MAP vs AFM

[Dayzii]

Hi ppl,

I have a AFM fitted car and i want to know if i can swap it over to a MAP sensor so i dont have to purchase another AFM for a duel air pod system i want to do...

I have a TT Mk3 supra if that helps...

thanx

[Mr Paint Job]

Hi ppl,

I have a AFM fitted car and i want to know if i can swap it over to a MAP sensor so i dont have to purchase another AFM for a duel air pod system i want to do...

I have a TT Mk3 supra if that helps...

thanx
the only way to ditch the mass air is to change the computer over to an AEM stand alone or buy the PowerHouse Racing "piggy back" which deletes the MAF meter. http://www.powerhouseracing.com/supratt_mapecu.shtml

[DK]

Why would you want a MAP sensor on a turbo car?

I've never been able to understand why Mazda put a map sensor on an FD ... a turbo car, but not just a turbo car, a turbo rotary, which is the least capable of handling lean conditions ... yet Mazda puts MAF sensors on Miatas.

I would give up some important organs to have a MAF sensor on my FD.

[Wolf]

Why would you want mass air over a MAP sensor? I've got a VAM on my car and would love to have a MAP sensor instead.

[Scott]

Why would you want a MAP sensor on a turbo car?

I've never been able to understand why Mazda put a map sensor on an FD ... a turbo car, but not just a turbo car, a turbo rotary, which is the least capable of handling lean conditions ... yet Mazda puts MAF sensors on Miatas.

I would give up some important organs to have a MAF sensor on my FD.

I'm in the same boat as you. I'd have been very happy to see my car come without a MAF sensor.

[fusionsport]

MAF sucks for turbo cars, as proven on the supras, eclipses, etc etc- people do whatever they can to get RID of MAF on those cars, and with good reason-

If you want a MAP on a supra you will have to change to a vpc or similar piggyback, or go full standalone like DTA or MOTEC etc, aem does not at this time offer a MIII supra box, although it is rumored to be near production

incidentally I wasnt aware that the M3 supra came twin turboed? howed you get to be so special?

[Scott]

incidentally I wasnt aware that the M3 supra came twin turboed? howed you get to be so special?

It all depends on where you live...

[DK]

Wait I'm not getting it ... Scott, you don't want a MAF sensor? What car do you drive?

It's always been my logic that on a rotary it'd make more sense to have a MAF sensor because it gives the computer more time to adjust to sudden changes in air intake and meet it with the proper amount of fuel. MAP sensors intuitively seem to be just a half-step behind, which can be deadly to a rotary.

I guess tuning would become more of a problem with a MAF, though ... I can see that now, since it's measuring passing air which would have to be converted and my not scale accurately, whereas a MAP sensor reads vacuum or boost and that'd always be accurate. OK it makes more sense that way, I kinda answered my own confusion. In theory it'd still be better to have the early reading of a MAF sensor, but a MAP sensor is more suitable/accurate for a turbo car. Got it.

[Scott]

I have a Mazdaspeed Protege. No rotary for me.

Putting on a simple BOV causes the car to stall out while driving (a 2-piston BOV, however, mostly solves that issue). Plus, any kind of tuning is a royal pain in the arse.

[Mr Paint Job]

Why would you want a MAP sensor on a turbo car?

I've never been able to understand why Mazda put a map sensor on an FD ... a turbo car, but not just a turbo car, a turbo rotary, which is the least capable of handling lean conditions ... yet Mazda puts MAF sensors on Miatas.

I would give up some important organs to have a MAF sensor on my FD.
speed density is far more accurate than mass air. You just need to have the propper tuning and anytime you change anything on the car you need to re tune it.

[NotNotAMonte86]

Having a BOV that vents to atmosphere can cause you to lag in between shifts, but if you vent it back into the intake tube between MAF sensor and turbo you'll be ok.
Both turbo cars I've owned have had MAP sensors, but they weren't used for any fuel adjustments or anything.
I can understand going with a standalone to eliminate the MAF sensor if it's restrictive. In the case of the Mr2 turbo, the AFM is quite restrictive... I wonder if the Supra has the same deal since they are both Toyotas. The VPC is way too pricey when you consider that you can spend a couple hundred more on a standalone with tuning adjustments.

