Cummins + Blower + 2 Very Big Twin Turbos.....

RacinDuallie said:
What can I say Astro, I'm lost in the ol skool ways.....

IMG_1263.jpg



:hehe:
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Can I have one?!?:woohoo:
 
joefarmer said:
Do it! Plumb dual 50mm blowoff valves around the blower so it wouldn't get in the way >14psi.
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The blower won't "get in the way".

It is positive displacement. It will still move the same volume of air per rev no matter the engine rpm. Getting the blower "out of the way" wouldn't be any different than trying to get the engine out of the way, because as you are well aware, the engine only moves X CFM per rev as well.

You can blow turbochargers through a positive displacement blower all day with great results. Go with a Lysholm ("helix") style if you can find one cheap, and the IAT will be nice.
 
seeker1056 said:
thoughts

671 and 871 blowers been makin in excess of 1000 hp on a gasser for 40 or so years - and it takes a lot of air (1000+ cfm) to make a 1000+ hp - so I dont think air supply from the blower is the issue here

the issue is that all of the centrifugal blowers with the exception of maybe the whipple need about 5-7000 rpm to make enough air to make that kinda hp

So take any centifugal charger, and hook it to a jackshaft so it is turnin say 3500 rpm at idle, thereby makin around 5-8 psi, then feed the turbo(s) into the charger
As rpm rises to say 3400 on the motor the charger is now turnin its 35-45,000 rpm (4:1 ratio after the jackshaft) it will certainly handle all of the air that a 3" intake feed pipe from the turbos can flow

And here is your stumblin block - nobody is runnin larger piping than 3" or thereabouts and a 3" pipe can only flow a certain amount of air - if memory serves thats about 1100 cfm at 80 psi and not many of us are makin 80 psi

At the end of the day in my mind and with current thinking and setup it will be the turbos starvin the supercharger not the other way around

Now take two modified s300 type turbos as singles, split the exhaust manifold, and then feed the blower with two 4" pipes and you might get somewhere

:blahblah1:$.02
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I'll fix your stumbling block...

CFM flow is not constant throughout the system. CFM flow is highest at your atmosphere inlet, whether it be a blower or turbocharger. It is then lower on the outlet by a factor proportionate the the density ratio across that stage. After an intercooler..... yep, CFM flow is again lower on the outlet, than on the inlet. Not because of "restriction", but because of compression. Thermal compression.

For instance:

Take a 5.9L engine turning 3000rpm. Say it's 360 cubic inches on the dot. Well, at 3000rpm that would be 540,000 cubic inches per minute, or 312.5 CFM at 100% VE. But wait a minute.... Don't all the 5.9 guys run huge chargers moving thousands of CFM? Yes, yes they do, but that is the CFM flow into the charger....

Everyone has to understand that the engine literally displaces a given amount of volume per rev. This cannot change unless you bore/stroke the engine to a larger overall displacement.

Now that would be "ideal", at 100% volumetric efficiency. However, you don't actually even get that much volume flow, because the cylinder filling is hardly ever perfect. And on a 2v head, it's probably closer to 80ish% or so at that kind of rpm. Lets figure 90% just for a number.

So now, at the 3000rpm, with the 360 cube engine, we're going to say 90% VE with a good cam. So in reality, that 312.5 CFM is only 281.25 CFM actual flow through that engine.

So no matter what, the engine will move 281.25 CFM @ 3000rpm. Period. When you compress the intake air with a supercharger or turbocharger all you're doing is altering the weight of those 281.25 cubic feet of air that go through that engine every minute. And by altering the weight per volume, you are altering the intake air density. And if the air is more dense, there will be more molecules for every unit of volume. Hence the fact that turbocharging brings more oxygen to the party. But the volume flow is unchanged. The mass flow is what goes up. And fwiw, the mass flow is unchanged throughout the system from inlet to tailpipe. The same mass is flowing through the system, but it keeps getting compressed and compressed on the way in, so the volume keeps dropping, and then it keeps getting decompressed and decompressed on the way out until the volume keeps coming back up and up until it leaves the tailpipe where the volume is back again, and a plume is shooting toward the sky.


The moral of the story is that CFM flow into a charger, is not the CFM flow through the compressor outlet, nor is it the same CFM flow actually traveling through the engine. You can see evidence of this in the fact that while a compressor might have a 6" inlet duct, it might only have a 3" outlet.

