Sea Level vs Altitude Tuning

[Jackpine]

Originally Posted by soutthpaw

Well You can't really look at boost as a percentage esp with diesels as there are quite a few diesels runing upwards of 50 PSI boost pressure

I don't think you're right here. Everything I've read on turbos says the good ones give a 50% boost, not 50 psi, but that since you don't get perfect efficiency out of it, you might see a 40% boost. 50 psi is about 3.4 atmospheres! That would be an enormous amount of air. You'd be burning 3.4 times the unboosted fuel volume just to maintain the correct A/F ratio!

And, there's simply no way a turbo could maintain that 50 psi boost as ambient air pressure drops. (How much boost would you get in space?) The boost value HAS to be a percentage of the ambient pressure, not a fixed pressure value.

I see I forgot to congratulate you on passing the 200 post milestone. :o I meant to, and I enjoy your thoughts.

- Jack

[soutthpaw]

Jack we are talking Diesel here, NOT wimpy gassers heck the old 5.9 cummins on my RV can hit about 28 PSI of boost.. remember Cody's post about air/fuel mixtures for diesel vs gas????

[Jackpine]

Where the heck are you getting the power to drive this blower? It's got to come from somewhere, and I doubt a turbine in the exhaust could supply it.

Is it a belt driven supercharger? And, even then, that much boost (at sea level) takes an enormous amount of power. You're talking a 340% increase!

You're dead right, southpaw. I know next to nothing about diesels, but the numbers you're quoting just seem way out of line.

I'm happy to have my opinion changed though. Just point me to one of these beasts that can produce those numbers and I'll crawl back under my rock.

- Jack

[soutthpaw]

Well just look at the boost gauge in any stock or modified diesel there is a reason you can buy 60PSI boost gauges.. But we are really getting off topic and would be better in a new thread as I would really like to get some feedback on the subject of this thread