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Dec 16, 2005 | 10:14 AM

#46

600 Megawatts

Muted User

Joined: Jan 2005

Posts: 640

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Got Diesel, exactly right... You are dead on correct.

KP

Dec 16, 2005 | 01:47 PM

#47

HOHN

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Joined: Apr 2003

Posts: 6,564

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From: Cummins Technical Center, IN

Quote:

Originally Posted by 600 Megawatts

Yes, Hohn, I would say you are very close. I allways figured about 3,000 Lbs/Hr at 50 Psi would cover 500 HP worth of fuel quite nicely. But I am shooting for about 1,300 F at full tilt. I am not onboard with cooling the combustion process with too much excess air ... Thats what alot of guys around here like to do... they take a combo which is about perfect at 1,200 F when maxed out, and then add more air so that its now at 1,000 F... and their happy about it ????

I am not sure they realize that they just dumped tons of excess air and diluted the combustion process so bad it cooled it 200 F and they lost power.....

KP

I agree. I believe that the "goldilocks effect" is much more applicable than people want to believe. There is a "right" size/amount/quantity for almost everything.

Yet people still persist in the simplistic views that if some is good, more is better. Y'know, if 4" is good, 5" is better. If an HX35 is good, an HX40 must be better.

People need to realize that there's "no free lunch." THAT'S why there's always a sweet spot, where more is bad and less is bad.

With EGT, excess air comes at a price. The turbine drive energy to create air you don't need represents lost engine HP. Plain and simple.

If I could have it such that such that max EGT was 1350° (*Empty*), I'd say I had it dialed in about right.

But because of that "goldilocks effect", the optimum setup exist only for a given set of circumstances. So you can set it up to be best for towing, and it's less efficient empty. Dial it in for empty running, and it's too hot towing.

NOthing but compromises in the world of physics and thermo.

Dec 17, 2005 | 07:33 AM

#48

RonA

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Joined: Feb 2005

Posts: 763

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From: Browns Valley CA

Just a note here about loosing power in conjunction with an egt drop. When I put on my first set of twins (DZ/3B) I had dyno'd my truck a few times with the Dodgezilla turbo and the 275 injectors and was consistantly at 360 to 370hp range. Would hit around 1350-1400 on the dyno. I installed and broke in the twins. At the same fuel settings I hit 465hp at 1150 egt. This load dyno was usually a bit on the generous side, but same dyno, similar conditions, 5 days apart. Just because he shed some egt it does not mean he lost power. Towing sized twins show a huge improvement over a moderately overfueled Hx-35 to 64/14 S300 size turbo.
Just what i have noticed with the few setups I have tried.
Ron