After seeing many people struggle with a car after getting a basic tune from the shop that installed their AEM EMS I have decided to put out my methods for your enjoyment and critique.


When I road tune, I do a 1st, 2nd, and 3rd pull up to around 90 mph while data logging. Then I stop and let the car cool as I analyze the data log. All I am looking at is Engine speed, A/F ratio, boost pressure and knock sensor voltage. Start out with low boost (as low as your boost controler will allow) and a known good timing advance curve and don't mess with it unless you have knock. Start out with a pig rich A/F ratio and over progressive runs gradually lean it out from one run to the next until you finally achieve the target A/F ratio. Now up the bost a couple lbs and repeat. Keep doing this till you have reached your max boost you plan to run. Leave the higher boost levels pig rich for safety in case you encounter a boost control problem at some time in the future.

That is how you tune the WOT portion of your fuel map.

Now on to your cruise mileage problems that you no doubt have:

Set up your "Automap" target table for 15:1 A/F ratio for all table points under 0 psi of boost except for in the idle area of the map. In that area set it for around 14:1 if you have stock cams or 13:1 with race cams (HKS 272's in my case). Now let the car idle for half an hour with the auto tune adjusting the maps for idle. After you do that start driving and tell the laptop to start auto mapping the cruise areas of the map. Now drive down the highway at 55 mph in 3rd gear. Do this for a while so the laptop can tune the fuel at that point. Then go to 60 mph in 3rd, then 65, 70, and 75 in 3rd. Now switch to 4th gear and do 55, 60, 65, 70, 75, and 80 mph to get those points mapped out. Then do the same in 5th gear. Then do the same type of thing in a slow speed area to use the auto tune in low RPM sections of the fuel map. Save that map and drive home. After you get home take that map and "interpolate" the areas that were not affected by the auto tune to match up well with the areas that WERE affected by the auto tune. Now your idle should be pretty damn good with no huge amounts of soot building up on your driveway and your should be cruising (60 mph, no boost) around 26 mpg.

Keith

PS: My cold start sections of the AEM EMS cal file were dead on and worked great so I didn't have to mess with them.... don't ask me how to get them right, when I messed with them I ended up with horrible results

PPS: Don't ask me how to set up the auto map function... my answer is "RTFM"

 

sounds great Fourdoor,
I don't have AEM, just a general tuning question. When you say, leave the fuel rich in case of boost control troubles,what does that mean? Is it knock control with a runaway boost? Most of these ecu units have knock sensor functions and have "plans" to "fix" knocking. Why is it that tuners leave the tuning rich to cover potential knocking instead of allowing the unit to cover that. Do the ecu s not have enough clearance to cover the knock? Seems they all are capable of adding fuel and retarding timing if need be, but maybe it is not enough(?)

ps. now I want to ask you how to setup the auto map....

 

boost control troubles = wild boost surges.

For datalogging, I try to have another person w/ me. I'll concentrate on driving while my partner (experienced tuner or not) can tell me when to romp on the throttle or not at certain rpm.

For tuning, I rather start on cruising first, because you spend most your driving time under WOT. No one drives WOT off an exit ramp from a HWY or trying to negotiate a 90 degree turn at 100 mph.

 

The AEM EMS does have knock retard function for the timing map, but timing is only half the issue. Running rich AND retarding timing is like wearing both suspenders and a belt on your pants.... much less chance something can damage the engine if you have boost control problems

Keith

 

So where did you get your base map with the advanced timing? Mine comes this week! I have been scouring the manual for a month now!