foxbat

sounds about right...similar numbers to the super chevy dyno (16 rwhp)

Buttercup

Is that after driving the car around with the MAF in place or immediately dyno'ing after install? You may find yourself with less power a few miles down the road. The modified MAF's are hit and miss, you may gain, you may lose, and with a stock style induction and no screen you will often have more inconsistent part throttle fueling. I have tested this (see sig.) as well as others.... people who have hands on experience with this are starting to agree with me more and more. Any gains/losses from these MAF's are from fueling inconsistencies because of an inaccurate sensor. If you get a car dyno tuned you are garaunteed to make more horsepower at WOT while keeping more precise fueling at part throttle.... all these mods that "lie" to the PCM are complete hacks. Adjust the PE tables for proper WOT fuel delivery, don't hack a precision instrument in hopes of falling onto a few extra hp.

Brent, I realize the GMS MAF is supposedly calibrated. It would seem that it is a much better approach than simply porting a stocker. I have no direct experience with the GMS unit but I have heard from people (like from those on the LT1_Edit mailing list) that at least some are inconsistent. It might be calibrated correctly at one frequency but sways off at another. If it gives the exact same reading per airflow as a stocker I bet you wouldn't see people making hp with them. My hunch is that GMS purposely leans the car out at higher frequencies.... see above statement about how I feel about that

If you guys hate the MAF so much just get rid of it. I must've gained 50hp by tossing mine

SiDeWaYZz28

WELL I INSTALLED IT YESTERDAY . . I NOTCIED BETTER THROTTLE RESPONCE . .ITS A COOL $100 SPENT . .I WASNT EXPECTING MUCH

SiDeWaYZz28

94 TA TT2S

Can you put the GMS ends on the stocker????? If so you would have the best of both worlds I would think....But what do I know?????

DarkRider

When I was researching the gran mafs I had a freind that bought his new and dyno tested his 95 formula and showed an 11 hp gain but when I got mine new I couldn't feel any difference, but then I put the stock one back on and could tell it wasn't he same.

SiDeWaYZz28

yea i did that too , , , swaped out the gran then put in the stock . .and i noticed i have better throttle responce with the granatellt

LT1Brutus

The lowdown on this is a bit tough, but some things have changed. Granatelli used to program these in house. They now have a contract with Delphi to do the programming for them. Those of us with direct links to Granatelli can get you a MAF w/ various internal diameters (depending on your use) and different programs....they now have a N/A tuned one, a forced induction tuned MAF, and a dry-shot N2O tuned one for the LS1 Nitrous kits that blow N2O through the MAF. W/ the Delphi tuning, they should be very accurate. I'll be trying one on my 383 LT1 once its done. The problem tuners have for it...is that they try to tune a car w/ the Granatelli the same as they would a car w/ a stock or modified stock MAF. A short/simple phone call to Granatelli would give them the information they need to accurately tune w/ the Granatelli in place.

SiDeWaYZz28

thanks for the info ill keep that in mind when i got get tuned after i slap my supercharger and cam in

BUBBA

Help me understand. If merely getting more air in increases HP, then a bigger TB would be in order. The MAF is just a sensor that measures the air going through and relays this data to the PCM which adjusts injector pulse and timing based on the amount of air reported and according to the A/F tables.

So if the GM is larger, flows more air and reports the increased amount of air, then the PCM should provide more fuel to maintain the A/F (more air and more fuel=more hp). Right?

The question remains: Will introducing more air along with correct calibration in fact produce more fuel introduction and hp when the engine is only going to induct what air it actually needs at a given RPM?

I.e., just because you have introduced the availability of more air doesn't mean your engine is going to use it, esp. NA. So if you have more air available and your G MAF reports more air going through, is all that air actually being used OR is the PCM going do anything but go too rich since the amount of air reported by the MAF is actually not reaching the cyls and no excess o2 is going to be reported by your O2 sensors indicating too lean condition and adding more fuel?

Please explain the benefit in NA 350.

LT1Brutus

BUBBA...where do I start.
Yes, you are right in both senses. With other modifications to the intake and exhaust and (possibly) lift (either by camshaft or roller rockers) the throttle body does eventually become a restriction. Yes the MAF is just a sensor to measure, but the downside to a MAF system is that all the air must pass through the MAF which is typically smaller to some degree than the inlet and outlet air tubing going to it. Thus, it can become a 'kink' in the inlet duct. If you take the time to measure the inlet area across the throttle openings on the factory throttle body versus the inlet area on the factory MAF, you'll see that the MAF has less...making it a restriction before the throttle body becomes one. This could also be done by flow testing the MAF vs. the Throttle body, which you can find the results of on many throttle body/MAF tuner websites.

