How Low Boost Can I Run Without Issues?

[mfgguru]

I know this may sound like a silly question, but how low can I set my T/M without having issues? I was thinking of doing a mileage comparison on lower boost vs. where I have it set now. 12-14 WOT, 4-6 sustained. My logic tells me that I should be able to run almost no boost and have no issues, but that could be wrong. I have been told running too little boost can result in high EGT's. What the story on that? Can somebody explain whether this is true or not, and why?
Thanks,
Mike

 

[Slim Shady]

Well I am not sure how little boost you can run without modifying the fuel table in the PCM. The way the fuel table is set up now you need some boost to burn the fuel that is programed in for a specific RPM and throttle setting. I know it will be a little fat at the 1500 to 1800 range but it depends on your boost level.

I would set your sustained running psi at 2 to 3 psi boost and see what you think, you may be able to get a little more economy. You may also find that your egt's may rise a little, I am not sure how much though.

 

[Deere Freek]

egt's rising would result from unburned fuel if i understand it correctly. If they go up too much then your just wasting fuel and negating any gains from less boost.