Discussion and questions related to the course Road Tuning
This is Morris from Hong Kong.
I am a new learner and am currently trying to start tuning my Toyota 4A-GE 20V Black Top engine by applying what I have learnt from the course and webinars, I have some questions below about a NA engine using ITB system,
1) Should I use TPS as load axis for Target Fuel Table or it is better keeping MAP as load axis for Target Lambda Table? Why?
I understand the reason of using TPS as load axis for the VE table and Ignition Table, I have tried keeping MAP as load for Target Lambda Table. When I start to tune in steady state from the 1,500 rpm column, I found MAP easily reach 100kpa at around 10% TPS, so that the target lambda at this point reflect 0.9 (as I set target lambda 0.9 at the cell 1,500 rpm & 100 Kpa).
2) If it is better keeping TPS as load axis for Target lambda table, what is the role of the MAP sensor in this situation?
3) Should I use MAP signal to build up a 4D fuel table to address atitude change situation (driving on hill).
I have tried to find answer from forum, webinar and the course I have, but I still can not get it. I appreciate if you can point me in the right direction.
Hello, Morris, you will need to use tps to control both ignition and fuel because as you have said it goes to 10kpa at about 10percent throttle the map sensor can be set up to use a 4d table where you could use map/rpm as an overlay to trim certain parts of the fuel map. an example would be high vacuum, low load and hi rpm low load areas, I would generally use map fr lambda target but it depends on the engine use
System I have uses TPS and rpm as the primary parameters, with trim for temperatures, etc.
As Ross said, using a MAP input is problematic because the delta pressure is very small with larger throttle positions and/or lower rpm.
There are also applications that run a plenem/air-box that use some form of mass airflow metering into the plenum, and there are hybrids, too.
André has done a video on this topic a few days ago, it may help - or confuse you more.
Appreciate for your explanation. I have though using 4D table with MAP/RPM as compensation for certain part of fuel map like what you suggest.
May I ask that is there any situation using TPS as load axis for Target Lambda Map is a better application than using MAP input?
Thanks Gord! Is 252 Introduction to Adaptronic the webinar which you mentioned ?
Just checked, yes, update 252 - don't know how much help it will be, but all learning is good.
Thanks Gord, I will take it tonight and believe I will enjoy it. :)
Morris, for a NA ITB engine you should have TP as the load reference for your lambda target table. Most of Andre's Alpha-N webinars are based on boosted engines which is why he would use MAP on the target table, in your scenario MAP is not useful.
If your ECU doesnot have a seperate Baro sensor then it would still be a good idea to keep the MAP sensor but dont have it connected to the manifold - just connect it to the air box to compensate for atmosphere/baro changes.
How the baro compensation is set up in the software will vary depending on what ECU you have, with most you wont need to set up a 4D table or special , it is usually just a matter of enabling a MAP or baro multiplier in the settings somewhere.