Timing pulled in different ACD modes
Anyone else notice that when the acd is changed from Tarmac mode to either snow or gravel that timing gets pulled? It was raining here a little today so I thought I would try to see how the car responded in a different acd mode and I was also logging with EvoScan. When I looked at a third gear pull I was surprised to discover that my timing was like 4-5 pretty much accross the rpm range. After a few minutes (and a few WTF's) it dawned on me that maybe the ACD mode in Gravel was telling the ECU to pull timing for lower likelihood of losing traction or some other unknown reason. I put the ACD selector back in tarmac mode and logged steady state throttle and changed ACD modes and the next log proved my thoughts correct. Although I have not spent a lot of time on this it looks like both gravel and snow pull the same amount of timing and the change happens "on the fly" because I started in tarmac then went to gravel and snow and back to tarmac and could clearly see my timing correspond to the correct cells after switching back to Tarmac. Maybe someone else could verify to make sure I am not crazy in what I experienced.
Anyway someone who is into it or one of the developers might be able to look into this further I could see where it might be beneficial to push a button and alter timing without having to reflash but I also realize the ACD parameters change.
PS Maybe this is old news I didn't bother searching or anything
Anyway someone who is into it or one of the developers might be able to look into this further I could see where it might be beneficial to push a button and alter timing without having to reflash but I also realize the ACD parameters change.
PS Maybe this is old news I didn't bother searching or anything
Hmm never seen timing pulled with the AEM in all of our logs. Even with stock ecu. My guess is that you have knock and the ecu is pulling timing.
I loaned my laptop to my boss and he will be leaving for Vegas. I have logs to prove there is NO Knock and tps indicates part/light throttle and RPM was around 2500-3200 range where typically ignition mapping (all three maps) timing is way over 20.
All three maps are the same and I briefly checked them to make sure my load to timing indicated in cell was not the steady sate 4-5 indicated in log. this was part of troubleshooting process before figuring out it might be ACD switch.
PS for those that care and or have access this data was gathered using the 2006 Evo IX Service manual Volume 2 section 90-130. 90-122 is For NON-ABS equipped models. not applicable to my vehicle
Last edited by oldevodude; Sep 21, 2007 at 07:59 PM. Reason: typo and extra rambling :)
Is this possibly to do with the fact the ACD uses reduced clamping force in the other modes? Wouldn't it make sense to cut some power if under a reduced clamping load, and slower lockup scenario?
Theoretical of course. I have no evidence to prove one thing or another.
Theoretical of course. I have no evidence to prove one thing or another.
hey nice find! can someone also confirm if the gravel and snow mode lowers mileage per gallon? I am in central jersey and weather has been bad so im always on gravel or snow when its icy or snowing out. I have been getting 15-16 mpg my last two fills at the bp i've been to for years. I've always got 19-21 usually. Also, i might want to add the car is stock no mods, 12k miles, had brand new ultra-performance all season tires (potenza 960as) put on and it began to lose mileage like this bad. Any input would be greatly appreciated!
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Hadn't noticed this thread before. There is one wire between the ECU and the ACD controller. I need to get to one of my other computers to see if the data path is from the ACD to the ECU or vise versa.
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ok, the Evo IX wiring diagram shows that information is going from the ACD controller to the ECU, so in theory it is possible that the ACD setting can affect engine performance. Now just need to sniff around to see exactly what's happening.
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I had some racing to take care of the other day and the car was very inconsistent, I kept bogging the launch for some reason.
later I noticed I left it in snow mode from last weeks sleet...I don't know if it was related or not but I turned it back on tarmac and so far so good.
later I noticed I left it in snow mode from last weeks sleet...I don't know if it was related or not but I turned it back on tarmac and so far so good.
I've dynoed the same car with all 3 ACD modes, same power every pull, within pull-to-pull variance of course.
Of course that's going straight on the dyno without any tire slippage...
Of course that's going straight on the dyno without any tire slippage...