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Old 04-23-2021, 08:37 PM   #314
IROCZman15
10 Second Club / Meet Coordinator
 
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Join Date: Dec 2004
Location: Roxbury, NJ
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Matt you are correct, I do not have the capability to make a separate 2-step table. What I have been trying to do is make a set "drag race' tune file that has the best VE table and timing table values in the area of cells where the 2-step comes off and closed loop comes in. Since this area of rpm/load will only be hit once during a full 1/4 mile pass, people have suggested I spend time tuning that area to eliminate the bog/spikes. It has been suggested that I do some street tuning using the 2-step on a steep upward hill or while holding the brakes during a launch. I did try this and thought I had it close, but apparently not. Oh well, something to revisit later on. I am fine with footbraking, and the free-rev I give the engine while in neutral while pulling to the starting line is helping build vacuum in the vac can and I am happy about that at the launch while footbraking.

As for WOT timing, I might try one more experiment with it, and this time I might actually lower it from 35 deg to 34 deg or 33.5. I have not played around with those numbers yet and some of my SBC buddies with similar setups run 33 and 34 deg timing. Maybe I have been over timing it just a tad; enough to knock off some power, but not enough to knock and cause noticeable detonation. Maybe I can get to the track next friday night for T&T.

As for the shift points, yup, I did give it a shot. A few of the shifts I nailed, right at 6,604 rpm and 6,605 rpms. I had another thread on this site listing my best runs and tech info, but here is the current sheet. I am liking the 116.59 mph, but thats weird because thats the first run where the engine bogged off the 2-step and then got going again, so it wasn't even a full pass.







As for hte lean spikes, as far as I can tell it is the computer coming out of a 2-step open loop table and then going closed loop with unburnt fuel in the exhaust, causing the oxygen sensor readings to get wonky. At least thats how I understand it. So, in theory, if I made a pass only in open loop, this would not happen. But then I run the risk of my CL comp and fueling being too far lean/rich if my base table is off... so I am hesitant to do that and make a mistake.
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