Quick answer:
Sell the Q45 maf, thats waaaaaay to big. If you want to swap mafs get a early 90s maxima maf (purple tag, I forget the number, pinout is the same as a Z32). Its a plastic housing maf like the Q45/Z32, same size as a Z32, but reads lower airflow than either. Good NA or anything less than 300hp maf. And cheap until everyone else figures this out.
That being said, for an NA car start tuning with the stock maf until you learn what your doing. Its not hard, but take one step at a time. This is what you need to tune your car, barebones:
1-Rom board (ala daughterboard), installed, duh. I like mine because its easy to use, but I'm biased of course. If you've never installed one and aren't starting a business let someone who has done it before do the install. Trust me.
2-Rom burner. I recommend the moates, but be aware of its restrictions. If your using one of my daughterboards everything is golden, else make sure you get roms it will work with. Other people like the willems, but I hate them. To each his own.
3-Consult connection. Consider this a must. Either through one of the many variations of consult boxes, or I think the nisdata display thing, or whatever. I've got an ultra top secret rom board that has the consult stuff built onto it, but don't tell anybody.
4-Consult software. Well, you've got alot to choose from, and alot of it is free, so life is good. For tuning I'm partial to my own, and for one single reason. Mine will datalog and plot as a function of rpm, and that makes life so easy when your working with a dyno and trying to figure out which points you need to change. I like the conzult freeware for setting timing and idle, his interface for this is very easy to use.
5-Rom editing software. I still use good old rom editor, mostly. Download it, play with it, get used to its little issues, and its quick and dirty to use. See this thread to get it to look right:
http://eccs.hybridka.com/viewtopic.php?t=11
Or for the lazy-
"I figured it out, go to control panel -> regional and language options. Then click on the advanced tab and in the first pull down box, it will say something like "Language for Non-Unicode programs" in blue at the top. From the pull down list select Japanese. Click ok and it will then say you need to restart your computer, restart it and the program should look like the picture. It worked for me and I hope it will for you guys having problems."
6-Other assorted tools:
You really should have a wideband. I've got an innovate currently, but that will probably change that when I have some money to burn. I like the innovate and recommend it for a low cost easy to use wideband. Oh, one trick, you either need to have a second o2 sensor bung for the wideband, or use the stock bung and feed the analog output of the innovate into the ecu. To do this I mounted a screw terminal block on top of an ecu and ran wires internally to the ecu pins. This makes for a quick way to work on someone else's car without them having to add a bung.
You also really need some time on a dyno. You can do the A/F curve on the street (and should do some datalogging on the street!), but the real power for an NA car (and a turbo car, but you've got other issues) is in the timing curve. This is something that most people on this forum seem blissfully unaware of. 2 degrees of timing in one spot can make quite a bit of difference. You need dyno time to really take advantage of this.
And thats it. I really really recommend not buying romulators (yes, you need two, and if you order a db from me for them make sure to request regular sockets, they won't fit in the ZIF sockets I normally use, they hit the ZIF handle) until you play with the above first. You can really do quite alot with just those tools. There are other toys out there too, but you don't loose much by starting simple. You can always resell what you start with...
Tuning the ecu (NA or using a stock codebase!) with the above tools goes like this: install the ecu without the cage and top cover, so just the harness is holding it in place. Don't worry, it won't go anywhere, I've autocrossed like this many times. Start working with your fuel map. The nice thing about an NA car with a stockbased tune is you only need to work with the last two (far right in rom editor) columns of the maps. Btw, use one of the tunes that has the timing map with the knock sensor disabled, this makes things easy to read. Big numbers make it richer, small numbers make it leaner. Make the last two columns identical. Adjust, remove roms, burn roms, install roms. Takes 30 seconds to do that, not a big deal. Only work with rpm points over ~3000 and up, under that is unimportant. What makes this take longer is you don't have any easy way to plot afr vs rpm with just a basic innovate or wideband, so you have to fiddle a bit. When you get this settled, move on to the timing map. This is easier, as CalumSult will give you a timing vs rpm curve:
Overlay this with your dyno curve and look for power changes with timing. Adjust timing points in 2-3 degree steps. Listen for knock. Don't worry, an NA SR20 won't blow up, even a 10:1, when you ping it. SR20s are tough. I've ran some crazy timing, it doesn't make power btw. Look for jaggies on the dyno curve, thats also a tale tale sign. For your application start with whatever the last NA rom I posted was (4?), but back the whole curve down 5 degrees and work from there.
Enjoy!
Edit: Just for fun, this is what the timing curve in my 9.5:1 NA tune looks like vs a stock timing curver:
Thanks from everyone Calum!