[PNG]

speed density is far more accurate than mass air. You just need to have the propper tuning and anytime you change anything on the car you need to re tune it.


Here we go again...

Neither system is "far more accurate" - in fact, mass air probably has an edge in accuracy in a technical sense because it directly measures air being used instead of calculating airflow from estimated VE the way speed density does. That's why SD systems need to be tweaked whenever mods are made and mass airflow systems don't. MAF engines generally run into trouble only when airflow exceeds the ability of the sensor to measure, or the MAF is physically too small and becomes an intake restriction. There are plenty of very fast EFI Mustangs running mass air without problems, in all-motor, nitrous, and centrifugal blower persuasions.

[fusionsport]

PNG hit the nail on the head- when you start raising boost or airflow the MAF gets out of its range or becomes an intake restriction, which is why I dislike them- and in MOST(not all) cases you cant just swap in a larger one- the new MAFT for dsm and a few other cars make this possible, which is a huge benefit for people who didnt like the idea of going full standalone- and units like the Greddy Emanage allow you to simply "correct" for the larger MAF, as long as it is the same type (karmann vortex, hot wire, etc). All in all I prefer MAP setups, but then I am used to them-

[PNG]

It's almost easy when it comes to Mustangs... Get a matched MAF and injector set and you don't have to change anything else. I'm not sure why the same sort of thing hasn't been done for import mass air systems. I guess that since standalone SD conversions got a foothold early on, mass air never had a chance to develop because everyone assumed it was unworkable junk.

[Ritz S14]

MK3s in japan came with a 1JZGTE, using twin C12a turbos. Or..he could have done a swap..

[Mr Paint Job]

Here we go again...

Neither system is "far more accurate" - in fact, mass air probably has an edge in accuracy in a technical sense because it directly measures air being used instead of calculating airflow from estimated VE the way speed density does. That's why SD systems need to be tweaked whenever mods are made and mass airflow systems don't. MAF engines generally run into trouble only when airflow exceeds the ability of the sensor to measure, or the MAF is physically too small and becomes an intake restriction. There are plenty of very fast EFI Mustangs running mass air without problems, in all-motor, nitrous, and centrifugal blower persuasions.
have you ever tuned either? if you have then you'd understand what i was saying and that i'm right.

Even when you swap a larger MAF meter and injectors it's strongly advised that you get it retuned since most MAF meters are not calibrated 100% on the dot.

MAF on boosted cars are also a HUGE dissadvantage because of the fact you have to recycle the hot air back infront of the compressor. it also seems to me that most large turbo BOVs are set up to vent into atmosphere because they have to move so much air so quickly when the gas pedal is released. When those are installed on a mass air car they start to fuck everything up.

So now once again you've followed me around and proved that I have said nothing wrong. What is the point of you questioning me once again?
Also explain why most all aftermarket stand alone ECUs are speed density instead of mass air since mass air is more accurate.

[max_misawa]

I doubt this guy is in Japan.
LOL

Max

[Scott]

I doubt this guy is in Japan.
LOL

Max

Australia, I beleive.

[PNG]

have you ever tuned either? if you have then you'd understand what i was saying and that i'm right.

Even when you swap a larger MAF meter and injectors it's strongly advised that you get it retuned since most MAF meters are not calibrated 100% on the dot.

MAF on boosted cars are also a HUGE dissadvantage because of the fact you have to recycle the hot air back infront of the compressor. it also seems to me that most large turbo BOVs are set up to vent into atmosphere because they have to move so much air so quickly when the gas pedal is released. When those are installed on a mass air car they start to fuck everything up.

So now once again you've followed me around and proved that I have said nothing wrong. What is the point of you questioning me once again?
Also explain why most all aftermarket stand alone ECUs are speed density instead of mass air since mass air is more accurate.


Yes, I've worked with both. As a matter of fact, I just did the EFI University "EFI 101" course last weekend as a refresher.

