vato2000taco

iTrader: (1)

what is an upgrade for an s4 t2 maf sensor?

Jager

iTrader: (10)

A standalone EMS.

1.3mazda

yes, stand alone and speed denisty, where you no longer use a maf sensor and u will use a map sensor.

Evil Aviator

To expand on the other replies, the old stock computer is more of a restriction on performance than the MAF sensor, but a standalone EMS allows you to replace both. Note that this is NOT a bolt-on modification, and it is not something that you can tune on your own. Talk to your local RX-7 EMS tuner if you are interested in this modification. Plan on spending $1,000 to $4,000 for parts, and $500 to $1,500 for labor.

Also, FYI, the internet ***** on this forum get upset if you call the Air Flow Meter (AFM) a MAF, even though an AFM is a type of MAF sensor. Much like calling a Turbo II RX-7 "supercharged", you incur the wrath of the ignorant even though you are technically correct.

HAILERS

Zeig Heil!

vato2000taco

iTrader: (1)

what i meant to say was will a s5 afm work on an s4?

DonVito

One of the guys who is more experienced than I w/ 7's should chime in on this, but if a 7 takes to a SAFC-II as well as my Nissans have, there should be no reason you couldn't switch to a S5 MAF, or a Z32 MAF, or a MAF for any other car that is supported on the SAFC-II. That's the simplest way I can think to use any other MAF on the car though, wire up the safc, set the output to whatever the instructions recommend for a S4 TII and the input for whatever car the MAF came came out of, that's how we always used Z32 MAFs on SR swapped 240's. Just my $0.02 Hope it helps.

NZConvertible

It'll work, but there's no advantage to it and it disables the fuel pump cut-of safety feature.

This is completely wrong. The S-AFC is not capable of allowing a completely different type of AFM to be used. If you connect a Z32 hot-wire MAF sensor to an RX-7 ECU it will simply not work with or without an S-AFC. The output from a hot-wire AFM is completely different to that of a flap AFM. The former increases as airflow increases and the latter decreases as airflow increases. An S-AFC cannot compensate for that.

The S5's sliding-cone AFM (I won't call it a "MAF" because that would be pointlessly confusing) works basically the same as the S4's vane AFM, so an S-AFC could compensate for any changes in the output signal.

vato2000taco

iTrader: (1)

thanks i just need to make some room under my hood and an s5 afm apperrs to be much smaller

afro88

iTrader: (2)

Ok since this thread is here I wont make my own. My s4 came with a afm that is sideways. Some one told me to level it out. but after I looked at it, it seemed as though it cant be leveled. The brackets seem like thats the way it came factory. Just to check thats how it's supposed to be right?

NZConvertible

It should be mounted level to work best, as it was from the factory. A sideways-mounted AFM is just a poor DIY job.

blmcquig

iTrader: (15)

i wonder why so many people on here say that it is a bad idea to mount the afm sideways, yet so many aftermarket (even rx7 specific companies) have the afm mounted sideways in their kits. anyone know why this is?

afro88

iTrader: (2)

Yeah I think the previous owner installed a kit on it. The brackets mount the afm sideways and it has a vented headlight cover. If I took off the brackets and mounted it upright it would bounce around and vibrate all over the engine bay.

Force Fed

It's possible maybe he used the stock bracket mounted differently? But yeah, I have a bone stock S4 TII and the AFM is mounted horizontally. I don't remember off hand if it has a bracket or if the air box holds it in place.

NZConvertible

What aftermarket kits mount the AFM sideways?

blmcquig

iTrader: (15)

RP's kit is the only one im 100% sure of (i have it on my car) its a very nice kit, but just puts the afm sideways. ive also seen the K+N kit put it 180* around (belly up, if you will) not that i could imagine that would make much difference.
but, ive never had any problem with my afm. ive got an AFC neo, and the airflow is always the same, ive never had any problems with it.
ive noticed that it would make a difference, however, as to which sideways you go. if the harness clip is on top, it seems to be better than if the harness clip is on bottom. that way, the flap isnt affected by gravity like it would be the other way.

blmcquig

iTrader: (15)

ill try to find a pic of it if i can...

DonVito

Thanks for the clarification, I was under the impression that the RX-7 AFM ultimately was turned into a 0-5volt signal for the ecu, and fuel was calculated based off the voltage like most other MAF and/or MAP equipped cars. That's why it's so handy on Nissans, because the SAFC-II and newer completely intercepts the MAF signal from any MAF it can be calibrated for, and then sends the appropriate corresponding signal to the ECU to read based on the input/output settings. I'll have to look into RX-7 ECU's more then it seems, thanks for the info.

NZConvertible

Upside down is not a problem, and it's installed that way in some OEM installations. But you won't find one OEM installation that mounts a flap AFM sideways. What does that tell you?

The problem is that the AFM flap can now be influenced by the car's vertical movements, like the bumps you drive over every day, that cause brief, rapid motion. Flap movements not caused by a change in airflow result in a corresponding change in mixture. You won't notice this on something as crude as an S-AFC display. This may not be a big deal for some, but then neither is mounting the AFM properly...

They do work that way, but the signal voltage starts ~4V at idle and drops to ~0.5V when the flap's fully open. Pretty much all of the later Bosch L-Jetronic EFI systems like the S4's used the same 0-5V falling-voltage AFM or a variation of it. Earlier versions like on the S3 used a 0-12V rising-voltage AFM.

An S-AFC works exactly the same for Mazdas as it does for Nissans, as long as the correct AFM type is selected. It can't correct for a completely different type of AFM though. The advantage many Nissans have is that larger AFM's of the same type are available, so you can swap them on and retune with an S-AFC. AFAIK the S4's AFM is the largest of that type made, and the supposedly larger 929 AFM has been proven to make little difference on an S5.

It would but interesting if Nissan AFM's could be swapped on though. I wonder how much difference an 80mm Z32 AFM would make? In reality though if you need a bigger AFM you should be looking beyond the stock ECU anyway.

blmcquig

iTrader: (15)

hmmmm. k. so, i will admit, i had never thought about this. however, have experienced it. when you go over a bump, hit a pothole, etc, the car chugs, and bucks rather violently. now i think i might know what it is. that makes me another statistic in why mounting them sideways is a bad idea.
but, it still doesnt explain why an rx7 tuning company sells the kit with the bracket to mount the afm sideways.

NZConvertible

Probably cheaper and easier to make; their bracketry looks pretty simple. There's certainly no other advantage to it.

DonVito

Ahhhh.. I wasn't aware that they used a dropping voltage, seems I have a lot more reading to do! Good info though man, much appreciated!