Boost by Gear Duty% vs Pressure table and range

jetspeedz · Post by **jetspeedz** » Sun Aug 01, 2010 5:29 pm

This is according to S300 documentation

Gear based target boost

With this setting the boost by rpm & gear table is first used to lookup the target boost level, then the pressure vs duty cycle table is used to calculate the solenoid duty cycle to reach the target boost.

Locash was kind enough to tell me the Hard boost Cut does not care about PWM so setting a pressure higher then the pressure in the Duty% vs Pressure table is not a problem.

My concern is if the pressure is higher then the max pressure on the Duty% vs Pressure table how does S300 handle a higher pressure in the Boost by Rpm & Gear table? Would the software crash while driving and hitting those pressures?

locash · Post by **locash** » Sun Aug 01, 2010 10:32 pm

No, the software will not crash. :) The software just commands a certain PWM duty cycle, if the boost pressure exceeds that of the table, it exceeds it, this is not a closed loop system, the software doesnt care what the actual boost level is or reference it back to the table.

jetspeedz · Post by **jetspeedz** » Mon Aug 02, 2010 11:42 am

Ok, how does the software know how much to set the duty cycle outside the table given the % vs pressure is not linear? Guess my question is what math function does it use to calulate modulation beyond the tables upper limit? I might have to get a scope on the signal to get my answer but if someone from Hondata can chime in on this it would save me a lot of time.

Thanks

Post by **Spunkster** » Mon Aug 02, 2010 12:25 pm

Please read your email. Do not email and post forum questions as they will only be answered in one location.

jetspeedz · Post by **jetspeedz** » Mon Aug 02, 2010 12:26 pm

I sent you an email back. This may be good info to post on here as others im sure might have the same question.

jetspeedz · Post by **jetspeedz** » Mon Aug 02, 2010 12:38 pm

Ok for anyone else concerned. The maximum boost by rpm & gear value can not exceed the max value in the Duty %vs Pressure table. And Linear interpolation is used between the points in the Duty % vs Pressure tables. Would be better if the methods was Polynomial interpolation since this is more of a real world output but hondata has decided to use Linear instead.