PeachParts Mercedes-Benz Forum - My Intercooler set up on my 300SD

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- - My Intercooler set up on my 300SD (http://www.peachparts.com/shopforum/diesel-performance-tuning/169992-my-intercooler-set-up-my-300sd.html)

Quote:

Originally Posted by MTUpower (Post 1328405)

I was commenting on the adding of a intercooler or upping the boost WITHOUT adding more fuel only. I am all for adding HP and doing what you'd like to the car- it's your car after all. Connclark has a history of saying you can add HP by increasing boost- and it is perhaps true in gasser theory- to the tune of about 1.5%- or three HP, max. I was saying dont bother upping the boost or adding a intercooler without adding fuel if you are expecting a real HP gain- which means you have to adjust the IP. See post # 47's butt-o-meter findings...lol

It holds true in a diesel

Go here and plug in 1.27 for gamma and use the defaults for the rest of the settings. http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/diesel.html You should get a thermal efficiency of 42.467% . Now lets say you upped the boost or cooled the intake charge enough to raise gamma .03 to 1.3. Thermal efficiency rises to 45.872% .

To calculate the percentage of power gain
(45.872/42.467 - 1)x 100 = 8.017%

It also holds true experimentally

"As the boost pressure increase, the rate of heat release is resemble to the injection rate and becomes sharper and combustion improves and also the brake thermal efficiency becomes better. The high boost and lean diesel combustion results in low smoke, ISCO and ISTHC without the ISNOx increase and gives good thermal efficiency."
http://www.jstage.jst.go.jp/article/jsmeb/48/4/648/_pdf

If you want to argue that it doesn't hold for prechamber engines here is a few tests done by NACA in the 30's . (Note the Fuel consumption lb/hp per hour part of the graphs (lower = more power per same amount of fuel))

Quote:

Originally Posted by ConnClark (Post 1329729)

Great- Thanks. I think somewhere in there it proves bumblebees can't fly also. Folks- in the real world, just adding boost will make nearly no difference.

Quote:

Originally Posted by MTUpower (Post 1330133)

I think somewhere in there it proves bumblebees can't fly also.

Nah, that's a urban legend based on inadequate and way outdated understanding of aerodynamics. Just as regular incompressible flow theory can't adequately explain or model supersonic flow, it can't adequately explain or model small-scale vortex flow (which is the regime the bumblebee operates in). Us aero folks know how to break the "sound barrier" and fly at supersonic speeds, and we know how the bumblebee flies. ;)