Rail pressure fluctuation with tc locked non vgt

Jonnydime

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When cruising in high gear with the converter locked I have noticed the rail pressure will fluctuate several thousand psi up and down with light throttle input. It does not do this at all with the converter unlocked. I am pretty sure it has to do with me running a stock like lbf map to keep smoke down and not having the ability to regulate boost with a vgt. Is there a way to tune around it or will a have to switch to a more canned tune type lbf file? Here is a pic of my lbf map. The truck drives great with the exception of maintaining speed on the highway along with small throttle changes .
Photo0113_zpsppvdsfwt.jpg
 

ckrueg

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Have you monitored your mass fuel and boost while the issue occurs? That way you can know where you're at on the lbf tables

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Jonnydime

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When cruising on the highway I am between 8-10psi on flat ground and pulling a grade I might get to 12-15. I think the lack of a vgt being able to maintain manifold pressure is my problem. Being non vgt the only way I can manipulate boost is with fuel. If I apply more throttle it comes out of it but lets say I want to accelerate from 70 to 75 slowly the rail pressure will jump up and down between 15k and 20k.
 

ckrueg

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When cruising on the highway I am between 8-10psi on flat ground and pulling a grade I might get to 12-15. I think the lack of a vgt being able to maintain manifold pressure is my problem. Being non vgt the only way I can manipulate boost is with fuel. If I apply more throttle it comes out of it but lets say I want to accelerate from 70 to 75 slowly the rail pressure will jump up and down between 15k and 20k.
You could try to slightly adjust the lbf table at the cell right where it happens and see if that is causing it. For instance if it is around 2k rpms and 8-10 lbs of boost, try increasing your fuel mass limit in those cells. That would at least give you an idea if it was causing the issue. Also what do your rail pressure tables look like, maybe there's a steep spike on those that could be smoothed out.

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Jonnydime

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This was all because of how tight I was with the low boost fueling. As soon as I loosened it up and pulled pulse width it cleared up.
 

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