I was wondering if the Series 5 AFM flows any better than the flapper door of the Series 4. And if so, is it possible to swap onto an S4 without much work. I know this sounds like a n00b post but I tried to search, but you cant search for "S5" or "S4" because they are 2 letters long.

 

no, I'm pretty sure they are not swappable. It doesn't make enough of a difference to worry about it. Yes the S5 flows better, but only by a small margin.

Just think, the s4 turbo uses the exact same sized afm as the s4 N/A, but it flows a lot more air. It takes a lot more air to run the engine at 7k with 10 psi boost than at 7k with no boost.

If you are really that concerned about it, buy a stand-alone and eliminate it completely, but that really isn't worth it on an N/A unless you have some sort of crazy port job and you need to tune for it.

 

I am concerned about it, because its probably the most restictive part of my powertrain. But Im not going to drop a few grand on a standalone to fix the problem.


Anybody know if you can port the AFM without messing up its sensoring?

 

No dont even bother trying to port it gains are miniscule if that, also swapping to a turbo AFM doesnt guarantee that it will produce any gains as well but in some cases has worked really well in conjunction with other mods. -Gabe

 

you can swap an S5 AFM to an S4 but you have to rewire it from the afm not extacly sure how but it is possible

 

https://www.rx7club.com/forum/attach...&postid=945053 ...dont remember where i got this i think that ted posted it one time.

 

A few grand? Hehehehe...

http://www.team140.net/modules.php?n...article&sid=17

Brandon
BR7 Racing

 

One grand's more than enough. I can get rid of it for under $200

 

The dude that has the pic of the little twirp from Family Guy did a write up on it, just can't remember his line.

 

Can't do ignition, tho! And the Microtech laptop software, with its datalog playback is mmm-mmm good. The Megasquirt is nice, but it's not nearly a complete solution.

Brandon
BR7 Racing

 

Megasquirt has datalog playback, I wrote most of it myself. And it'll do ignition soon enough, but a 12a dizzy always works, and piggybacking the stock ECU is fine!

 

weber 48IDA's do not need an AFM...or anything else for that matter.

 

The resistances are still not quite compatible, so some trimming is in order if you want an accurate signal. I think the temperature sensors are at least the same. See the factory service manuals for resistance values of each AFM.

IMO the AFM swap is a complete waste of time, especially given the low price of modern aftermarket EMS products, but to each his own.

... except for the expensive 48IDA's, the manifold, new air cleaner, and other hardware, lol.

 

lol...yeah...but think about how clean the engine bay is...right?

 

That was funny as hell

 

So your systems can tune themselves?? I can pick up a Haltech for $600, but I dont want to spend all of the money to tune it. Plus Im trying to save up some money.

 

Wozzom fitted a s5 AFM on his s4. He did this way before he dropped a s5 Motor In all together. PM for details. He did not suggest In the least that their were any drawbacks to this conversion.

 

Heres the follow up.

 

Nice work silverRotor, I might do this if I ever find one for sale.

 

He also said there were no benifits either. Again, PM him. He may have additional Info to add to this thread.

 

Wrong. If you know what you're doing you can make an EFI engine bay look just as clean as a carb one. I know someone with a 1st Gen powered by a 13B BP with an IDA-style TB and Microtech ECU that has only one wiring loom about the size of your thumb in the entire engine bay...
Besides, the benefits of EFI far outweigh having a few extra wires in the engine bay.

As for the AFM swap, the S5 AFM causes no less restriction than the S4 one, and is not calibrated to work with the S4 ECU. There will be some changes in the A/F ratios, and since no one appears to have ever done any before-and-after testing of this, you don't even know how much they'll change. That's not smart modifying. IMO this is a pointless exercise.

 

I think he was joking in reference to another thread.
https://www.rx7club.com/forum/showth...hreadid=183851

I would imagine that the S5 AFM is in fact less restrictive than the S4 AFM, but only by a very slight margin. I would normally say that I would like to see someone measure the restriction differences, but in this case, I don't think it is worth anybody's time to bother.

I agree that this is a pointless exercise because you still can't tune the ECU, and it is still running with the ancient S4 computer that is half the speed of the S5 computer.

 

if u want to play w AFMs he S4 is a beter one to use...be sure to do it on a dyno but the crude spring adjustment method can yield gains on an NA by leaning (worked for me, run a solid 850 celcius on my EGT 3rd gear WOT). or richening on a TII if you're running a little more boost. dyno only...or you may pop your motor.

 

Yeah i told people about that screw and i got flamed so bad so i kept my mouth shut and basically am waiting for dyno proof.

 

Here's my reasoning. The inlet of the S5 is actually smaller than the S4 one. The S4's is 63mm x 50mm = 3150sq.mm, the S5's is (I believe) 60mm ID = 2827sq.mm. That's quite a big difference. Plus when the S4's flap is open, there's nothing blocking or affecting airflow. When the S5's cone is fully retracted, it's still in the way, even though it is a relatively slipperly shape.
Like you say, there's probably not much in it, and there are other reasons why there's no point to doing this swap. I still believe the risk of unknown changes to mixtures should be enough to stop anyone doing this to a modified car that might not have ideal mixtures as it is.

BTW, if anyone's curious as to why Mazda (and most other manufacturers) swapped if there's no flow benefits, it's because they give a more accurate reading and have a more linear output than the flap types. But it's impossible to take advantage of these benefits unless you have the matching ECU.