Odd pressures from twin setup.

Ron, I'm having a tough time seeing that issue kick your ass :hehe:

Seriously, you have built and tested more than anyone of us has and Cliff's formulas makes some of us say.......yea, cool dude. I would actually have to see it, and see what is happening.....that's how I learn.....just like now.

Jim
 
I'm going to send him my S480 to try. It may just be that he needs alot bigger chargers. I was at a dyno a while back and every truck that blew smoke would blow it to the middle of the alley and then it would just kind of head upward and thin out. When this truck dyno'd the smoke went straight across the alley, hit the building and went straight up like a giant black slug on speed. Funny as heck to watch the women and kids scrambling to get out of the way.
 
Diesel Freak said:
to get the true inlet temp, just calculate using the second stage inlet at the high temp air from the primary.

It's two compression steps. Each one has to be calculated seperately.
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Yeah, that is what I am trying to do. I must have a mistake somewhere.

Thanks;
Jim
 
Diesel Freak said:
Mathematically: Total boost (gauge presure) = (((PR1)^2)x14.7)-14.7)
Click to expand...

I think I understand why DF says this now.

In "Diesel Freak Speak" this means:
Primary PR = Secondary PR (or pretty darn close)

Ideal per DF
Boost = 66
Primary = 19psi = PR 2.3
Secondary = 47 psi = PR 2.4

Matched Pressures
Boost = 66
Primary = 33psi = PR 3.3
Secondary = 33psi = PR 1.7

RonA's Friend
Boost = 66
Primary = 45psi = PR 4.2
Secondary = 21psi = PR 1.4

I can see how the drop in CE for the primary could drive up the IC outlet temperature comparing that to matched PR's.

*bdh*

Jim
 
The pressures dont add together to get total boost. The pressure ratios are multiplied so you have to calculate the secondary pressure.
 
Where do you find the formula's for compound set-ups. There is a lot of great info here just not how to figure it out for yourself.
 
they are derived, ideal gas laws and such....most thermo textbooks have it all there for you to play with.

The best book I know of is Thermodynamics: an Engineering Approach 3rd Ed. by Cengel and Boles...it is one of the most usefull books on my shelf.

Also Maximum Boost by Corky Bell is a must have!!!
 
I would want to know the airtemps between chargers and into the manifold

Hot hot hot air doesnt behave consistantly and is hard to compress
 
Diesel Freak said:
that works too...the actual number in .707
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Actually the flow is a better indicator then wheel size because housing AR as well as other things effect the flow. So a 60mm wheel in one housing can flow considerably more then the same wheel in another housing. Compounding with the maximum difference in flow wont always make the most power (and very rarely does) ;)
 
I wonder if there is a reason why the number is so close to the sine of 45 degrees?
 
Idaho CTD said:
Actually the flow is a better indicator then wheel size because housing AR as well as other things effect the flow. So a 60mm wheel in one housing can flow considerably more then the same wheel in another housing. Compounding with the maximum difference in flow wont always make the most power (and very rarely does) ;)
Click to expand...

That was sort of confusing me. I had learned in the past that decreasing volume per stage due the gas compression and the discussion became involved with decreasing cross sectional area. I guess I assumed that for this application the two were roughly the same. DF did say that even for cross sectional area method you still needed to subtract the area of the hub.

Jim
 
He should get the turbo tomorrow. If he can get 50psi out of the 480 I'm going to be jealous. I guess there is something to be said for injectors rated in gallons per second.
 
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