Mr. Self Destruct

Ok, full disclosure: This is not for a Honda. Car is a 2001 MR2 Spyder with Hass turbo kit. However my questions are about tuning in general and are not specific to any type of car. I'm posting here because I'm a long time Honda-Tech user and I trust this site much more than any of the MR2 forums I've found.

My question is about closed loop tuning using the AEM F/IC.

A couple things to go ahead and get out of the way...

- There are strict emission regulations where I live, so I have to stick with the piggyback. Don't come in here and tell me to "get some real engine management". Believe me, I'd love to... But I can't, so those comments are neither relevant or helpful. Please keep them to yourself.

- I will not swap out my engine management and injectors every year just to pass emissions. The purpose of this is to get my setup fine tuned and forget about it, so I can just drive the car like it's stock while passing emission flawlessly.


Phew... OK. This is probably going to be long winded. Bare with me.

This is my first time tuning an OBD2 car (or anything other than a Honda for that matter...). I've had plenty experience with open loop tuning, so I'm fine with that. My problem is figuring out how to tune my closed loop maps, specifically where boost comes into play. I've found some great info on the topic -

Turbo D16 thread - http://www.turbod16.com/viewtopic.php?p=443290#p443290

AEM Video - http://www.youtube.com/watch?v=Z_IyLEJFEB4

Now, I completely understand why it's necessary to make changes to the O2 map for when boost is present in closed loop. And I completely understand why I have to make changes to the fuel map to compensate for the O2 changes. What I DON'T fully understand is step 10 in that TurboD16 post (~6:39 in the video).

He says "start increasing the cells by small percentages until your air fuel ratio stabilizes"... Which cells? I understand that we're trying to reach a STFT of 0 with this step, but should these small percentage changes be made globally, to the entire map? Or just to a specific section of the map? Both the thread and the video say to hold the car at 2,000 rpm to make these changes... Revving the car to 2,000 in neutral will only allow me to tune a very narrow portion of the map. What about the parts of the map where load is greater @2,000rpm than it will be when I'm just revving. What about parts of the map greater than 2000rpm? I don't understand how just revving the car to 2,000rpm and making changes there will fix the other 95% of the table...

So, to be clear, just as an example... Let's say the car has a load of 15 when I hold the revs at 2,000. I make adjustments to that portion of the map and nail a STFT of 0. Yay!... Except, so what? What about when the load is 18 @ 2,000? Or 18 @ 3,000? Or 22 @ 3000? Or 25 @ 5000???

What is the significance of holding the car at 2,000rpm? There must be one since both the video and the thread say to do it...

Thanks in advance for any help. This is the last little bit of the tuning that has me stumped.

Also, as a little bonus question- Does anyone know how long it takes a STFT to become a LTFT on a Toyota ECU? Seconds, minutes, hours, days? Just curious. Don't want to have to speed tune to avoid LTFTs, lol. :p

chuckles993

Thank God I'm not alone. Everyone wants an easy way out-- an illegal racing setup. I am getting started on a 2007 Honda Pilot T4 Turbo install and would like your advice. I am in the same boat with the ECU piggyback setup (MAP ECU2) and want to stay legal. Please let me know if I can keep the stock ECU and tune. Need to keep as a daily driver. Turning into another big project, no "off the shelf kits", no one with REAL experience around me to help.

Thx.

wantboost

iTrader: (2)

why the **** did you bump a year old thread... noob?

and your best bet for learning short term and long term fuel trims is to go over to the HP Tuners forum and lurk around... I could go into detail but its an assload of typing and trying to convert tuner talk into idiot speak.