Yes...but, the chip contained within the MAF controls injector pulsewidth. This allows MAF tuning to have SOME control over a/f ratio. MAF tuning may take a tenth of a point or so out of the a/f to "lean out" the top a bit which is pig-rich on GM factory tunes.

One phrase could answer this: PUMPING LOSSES
If your basically saying that removing a restriction for the motor to have more air won't add horse power on an N/A car, then you'd agree that getting a free-flow air cleaner or any other intake upgrade is nonsense as well. Try this, pop of your intake in front of the MAF. Cover 1/2 of the MAF w/ a board or other strong object. Now turn the vehicle on and bring up the rpms. The motor will still reach redline...does that mean you're making as much power? A N/A engine "vacuums" air through the entire air inlet as it needs it. Increased restriction robs the motor of power through pumping losses, something every internal combustion engine has. No (or very little) air is going to pass through the MAF at any rpm above idle that the engine cannot utilize. If the motor is using all the air it will take there would be a near zero pressure in the intake....thus no more air would move through it. Now yes, this is getting kind of laymen...I could go into fluid dynamics and the like but this should present my argument fair enough. I don't mean to pick apart your question/statement....just analyzing and "correcting." Care to counter my argument?...I have been known to be dead-nuts wrong once or twice (per day).

JWINN

I didn't read all of the posts but after seeing a few I'm surpprised that all you girls that think the purchase of this is a waste of money, I would disagree.

Fact is this MAF is larger in DIA witch in turn will allow to flow more CFM and the most important IMO and what has been proven to hurt power is the OEM unite is made from cast alumn and will heat soak! The Granatelli is also made from composite. Why do you you think GM engineers switched to a composite MAF body for the ZO6. Because it doesn't heat soak as bad. The OEM MAF sucks! The Granatelli unite will show power increase if your motor can use the CFM to justify it.

BUBBA

Makes sense to me, Brutus.

I sincerely doubt that the claims of the increase in performance of the G MAF over stock are valid, however...

I remember when I had my 97 dynoed, I leaned out the mix with AFPR and gained 17 RWHP.

However, we probably agree that the gains were not long lived with the OBD11.

Sometimes I believe the same technique is used by the A-Market people to claim significant gains, when in fact, the gains may only be temperary.JMHO

96LT1Fan

If flowing more CFM and having a composite unit that is less prone to heat soak is the real key to making more HP, would the ZO6 MAF from LS1speed.com not be a cheaper alternative than the $300 Granatelli?

Buttercup

Precisely what I thought. Most of these gains are from "tweaking" the frequency output to lean it out.

Many of us "tuners" don't like it because we have to lie to the PCM about the changes we want because of sensors that lie to the PCM. I like things to be accurate. Hack tuning to cover hack modifications is just messy, certainly not "proper". Not to say this won't make power, and is certainly preferred to just porting an MAF.

Another problem I see with this is every car is different. It'll work better for some than others. Since you're tuning fuel delivery based on airflow alone it is rather limited in resolution. "Proper" fuel tuning is done with much more resolution, we can control RPM point to RPM point, not just on airflow. A healthy 396 is going to reach your leaned airflow much quicker than a bolt-on stocker. The other thing is with "proper" tuning these adjustments are ONLY at WOT, and part throttle tuning is unaltered.

You are absolutely correct with pumping losses but you missed a very important point of diminishing returns. Bigger can always make power, but it also costs money and tends to lead to drivability problems (in general for induction and exhaust), you have to draw a line. I could put a 6" pipe on there and it's not going to make any appreciable power over a 4" pipe, at least not on these engines. Maybe an Impala would see more gains from size alone but I don't think it's all that effective on the 'Vette and F-body.

Being lighter and thermally less conductive is a great thing, just not sure it's worth the money for the gains. I tell myself that's the good thing about having a straight piece of plasting tubing where my MAF used to sit, I sure as hell wouldn't pay $300 though

I just don't understand swallowing the price. It would be better to invest that money on a real dyno tune where the fuel and timing is set to YOUR car and will be consistent without affecting part throttle in any way. The only cars that could actually take advantage of increased size are so modified that "proper" tuning is going to be done anyway. I'm sure a big reason is ease of install