correct , 175 gps is the max reading, well enough to hit the 250-275 threshold.

Ported MAF and GMS's when first put on since timing is added and if it does not ping will give you horsepower, but it will be tuned out over time due to the 02's picking up a lean read, it will then command the OBD to pick new variables taking away your timing and richening it back to where it should be, we call it OBD learning.
Book smarts, no backup, well I went throught all this and dynoed it, at first a gain, after some time, loss of 7 h.p. Kossuth and one other reported the same findings in a post I had retorted against , just like this one about 2 years ago. Bill jumped in and kinda backed it all, giving the gps numbers and how tuning and over 3 psi it was needed, NA your choice. All forums, all over are posting up the same thing with a small majority of people taking your position. Dont believe, go read like LS-1 sites, F-bodies, full sized trucks etc, why is it that around 80% will say what I allready posted and so on with a few early bird dyno people taking the side with the butt meter people.

So I take it then we all should get a GMS and have Bill do his $500-$600 tuning, so we'd have $1000 into .3. Over half of Bill tuning gains are on the torque management side, the rest of it is light tuning on timing and pushing the fuel cells around some, maybe netting 15 h.p. if your lucky.

As far as the heat issue, its a non issue, its been gone over to death that plastic versus metal in MAF ends, Intake tubes etc, doesnt mean squat when air speeds are as great as they are. The wire elements are sheilded with a plastic retainer so heat wont travel from the MAF ends into the wires skewing the reading, nice touch though!!
 
#20 ·
964pt3 said:
So I take it then we all should get a GMS and have Bill do his $500-$600 tuning, so we'd have $1000 into .3. Over half of Bill tuning gains are on the torque management side, the rest of it is light tuning on timing and pushing the fuel cells around some, maybe netting 15 h.p. if your lucky.

Well I picked up .5 and Yes I think Bill's tuning is alot better than a HPP3 that gives you no Power increase. And I am going to the track soon and I will switch the MAF's out and see what happens. at The track.
 
#21 ·
I didnt say anything about Bill tuning in the way you seem to be presenting it. The debate here was getting a GMS unit. Plain and simple isnt worth anything. You said yourself you needed a Bill Mach tune to really take any advantage of using the GMS unit, I merely stated dont think the GMS did anything, it was the tune alone that did, and most of the tune pickup is due to the torque management area. Your gonna pick up about 15 h.p. max outta the tune at best, the stock perimeters do a very good job of giving you the most it can and only fine tuning the timing curve and fuel curve will make it better. You cant fully unlock the OBD2 to run it much eslewhere, OBD1 yes, you can just about completly unlock one of those.
As to the track test, that wont prove anything and will misskew the findings. It takes many miles of driving and conditions to be met before the OBD2 will respond kindly to any mod. Once the OBD2 has its perimeters set, changing things out can help or hurt times until its learned and locked it in. Even resetting the OBD2 back to square one, it has a learning curve it must go through. If you reset it and run with a GMS, then reset it and run with a stock MAF, the GMS times should be better off the bat since it leans the readings and adds timing the stock MAF wont. After its learned in, it will be a different story! I've learned to scrap the track test for the most part, too many variables can effect it, now most laugh at Gtechs, but there more accurate as to how a mod reacts. I can take a mod, run the same area on all kinds of different days and conditions and average what I find and put it against prior averages. The only way to do that track wise is the same way, many runs in all kinds of condtions etc after youve given some miles to learn it. The track here isnt next door, and for most it isnt, so I doubt the times are really reflecting any accuracy. You can have all kinds of stuff play in, how well you feel that day, the running condition of the motor, how fast your reactions are and the list goes on!! If you did it every weekend, that would be a different story!!
 
#23 ·
Doesnt the Granatelli increase the speed of IAT readings....that is just what i read from a "certified Granatelli dealer" maybe that is how they claim their 10-15h/p gain numbers?
p64pt3- wtf are LTRIMs ? sorry if that is a stupid ?
 
#24 ·
Custom MAF

If you are really set on the maf to be less restrictive my friend does a bunch of them. has has done over 20 mafs for s series and he does a real good job. 50 bucks puls shipping to and from and maybe a 2-3 day turn around and u can get one to about the same specs as the granetelli.
 
#25 ·
Long term fuel trims-Fuel addage based on computed adjustments over time to allow for aging sensors.

Short term-Fuel adjustments based on O2S sensor input as it runs in closed loop.

IAT reads alone and the MAF has nothing to do with it.

A LS-1 3 1/2 MAF sensor would mess our truck fuel trims all up!!

There 10-15 h.p. is what they got on the best vehicle , tune, setup they could over a stock one. Timing and leaning is how you would pick up H.P. on our motors. Leaning to a point of not being excess would make a tad more power, but taking risks. Anytime the MAF reads lean per map it'll add timing and 1 degree is worth from 3-6 h.p. depending on who you talk to.
 
#26 ·
i know this is old post but i still wanted to comment:
thank you for the responses everyone and i just ordered a MAF and jba headers, i am going to borrow my friends g-force or whatever wehre you can plug in your cig. lighter and it will give 1/4 mile times and i think h/p and torque, i am going to intstall just the MAF and run the truck b4 and after on the same road and see what happens ( i dont know how accurate the g-force thing coudl be although i hear it does real good, but i figure it will be off the same amount w/ or w/out the MAF so i should still get an accurate differance in the two readings)
anyway thanks again
-JAke
 
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