Q45 AFM Turbo or Non Turbo

[B120WNY]

Hi, Im looking for info on how to tell the difference between the Air Flow Meters on the turbo and non turbo models. part numbers of the two would be great.

Im looking at buying one to use on my GtiR but the guy doesnt know if its the right one, as it needs to be from a turbo model.

Thanks in advance guys ! !

[MinisterofDOOM]

Hi, welcome to NICO!

Im looking at buying one to use on my GtiR but the guy doesnt know if its the right one, as it needs to be from a turbo model.

Actually, there is no turbo Q45.

BUT, if you're referring Q45 vs Q45t: The "t" doesn't mean Turbo, but rather "Touring."

As far as I am aware, the AFM is the same for both. Our resident Q experts should be able to give a definitive answer. I'm going to move this to the Q45 forum.

[CrimsonQ]

Both are the same

Only difference is connectors between 90-93 and 94-96

You sure this guy knows what hes doing?

Or is your post titled incorrectly? Maybe your looking for the Z32 maf?
Modified by CrimsonQ at 6:50 AM 12/19/2006

[B120WNY]

Thanks for the info guys. I was under the impression there was a turbo version of the Q45MAF. Im after the Q45 MAF as im planning more power than a Z32MAF will allow for, and i have the chance to get one cheap

Are the connectors on both still 3 pin ?

Thanks

[elwesso]

its actually 90-94 and 95-96 that are different. Theyre technically the same MAF just with different connectors...

[Q45tech]

Besides the restriction of the wire screen to keep large chunks from hitting the MAF element, the inside diameter creates the pressure drop vs flow thru the unit.

Measure the pressure drop at whatever maximum flow you expect to size the diameter......for example the Q45 MAF has a 7" water column pressure restriction at ~~ 300 HP and reads 4.4 volts...........most MAF top out at 255 grams per second ~~ [380 HP]. 8 bit signal [0-255=256 steps]

lb/min x 7.5 = gm/sec or gm/sec x .132 = lb/min

The calibration grams per second of air vs the MAF voltage output is set by a group of resistances in the bridge circuit.

Inside the ecu software is an exponential equation [creates the scaling map] that translates the MAF voltage to something useful LIKE a VE% of that size [displacement] engine.....................

http://www.gnttype.org/techare....htmlh ... re...s.xls

Some engine use a real [measuring half of the cylinders] and a dummy maf and multiply the air flowing thru the real unit by 2.

[PoorManQ45]

Way to scare the newbie off Dennis. LOL

[hannibal]

My head hurts...

B120, the Q45 MAF is 90mm and the Z32 MAF is 80mm. But the Z32 MAF can read more airflow (over 500whp from what Ive read). I'm not sure where the Q45 MAF maxes out, but I think its less than the Z32's.

FYI, the Z32 NA and TT use the same MAF (labeled N62)...

[Q45tech]

part # 22680-30P00 75mm

In stock form the 300zxtt was designed for a peak of 9.5 psi which on the surface looks like [14.7+ 9.5]/14.7= 164% of 3.0 liters or ~~ 4.93 liters however the pressurizing adds heat which brings the air flow density down to roughly equal to what the Q45 injests.

While a stock Q can only show a 4.4 volt MAF peak..............the MAF continues to function up to 5.0 volts............which might be close to 300gms or 450 HP at some higher restriction.

Think you are missing the point that a MAF can support any amount of HP just that when the 5.0 volts is exceeded that the ecu won't know what to do.

[si]

z32 can suport up to 350rwkw (near 500hp)Q45 maf/afm has been known to reach 450rwkw(600hp)

So if your little SR is going to max out a z32 afm then you must be running a rather large turbo!

[PoorManQ45]

Think you are missing the point that a MAF can support any amount of HP just that when the 5.0 volts is exceeded that the ecu won't know what to do.

Is it possible to alter the sending unit in the MAF to allow an output greater then 5V?

Or will this decrease the sensitivity/accuracy?

[Q45tech]

You are missing that the A to D convertor in ecu only generates digital words to 5.00 volts and 8 bits is only 256 steps...............also 7" W.C. is 1/4 psi flow restriction.

5.000 volts can be any flow you want as long as you are willing to accept the pressure drop across the MAF at that flow

1.0 psi restriction drops the barometric pressure thus density by 6.8% so most limit to 1/4 psi ~~ 1.7%.

At some point the MAF gets maxed out [5.0 volts] and then you use a MAP sensor to measure the boost pressure and IAT [temperature] to calculate the EXTRA density from supercharging..........this drives the ecu forward.

You spec a MAF at max grams per second at 5.0 volts with X pressure drop.