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Message: [QUOTE="Charles, post: 1308201, member: 103"] It's not a matter of "fuel" ramp, in the sense that fuel is fuel is fuel is fuel anyway. The total quantity delivered can be done with massive differences to atomization and piston position/crank angle/window. With a larger nozzle usually [i]less[/i] fuel can actually be delivered in a more timely and properly placed window that makes better use of available air, or more precisely, available TIME to do something with that air and TIME to act on the piston and TIME to finish doing both before the pressure is falling to nothing on the end of the power stroke and you're just blowing unburned fuel past the exhaust valve. The key isn't in the absolute quantity of ICP or PW, but in the relationship or proportion of one to the other. If PW always leads ICP, which will vary for each nozzle where this point is, then the truck will ALWAYS be soft and doggy. If ICP always gets out ahead of PW, the truck will be crystal clean and snappy like a blown big block. The difference between the two is SOOOOOO small with larger nozzles. Smaller and smaller the bigger the nozzle gets because a smaller and smaller increase in duration is a larger and larger percentage increase to actual fuel delivered. And when you get the injection window too long, delivering even slightly more fuel makes problems get dumb, fast. As a for instance.... If a truck is doggy, start pulling pulsewidth at the top end and re-sloping the map from the bottom end (assuming the pedal feels good on tip-in) so that it stays progressive from the bottom to the new lower high end values. Shallowing up the slope of the map. If you want power to come down then this will crispen and clean the truck while lowering power..... ONCE you reach the pw range that MATTERS! If you're at 7ms and you drop it to 6ms and reshape everything back to 6ms on the top end then NO..... you're not going to see the truck clean up or crispen up ANY, lol. But if you were at say 2.1 and you dropped that max value to 1.8 and reshaped between the bottom and a new top value of 1.8 then you would, with almost any nozzle, unless you were already perfectly clean and crisp. Then you would just lose power alone. In all cases you would lose power, unless you were so hideously over-doing the pw that the truck was falling on it's face and dropping oil pressure and such, then you would actually GAIN power by dropping pw! Back on track.... If you drop pw, all else equal until the truck starts cleaning up and getting snappier you should also be dropping power. To level that out you have to plug ICP back in at the same MFD areas you're taking duration out. That keeps the fuel QUANTITY in check, while getting the injection window where it needs to be. And if you're injecting the same quantity with higher ICP..... you guessed it.... you're atomizing better too. Tighter injection window and higher injection pressure..... does it make sense why a truck would run stronger and cleaner? Anyway, it's the proportion or relationship BETWEEN ICP and PW that determines the "attitude" of the truck. And if you want the truck to drive nice without falling on it's face so that it has "balls" off a shift and when you drop it in gear, you have to shape the MFD table so that it's relatively steep as rpm climbs. MFD has to fall rather steeply as rpm rises and the ICP table CANNOT be allowed to rise and rpm rises else you will have a truck that's a total bitch on a shift. Just dogs right out. If you slope the MFD down quickly as rpm rises the truck will act like a mech truck with a tight governor. The steeper you make the fall, the more you move toward an ag governor. The shallower you make the MFD, the more you move toward an automotive governor. [/QUOTE]