Reply to thread

Message: [QUOTE="Charles, post: 307368, member: 103"] My ICP at low pedal positions is damn near flat with rpm. Rpm changes the ICP by just the slightest amount, and then, only really coming right off idle. For the remainder of the range, it's damn near unphased, making the engine drive with a lot of control over the vehicle and the trans. It basically doesn't give a damn what the trans does.... it's going to make ____ power as long as my foot stays steady. That is of the utmost importance to me on a preferential note. I want a truck that accelerates evenly as long as my foot stays planted in one spot. I cannot STAND to drive a truck that accelerates on it's own like a runaway, and then falls down on a shift. It makes the shifts very uncomfortable and generally makes the engine feel like a little bitch. On a side note.... when this is happening you can forget about tuning the trans in. Nothing you do will make the shifts smooth. Conversely, with solid ICP through the shifts, you can run the line up until the tires are spinning on the shifts and it will be smooth as silk... On Edit: Here's an ICP map from my 550 that I had on webshots: [IMG]http://inlinethumb35.webshots.com/49698/2251939120082519711S600x600Q85.jpg[/IMG] Notice how the ICP is flat and stable from 800rpm down to 550rpm (smaller bubbled area). That won't let it get into a cycle if the rpm starts to swing. The rpm can climb from 750 all the way to 800, or drop all the way to 550 and the ICP will not flutter, so long as MFD remains the same. Which it won't, but at least you don't get compounded bs like you would if both were changing and fighting with one another. Imagine the engine lulls a little, so the MFD goes up, running the ICP toward the back of the map (increasing pressure) while the ICP is already headed toward the right (lower rpm) where if you had a ridge there you would be incurring double increases in pressure, which would quickly push the rpm up even with pw constant, which would fall back into the trough, causing a lull, yada, yada, yada..... next thing you know you've got a topfuel D9 sitting there idling... As for what I was talking about above.... notice on the map how at very low MFD, the ICP is basically unchanging as rpm climbs (larger bubbled area). All it's really doing is accounting for the shrinking injection window and keeping the power consistent. That is what makes cruise control super smooth, and gives the engine tons of balls. Believe it or not, keeping the ICP DOWN as rpm climbs is what makes an engine strong. Because when it ramps way up, you have to lift out of the pedal to maintain your acceleration rate, then when the shift is underway the rpm drops, and the ICP falls on it's face. If you watched my ICP gauge during shifts you would see it just sitting there in one spot as the truck ran through the gears. I'm just saying.... that MAKES a truck, IMO. You get all the other stuff good, and that will make the truck have so much balls. [/QUOTE]