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Originally Posted by Jeff Niceswanger
Hi Kyle !
Kyle and I disagree on this one. It's like Chevy and Fords. There are two distinct different theories. I do not tune in Alfa, as its old school. Very similar to a Carburetor. It repeats and does the same exact thing every run. And many people prefer that approach. When your running a carb, you have the availability of rods and jets to stay on target. Air goes from 1000 feet on Thursday to 3000 feet on Sunday, you can change rods. The Alfa on open loop is locked into what ever tune is in it.. It just repeats.
I use VE, usually with a Alfa idle circuit. All the low RPM #'s are in Alfa with a separate Alfa Map,. But as soon as you start getting into the higher RPM's it switches into VE. VE is just a glorified Speed Density Program. On some tunes I stay with Speed Density, as I already have pre made tunes that are really close to the customers combos (in SD). Its just easier and quicker to use one of them. I've seen no advantage ET wise in either of the two.
The trick is to get the tunes to where you can feel confident you need no Closed Loop Compensation. That includes burnout, and slightly after (milliseconds) you go full throttle after launch.
That way, you can set your Closed Loop Compensations very low, like 3 or 4 percent, and know that the tunes will stay dead nuts during the entire run. Even IF, the air changes. If you look at your Data after the run and your car was using more than that 3 or 4 percent of adjustments, then your tune is not correct. You will know that as your Learned Compensation is 4 percent in places and your Target will be slightly off. Reason being that 4 % was not enough and the CL "Could not get there" . There are dis advantages to having CL active. IF the 02 fails, and they do occasionally, the 02 always fails lean. Meaning the Holley will think it's in a lean condition and puts all what's available in the tune. In this case all 4 %. But if your up high, like 50%, the car will instantly go full rich, die or be impossible to keep running. If it does run, it will be horrible. Its not a bad idea to change 02's occasionally if your depending on your 02 ....
Hope this helps...
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Jeff,
Nice that you weighed in and your points are well taken and you bring up some things that reinforce why I tune ours in Alpha N/Open loop. Your comment about it being old school and somewhat like a carburetor is correct, but that doesn't make it necessarily a bad thing.
Electronics are quite fickle and hard to diagnose in many cases. Nothing is more electronic than an ECU relying on electronic sensors and prone to gremlins than in our environment in my opinion. Alpha N/Open loop is much like a mechanical gauge vs and electronic gauge with Speed Density/Closed loop. Blown cars have to use Speed Density, but I am referring to our NA combinations.
Our sensors are not always reliable like the throttle position sensor that is key to Alpha N for example. I block out our fuel map to have the same MS pulse width from about 75% throttle all the way to 100% incase I have a TPS that is being touchy. I know that the throttle is wide open going down track so it won't matter if the TPS is showing something like 81% or something. I don't want it to lean out on me by mistake.
My approach is somewhat like trust, but verify and count on some failure by sensors at some point. Another thing about my tuning approach is that you immediately know if it helped or hurt. I don't want the ECU acting like Hal on 2001 Space Odyssey saying "Kyle, we are not going to run fast today."