i got a MAF claiming to be a tII s4 MAF but the numbers are worn off. i searched and didnt come up with anything... is there a way to see the difference?

 

There is no MAF on a FC it is a AFM. Anyhow yes the TII S4 AFM is much larger has a biger door and channel as well the spring tension is much harder.

 

Well, you got the stiffer spring right but the size wrong. One out of three ain't all that bad. humor

(P.S. be careful on any response. I have calipers and turbo and non turbo afms laying about). humor

I'd go to the FSM for the S4 and look at the Fuel (Intake Air) section for Turbo and non turbo. Compare the Vs -E2 reading you get with the n/a and turbo readings in the FSM to see which you have.

 

I have both in front of me and the TII AFM is noticably larger in size and had a larger internal channel. I can feel it with my hand and visualy see it.

 

Here's a few jpgs of a N318 13 210, Turbo AFM next to a N326 13 210 Non Turbo AFM.

The round hole has a diameter of 3.210 OD on each afm. The inner diameter of that round hole is 2.935 ID.

The square opening is 1.930 by 2.49 (oops, rectangular not square).

THere isn't more than 0.30 or so difference b/t a measurment on the turbo vs the non turbo.

 

Here's some afm gut pictures. No real meaning, just some pictures.

 

there is no difference in the size, you sure the other AFM is from a RX7? Denso made AFMs for many different cars and some are larger but same design. All S4 AFM housings are the same but who the hell cares, the main difference is a T2 will run richer with a n/a AFM but it can be driven with one for a short period until a T2 AFM can be found.

 

thanks.. i just want to be sure since i thought i got a boost sensor from a turbo and this came with it so i figured this might be a n/a afm to.. i did notice that when i put my ebay cone filter and that black plastic gasket they give seemed to fit the square side better so maybe its right, ill have to check again.. and is the spring that noticably different in strength??

 

Well let’s see here. I just went out to the shop to take measurements with a mm tape and pictures. I had recently put one of my NA AFMs on the 13bt car while I fixed the fuel pump switch in the TII AFM. So I dug threw parts to compare and I start to compare and notice the inside is a good bit smaller . So after I do all this I relies what I just did was compared one of my Miata AFM’s to one of my TII AFM’s. Then hunted and have no clue where my NA AFM ran off too.

In your pic the TII AFM inside looks noticeably larger.

 

there is no noticable difference....

without the numbered tag it is near impossible to tell them apart unless you have one of each side by side to feel the difference in spring tension.

 

I blew the pic up they do look about the same. Must have compared my MX5 one the whol time.

 

thanks, ill check the spring difference..

 

Two jpgs attached. One for checking a Turbo afm and the other a non turbo afm.

 

thanks hailers!! i will check this some time this week and report back.. your a big help!!!
and thanks everyone else..