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Old 06-20-2012, 07:58 AM   #95 (permalink)
IDZRVIT
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I was talking limp mode when overheating becomes severe. Any ecu in any vehicle will pull timing to prevent 'ping' which is more prone to happen as the engine gets hotter. So, the engineers have that figured out and developed the maps in the ecu. The tuners are limited to how much advance can be introduced in the timing maps of the ecu afaik. I've played with these maps when I had my Harley. They are all similar in their function. You can increase the timing but up to a limit and then it won't let you go any higher. That limit was as high as ~48* or more advance depending on load/rpm for my Harley. You wouldn't want to go any higher than that anyway to be safe. You could also adjust your AFR directly or 'fool' the ecu to increase the AFR by increasing the values in the volumetric efficiency map - increase fuel. Run a little richer and add a little advance. That said, tuners do have limitations but there is a fair bit of leeway. All cars pull timing or vice versa, add timing, under the prevailing operating condition. Tuners just put timing closer to the edge which is less safe for your engine. So, you better have a darn good tuner because they are not all the same and it can fuk your engine.


Edit: Just to add, your timing is retarded when the anti-knock sensor (a common method) detects a knock or ping. Lower octane gas can bring on the onset of pinging and the resultant retarding of the timing which equals to a loss of performance. Using higher octane gas is the reverse. Unless you've had an ecu tune, Nissan most likely tuned our ecu's for the most commonly available gas, 91 octane.
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Last edited by IDZRVIT; 06-20-2012 at 02:17 PM.
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