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Discussion Starter #1
Ok Guys, Help a Brother Out


I was asked this last night while having a few beers
I couldnt come up with a solid answer



What does the term "turbo spooling" or "turbo spooled Up" mean?


#2. When do I know that the turbo is engauged? Or is it operating all the time?


#3. "Black Smoke" We have all seen this from semi trucks but what does it take to make a stock duramax 1 ton P/U do it? And why would I want to? Is it a power thing? Does it clean out the engine?


Inquiring Minds Want To Know
 

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Don't know what spooling is, but anxious to find out. Turbo runs all the time the engines running. Black smoke is a sign of unburned fuel and poor efficiency, you don't want it.
 

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Hi-


1. Spooling is how fast the turbo blade is spinning...


Now for probably more than you want but it's good for baffeling those beer drink guys with your brilliance.



How fast the turbo speeds up and to what maximum speed is determined by the pressure differential at the inlet and outlet, raise the turbo inlet pressure, or lower the outlet pressure, or both, and you make more power
.


The heat of your exhaust determines how much pressure you generate.


"Scotty! I need more power... But Captain the turbo is melting!!!"


Now playing with your turbo performance is all about balance.


"Input! I need more Input"


If you increase the input you want to increase the output flow first: To raise the inlet pressure you need more heat.More heat you need more fuel... To get more fuel, you need things like Juice that allows the injectors to remain on longer.


Before you do that you really should open up your exhaust (Output) first. Lowering the output pressure is easy - just bolt on a bigger, free flowing exhaust. I've seen a couple of posts from people who added aftermarket exhausts, who report "my turbo spools up faster now" Well, that's because by lowering the outlet pressure, you increased the pressure differential, and now the exhaust gas can expand more, and do more work. That increased work pushes harder on your turbo, and it spools up faster.


With a free flowing exhaust you will also see less boost drop when you are maxed, because you increase the amount of exhaust gases you can flow. With a restricted system any additional gasses you try and force through it only raise the outlet pressure. Higher outlet pressure, lower pressure differential, less heat converted to work, less boost more EGT.





2- The turbo is spinning all the time.


3- Black smoke = unburnt fuel. = waisted energy.


Go dazzel them!








Edited by: JohnnyO
 

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johnnyo
 

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Paul3500


The surge of black smoke immediately after stepping on the accelerator on a turbo diesel is caused by a poorly combusted fuel lacking enough air, and this is do to the delay in the turbo spooling up. This is sometimes refered to or called "turbo lag".


Engineer Bill
 

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JohnnyO is dead on target!



The turbo as stated is always spinning but it is not always producing enough compressed air. The spool-up happens when the exhaust passes through the turbine and out the exhaust. The more exhaust passing through the turbine the faster the compressor spins...it is not a instaneous supply of compressed air...it needs a second or two too compress the intake air...but once it is compressing and you are keeping a steady supply of fuel it will always be "spooled-up".


Just remember the exhaust is driving the compressor....just like the big jet engines.
 
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