Quote:
Originally Posted by diesel_john
Hey, guys, i didn't read all the threads but has anyone allowed the boost to occur normally but defeated the ability of the injection pump to add more fuel as the boost increases? Depending on the type of pump prevent the pump from knowing that the boost went up. Just a thought. And if cooling the fuel gets you more horsepower will heating the fuel get you more mileage? When using exhaust temperature to optimize timing, is the lowest temp. on the advanced side of TDC the best or the highest temperature?
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What you are asking is can the diesel ECU be re-mapped. If you re-map it then you can tell it to put in less fuel than there is air. It gives you lean burn. Downside is you sacrifice power. With lean burn your going on you're going to want regular temp fuel not warm.
The warm fuel will evaporate easier and the temps will climb faster(as there is less fuel overall per air(the fuel in direct injection engines cools the charge to allow for higher compression without pre-detonation)). If you take away some of the cooling ability of the fuel you run ugly risks.
Yes the HF only goes lean-burn when everything is warm, but its not DI. Its compression is nowhere near so aggresive as a DI engine so it doesn't matter there. In your diesel heating the fuel and leaning out I predict would have neutral benefits because the engine is going to try and counteract you to avoid pre-ignition.
If you just change the ECU and leave everything else alone you'll see an increase in FE, but a pretty drastic decrease in power. What you really want is an onboard system that allows for 2 maps. One for normal driving and one for ultra-lean/lean burn. So once you get to speed hit the button and it coasts along at reasonably high rpm with very little fuel getting injected and your turbo cramming air in there.