Help with low vacuum Map readings on ITB setup

[Suzukii]

Hi guys,

I have tuned at least more than 10 ITB setups. I found that the Hondata s300 or Kpro requires a constant Map reading to function properly.

I'm running Alpha N, TPS vs RPM indexing for an ITB setup. This particular ITB kit has problem with low map readings because the throttle plates are slightly opened even at 0 tps. This is a problem as the map readings become very low.

I believe the S300 is still utilizing MAP as a correction factor even when we are running Alpha N settings. Its not true Alpha N settings independent of Map readings.

The engine could not hold idle. It goes up and down the rpm from 1000rpm to 4000rpm. Map readings were dismal. 0.4psi at 1000rpm and rising to -4psi only at 3000rpm from datalogs.

I finally managed to get a good idle at 1000rpm when i adjusted the parameters under Alpha N settings:

'Map when throttle fully closed value', changing from 1 to 50.

The car happily idles at 1000rpm with this setting.

However, the table index starts to read -5% tps, -10% tps etc.

what strategy can i use to compensate for the low Map readings and still ensuring the engine could be mapped properly for other load sites if the map readings are so far off?

your inputs will be great.

Thanks!

[Suzukii]

Problem resolved. Rescaled the load axis and fully tuned on the dyno today.

[snerky]

Problem resolved. Rescaled the load axis and fully tuned on the dyno today.

i know this is a old thread, but how do you really rescale the load axis? :)

Thanks anyone! for answer
im struggling with a bad idle on my b20vtec with 2009 Hayabusa ITB's
goes from 800rpm-3200 continually. and is going to try this out tomorrow