Northeastconfederate

This is a great discussion.

Very interesting stuff on pipe size, velocity and the effects of heat and temp on same. Really makes me wish I didn't drop out of engineering school.

I wound up talking with a piping engineer a few years ago and asked him why the control valve in a pipe system is always smaller than the pipe size. For example, a 6" pipe system in a power plant always has a 4" valve; 8" pipe has a 6" valve, etc. He didn't have the theoretical answer off the top of his head, but he did say that when MORE flow is needed a SMALLER valve is used.

Obviously there's a point at which this will go the other direction, but it's instructive.

Another related observation, again from pumps and piping. I'm talking about primarily centrifugal pumps here, which are very similar in construction to the compressor side of a turbo. The discharge pipe from a centrifugal pump always quickly transitions from whatever the volute size is - let's say 4" as an example - to a larger size pipe - in the 4" volute example it would be 6". The purpose is to increase discharge head (pressure); this also dramatically slows down flow.

So relating this back to the current discussion it makes sense that a smaller pipe to keep velocity up would help spool the turbo. "Static" pressure sure isn't going to do it.

Northeastconfederate

I forget where I saw this book recommended, but someone on one of the forums highly recommended the book, "How to Turbocharge and Tune Your Engine" by J. R. Crosby so I bought it. Extremely disappointed. It is abysmally written from an English language perspective, whichbmakes it very difficult to read. Missing apostrophes all over the place; "There" used when "their" should have been over and over again... I could have overlooked all of that (with some difficulty; **** like that really bugs me) if the book was packed with good information. But it isn't. Don't buy this book, unless you want to buy this one from me.....

Northeastconfederate

Here's a more specific question: I'd like some opinions - or better, experience - on how much boost a stone stock 2011 4.8 with about 75,000 miles can handle and remain 'daily-driver reliable'. This truck isn't truly a "daily driver", as I try hard not to drive it in the rain (though it has seen plenty this summer and fall) and it gets parked when the road salt comes out. It doesn't come out again until a few good rains in the spring. BUT, I do drive it to work when I feel like it or need to if the other truck is down for whatever reason.

SO, I want it to remain a "turn the key and drive it" reliable truck.