How much HP???
#11
11-21-2012, 10:19 AM
Diesel Enthusiast
I disagree actually, boost is the amount of air pressure on the intake side which is being force into the piston area when the intake valve is open and the more boost you make the more forced air you get into the combustion chamber and the more forced air you get into the combustion chamber the more air volume you get into the combustion chamber thus more air in a more confined space equals a bigger boom in short. 
#12
11-21-2012, 08:06 PM
#13
11-21-2012, 08:28 PM
I disagree actually, boost is the amount of air pressure on the intake side which is being force into the piston area when the intake valve is open and the more boost you make the more forced air you get into the combustion chamber and the more forced air you get into the combustion chamber the more air volume you get into the combustion chamber thus more air in a more confined space equals a bigger boom in short.
There are a number of things that can alter the "Boost" without changing the turbo(s). For example:
- In my heap, with a stock/OEM cam, my mess came up with almost 70psig of boost at WOT. Swapping in an aftermarket cam and changing nothing else, had the boost drop almost 15psig (down to 55psig).
- With 3" charge-air plumbing and a huge custom made IC, the WOT "Boost" at the outlet of the secondary turbo, is 3psig higher than the "Boost" at the engine's intake-log.
- Speaking of ICs, the typical IC will cause a drop in "Boost" as a result of the charge-air being cooled, as compared to the NON IC'ed engine (ignoring the drop due to resistance to flow through the IC).
An extreme example might be; a stopped-up muffler, can cause apparent high boost.
At the end of the day, boost means squat as far as power goes so don't be getting cocky cause your mess can do so-and-so pounds boost. As far as the forced induction system of our engines goes, it's the volume of air going through the engine that matters.
Last edited by BC847; 11-21-2012 at 08:50 PM.
#15
11-21-2012, 09:27 PM
- > @ firstgenfreak93. I'm not picking on you with the following. A LOT of folks have asked the same question and gotten a million different answers. The following is to everyone wondering the same . . .
What is a "Turned-Up pump"?
- Does it include the Smoke-Screw run all the way in with the Star-Wheel all the way down? The Fuel-Screw run in til just before run-away? 1/8" IP timing advance?
OR . . .
- Does it include the Smoke-Screw and Star-Wheel adjusted for ample light to mid-throttle response and power with minimal smoke? Is the IP timing set to compliment the fuel settings given the intended use of the truck? Is the Fuel-Screw run in till just before run-away with all the other components of the throttle system set to work together? Has the AFC been altered to work with the new boost figure?
That after-market Fuel-Pin . . . has the AFC system been adjusted to properly bring the fuel on with the increasing boost, considering the Fuel-Pins custom ramp?
That "Cold-Air" intake . . . is it a true Cold-Air intake? Or is it a Swiss-cheesed stock/OEM air filter housing? Regardless, is it actually pulling in 100% cold air from outside the engine bay?
That "4 inch exhaust" . . . your question includes mention of 4" exhaust. You Sig says 4" straight pipe. The first could include a muffler. Does it dump behind the front tire? In front of the rear tire? Or in front of the rear bumper?
Without knowing the above for sure, there's NO way anyone can give a reasonably accurate answer as to how much power the engine would make. Crap! . . . Your engine WILL make less power in the mountains than compared to being at the beach.
We still don't know what transmission you're running.
- Weight the truck and take it to the drap-strip. Make three passes and average the times and speeds. Those numbers combined with the weight of the truck, can be mathematically worked to show the the power to the wheels. And that, assumes about a 20% loss through the drive-train . . . . . sorta.
- Take the mess to a dyno and hope the driver can properly load the diesel to present a reasonable estimate. Don't accept BS numbers inflated with correction-factors.
After a while . . . who cares?
@ firstgenfreak93: If you're only seeing an accurate 16psig of boost, then something's wrong as the stock/OEM truck presents with 18psig.
Last edited by BC847; 11-21-2012 at 09:30 PM.
