David @ Thunder

Well, twenty years of the first TPI car utilized the MAF sensor we finally get something aftermarket. The Granatelli MAF is a direct replacement for stock, flows about 30% more and is adjustable. I'm sure you guys heard about them and it is for real. We now have them in stock ready for shipping. I will offer a 10% discount to any Thirdgen.org members that places an order for one by April 30th. Regular price is $319.99 so 10% off would be like $288. You must mention your a member and you saw this ad to get the discount. You can order online, and just note it in the special comment section. Online order discounts or coupons will not be applicable with this offer. Just email or call if you have any questions. Below is a link to the product on our site:

Granatelli TPI MAF sensor

p.s. I don't recommend sending me a PM from the board as I'm not logged in very often.

89Warbird

This looks like a modified Wells Su-145 unit. Those have a lifetime warranty, what about these, any warranty?

David @ Thunder

The Granatelli MAF's have a 3 year warranty.

OMINOUS_87

The question of most concern still remains.

What is the actuall purpose of a adjustable MAF, and what benefits would it provide?

From what I see it has one adjusting screw and am assuming it makes a global change in voltage output.

So what is the point, I dont see any purpose for this product.

Someone shed some light on what might be the benefit for a $300 sensor.

David @ Thunder

Ominous....good questions.

It provides the end user with quick and easy adjustment of the air/fuel. Sorta like the MAF tuners for the LS1 cars. A lot of people don't have access to the chip burning or maybe the custom chip they are running could use some slight tweaking. Optimally, this needs to be done on a chassis dyno or track at the very least. Also, since this is a bit larger housing, it should be worth a few ponies depending on how extensive the engine is modified. I'm not saying this product is the solution for all the MAF cars, but it definitely should help. And I do realize that an AFPR could do simlar things, but fuel pressure should really be set to whatever the injectors are tested at to ensure proper chip tuning.

OMINOUS_87

Not to try and bash the product but there are some key points that need to be cleared up.

Since it is a 1 screw adjustment I imagine that it is a global change that is linear in nature and constant through the entire range of airflow, I assume here but dont imagine it to be any other way as it is only a single adjustment.

This may dupe someone into believing that a change at one point may not have a huge impact at other points. If you consider the fact that a hopped up MAF car with a cam often runs very rich at idle but 14.7: everywhere beyond idle. So if someone were to use the adjustable MAF to get their idle in line they would also then in effect lean out the mixture everywhere beyond idle, causing the ECM to be unable to control AFR within the 108-160 BLM range.

Itis also very important to note that PE lookup tables are used when the 165 is under WOT, so an adjustable MAF will have no real use in providing gas when the pedal is down.

I dont want to be a big hater but the limitations should be exposed and talked about.

89Warbird

One advantage is that a lot of us tune with fuel pressure. We are better off setting the fuel pressure higher like 52 psi and then tuning the chip or in this case the MAF. The higher fuel pressure allows for better atomization, which is one of the reasons raising fuel pressure makes more power.

David @ Thunder

Unfortunately I don't have much experience with the MAF cars, but I had a good conversation with Craig Moates who is. Hopefully he will chime in to give better details, but a few points he mentioned.....(hopefully I get this somewhat right):

One, most people already know about gutting the factory MAF. What this does is actually allow more air to squeek by given a certain voltage. This air that is "unregulated" so to speak, leans out the mixture some and usually results in power. With the Adjustable MAF basically you can do the same. Most factory tunes are quite rich, so dialing back the voltage should produce a leaner mixture, right?

Two, from what Craig explained the 165 computer looks at a certain voltage when in PE along with the applied fuel map. Based on the voltage the MAF is providing, fuel will be added accordingly. So if the MAF is providing 4.0 volts at WOT, you can make an adjustment to say 4.5 or 3.5 volts, to either richen or lean out the mixture, right? One problem is though, if the voltage is maxed out(255gms), then you obviously have no way to richen up the mixture as you can't provide anymore voltage over this. However, installing larger injectors without a chip retune(which people do quite a bit) should allow you to adjust the MAF again to a certain extent as to not screw up the BLM's. The BLM's will adjust (as long as your in the range) so part throttle shouldn't be effected but you still get the adjustment with WOT.

Again, Craig is much more technical and hopefully he will comment on the subject. Unfortunately, comprehension is one of my weak points, and trying to remember what all Craig told me has me lost with details or a better explanation.

OMINOUS_87

That is right. The better the atomization the the better the burn as your mixture in the bore and ultimatley compressed into the chamber will be more uniform. I run my injectors at 56psi.

