turboawdfanatic
Moderator
Joined: Tue Aug 14, 2007 2:39 pm Posts: 3013 Location: La Habra
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Pressure based fuel and timing maps
Anybody using pressure based fuel/timing maps with their engine management? If so, what's your take on it? What are the pros/cons? I was talking to someone about this a few weeks ago (Dustin, I think?). . I think I'm going to try this code out sometime this weekend now that I have the map tracing feature figured out. I like the idea of not being stuck on one timing map row, and there's no need for extended maps.
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Illeagle
Talon of Doom
Joined: Wed May 23, 2007 10:07 am Posts: 3615 Location: Long Beach
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Re: Pressure based fuel and timing maps
AEM does it. BoostComp.
Aem works on a user made fuel map that is then multiplied, divided, added, subracted, through a series of 10 to 50 "trims" to get a final injected number. In theory, if you get all trims set properly, you can dial in a entire fuel map for any boost level and all the final numbers on the fuel map come out the same, at any given boost level. So for the entire map at 5000RPM, If I set say 35% Injector duty cycle no matter if its at 0PSI or 35PSI, its all set to 30%. At 5K and 0PSI, +0% boost trim, +100% throttle trim, +0% AIT trim, my final fuel value is 25% IDC at 0PSI and 5K RPM. Say Im at 14.7PSI, +100% boost trim, +100% throttle trim, +5% AIT trim. Final Fueling number will be 61.5% Duty Cycle. Now at 29.4PSI, +200% boost trim, 100% throttle trim, +10% AIT trim. Final IDC 93%
All trims get adjusted witht he exception of boost trim, being linear. But throttle trim allows for more fuel at higher TPS vales and less at lower tps values. Generally 45% TPS and higher is set to 100% and 45% and lower is ramped down so AFR at idle is good. TPS trim is built driving around and at any given RPM at same load value but different TPS values, you adjust it so you get the afr you want at any given TPS at that same load value.
Ill post a screenshot with a AEM fuel map for reference when I get to work. But a boost come map just looks better and once all trims are set properly, adjusting fueling is as easy as a 2D map without the difference in AFR as you raise/lower boost. If done properly, on AEM, you can tune the AFR map at 0PSI (disconnect wastegate actuator arm) then just raise the boost to whatever level you want and AFR will still be the same at every RPM.
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turboawdfanatic
Moderator
Joined: Tue Aug 14, 2007 2:39 pm Posts: 3013 Location: La Habra
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Re: Pressure based fuel and timing maps
Wow, that's pretty cool...and involved. Have you run it on boost comp yourself yet? The TunerPro code is much more simple, basically just using your MAP as a reference so you can tune specifically for boost levels rather than 12 load levels. This removes the cap so you're not pegged out on the top load level once you're above something ridiculous like 12psi. Dustin, are you running this on jackal/werewolf yet?
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