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Old 11-24-2009   #5
scheides
flips McGee
 
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Re: Speed Density on Evo ECU

Quote:
Originally Posted by Kracka View Post
How do the EGR settings play into all this? I'm a bit lost on that considering you don't even have EGR on your car.
Despite actual EGR being deleted, there is a subroutine that increases timing off of your timing map while you are at cruise, basically to improve fuel mileage. If you log your car, you'll notice that the timing values while cruising will hover around 40, while the max timing values in your timing table are 38 (on a stock rom). There is a full timing table that allows you to select rpm and load points and how much timing advance you'd like this EGR timing function to add. I don't think it will automatically add 100% of the values in this table, but progressively add some and pull some as needed to keep things running nice and efficient.

On the same note, there is an actual timing table for the cold start/cold coolant temp. It modifies the stock table up to these numbers (they're all negative, right in the cruising area and 0 everywhere else), and the table that we have been messing with over the last year or so (dropped the middle values from 256 to 200, 128, 100, etc) are a reference to this table and the percentage up to which it should be used. Just more ways to tweak tweak tweak!

Anyways, I tried fulltime open-loop and it did not help the 2000-2700rpm studder/jitter problem at all. I tried afrs from 15.5 down to 12.9 w/o any difference (other than it smelled like gas a lot more LOL!). I want to elaborate on this, it is not really THAT bad, it is just a mild 'nervous' feeling the car has in these rpm ranges while cruising steadily. It is really the last thing I do not like with this speed density conversion. My AFR, timing, boost values are all perfect and the car rips on pump gas.

Time for alky
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