However a radical bump in FP may turn out to be very excessive at WOT as the PE lookup tables will still add fuel based on the injector constant in the .bin this will in effect most likely produce an overly rich condition as the added FP makes for a bigger injector on the rail that the computer doesnt know anything about.



Yes and no, even with the screens out the net effect is very small, in my case it changed my BLMs by +/- 2 at the most. The O2 will trim PW to accomodate. When the screens are out the MAF actually reports a slightly higher amount of airflow as the screens in effect disrupt flow and equalize the flow to be more unifom across the MAF. Removing the screens allows air to flow in a natural state which is more concentrated in the center of the MAF. The center of the MAF has the least amount of friction when compared to the walls of the housing. The end result is that more air will actually then flow across the heating element in the MAF giving a report to the ECM that there is more airflow in effect then what is actually occuring.

That is the kicker. Pegging 255 is not hard to acheive with a hopped up motor. Once that occurs additional fuel for WOT absolutley have to be adressed though the PE lookup tables. I peg 255 in the 4500rpm range.

OMINOUS_87

The idea itself is not bad and is actually quite practical for many applications that are not max performance combos.

However it is definitely not the end all be all. Thats all I am trying to point out.

I guess I am still a little biased towards my 1987 era original Bosch sensor, lol.

89gta383

iTrader: (5)

Nothing wrong with an adjustable maf. Other cars like the 4 cyl turbo cars and lt1 and ls1 cars have maf translators/afc's so this shouldn't be any different. I've played with an afc on an eagle talon with modified motor, and it does let you change injectors without touching the chip. You just need to find the right settings by reading the plugs, blm's and o2's.

I could see where this maf would be beneficial for a modded car with 24 lb injectors instead of the 22's, and the adjustability of the maf would help with the fatter injectors.

Chris89GTA

iTrader: (2)

Agreed. A lot of LS1 guys are running the MAFTranslators for bolt on cars to avoid the tuning in the ECM. Works pretty well, you just have to play with it and check 02s etc to get it right. It will have a an affect on mostly WOT, being that is where you are going to be dialing it in at. So idle and others might be off a little...

IronbackTA

I'll let you know how it performs. I just ordered one.

89Warbird

After talking it over with GMS tech earlier today, I'm convinced it's worth the money, especially since my MAF died a week ago and I'm making due with a stock MAF right now. So I just ordered one.

David @ Thunder

Be sure to post some feedback once you guys try them out!

speed88

I just ordered one. I will post my results with it.

jack harrison

well, i ordered one, fitted it and am very dissapointed. it idles fine, but as soon as i went for a drive th SES light came on. had a scanner read the diagnostics and an emmisions test up the tail pipe and just could not get it to run right. what a waste of money.

CashMunson

iTrader: (1)

what code did you get from adding the new maf?

jack harrison

cant remember the code now, but i know it said it was 'too much maf'. what ever that means!

CashMunson

iTrader: (1)

maybe you didn't adjust it correctly. did you even try adjusting it? or did you just throw it on there and go and expect it to be perfect out of the box?

Shagwell

or did he already have a bad MAF or burn-off relay and even a new MAF can't fix that?

Just because it threw a code that you can't remember doesn't mean there's anything wrong with it. Often MAF codes are not due to a faulty MAF, usually they are either a relay problem, or a wiring issue, etc, etc....

jack harrison

of course i tried adjusting it!!! the exhust tone changed, the read out on the emisions machine read it was ok, it just threw a ses light after a bit of driving. spent about an hour fiddling with it!

Shagwell

if adjusting the MAF showed a change in the sniffer test, then there's nothing wrong with the MAF. The SES is being trigger for another reason. BTW, there is no such code as "too much MAF" It could read low voltage, high voltage, improper burn-off, etc, etc, etc which may or may not(usually not) mean that ther is a fault w/ the MAF. Most MAF codes are relay or wiring related. These cars are getting old, crap happens, grounds get loose/weak, wires corode, etc.

red rock

iTrader: (2)

I'm digging up a 9 year old thread. Too bad there wasn't any follow up. Anyone have any feed back from this MAF? Good, bad, indifferent?

The Project

iTrader: (6)

IIRC there are a few threads on the Granatelli MAF....i remember reading that a few guys picked up 2-3 hp...that's about it. Expensive for what it is.

Bullydawg

iTrader: (7)

I ran one for 4-5 years, but never messed with the adjustment. Not worth it... I eventually converted to SD when I swapped to an EBL ECU.

red rock

iTrader: (2)

Thanks for the reply fellas. That's kind of what I was reading from other forums also.