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Old 12-07-2008, 10:15 AM   #155 (permalink)
robains
2007 Exige S
 
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Join Date: Jul 2007
Location: CA, Bay Area
Posts: 1,820
DBW EFI users, would like to get your input/maps if possible -- specifically interested in the DC Motor and Accel/Decel sections.

I've got a low rpm "run-on" (<5K) that I'm trying to tune out. What I mean by "run-on" is that if I accel to 4K rpm, lift throttle and then press in clutch the rpm's will continue to increase (about 1K or so). I've read up on PID tuning and also looked at the Accel section and have a few questions:

DC Motor - Constants
Base Duty Cycle - currently at 50% - not sure how this factors in there is no table?
Proportional Gain - 100
Integral Gain - 40
Integral Timer - 8
Derivative Gain - 20
Integral Band - 10 (degrees)

Final output is defined as P+I+D so in case above 160

Integral timer and Integral band aren't really explained much. What I can gather from the documentation is that all of these values are used to basically smooth the DBW input/output and increase it's accuracy -- does that sound right?

Accel / Decel - Constants
Accel Decay - currently 8 bits, docs suggest 2-5 bit, reduce value perhaps?

So, these are the elements I'm looking to adjust to try and solve the low rpm run-on issue. I start with Accel Decay since docs suggest 2-5 bit and I'm at 8 bit.

Any hints/suggestions are most welcome.

Cheers, Rob.
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'07 Exige S (Track Pack & LSD) + EFi 550ci injectors + Mahle 9:1 + DRS Port + SuperTech Valves + Weapon R Header + 2.9" pully + TODA Clutch + FF Engine Damper + RLS IC + Greddy catch cans + opened roof slot + RTD brace + Milled steering arms + Larini 8" + FF air intake + Moroso oil pan + Ultradisc 2 piece front/rear + Reverie 1650mm wing + ReVerie front splitter + IQ3 Dash + 4pt ASM + Pioneer AVIC-N2 nav + rear camera + RAC monolites 888s 195/225 + Lotus LSS Hoosier R6 205/225 @ 1921 lbs
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