Actually, most high-end standalone systems will accept either SD or Mass Air input. The reason SD is more popular for "consumer" level systems is because it's a hell of a lot easier (and cheaper) to connect a vacuum line to a MAP sensor than it is to rig a MAF properly.

Yes, MAF and "vented" BOV's don't work particularly well together. That's why every OEM compressor relief valve that I can think of is set up to recirculate the "hot air" (which would be going into the engine or intercooler anyway if it wasn't being sent back through the coasting compressor again). I don't see how this supports your point in any case - Putting a ported manifold on a SD engine will "fuck it up" just as bad as a vented BOV will mess up a MAF car. All it takes to make a vented BOV work with a MAF system is a little bit of time tweaking the fuel tables at low throttle position/high airflow to accomodate the momentary rich condition caused by the loss of metered air. But you know that, of course, since you have such extensive tuning experience.

I'll put the question back to you: Explain how a SD system that comes up with a calculated airflow value based on estimated VE, manifold pressure, and engine RPM is "more accurate" than a MAF that directly measures the amount of air flowing into the engine.

As usual, your absurd absolutes are the problem here. Try presenting facts instead of opinion, and maybe you won't get clowned as much.

[Dayzii]

ok let me clarify a few things about my car.

It is a rare 2.0lt TT GT, it came with a 1GGTE engine not the 1jz, I dont think any ever got imported to the US.

i want to get rid of the air flow meter that sits behind the air filter because:
1. they are expensive
2. i want duel pods for my turbos.
3. Air from BOV needs to be recirculated otherwise you get stalls when changing gears and stuff.

I will be swapping management if need be. but I would be buying a good Australian package so its cheaper. Alot of the jap stuff is too expensive and not as good.

[Mr Paint Job]

Actually, most high-end standalone systems will accept either SD or Mass Air input. The reason SD is more popular for "consumer" level systems is because it's a hell of a lot easier (and cheaper) to connect a vacuum line to a MAP sensor than it is to rig a MAF properly.

Yes, MAF and "vented" BOV's don't work particularly well together. That's why every OEM compressor relief valve that I can think of is set up to recirculate the "hot air" (which would be going into the engine or intercooler anyway if it wasn't being sent back through the coasting compressor again). I don't see how this supports your point in any case - Putting a ported manifold on a SD engine will "fuck it up" just as bad as a vented BOV will mess up a MAF car. All it takes to make a vented BOV work with a MAF system is a little bit of time tweaking the fuel tables at low throttle position/high airflow to accomodate the momentary rich condition caused by the loss of metered air. But you know that, of course, since you have such extensive tuning experience.

I'll put the question back to you: Explain how a SD system that comes up with a calculated airflow value based on estimated VE, manifold pressure, and engine RPM is "more accurate" than a MAF that directly measures the amount of air flowing into the engine.

As usual, your absurd absolutes are the problem here. Try presenting facts instead of opinion, and maybe you won't get clowned as much.
MOST high end stand alones do not allow both, although some do, but not MOST. The reason no one takes their time to "properly" install an MAF meter is because there is no reason since the calculating and estimating is actually more accurate than the way a mass air meter "meters" air. That is why you see SD EFI race cars when they have a stand alone.

It would be 300 times harder to "simply tweak the fuel tables" for a vented BOV when you consider you have to tune for it at every possible rpm and load which has now taken the only real advantage of mass air and that is it's adaptability (the reason it's on so many factory cars).
As far as the "hot air" going into the intercooler comment (assuming you have an intercooler which not all of us do) it shows you don't know much about physics. If the air coming into the compressor is cool then becomes hot and recycles back through the compressor then it's only going to get hotter, intercooler or not. You end up kicking your own ass when it comes time to get on the throttle.

The calculations that a SD ecu makes are actually more accurate than the way air is "metered" with a mass air flow meter. I have seen MAF cars tuned at a certain engine temp and air temp and then when either of those change drastically the a/f ratio is a bit off. I have seen the same from SD cars and their a/f stayed almost identically the same as it was when tuned under different conditions.

