'91 #473 Tuning

[mike100]

sounds like it is time for an ostrich2 emulator so you don't wear out your chip socket.

maybe the lean condition is due to modern fuels?.. or maybe that' how they always were since new.

[jss06c6]

Probably a correct assumption! I've got the APU1 so can emulate and tune real time with it, but it's too bulky to leave it installed on a semi permanent basis. Would work well for tuning work however and could then burn a chip "every so often"..

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[BigIke]

Need another Montgomery County LT5 to tweak on? I'm getting a little detonation right now...

[XfireZ51]

Not a fan of "real time tuning" L'd rather collect as much data in as many driving situations as possible and THEN make changes based on overall results. Besides it can dangerous.

[jss06c6]

Originally Posted by XfireZ51

Not a fan of "real time tuning" L'd rather collect as much data in as many driving situations as possible and THEN make changes based on overall results. Besides it can dangerous.

Not doing any real time tuning. Would be good to use the emulator to upload new tunes rather than swapping chips, but I'm not changing that often anyway..

Here's a BLM data log from this morning. This is against stock Port Open VE tables, no modifications. Low kPa low/midrange RPM shows rich. Commanded Secondaries open via BIN table. Gathered data after 25 minutes of driving to achieve stable temp and integrators relatively stable.

[jss06c6]

Originally Posted by BigIke

Need another Montgomery County LT5 to tweak on? I'm getting a little detonation right now...

sent you a PM. I'm still learning.. let me get comfortable and happy to help!

[jss06c6]

Gents,

Have the VE tables dialed in pretty well now. Passenger side is lean side, driver side averaging about 3 BLM units lower than passenger side. Above 2000 rpm and MAP of 40 kPa, they are only 1 BLM unit apart. 126-127 on driver side and 128-130 on passenger side.

WOT work now. AFR pretty steady at 12.5-12.6 from 2200 to 6000 in fourth gear. Seeing some knock retard in this zone. Spark tables at 27 degrees advance. Will pull a degree and re-log to see if I can tweak the knock retard out. Doesn't need fuel since I'm at 12.5+, so will pull some timing and repeat data log. More to come..

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[XfireZ51]

I'm guessing KR is kicking in somewhere around 4500-5500 rpm. U could think about backing off timing in that area depending on how bad the knock is. Altho the motor isn't there for long during a WOT run. BTW, the KR is very conzervative in the cal, so u could reduce the sensitivity and amount as well.
I tried 34d at top end w No Knock detected. I just lost power.

[Hog]

Originally Posted by XfireZ51

I'm guessing KR is kicking in somewhere around 4500-5500 rpm. U could think about backing off timing in that area depending on how bad the knock is. Altho the motor isn't there for long during a WOT run. BTW, the KR is very conzervative in the cal, so u could reduce the sensitivity and amount as well.
I tried 34d at top end w No Knock detected. I just lost power.

The KR is aggressive that results in timing advance that is conservative, or the actual KR is conservative resulting in aggressive timing advance?

[XfireZ51]

Originally Posted by Hog

The KR is aggressive that results in timing advance that is conservative, or the actual KR is conservative resulting in aggressive timing advance?

The Knock Retard in the stock calibration is pretty aggressive, meaning that it reduces timing rapidly and extensively. In all my datalogging, I have found little need for that level of timing retard. So I have reduced it significantly from stockwith no detrimental effect. I try to time things just so it "tickles" the KR.. ��
Also want timing at where MAP is at its lowest, indicating highest vacuum.