ITB Mode

[Mario]

Ok, I have been working with MS for a long time and am very well versed. Been into it since the second group buy for reference.

In the last year my client base have largely gone from single throttle body's to ITB's. Some are sized well and I can get a good vacuum signal from a summed vacuum log and tune well with SD. Others are from 70-100 kpa and SD doesn't work so well.

So I have switched to Alpha-N for some of these because I can't wrap my head around tuning ITB Mode. It may be because I'm a lefty and look at the world differently, or just that I don't understand the load switching thing. In the manual it states the "ITB load at TPS switchpoint" should be kept at 50% at all RPM's. So why have it exposed? This also puts the "dot" in my VE table at 50% even when the throttle is at zero and the engine off. If under this 50% line is TPS based, why would it not sit at zero?

I'm just hoping someone can share their perspective on this so it's not clear as mud. I would really like to utilize it!

Thanks in advance!

[grom_e30]

i used it on my bike it sat at about 85kpa at idle so no sd and alpha-n was great if you are going for it but not so great for normal driving

you need to do some decent data logs to map out at what throttle % it takes the engine to get to the 90kpa baro switch point thats the key to it, Getting the (itb load TPS switchpoints) correct.

The (itb load AT tps switchpoint) is basically used to divide the ve table 50 equals a 50/50 mix top half is tps and bottom half is sd. i left mine all at 50 and works great.

if you are over 90kpa (the switch point) it will in the tps half of the table so basically from 50% itb load to 100% itb load would be 0 throttle to 100 throttle

eg over 90kpa but 0% throttle will be 50% itb load but over 90kpa and 100% throttle would be 100% itb load and over 90kpa and 50% throttle will be 75% itb load. roughly anyhow.

[Mario]

Thanks! I think that clears it up pretty well for me. I will need to go out and give this a try now

[muythaibxr]

The load at switchpoint curve is there in case you want to dedicate more resolution to one or the other at a particular rpm.