Modding a MAF engine

[xxrollin]

Has anyone here got a newer 3X00 motor and computer using a Mass Airflow Meter done any major mods to these engines, like bigger cam (regrind for more lift/duration), upped compression, or even turbo/supercharged these engines have any problems running with the MAF? Some people are wondering if these act like most other types of engines under high performance use. Some mustang guys, like my brother, have not touched the computer but is running a 70mm TB, Comps power box UIM, the X303 cam from ford racing, and World products Windsor sr. lite heads fully ported/polished. Other than a 75mm MAF upgrade that came with matching injectors, the engine runs sweet and doesnt trip any SES senors. So is this almost the same for GM's set-up. Can these systems take alittle more than a reg. MAP sensor engine. Some GM V8's running MAF claim the same thing. Can anyone clear this up??

[ikessky]

phantom505 is running a turbo setup on his 3400.

Isn't the principle behind the MAF the same regardless of what car it is on? I would think that if the F-Body and Mustang guys can do mods like the ones listed, then we can too without any trouble.

[xxrollin]

Thats what I'm wondering. I know that these guys can do almost anything without hacking the factory ECU. I know the MAP cars are to sensitive to vacuum changes. Anyone tried anything else??

[vsop4me3.1]

i got a 2002 3100 I put on a pro-m M.A.F., custom fenderwell intake, duel exhaust, ffp udp, and an ebay chip. runs a little rough up to 3,500 rpms. Not too bad though can hardly notice it, but when I take out the ebay resistor it seems to run a little rougher, so I leave it in for now. I should probally take it to a shop that is more knowledgable with this sort of thing, but it's not that big of an issue...... plus I'm broke

[93LuminaZ34va]

MAF's are less sensitive to engine change vs a MAP engine. It can calculate required fuel for the air flow that the engine is taking in.... a MAP engine never sees how much air it is taking in..... it is instead calculated from dispacement, RPMs, and manifold vaccum. Hence, they will be more sensitive to that kind of change.

[z24turbo93]

That really doesn't make sense to me. The map sensor reads vaccum yes (as in vaccum in the intake) once you put a turbo on the map sensor has to beable to read how much boost the car is making (as in psi is in the intake) So in a way the map sensor does read what is in the intake for air. This is how the computer knows how much fuel to give the car

[xxrollin]

Yeah but the factory comp. doesnt read boost and wont calculate the needed fuel. Thats why I'm asking about the MAF cars really. We couldnt turbo my friends Beretta V6 without a check valve. Once boost came on, it ran like shiznit. So he had to go for an aftermarket ECU, its a MAP set-up still and reads boost with a 2-bar map senser. Same as mine but a different system. I am getting a new GM, and most if not all are MAF now. I want to boost it but stay on a low budget. Its a truck....... Need the extra power... How about a turbo 3.5L I5... Thats what I'm planning.

[geoffinbc]

MAF cars still use a MAP sensor. There are good things and bad things about MAF but in the long run they are more acurate for reading the actual amount of air going into the motor.

[brian89gp]

And MAF is more mod friendly. MAP relies on VE calculations (what you tune) to guess how much air the engine is using for the given RPM and vacuum. MAF just reads it.

The only things that throw off MAF are:
-any changes to the MAF sensor itself
-screenless, the MAF becomes finicky and innacurate at low-flow
-to a small extent, piping on each side of the MAF
-any changes in the fuel system... injectors, pressure, etc
-and lastly, out flowing the MAF

[Corpse]

I would prefer the thought of a combo type setup. In both ways, there are some pros/cons.

Like on a turbo setup. Then you must worry about it being outflowed and, I would worry a little about accuracy. Would the MAF be better before or after the turbo? I would assume that before the turbo would be better. Less heat and density would probably mean better accuracy numbers.

Although, it would probably serve as less of a restriction on the pressure side.

Now look at MAT/MAP, pressure sensor in plenum (ideally) and MAP sensor (located as close to plenum as possible, isolated on it's own vacuum channel). You have to figure that, by the time the air hits the sensor it ought to be quite hot, hotter than at the point where you would have the MAF. And of course, a hotter reading is better because, it is more accurate of temperatures in the lower engine.

Another advantage, no MAF, so no restriction or possible out-flow condition. Also, as the plenum is put under boost, the pressure that the plenum looses as the intake stroke progresses is accounted for and fuel is changed accordingly.

Which means, the fuel control will probably be more responsive. Having a MAP sensor allows the Injector Controller to do the equivalent of a Carb's power valve. Add extra fuel as vacuum drops. If the programming was done right, it would just keep squirting, and there would be little need for computer retooling for fuel (not as much).

Basically, both systems are designed for expansion and can handle boost fine. They are both good methods that are excellent to use together. Now, the unfortunate side is that, GM mixed the systems on our cars and we are stuck with it.

Wether it be All MAT/MAP or 50/50 MAF/MAP or a strange mix like GM does, it is only as good as it is designed for. Unfortunately, I believe that we are finding an area where GM's MAF/MAP are proving to be more flexible than non-MAF systems.

Also, there is a grey area on MAF/MAP cars. They mainly rely on MAF so, what do they really do with the MAP sensor for calculations? Could just be used for fuel enrichment/load/baro-pressure etc.. Realistically, I don't see why GM's coding isn't more flexible to handle more calculations.

Now, if you made a MAF/MAP setup and could pick all the options yourself, it would be the ideal setup.

-Dave

[Cliff8928]

MAF should be before the turbo. The compessor bypass valve should recirculate the air back into the intake pipe before the turbo, but after the MAF..

typically, MAFs don't like heat

Cliff Scott
89 BerettaGT
89 Volvo740