You can supercharge the engine with a positive displacement blower, and the only change will be that for the task of sizing the turbo to feed it, you simply size the turbo for an engine of the displacement the blower will be moving. As that's all the turbocharger will see. It doesn't know there's a blower on a 360ci engine. For all it knows it's bolted to an NA 800ci engine....
 
Charles said:
I'll fix your stumbling block...

CFM flow is not constant throughout the system. CFM flow is highest at your atmosphere inlet, whether it be a blower or turbocharger. It is then lower on the outlet by a factor proportionate the the density ratio across that stage. After an intercooler..... yep, CFM flow is again lower on the outlet, than on the inlet. Not because of "restriction", but because of compression. Thermal compression.

For instance:

Take a 5.9L engine turning 3000rpm. Say it's 360 cubic inches on the dot. Well, at 3000rpm that would be 540,000 cubic inches per minute, or 312.5 CFM at 100% VE. But wait a minute.... Don't all the 5.9 guys run huge chargers moving thousands of CFM? Yes, yes they do, but that is the CFM flow into the charger....

Everyone has to understand that the engine literally displaces a given amount of volume per rev. This cannot change unless you bore/stroke the engine to a larger overall displacement.

Now that would be "ideal", at 100% volumetric efficiency. However, you don't actually even get that much volume flow, because the cylinder filling is hardly ever perfect. And on a 2v head, it's probably closer to 80ish% or so at that kind of rpm. Lets figure 90% just for a number.

So now, at the 3000rpm, with the 360 cube engine, we're going to say 90% VE with a good cam. So in reality, that 312.5 CFM is only 281.25 CFM actual flow through that engine.

So no matter what, the engine will move 281.25 CFM @ 3000rpm. Period. When you compress the intake air with a supercharger or turbocharger all you're doing is altering the weight of those 281.25 cubic feet of air that go through that engine every minute. And by altering the weight per volume, you are altering the intake air density. And if the air is more dense, there will be more molecules for every unit of volume. Hence the fact that turbocharging brings more oxygen to the party. But the volume flow is unchanged. The mass flow is what goes up. And fwiw, the mass flow is unchanged throughout the system from inlet to tailpipe. The same mass is flowing through the system, but it keeps getting compressed and compressed on the way in, so the volume keeps dropping, and then it keeps getting decompressed and decompressed on the way out until the volume keeps coming back up and up until it leaves the tailpipe where the volume is back again, and a plume is shooting toward the sky.


The moral of the story is that CFM flow into a charger, is not the CFM flow through the compressor outlet, nor is it the same CFM flow actually traveling through the engine. You can see evidence of this in the fact that while a compressor might have a 6" inlet duct, it might only have a 3" outlet.

You can supercharge the engine with a positive displacement blower, and the only change will be that for the task of sizing the turbo to feed it, you simply size the turbo for an engine of the displacement the blower will be moving. As that's all the turbocharger will see. It doesn't know there's a blower on a 360ci engine. For all it knows it's bolted to an NA 800ci engine....
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Thanks Charles. That clears up some things I had been pondering. :woohoo:
 
Thanks Charles, good explanation. Would there be much if any response lost if the blower were side mounted near the turbo and pushed through the intercooler? The discharge plate could just be a square by tube adapter. Would the IATs be any better if the intercooler is allowed to cool both stages?
 
Charles said:
The blower won't "get in the way".

It is positive displacement. It will still move the same volume of air per rev no matter the engine rpm. Getting the blower "out of the way" wouldn't be any different than trying to get the engine out of the way, because as you are well aware, the engine only moves X CFM per rev as well.

You can blow turbochargers through a positive displacement blower all day with great results. Go with a Lysholm ("helix") style if you can find one cheap, and the IAT will be nice.
Click to expand...

How to get blower ' out of the way' ? It's actually very easy,you need just boost controlled valve.

Here is picture :
mb%20037.jpg


At lower rpm's and low boost condition all air goest throught turbo to supercharger and parallel pipe from turbos are closed (bloced because air want to go back to turbo)
At 30 psi boost controlled valve will open and air can go directly from turbo to engine.
Because boost pressure before and after supercharger are identical it just turns freely.........................:rockwoot:
 
AsTroSS said:
How to get blower ' out of the way' ? It's actually very easy,you need just boost controlled valve.

Here is picture :
mb%20037.jpg


At lower rpm's and low boost condition all air goest throught turbo to supercharger and parallel pipe from turbos are closed (bloced because air want to go back to turbo)
At 30 psi boost controlled valve will open and air can go directly from turbo to engine.
Because boost pressure before and after supercharger are identical it just turns freely.........................:rockwoot:
Click to expand...


