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Quick question...How many CFM does 6.2 engine take at 2000RPM & 3000RPM @ Intake man?

TOBASH

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Quick question...How many CFM does 6.2 engine take at 2000RPM & 3000RPM @ Intake man?

So on a 6.2 liter military detuned engine, how many CFM does the intake manifold flow at 2000 and 3000RPM. How many at WOT?

Thanks,

T
 
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kingston/ NH
Non turbo has same cfm through entire rpm range unlike gasoline engines. Assuming 100% volumetric efficiency, 218cfm at 2000 and 328 at 3000.
.11 cfm per rpm
 
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MattNC

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If you had a "turned up" injector pump this would increase correct? The engineer in me would think so. Pretty certain mine was turned up given its pep compared to other ones I've seen and the ability to just give a hint of rolling coal when getting on it (I prefer not to roll coal!!). I was wondering if I helped it breath if it would perform better and not have black smoke when accelerating hard. I was thinking simple stuff like opening up internal deflectors and raising the snorkel height away from the hood a bit. No compromises on filters.
 

MattNC

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On the values listed above wouldn't it be 220 cfm and 330 cfm at 2000 and 3000 rpm respectively? Just multiplying the 0.11 value
 

Coug

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If you had a "turned up" injector pump this would increase correct? The engineer in me would think so. Pretty certain mine was turned up given its pep compared to other ones I've seen and the ability to just give a hint of rolling coal when getting on it (I prefer not to roll coal!!). I was wondering if I helped it breath if it would perform better and not have black smoke when accelerating hard. I was thinking simple stuff like opening up internal deflectors and raising the snorkel height away from the hood a bit. No compromises on filters.
Air intake and amount of fuel injected aren't directly related in a diesel, unlike a gasoline vehicle.

A diesel will intake the same amount of air at a given speed no matter how much fuel is injected, as it doesn't have to mix the fuel and air before combustion, it just injects fuel into the cylinder, and as long as there is enough air the fuel burns. When you start getting more fuel than the air can burn efficiently is when you start getting your "rolling coal" or soot from the incompletely burned fuel in the exhaust.


Edit: That being said, if you can get more air into the cylinder, you can burn more fuel efficiently and get more power (the entire purpose behind using a turbo). Some people have modified the baffles in the air filter canister to give the incoming air a more direct path through the intake system, but in severely dusty conditions that allows the dust and dirt to hit the air filter directly in one spot, quickly loading up that one place with dirt/dust, and I can see potential for it to start sandblasting the air filter media in that spot if the dust is heavy enough/bad enough for a long enough period of time. Might not be a big deal if it's a pavement queen in a relatively clean environment, but might not be the best idea if you're going to be off roading in the desert a lot.
 
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TOBASH

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Thanks guys.

I'm considering a little sacrilege, so this information is helpful.

Best,

T
 
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Location
kingston/ NH
No, Internal combustion engines are air pumps at their core. Each stroke of a piston can only suck so much air. The numbers I listed above assume perfect flow, which is unattainable, but what we use to help size systems (exceptions include injectors, then we really do need the volumetric efficiency) but intake filters, ducting, exhaust use figure 100%. This is why air intake, exhaust, head design, valve size, all matter with the goal being more air for the same amount of work .

Gas engines utilize an adjustable throttle body (butterfly valve) unlike diesels. This adjusts the air flow to match the fuel required for the demanded power needs. So 1/4 throttle 2500 RPM flows way less air then 4/4 throttle in the gas. A non-turbo diesel flows the same at a given RPM regardless of fuel demand.

If you had a "turned up" injector pump this would increase correct? The engineer in me would think so. Pretty certain mine was turned up given its pep compared to other ones I've seen and the ability to just give a hint of rolling coal when getting on it (I prefer not to roll coal!!). I was wondering if I helped it breath if it would perform better and not have black smoke when accelerating hard. I was thinking simple stuff like opening up internal deflectors and raising the snorkel height away from the hood a bit. No compromises on filters.
 
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