considering changing to ITB load and need some help with Q's

[Yves]

I have been doing some testing yesterday with my car. I did several test drives, this time with EGO correction off and checking out the roughed in tune that VEAL gave me. It was pretty apparent that at constant speeds and in the lower kPa areas the car ran lean. Had to up the values by several points in certain areas.

I suspect VEAL doesn't work too well on this engine, that creates some 30% changes in VE with something like 5% tp change especially in the higher kPa zones and I'm considering changing to ITB load.

Based on my logs I have figured out my TPS at switchpoints with 90% baro. that was easy enough. My question here is :I read the manual suggest setting the tps values several percentage lower. Is that correct ?

I had more difficulty in finding the load at switchpoints. Basically I logged the map values that I was getting at 8% tp. Is that a good way to do this one ?

What from my current map can I keep and what has to be retuned ?

Do you also run ignition timing map in ITB load ?

[kaeman]

I am just setting up my engine to try itb mode also. I went to megalog viewer and opened logs and then searched for map readings above 89.9 and just did the search through all the logs that I have had available. I came up with numbers in the curve that started at 3.4% tps at 650 rpm and went up to 21.1 % at 4700 rpm. I ran the search until I had about 200 points in the spreadsheet, then I opened tuner studio changed the fueling to itb mode then went to the menu selection for itb load settings to put in the numbers found in the searches. That gave me the engine information to plot the curve itb load tps switchpoints, then as I was inputting the values into that curve tunerstudio was changing the values in the other curve itb load at tps switchpoint.

Just make sure you have plenty of logs with a wide range of driving speeds so that you get enough good numbers to make the 90 kpa switchpoints curve real for your engine.
I had over 200 points in my spread sheet to come up with my numbers. you will want the same or more...... to insure that your manifold is accurately curved. I noticed that my engine the curve is not a flat line, it has a bump in the curve which I must attribute to the length of the stacks changing the air flow when they hit their tuned length.

Good luck.
I believe they suggest using itb mode for timing control also, but if you are happy with the timing controlled by speed density you can leave it triggered that way and just control fueling with itb mode.

[Yves]

My line is pretty flat.

Are you saying that TPS load at switchpoints is set automatically by TS ?

[kaeman]

Yes it seems to be, when I typed in the values on the ITB load TPS switchpoints curve, tuner studio changed the Curve in the ITB Load at TPS switchpoint. That curve is way different than a straight line.
I will load my ITB tune so you can see what my ITB setup Curves look like. I made the switchpoints curve from the datalog search info, tuner studio created the other curve in the ITB Load at TPS Switchpoint window.
Good Luck

itb mode 1st tune.msq