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Old 05-02-2013, 12:14 AM   #1
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Default Free revving vs load

This may be a silly question, but I haven't seen it explicitly addressed in my searches.

How do you guys tune for free revving?

If I drive around and let VEAL do it's thing, I can get a nice smooth map that does pretty much what I want it to do while the car is in gear and moving. But then if I sit in the driveway with the car in neutral and rev-and-hold the engine without any load, the AFR is very far (lean) from the target for that cell.

I can tune those cells by hand, but if I don't lock them then VEAL will pull all the fuel again. Do you guys just tune them and lock them once you've got them sorted out? Does MS2/MS3 have additional provisions for enrichment with load-vs-none that the MS1 is lacking?

For the most part these are not important cells for me--though I assume they might be to drag racers and autocrossers who are looking for the perfect launch--but I'm hoping to clear this up as it's something that I've often wondered about.
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Old 05-02-2013, 12:16 AM   #2
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you'll never see those sells driving, because you'll either be at higher load or your fuel overrun cut will be active

so tune them while free revving if you want, lock them, and concentrate on the more important cells.
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Old 05-03-2013, 09:42 PM   #3
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yea, I noticed that too. Maybe add a touch of gas after letting VEAL finish?
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Old 05-05-2013, 05:16 PM   #4
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Turn off any aid.
Tune all non-load rpm cells for 14.7 (unless you boost at higher rpms) turn aids back on and enjoy.
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Old 05-05-2013, 08:44 PM   #5
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free rev is hard because the transient nature of the movement across the map.

your best bet is to try to fake the regions you want to tune by doing a few things:

idle with accessories / ride the clutch / brakes / etc. to get high MAP low RPM.
coastdown at various RPM to get the low MAP values sorted

You can start by copying your cruise values across to the lower RPM for the same MAP as a rough baseline.
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