nickg

looks like a neat thing to do...

sharky47

Yeah, MAF is inbound - just gathering parts and posting as I go along.......

chrly924s

I thought the GM Maf's used a digital signal and Ford used an anolog signal.

Jfrahm

Offhand I think a concern is that the output voltage is a lot different in the middle part of the curve, AFM vs MAF. Perhaps not a big deal when you are in closed loop but at WOT it might be a way off (lean in the midrange I would guess.) Full-throttle tuning will be key.

Another issue is that with a mass signal, you are providing different information that you are with air flow. Humidity and temperature extremes, I think, might put you into some weird places where the tuning will be way off. I'd suggest a good wideband.

Also if you do something weird with the intake tubing, you might have to try the MAF in different clock positions to find the best air signal. The AFM measures across the entire air column, but a MAF samples a pencil thick part of it. If there is turbulence in the intake you need to find the best place to take that little sample.

Cool project! Good luck.
-Joel.

sharky47

Well, according to d_roedel - who had the ability to modify the signal - the output signal is correct in stock form. I do plan on getting an AF guage, the rennbay one is pretty cool - and I also have a brand new 02 sensor to install.

The DareDevil

Looks like the Rennbay A/F gauge is still out of stock.

lleroyb

Daniel,
What about adapting an S2 filter an inlet air piping?

Lou

jgporsche

No, don't get an A/F gauge. You need a wideband.

Jfrahm

Yeah forget the narrowband gauges. I'm not sure if they are good for anything. Yes the original poster claimed it worked well w/o signal modification but I do not know if he was testing in closed or open loop, plus I think he was using a narrowband. In closed loop the DME will help you with the A/F. At WOT, that's another story.

I would suggest testing at part throttle in open loop with the O2 disconnected and watching the wideband for a while before trying WOT. At WOT you will need a long hill, or some brake standing to get a sense of the A/F. Can't let the tach wind too fast or you won't get much good data.

-Joel.

d_roedel

I just put 400 miles on the car this weekend, with the ford MAF wired in. Everything runs fine, and drives well once warmed up. mid rpms 2800-4000, the car is actually a little sluggish in full throttle, above that it is very quick, and below works fine also. I came home and modified the signal to actually lean out full throttle (higher output voltage) between these rpms, by 10% at 2v range to 20% at 3v range. but if you go through at part throttle, great response.

sharky47

Did the signal modification have a positive effect?

Travis - sflraver

That's one of the reasons why we haven't made another production run of the AF9s. It is a great little gadget that was a lot of fun to design and build but in order to do serious tuning you do need a wide band. The AF9 (or any narrow band) would just tell you if you were critically lean. This is important to know but if you are running on the edge like that... you need a wide band.

As soon as I get some time I will layout a replacement clock. It will take the place of the AF9 on Rennbay. I have the circuit drawn but now I just have to source a LCD glass and cram it all into the small board size. Its on my seemingly never ending list of "things to do."

d_roedel

actuallly, woke up and drove to school today - the car did not like the new fuel map, even though it was warm outside, so I am going back in the other direction where the car ran better, and looking to dyno tune. I have a connection with a shop that has a smog dyno, it won't give me HP numbers, but I can check the accuracy on this thing,

sharky47

That would be AWESOME if you would share those numbers.......

EDIT - where did you purchase that signal modifier???

mrmunky

BUMP

status?