Clarification as to why on an issue that has me duped

T

TxDiesel007

Uncommon CR problemed
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Jul 15, 2007
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Just wonderin what it is that makes this occur

If the magic rule is one lb of boost per 10 hp a truck has, why have some people, includin myself, seen boost numbers in the 50s and horsepower in the 400s, What is missing in that equation?

I am not sure i understand that logic... especially on a 12V

Rick
 
i dont think that equation works always, just think the boost you would push out of a little hx35, then how much would you push on a 64 or a 66?
 
You also have to remember that with a bigger turbo you can push more air with the same boost #'s, at least I have heard that. Correct me if I'm wrong. Plus, once you get past a turbo's "optimum" range you are just making hot air with minimal power. Sure you might get a HX35 to make 60 lbs, but it will quit making any noticeable power around 35-40lbs.
 
im aware of this

but why did my ride make 450 horses with 55 lbs of air? when rips twins are good till about that amount?

Thats where im stuck... and i have seen truck also do the same with super high boost, and not enough power...

Rick
 
Cause we burn diesel fuel not rice fuel.
 
Not all boost is equal.... Its about oxygen density not boost. A cooler charge with less backpressure will produce higher HP. It takes power to drive a turbo its really not free, so allowing the engine to breath and a cooler denser charge combined with proper fueling makes for a higher number.
 
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Boost is not really a true indication of horsepower. High boost can be as much of a problem as too much fuel. Effective combustion is the key.
I'll take 40 lbs of boost with a clean pipe over 60 lbs of boost and black smoke rolling.
 
Forrest Nearing said:
that's an old gasser addage, doesn't really apply to diesels
Click to expand...

Yeah, very true.....

It works because for gas the air-fuel ratio has some real importance. The ratio tolerance for combustion is tight and is mathematically definable. So many molecules of air for so many molecules of fuel releasing so much energy. The resulting energy proportional to both air and fuel quantities.

For a diesel, there only has to be enough air to support combustion. Simply enough molecules of air for so many molecules of fuel releasing so much energy. The resulting energy proportional to fuel quantity. This is true only when excess air is present.

Throw those numbers out there for a diesel and only think of any excess air for the optimum air-fuel ratio as "un-realised Hp potention". The unburned excess air just controls EGT's. In my case, thats about all it does.

COMP said it best I think. He wrote, "It is pounds of air not pounds per square inch of air". $.02

Jim
 
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The new diesel power has the D-Max Nasty Girl in it, he dynoed over 1000hp with only 55# of boost.
Yes I know, this is the dodge forum. I was just making an example.
 
At the time I did that dyno run I was using an HTT ProStreet 66, Floor It Stage 2 pump, DonM Flux injectors, Smarty, and a pressure box.
 
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