It seems to me the difference is that MAF cars are guessing at the amount of air in the engine and SD cars have been told how much air is in the engine at a given manifold pressure/rpm, then the SD car is better at making adjustments for temp/alt changes. That is why i think it is more accurate.

Now please let me read yet another post about you trying to prove me wrong when i'm not.
:sleepy: :sleepy: :sleepy:

[PNG]

You're going to an awful lot of trouble to defend your position on this, and don't think it's not appreciated. Of course, you're still wrong, but you seem to really like that, so we'll keep going.

By the "300 times harder" comment, it becomes apparent to me that you've never actually used any standalone EFI system. "Every possible load and RPM"?!? Uh, no. Manifold vacuum (if you've got a MAP sensor as an auxiliary input) or a zero on the TPS (if you don't) plus high RPM are enough to do it if you or the software are dumb enough to brute-force it, but chances are that whatever software you're using will have some kind of blanket modification table to handle tip-in enrichment (that's the equivalent of an accelerator pump if you have a carbureted blow-through supercharged '67 Mustang... or even if you don't, for that matter) that can take care of this nicely as well without plugging numbers into a jillion cells.

As far as the recirculation goes, perhaps you better think it over again, Mr. Physics. Imagine a closed loop with the outlet of the compressor directly connected to the inlet. What do you suppose the pressure and temperature (taken at any point in the closed loop) will do as the turbocharger spins? I'm really looking forward to your answer on this one...

[Mr Paint Job]

if the BOV is releasing air then it's doing it at all different TPS points, you're not always completely off the gas, just enough to cause vaccuum before the butterfly is all that it takes to open the BOV, this makes tuning very hard. It isn't as easy as just adjusting the tip in enrichment, if your software even supports that. There is no clean way to completely eliminate it and that is why it's a problem.
That is also why there are kits that place the MAF AFTER the compressor, then you can put the BOV before it and problem solved. (no i didn't just contradict myself, i showed the differences between a blow through MAF and the traditional draw through that we have been talking about... now you can't split hairs :sleepy: )

Not really sure what your last question is but if you're just cruising then there will be no possitive pressure, the air coming out of the turbo is hotter than the air going in. and the hotter the air going in, the hotter the air going out.

[Dayzii]

Ok my original question was:

Is it possible to swap a AFM to a MAP? Yes, thanks to a certain few, now i pose the next question: After market Mangagement that uses MAP...

Ive got a few options:
HKS FconV and varients
EMS
UNICHIP
LinkSys.
The above all support my engine im pretty sure so if anyone has had experience with any of the above can you advise?

Cheers

[Mr Paint Job]

Ok my original question was:

Is it possible to swap a AFM to a MAP? Yes, thanks to a certain few, now i pose the next question: After market Mangagement that uses MAP...

Ive got a few options:
HKS FconV and varients
EMS
UNICHIP
LinkSys.
The above all support my engine im pretty sure so if anyone has had experience with any of the above can you advise?

Cheers
you can add

Accel DFI
F.A.S.T.
MoTeC

to that list if you'd like. i don't suggest any of them for your set up though.

[fusionsport]

accel dfi blows goats
fast is even worse- I was just saddled with tuning a fast system and it is fucking horrible-

Motec is the shit- but unless you have a deep wallet get ready for a steep learning curve
DTA is almost as good as MOTEC, but you would have to make a harness

AEM EMS isnt yet available for your car, and may not be available for it if it is a really limited production car- but if it is I would seriously recommend it
I wouldnt use a unichip, I wouldnt use the link system, and the HKS is far overpriced-
I would highly recommend the DTA, but you run into that harness issue again

[Mr Paint Job]

accel dfi blows goats
fast is even worse- I was just saddled with tuning a fast system and it is fucking horrible-

Motec is the shit- but unless you have a deep wallet get ready for a steep learning curve
DTA is almost as good as MOTEC, but you would have to make a harness

i think for the price fast and dfi are perfectly fine, we'd all rather have a motec but better means it costs more, A LOT more.