| of A/F ratios should an NA Z be running at? I'm not going to make any attacks here - that is not my motive. I've just seen you make this comment a few times and I think perhaps we should compare notes. I can present what I feel is a considerably large pool of data that supports the A/F ratios that my non-turbo programs run at. My ECU database has over 300 non-turbo units that have been running the same NA V.4 program that I developed on Kai's (SkiFly) non-turbo back in the early days of the ZEMulator. There is an unkown number of cumulative miles amongst that pool of vehicles. It is well known that running an engine lean will burn up parts - namely pistons and valves, but that is an excessively lean condition and it will occur in very short time if it is continually run. As you move more towards a richer condition into the region where parts wont melt down, the cylinder temperatures are more elevated as compared to a leaner condition, which is going to create a little more wear than if it were, say, running richer. Private pilots are keen on this understanding - sure you can pull the mixture and get better fuel economy, but you are going to be rebuilding the bottom end more often due to excessive ring wear. But airplane engines are car engines operate under quite a different set of conditions. Most miles on a car, except for track only vehicles, spend most of their time at low load and low RPM condition. The % of time that they spend in this WOT condition is significantly less. By configuring the A/F such that they dont melt down even under long-term WOT condition, you will achieve the best reliable power at the sacrifice of some additional wear. The stock NA program at WOT condition runs the engine a bit on the rich side - that being a little richer than an enthusiast who is looking for some more power would want to run. By pulling the A/F up a bit, you stand to gain around 7-10RWHP. With some additional timing advance, you can squeeze another 7-10RWHP out of them safely. Many non-turbo applications run the engines around 13:1 without any problems. You can stand to go even leaner than this with a non-turbo engine and still not have meltdown, but the torque begins to drop and it becomes pointless to risk meltdown to make less power. I have tuned several non-turbo Z's to this point and have many Z's out there running the same and are quite happy with the upgrade. To my knowledge, no NA Z engine has ever suffered meltdown shortly after installation of one of my programs. I dont know of any that have occured at any length of time thereafter. This does not discount the idea that maybe they dont post here or didn't post about it, but given the record, it seems that if there were one that this happened to, it would not be as a result of the program. All of this is much like extracting power from a TT though.. More boost = more wear. To get power from the NA, you gotta run a little leaner mix which = a little more wear. But because they dont have forced induction, the combustion temperatures at 13:1 are considerably lower than that of a TT running 15psi of boost and the parts will hold up very well. These are the things that bring me to believe that my programming at a 13:1 ratio for non-turbo applications is safe and will provide good power increases.
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