You missed my point....

A positive displacement blower atop the engine wouldn't be in the way in the first place. Nevermind how to get it out of the way. It's just a pump. It doesn't care one bit whether the atmospheric conditions are 14.7psig or 60psig. It just knows that it moves __ CFM per rev. The end.
 
gt47+whipple

hello!i am newbie here and my english is wery bad but maybe youre understund me.here is link my dodge burnout and if you watch the video then turn volume little bit louder and listen the sound YouTube - P1020531 there is garrett gt47 and whipplecharger.some pictures in future then truck is ready
 
prospector said:
hello!i am newbie here and my english is wery bad but maybe youre understund me.here is link my dodge burnout and if you watch the video then turn volume little bit louder and listen the sound YouTube - P1020531 there is garrett gt47 and whipplecharger.some pictures in future then truck is ready
Click to expand...

Iltaa Jussi , tervetuloa



We need more infrmation and pictures about your setup. :rockwoot::bow:

How big supercharger and how you have mount it ?
 
AsTroSS said:
Iltaa Jussi , tervetuloa



We need more infrmation and pictures about your setup. :rockwoot::bow:

How big supercharger and how you have mount it ?
Click to expand...
no ei ihan jussi mutta melkein! pictures is "evo1" and i have some test drive but in future and "evo2" then i post picture in here.supercharger is lysholm 2300ax and it is top of turbocharger
 
prospector said:
hello!i am newbie here and my english is wery bad but maybe youre understund me.here is link my dodge burnout and if you watch the video then turn volume little bit louder and listen the sound YouTube - P1020531 there is garrett gt47 and whipplecharger.some pictures in future then truck is ready
Click to expand...
Yes more info PLEASE!!!
 
Detroit did have a blower bypass on their 149 series engine. IIRC they had about 25 or 30 psi at 1800rpm at no load then when the turbos got above 30 psi it would start pushing a spring loaded valve open in the intake hence bypassing the s/c. Max boost was about 55 or 60. And they all had quad turbos parallel mounted with a common intake
 
Charles said:
The blower won't "get in the way".

It is positive displacement. It will still move the same volume of air per rev no matter the engine rpm. Getting the blower "out of the way" wouldn't be any different than trying to get the engine out of the way, because as you are well aware, the engine only moves X CFM per rev as well.

You can blow turbochargers through a positive displacement blower all day with great results. Go with a Lysholm ("helix") style if you can find one cheap, and the IAT will be nice.
Click to expand...
Thanks Charles. I wasn't thinking clearly when I posted that and thought a supercharger would surge if you applied to much flow to its inlet. I guess it's much like a twins setup in that respect.
 
Charles said:
You missed my point....

A positive displacement blower atop the engine wouldn't be in the way in the first place. Nevermind how to get it out of the way. It's just a pump. It doesn't care one bit whether the atmospheric conditions are 14.7psig or 60psig. It just knows that it moves __ CFM per rev. The end.
Click to expand...



Blowers can get in the way, for one just look at the old detroits, had a blower bypass for that reason. You could get way more out of one with a bypass than one without.
 
Joesixpack said:
Blowers can get in the way, for one just look at the old detroits, had a blower bypass for that reason. You could get way more out of one with a bypass than one without.
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Explain why....

Cause I can't see it. CFM flow into the engine is constant @ any given rpm. CFM flow out of the blower is constant @ any given rpm. Basically, just making the engine larger.

All the turbo does is make each of those CFM weigh more. Why does the blower care?



The only thing I can see, is that the blower isn't in the way at all..... but, the blower requires crankshaft hp to drive. And once the turbo is up on top, it's more efficient (from a drive standpoint) to take the load off of such an inefficient device.

Hence my having suggested a Lysholm compressor in the first place.


And I'm not saying "I'm right, you're wrong", as if we were standing in a sandbox arguing over a toy... That's just my logic above. I'm posing an argument in hopes of getting a logical explanation as to where it is wrong, or right. I can't see where it's in the way. Maybe somebody else can show me why it is.
 
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prospector said:
hello!i am newbie here and my english is wery bad but maybe youre understund me.here is link my dodge burnout and if you watch the video then turn volume little bit louder and listen the sound YouTube - P1020531 there is garrett gt47 and whipplecharger.some pictures in future then truck is ready
Click to expand...

Holly crap that sounds and looks awesome!
 
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