This is a copy of an e-mail I wrote for a customer. These are basic instructions detailing how to use rom editor (still my favorite quick and dirty rom tuning program) to tune a basic DE rom (stock injectors stock maf). I've attached all the files mentioned in the e-mail as well, except the base zip file for Rom Editor, its attached in this thread:
http://www.sr20forum.com/showthread.php?t=95535
I figure this might be helpful to some of you guys that are new to this stuff.
Enjoy!
START:
Attached should be the following files:
rom editor.exe
romeditor19848e.zip
B13_SR20DE.adr
base.bin
Rom Editor is my favorite quick and dirty editing program. Its clunky and getting long in the tooth, but its still my favorite.
Install the program contained in the zip file. Hunt down the directory it installed to and overwrite the installed executable with the one attached. Rom Editor was originally written in Japanese, so I've hacked most of the worst Engrish phrases to read correctly. Also, the tab structure does not work properly for English versions of Windows, but its workable.
After installing and launching Rom Editor, you need to give it an address file for your type of rom. This is the .adr file I've attached. Save that file in whatever directory you are going to keep your roms in and don't move it, Rom Editor will access that file each time you use it. To set the address file, go to Setup -> Load address file, then point it at the address file.
You will notice the tab structure is not quite displayed correctly, specifically you can't see the name of the tab your currently on and all the different tabs are not available. This is annoying at first, but workable. The only two tabs that are of importance to you for now are the "hi-octane fuel map" and "hi-octane ig timing". (These are really misnomers, they should be called "primary" maps. Your car will never switch to the secondary maps. Just in case, you can copy the high maps to the low maps using Edit -> Data copy -> Fuel Ignition time, and copying high to low.) For stock injectors and maf, you shouldn't need to touch the other tabs. To get to a tab, if you can see the name, just click on it. If you can't see the name flip to different tabs until the name is visible. If your not sure what tab your on, click to another tab and go to whatever tab you want to be on. You will get used to it with a little use.
Firs things first. Load up the attached rom, base.bin. To do this, goto File -> Load -> Load (BIN). This rom is pretty much stock, with the following exceptions:
First, its based off a JDM primera rom with no EGR or AIV.
Second, the rev limiter has been bumped to 7800. You can set this to whatever you desire. Under the global tab, just change the value in rev limiter 2 to whatever you want (the value must be divisible by 25). Do not change rev limiter 1.
Third, the feedback for both the knock sensor and O2 sensor has been disabled. Normally I eliminate the knock sensor feedback but do not touch the O2. For your car, since gas mileage is not really an issue I eliminated the O2. Once you get your feet wet I'll show you how to add them in if you want.
Fourth, I've smoothed the maps very slightly to make them a little easier to read.
To the fun part: The fuel and timing maps are fairly easy to read. You'll notice the x-axis is labeled "TP" and translated to "Boost" values, and the y-axis is in RPM (and the trailing 0 on the RPM axis is cutoff). Ignore Rom Editor's attempt at translating TP to pressure ("Boost"), this is incorrect. TP is actually a round about way of measuring volumetric efficiency, or load (TP stands for theoretical pulse width, and is the pulse width needed for a given mass air flow to achieve 14.7:1 afr, this can be converted to VE with some hand waving, and the exact formula is buried in the last excel spreadsheet I sent you). For now, just fiddle with the last 3 columns of the each map. This is where you'll be at WOT generally. Other regions of the map are trickier to play with because they can't be measured on a dyno. Btw, the values on each axis can be changed (the rpm scale must be in units of 50). Later you may want to try adjusting the top end of the rpm scale, I never got much out of it on a stock cammed car but its something to play with. When you run off scale (either TP or RPM) the ecu simply uses the last value on the map (and running off scale is ok, the TP is scaled purposely so WOT pushes you slightly off scale most of the time).
Ok, you'll notice that timing is very straightforward (the value is simply the timing at that point), but the fuel map is not. Each value is actually a multiplier of the current real TP (which is not limited to the values on the axis btw, and hence why you can run off axis with no consequence). You can translate this value to a theoretical AFR, but this ends up being out in left field. Btw, larger values are richer and smaller values are leaner. What I do is do a baseline run and measure the AFR for a particular rpm and value, then adjust some fixed amount and do a second run. Basing on how much the AFR changed I then scale my adjustment to hit the AFR I desire. With a little practice you can get the AFR where ever you want.
There are two ways to edit the fuel and timing maps. Either 2-D (as viewed normally in the tab structure), or in 3-D mode. I like 3-D mode the best. To get to it, when your on the map tab you want to edit just press ctrl+G. For your rom the learning bits won't do anything (these toggle the knock and O2 regions) because your base rom has these all set to 0. Do not change the marginal value. Display direction simply rotates the map. The ratio lets you scale the map to make it more readable, I like a ratio of 3. The COMP.display flag lets you compare your map to one in another rom. If you save every change you make, this is a good way of seeing what you've done previously. To load a comparison file, under the normal screen (not 3-D) goto File -> comparison file -> Load (BIN). To edit points on the map click on the map, then move the cursor with your arrow keys. Use the "+" and "-" keys to change values.
I'll send you a copy of LiveEdit later this week. Its got a similar interface and some other features. Also, I will have a consult box for you soon. That really makes this fun, you'll get to use my software.
-Calum