#16
11-21-2012, 11:02 PM
Diesel Enthusiast
A turbocharger, or turbo (colloquialism), from the Greek "τύρβη" (mixing/spinning) is a forced induction device used to allow more power to be produced for an engine of a given size.[1][2] A turbocharged engine can be more powerful and efficient than a naturally aspirated engine because the turbine forces more intake air, proportionately more fuel, into the combustion chamber than if atmospheric pressure alone is used.
In automotive applications, "boost" refers to the amount by which intake manifold pressure exceeds atmospheric pressure. This is representative of the extra air pressure that is achieved over what would be achieved without the forced induction. The level of boost may be shown on a pressure gauge, usually in bar, psi or possibly kPa.[22]
In aircraft engines, turbocharging is commonly used to maintain manifold pressure as altitude increases (i.e. to compensate for lower-density air at higher altitudes). Since atmospheric pressure reduces as the aircraft climbs, power drops as a function of altitude in normally aspirated engines. Systems that use a turbocharger to maintain an engine's sea-level power output are called turbo-normalized systems. Generally, a turbo-normalized system will attempt to maintain a manifold pressure of 29.5 inches of mercury (100 kPa).[22]
In all turbocharger applications, boost pressure is limited to keep the entire engine system, including the turbo, inside its thermal and mechanical design operating range. Over-boosting an engine frequently causes damage to the engine in a variety of ways including pre-ignition, overheating, and over-stressing the engine's internal hardware.
In automotive applications, "boost" refers to the amount by which intake manifold pressure exceeds atmospheric pressure. This is representative of the extra air pressure that is achieved over what would be achieved without the forced induction. The level of boost may be shown on a pressure gauge, usually in bar, psi or possibly kPa.[22]
In aircraft engines, turbocharging is commonly used to maintain manifold pressure as altitude increases (i.e. to compensate for lower-density air at higher altitudes). Since atmospheric pressure reduces as the aircraft climbs, power drops as a function of altitude in normally aspirated engines. Systems that use a turbocharger to maintain an engine's sea-level power output are called turbo-normalized systems. Generally, a turbo-normalized system will attempt to maintain a manifold pressure of 29.5 inches of mercury (100 kPa).[22]
In all turbocharger applications, boost pressure is limited to keep the entire engine system, including the turbo, inside its thermal and mechanical design operating range. Over-boosting an engine frequently causes damage to the engine in a variety of ways including pre-ignition, overheating, and over-stressing the engine's internal hardware.
#17
11-21-2012, 11:35 PM
#18
11-22-2012, 01:00 AM
With respect to the original author apparently referring to an Otto-cycle engine (http://en.wikipedia.org/wiki/Otto_cycle) . . . .
Just to expand on the difference of the diesel engine from the Otto-Cycle based engine the original author is talking about, I'll quote from the WIKI ~ Diesel Engine article linked to above:
At knifemotercicle, it's rude to quote another's work without referring to them. Look up Plagiarize. 
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Not true, but thanks. 
A turbocharger, or turbo (colloquialism), from the Greek "τύρβη" (mixing/spinning) is a forced induction device used to allow more power to be produced for an engine of a given size.[1][2] True. A turbocharged engine can be more powerful and efficient than a naturally aspirated engine because the turbine forces more intake air, proportionately more fuel, into the combustion chamber than if atmospheric pressure alone is used. True with the exception being the diesel does not have fuel mixed with the charge-air.
In automotive applications, "boost" refers to the amount by which intake manifold pressure exceeds atmospheric pressure. True. This is representative of the extra air pressure that is achieved over what would be achieved without the forced induction. True. The level of boost may be shown on a pressure gauge, usually in bar, psi or possibly kPa.[22] True.
In aircraft engines, turbocharging is commonly used to maintain manifold pressure as altitude increases (i.e. to compensate for lower-density air at higher altitudes). Since atmospheric pressure reduces as the aircraft climbs, power drops as a function of altitude in normally aspirated engines. Systems that use a turbocharger to maintain an engine's sea-level power output are called turbo-normalized systems. Generally, a turbo-normalized system will attempt to maintain a manifold pressure of 29.5 inches of mercury (100 kPa).[22] Not applicable in our Dodge/Cummins diesel / Useless information for our conversation.
