Quote:
Originally Posted by Nixlimited
Actually, it is. When I drive my TT Z around, the AFR gauge is almost always reading near 14.7 because most of the time I am not accelerating and moving into a richer area of the fuel map. As for lean tuning cruise mode, just do a google search on that and you will get educated.
But if you think you have a better understanding, please, do enlighten us.  |
Actually it's not how it works, lean fuel mixtures do not make the engine run hotter because there is less fuel vaporizing and sucking heat out of the motor, it is because a lean mixture burns more rapidly which means peak cylinder pressure is reached earlier in the stroke forcing the engine to fight itself while retaining a hotter mixture of gas in the engine for a longer time, in a rich burn situtaion the fuel will still be burning exiting the engine which tends to increase egt's but is not as hard on the engines cooling system. the latent heat of vaporization is less important until you start getting into alcohols and nitro mixes that really can cool the entire top end of the engine just by evaporating.
As for the closed and open loop stuff, what you are suggesting is already in place in the ecu, from the factory the car tapers from the low load sites which are 14.7ish and as load and rpm increase the afr tables drop in the ecu. If tuned properly your tuner should only be adjusting the mid and high range/load sites to keep it rich enough to prevent detonation, the low end only basically needs to be tweaked to fine tuned for changes in maf size. As seb had said in his earlier post if you were running 10.5-1 at idle that wouldn't be a good thing because it shouldn't be doing that. The only other time the low load sites should go richer would be if there is a tip in lean issues that can't be tuned out some other way.