Has any one installed a manual boost controller with in cab controls and played around with lowering boost while cruising for better mirage?

I've been looking at:
Applications

Seems like lowering boost when not needed would reduce fuel consumption. Any input, experiences or advice?

 

Boost =/= mpg. In fact, often the opposite is true.
Also, unless you're info is filled out wrong, this isn't the forum you want to be in.

 

both my trucks are p pumped. One has 12v head other has 24v head. Guys running electronic boost controls are not who I'm looking to talk to. Can you explain how lowering boost does not help with fuel economy? I'm sure that at some point you could run to little boost for the most efficient cruising. I've got a 64/71 turbo on the 24v with a built p pump and was thinking I could recapture some lost mpg if it was toned down when just cruising empty. Any thoughts or experiences would be helpful. Thanks!

 

I suppose to an extent a lot of it has to do with how you're driving it, but boost is the only reason these things can get out of their own way with any efficiency at all. Take away the boost and all it does is lug. Lugging sends the EGTs through the roof, and EGTs are about as accurate of a gauge as you can get of how much fuel you're burning.

 

OK, for some reason I woke up this morning thinking about this and realized I'm not explaining it very well at all. I assumed someone who can explain it better would chime in and clear things up, but it doesn't seem to be happening [yet] so let me see if I can expound a bit:

This isn't 100% scientifically accurate, but for our purposes it should paint a reasonably clear picture. Boost is generally a function of fueling and rpm, not the other way around. There's probably a less flawed way to say it (and everything else I'm about to say), but I digress. If you want more boost and know your turbo could make more than it does, you turn up the fuel. But with a diesel, more fuel usually means more MPG, yes? Depends on what you do with it, and if you drive like you want to save fuel, absolutely- but not because you magically burn less fuel by dumping more in.

That having been said, people who drive by their boost gauge thinking they're going to get better MPG simply by staying out of the boost aren't going to get the MPG they would if they ignored the boost gauge entirely and drove instead by their pyrometer. More boost may mean more fuel, but more EGT almost always does. The upside is that more EGT means more spool for the turbo, so you have more power available to do the same amount of work with the the fuel you're burning anyway. If you're disciplined, this means you can do more with less.
Concurrently, and more importantly, less boost doesn't always mean lower EGT. As I said- boost doesn't control fuel, fuel controls boost (for our purposes here). If you choke off the boost, you'd still be dumping the same amount of fuel. Probably more, because you'd have less power with lowered boost so you'd be doing the work all motor, wasting "free" power right out the exhaust and using more fuel in order to do the same job. If you have boost and pyro gauges, you can see how this relationship functions both in and out of the optimal RPM range of your turbo, and observe the pattern that emerges every time you fill your tank under various driving conditions.

But to answer your question more specifically (with the limited specifics I have), you'd probably be better off toning down the pump than the toning down the boost. This may ultimately tone down the boost, because that's how it works... but it won't be the lower boost that ups your efficiency. What's far more likely (as it's the case with at least 90% of these trucks running around with modded p-pumps) is that your pump is set up with fueling that will support more boost at most loads (i.e. fueling + RPM) than your turbo makes at those loads. This is an inefficient situation, and it isn't the turbo's fault. The engine is just a big air pump after all, and the more air you can pump with a given amount of fuel the more efficient it is. So IMO, making your turbo help the motor even less isn't the solution.
Honestly, it sounds like you have a dual purpose 24V and maybe you shouldn't have p-pumped it. That turbo and built pump probably work well for whatever you picked them for, but not so well for just cruising around. With the VP44 and the right tuner, you could run various tunes on the fly to idealize the fuel mapping for your situation. With the p-pump, you gave that option up. The P7k can be made to do any one thing very well, but doing two things well that require very different fueling profiles means compromising one or both. I may be misunderstanding you, but if I'm not: trying to simulate the convenience of a multi-position chip with a manual boost controller just means when you tone the boost down while cruising you're going to have to give it more throttle to maintain speed. See the problem?