In all turbocharger applications, boost pressure is limited to keep the entire engine system, including the turbo, inside its thermal and mechanical design operating range. Over-boosting an engine frequently causes damage to the engine in a variety of ways including pre-ignition, overheating, and over-stressing the engine's internal hardware.
I can't say I've ever read or seen where one of our diesels had an issue with too much boost. (except maybe that pull-tractor that ripped the block clean in two. But then, a gazillion psi with a couple of gallons a second of inter-stage water injection may have had something to do with it). Excessive peak combustion pressures maybe. Excessive drive-pressures maybe.
Pre-ignition in our diesel is, . . . well, effectively what makes the thing run, being a compression ignition based engine and all. (http://en.wikipedia.org/wiki/Diesel_cycle AND http://en.wikipedia.org/wiki/Diesel_engine)
As far as overheating, generally, more boost is usually needed to lower the EGTs changing nothing else. But then you can add more fuel!
Over-stressing the engine? Well, I've heard that you're not really getting all you can out of it till you're hurting it by the end of the pass.
In automotive applications, "boost" refers to the amount by which intake manifold pressure exceeds atmospheric pressure. True. This is representative of the extra air pressure that is achieved over what would be achieved without the forced induction. True. The level of boost may be shown on a pressure gauge, usually in bar, psi or possibly kPa.[22] True.
In aircraft engines, turbocharging is commonly used to maintain manifold pressure as altitude increases (i.e. to compensate for lower-density air at higher altitudes). Since atmospheric pressure reduces as the aircraft climbs, power drops as a function of altitude in normally aspirated engines. Systems that use a turbocharger to maintain an engine's sea-level power output are called turbo-normalized systems. Generally, a turbo-normalized system will attempt to maintain a manifold pressure of 29.5 inches of mercury (100 kPa).[22] Not applicable in our Dodge/Cummins diesel / Useless information for our conversation.
In all turbocharger applications, boost pressure is limited to keep the entire engine system, including the turbo, inside its thermal and mechanical design operating range. Over-boosting an engine frequently causes damage to the engine in a variety of ways including pre-ignition, overheating, and over-stressing the engine's internal hardware.
I can't say I've ever read or seen where one of our diesels had an issue with too much boost. (except maybe that pull-tractor that ripped the block clean in two. But then, a gazillion psi with a couple of gallons a second of inter-stage water injection may have had something to do with it). Excessive peak combustion pressures maybe. Excessive drive-pressures maybe.
Pre-ignition in our diesel is, . . . well, effectively what makes the thing run, being a compression ignition based engine and all. (http://en.wikipedia.org/wiki/Diesel_cycle AND http://en.wikipedia.org/wiki/Diesel_engine)
As far as overheating, generally, more boost is usually needed to lower the EGTs changing nothing else. But then you can add more fuel!
Over-stressing the engine? Well, I've heard that you're not really getting all you can out of it till you're hurting it by the end of the pass.
The addition of a turbocharger or supercharger to the engine greatly assists in increasing fuel economy and power output, mitigating the fuel-air intake speed limit mentioned above for a given engine displacement. Boost pressures can be higher on diesels than on petrol engines, due to the latter's susceptibility to knock, and the higher compression ratio allows a diesel engine to be more efficient than a comparable spark ignition engine. Because the burned gases are expanded further in a diesel engine cylinder, the exhaust gas is cooler, meaning turbochargers require less cooling, and can be more reliable, than with spark-ignition engines.
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Last edited by BC847; 11-22-2012 at 01:53 AM. Reason: Automerged Doublepost
#19
11-22-2012, 01:47 AM
#20
11-22-2012, 02:12 AM
IIRC, I'd had my truck perhaps 5 years or so when I saw a full page ad for a BANKS system in a 4WD magazine. 
My pants fit funny while looking at the page. I couldn't afford it though.
(At the time, it pretty-much was da'chit to the average Joe. The kits made more power and actually met the existing EPA regs).
We all learn stuff as we go.
My pants fit funny while looking at the page. I couldn't afford it though.(At the time, it pretty-much was da'chit to the average Joe. The kits made more power and actually met the existing EPA regs).
We all learn stuff as we go.
Last edited by BC847; 11-22-2012 at 02:18 AM.
