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Discussion Starter #1
How volumetrically efficient is the 24valve motor? Percentage wise.
 

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Would that not depend on the total amount of boost, velocity of charge air, and operational ambiant conditions? Just a guess 70 to 80 percent.
 

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Discussion Starter #3
For starters just zero boost, sea level (atmospheric) pressure of 14.7 and abient temperature of 68*F
 

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Discussion Starter #4
Just looking for knowledge, seeing if anyone already knows. I dont have the equations memorized yet.
 

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Normal percentages are 70 to 85 percent much of that will depend on intake track valve sizes, valve timing, compression ratio, and exhaust and intake restriction (air filter, muffler).
 

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Discussion Starter #6
I know a good standard for actual inake restriction is a loss of 1psi. I've been seeing that. exhaust restriction should be zero with it straight piped turbo back right? What are track valve sizes?
 

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Sorry about that, I should have writen Valve Timing.

On the exhaust you will have restriction, every 10 degrees of bend in the pipe = a foot of travel, and add the length of the pipe.
 

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Discussion Starter #8
Thats alright. What would be a good loss number for every foot of travel?
 

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You have a few factors involved.

A hx35 flows about 600 cfm peak --- run it thru the engine and it comes out as hot air and is expanded say 4 or 5 time.

A 4 inch exhaust pipe cools quickly --- your turbo inlet temp may be 1500 deg. f. but the exhaust tip may only be 350 to 400 so the exhaust gas condenses back, making things more difficult to figure. But just throwing a number at the pressure lose would be depending on volume, heat and drive pressure, ambent temp, maybe something else.

Just for a number, at 2400 cfm and 40 psi 100 ft of 4in ID pipe looses 2.2 psi of pressure.
 

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Discussion Starter #10
Just wondering if the trucks only idling does the turbo compressor still increase the air intake or is it basically naturally aspirated at an idle?

Thanks for the exhaust info.
 

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You would need some very accurate gauges to measure that, the turbo does something but not much at a idle and depending on what engine and what turbo it could even be some resistance.
 

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Discussion Starter #12
Interesting. Guess I'll be saving for the best there. So the turbos could produce different ranges of resistance even none? I know the intake plumbing and manifold definitely add some resistance.
 

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I guess that would just depend on how you look at things, I see a turbo a variable compressor driven by the exhaust gas. When you use the exhaust gas to drive the turbo it creates back pressure.
 

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Discussion Starter #14
But that would almost seem little compared to getting rid of the cat and muffler restrictions. Are all turbines made the same? Some could create more restriction than others.
 

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Nope they are not created the same, the newest and most type specific will give the best results. We tend to just want more and use what is available due to cost restraints, but if you were to design for a specific target and a set of design limits you can come up with something that will do the better at that one thing.

Example the newer EFR turbos by Borg Warner. The should be great but not many people will know due to their cost. Their lighter wheels and newest design help spool quicker and provide more air but they cost 3 to 5 times more than another turbo with the same size wheel and gentlemen we get stuck on size and numbers that just don't allways equate to performance.
 

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Discussion Starter #16
Interesting. The EFR series turbochargers EFR-6758, 7068, 7670 and 8374 models are in the price range of $2,000-2,500.
 

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Discussion Starter #17
As far as guages and being very accurate is there anything to measure actual cfm intake. I know it would be pretty ridiculous to start drilling holes in everything for temps at all the manifolds and getting stuff like ambient temperatures. Be a pain to monitor several upon several guages.
 

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As far as guages and being very accurate is there anything to measure actual cfm intake. I know it would be pretty ridiculous to start drilling holes in everything for temps at all the manifolds and getting stuff like ambient temperatures. Be a pain to monitor several upon several guages.
You just need to measure the pressure differential accross a know size venturi and it is not uncommon it is done on most new cars and diesel trucks, you know that little thing called a Mass Air Sensor. All of these things are currently on new vehicles The mass air sensor all so tells the computer what the charge air temp is, humidity, the computer checks the O2 sensor to make fuel adjustment and the Knock sensor to make timing adjustment. If you are wanting to go to the next step from a 12V it would be a 24VP they have all of these things (maybe not the knock sensor) and the common rail is another improvement.
 

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Interesting. The EFR series turbochargers EFR-6758, 7068, 7670 and 8374 models are in the price range of $2,000-2,500.
That is right, A new 64mm turbo can be had for 600-700 but that is not one set up for what we want. A HT3B is about 650, and will support about 600 hp. You can make a piping system and make a set of twins that will work well for 1500 and your time but it will not be the same. I think a EFR 6758 would be much more fun, less time consuming to install and less problems down the road, less expense over all. So you want a set of twins?
 

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Discussion Starter #20
Knowing the pressure differential across a know size venturi would tell you what? Yeah I just read about the mass airflow sensor and its workings, was wondering how a person would actually see all the numbers, temps and such that its reading.

I believe from the EFR series chart that I saw the 6758 could only handle up to alittle over 400hp.

I thought about twins awhile back, also contemplated a compound setup. Not sure which direction I'm going to take. Mostly going over numbers, research and saving while doing that now. Learning as much as I can.
 
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