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Maxx Tuning: Stock ECUs w/PiggyBacks |
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 Stock ECUs w/PiggyBacks (No Standalone Talk) I’ve learned a lot even from tuning my own car, I’ve spent over 100 hrs easily w/ documenting everything as will be explained below. I have a good amount of experience with piggybacks, and I’ve learned alot of tricks that the majority of enthusiasts may not know. Lets get started...
Good Quality wideband
Diagnostic OBDII scanner or Laptop or Palm device that can read and reset MIL(SES) *Datalogging capability is a plus, and if you can afford a True datalogger w/ wideband, this makes it a whole lot easier than explained below.*(I doubt people have that kind of resource to put into their car, please keep reading the whole thread.)
PiggyBack device, may it be a simple fuel controller, AEM FIC, EManage B/G/S/U.
Now you may be asking why a OBDII scanner? I've talked about this a few times about the Nissan ECU's Self Learn, which in general is called Long Term Fuel Trim (LTFT %) Take your Scanner and "Clear Codes" This will reset your LTFT, and bring you to make a baseline pass, but read on, it will get more interesting. I promise.
Before we go on, please make sure your car is properly maintained. I can't stress how important this is. Do an oil change, check the gaps on your spark plugs (sorry VQ35 owners), check tranny fluid levels, and for all of you NON Drive By Wire (NON Electronic) Throttle Bodies, check your TPS voltages. Make sure your brakes are in good shape. Tire pressures @ 35psi street, suspension is in good shape. If you have any problems, please fix it first. If you have a MIL(SES) lamp on, please get it fixed, especially if it's for a MAF, Oxygen sensor, coils, etc.
Why?
MAF reads how much air is coming in, references with MAP and Baro sensors.
Oxygen sensor, your factory ecu reads whats happening and if its reading wrong your whole street tune session will go to poop.
Coils, spark would be nice, make sure its all working.
Better to spend a few extra $ now than re-building a motor or purchasing a used one to replace the one you blew because you were a cheap ass when it came down to maintaining your car.
Now, its getting interesting right??? Let's move on to some more technical stuff.
Some scanners have datalogging, and this is crucial. You will learn a boat load when it comes to the Throttle Position Sensor (TPS), Ignition Timing (IGN) vs. Intake Air Temp (IAT) vs. Engine Coolant Temp (ECT) and Knock Sensor (KS). If you can, modify your list of items to datalog, RPM, TPS, IGN, IAT, ECT, LTFT, KS. Make sure you know how to use the datalogging functions, and can freeze frame it.
Start the car, and let it warm up to operating temperature. Drive casually so you have real world temps when you "need the power." NO WIDE OPEN THROTTLE, YET. This is a very crucial step. I've done dyno tunes before, and street tuning as well.... I will say this as a FACT Dyno + fan = car runs hotter than on the streets.
Example: Typical tune session, car is on dyno, fan turned on, I've read IATs in the 130*F w/hood open, heat on the dash...etc.., and watched timing get bumped down cause of the hot air, same for ECTs reaching 205*F+.(This all depends on Dyno location at the facility vs Ambient Air from the outside).
Complete the tune to what I feel comfortable w/the owner.(NA @ 12.7-13.5, Boost 11.5-12.5) The same car I drive up and down the block, my IATs are at 80*F and ECT @ 190*F, most modern car ECUs will start to bump up timing, and very minimal change in AFRs, but I have seen timing bump up in spots where I have leaned out on dyno tune session, only to add fuel in that area during a 'spirited' street run. This is where things will get a bit twisted. Remember Dyno Tune = HP/TQ #s to brag about to your friends, and as some of you have found out, all the inconsistent dyno #s and time and $$$ spent, here is the ugly truth of it all. Keep reading.
(This is not a guideline to 'street tune' all the time, but once you read all of this it will make some sense.)
Ready????? RESET YOUR FUEL CONTROLLER to Zero, as if running off factory ecu only without any corrections made by fuel controller.(This applies to NA Tune w/ stock injectors.)
Checklist: car is at 'street' temp, clear codes(reset ecu), GO !!!!!
Make a WOT from 2500rpm up to redline, 2nd gear on 5spds, 3rd gear on 6spds, or 2nd on Autos. I usually have a sticky pod w/high quality digicam to record the run, dash RPM and AF gauge. If you have been recording in real time on your scanner/datalogger function, pause it after first run. You will see 1-2% correction made on LTFTs, make another pass, WOT as above, the most I've seen a ecu correct itself with mods has been around 9%. I've seen 'tuned' S/VAFC settings so leaned out that I have seen 22% correction on LTFT. Congrats you made HP that day, but your ECU just PWND you and your settings, and I guarantee you when you drove your car back, it bumped up timing cause it's running cooler than on the dyno. You feel like a MAN now, 2 days later, feels like nothing has changed from before tune.
The overall LTFT should be from 1-9% <-- This is the goal you want when you start to play with fuel settings. Keep it as close to stock as possible. If I lost you at this point you can stop and start to Wiki everything I mentioned. If you feel me, keep reading...
Go back to your datalog, and watch the video you just made of the run. If you cannot decipher RPM vs. A/F, refer back to datalog on your OBDII scanner. Stock ECU will run fairly rich, especially near redline. Freeze frame it from when you went WOT. Your TPS reading should be at its peak and run across the screen like a flat line, if you are quick with your right foot, you will have a flatline from 2700-6500
Take a look at how IATs may have gone down, and IGN may have started to rise after going WOT. Take a look at how ECT may have gone up and IGN may have started to go down after hitting 195*F or so during WOT. Compare IGN to KS, when does it detect pinging? Remember you should be able to scroll down to check at set interval of RPMs.
Now is a good time to start writing down or typing into a spreadsheet and make categories. Reviewing your video of the run, you will be able to see at what RPM and AFR you were, and compare to your datalog... now is it starting to make some sense?
You may need to make several runs and get a median # of where your AFRs are at each interval of RPM.
Please remember to reset your ECU using the OBDII scanner.
I've even done 2500 to 4000, 2500 to 4500, 2500 to 5000, etc @ WOT to fine tune a smooth transition, and you should be documenting how it's all reacting. Start adding fuel or subtracting fuel as necessary to reach your ideal AFRs, Your Goal.
Here is the twist, using the OBDII scanner, reset the ECU each time will bring you back to "control" level.
TO BE CONTINUED |
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Twitter Followers' Christmas Cookie |
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Newsflash |
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Merry Christmas!!!
Just for our Twitter followers =)
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Tuning Area 
