this has been covered on the nopistons.com website. I followed the instructions the best i could, still my car wouldnt start. Frustrated, I whipped out the trusty manual and compared wiring diagrams between the two series(s4/s5) and made my own wiring decisions, pulled codes and made more wiring changes.

so here it is kids, the definitave wiring instructions!


...........S4................................S5... ..........
GRN/ORG...............+.........GRN/ORG
............BRN/BLK+BRN/BLK.......................
............BRN/BLK+BRN/BLK.......................(join these four wires together)
GRN/BLU................+........GRAY(green wire inside gray insulator)
BRN/WHT...............+........BRN/WHT
BLK+BRN


note: my car has a 87 wiring harness-- according to the book the wiring is different between 87 and 88.

 

Is there any proven gains by doing this? Im talking dyno chart, not butt dyno....

 

the s5 flows better than the s4.

gain? not much if any... the throttle response is better.

 

originally posted by Aaron Cake...... Not true. The cone style was designed and used because it was cheaper for Mazda to produce. It actually will flow LESS air then the flapper.

 

so there is NO benefit to doing this...to my knowledge

 

hmm...... interesting.....

seems to me to be a better design. i just drove the car just now, the car feels a lot smoother.

 

Also the outputs of the meters are different. So not only is there no gain, but you're messing up probably the most important input to the ECU.

 

i was thinking this... doesnt the computer use the afm as reference?

im not pulling any codes, and i do plan on getting the safcII for fine tuning.

 

i have done this before and it shows NO difference before and after using wideband.
it is not messing anything up.

difference i experienced was the afm doesnt care how you put it - it is definately a big plus and it looks ALOT nicer under the hood.

 

exactly... i love it.

 

yeah
gotta love it when people who have no experience with it say it isnt good...

 

the maximum flow potential of the s5 type afm is much higher than the swinging door type of afm.

 

Getting a relocated S4 AFM to sit right is easy. Definitely easier than swapping the whole thing out. I have no idea why people whine about this.

Stop posting this BS unless you can prove it. The fact that the S5 AFM has an inlet some 10% smaller than the S5's makes it far more likely the S4 actually flows better.

As well as offering no performance gains, this swap also removes the systm that cuts the fuel pump if the engine stalls. That system is there to stop your crashed car turning into a fireball. Does removing this sound dumb to anyone else?

 

I've heard people say the same thing nzconvertible say so I'm sure he is correct however I thought about doing this for a while because the s5 afm fits in the piping of a fmic alot easier than the s4 however I descided against doing any of this because I just got a standalone

 

The last car I worked on with this "mod" was running randomly overly rich throughout. Put the proper AFM back on and all problems went away.

Totally forgot about the fuel pump cut as NZ mentioned. Without that feature, the ECU will continue to run the fuel pump even if the engine is not sucking air. VERY dangerous in the event of an accident/collision.

 

On the flip side, to the people that think the S4 afm flows better than the S5 afm, prove it. I've never seen a single person provide any shred of evidence to support this claim other than hearsay. I really hope this isn't based on what they look like or what their physical size is. The internal shape is a huge factor in airflow. This is why slide throttles suck compared to butterflies everywhere except for wide open. I'm not saying you'll get any more or less power with each one. Personally I think using an afm is archaic and it should be replaced with a decent system. I'm just pointing out that one side likes to tell the other they are full of it but neither side can ever provide a shred of evidence to support their claims except a visual observation and I do know from flowtesting other things that air doesn't always do what you think it will. Maybe one flows better, maybe not. It's probably not worth switching from one to the other though. I might actually try to flowtest each one someday but I don't have an afm anymore so I really don't care what the results are anyways.

 

how was the s5 afm wired? I got the car to run with a code 4 (air temp sensor), re-wired and the code went away.

so thats the wiring instructions i posted...

 

i think the main factor in this mod, is determining if both AFM are calibrated the same or not?? if they are different the car is etiher going to run too rich or too lean, both hurt performance( or can cause damage!)

does anyone know if they are calibrated differently??

 

The only reason I wanted to do this a while back was becuase the S5 afm can be positioned anyway you want, where as the S4 afm had to be flat and straight to work properly.
Still though, like everyone has said here 1000 times before, there is no evidence to support that the s5 flows better than the s4 and vice versa.
I think its also a good point that the few people in this thread have pointed out that the calibration of the afms are different.

Really this mod is one that is not worth the effort.

 

i got my s4 runnin side ways and facing upward a little. its the only way i could run it being that i turboed it. is there any way to let the fiel pump know when to shut off doing this mod. my setup has got to be making it run wierd.

 

my new and improved afm

 

interesting.
i done it on a few cars. and they ran just as well as each other, infact, even better. after a wideband run for kicks, they were pretty much the same before and after the afm.

then later, i tuned the afc and got a flat reading. the readings stayed consistent thru out the whole map.

maybe it was something else that was causing your problem. ?


although i agree on the fuel pump switch



NZ. but could the design of the S5 afm allow for a smoother airflow?
just because it is 10% smaller doesnt mean it must flow 10% less.
think of exhaust pipes, or intake port sizes, velocity, turbanence, etc etc


maybe it just evolved from the swinging gate to cone, and into speed density



and on the afm position. for the s4 one, you cant just hook it up and just let it sit anywhere and still have a clean look. for the s5.. you can.

 

On testing the AFM, I am planning to book some flowbench time to test my intake manifold as soon as I get around to it. I could always throw each AFM on the bench and get some numbers...Not sure when I'll get around to doing this, however. My best guess on flow is that the S4 AFM will always be better because it is unobstructed when open. The S5 always has the cone in the way.

On wiring, the car I played with was wired according to the usual way it's done. There's a GIF wiring diagram that has been floating around for years which I have attached for reference.

 

yeah, thats the one from nopistons.com, it doesnt work.

 

So you finally got rid of your jdm tyte air box mike?