WTF is Mule trying to say (poll)

[Red Baron]

It took a while but someone finally got it.

Originally posted by m21sniper
In a 100% efficient system 1 bar of boost is the equivelant to doubling displacement, so yes...it is the same as doubling HP.

In reality, no street legal system gets much beyond 90% total system efficiency.

The reason a forced induction setup MAY create more HP per % of boost at say 30psi as it might at 20psi is a matter of intended system efficiency at a given RPM range and boost level. However, even in a 100% efficient system, 1 bar of boost will produce EXACTLY twice as much HP as a 100% VE NA motor in motors of identical displacement.

There are many factors at play here.

Also, it is entirely possible to achieve positive boost on a naturally aspirated engine in an intended operating range.

One example would be a "Tunnel Ram" dual quad intake.

[Danglerb]

Originally posted by m21sniper
In a 100% efficient system 1 bar of boost is the equivelant to doubling displacement, so yes...it is the same as doubling HP.

Sorry, but that isn't confusing enough.

Whether volumetric efficiency stays the same is part of the basic question, and I think input pressure does effect VE.

If you double displacement at half the input pressure does the HP stay the same? I don't think so, it mucks around with the thermodynamics and you get less power.

*******************

Two practical issues make this question seem silly, the amount of boost is easy to change, and an engine optimized for boost is setup differently from a NA motor, other than low boost systems like 7 psi lots of other stuff gets added or changed.

[Red Baron]

Originally posted by Danglerb
Sorry, but that isn't confusing enough.

Whether volumetric efficiency stays the same is part of the basic question, and I think input pressure does effect VE.

If you double displacement at half the input pressure does the HP stay the same? I don't think so, it mucks around with the thermodynamics and you get less power.

*******************

Two practical issues make this question seem silly, the amount of boost is easy to change, and an engine optimized for boost is setup differently from a NA motor, other than low boost systems like 7 psi lots of other stuff gets added or changed.

The real question that should be a poll, is what are you trying to say?

[Danglerb]

Originally posted by Red Baron
The real question that should be a poll, is what are you trying to say?

If Mule doesn't like some of the HP claims, he is not alone, most of us are saavy to the "up to 30% HP gains from a muffler" rules of the marketplace. Posting it as a question for all of us to try and explain the issue to him when he is as familiar with the answer as any of us is by definition a troll, and I am all done feeding this one.

[m21sniper]

If all other conditions are the same a motor operating at 100% efficiency at 1 bar of boost will produce exactly double the HP of a 100% VE naturally aspirated one.

Of course a 100% VE motor or a 100% effiicent turbo or supercharging system are both unobtanium.

[Mule]

Sorry if you got your feathers ruffled Dangler. Sniper hit the bull's eye. My point is this. When you see claims that exceed this ratio, you are looking at claims, not reality. Sniper was also 100% correct in saying that there will always be some loss of efficiency so the best anyone will ever do is going to be less than 100% improvement.

Thanks Corky.

[Mule]

Ready fro something better than that? I'm at the track one day talking to a guy who builds $50 - $60k turbo motors (mostly sb Fords). Not your typical race car guy, more like a college professor. His motors have lots of championships. I say Ronnie, how much power are these motors making, is 1850 real? He shrugs his shoulders & says "if you've got to pick a number that's probably a good one. But what difference does it make?" I says Huh? He says "what really matters is how quick it will rev not how much power it will make." Now I'm really confused.

[m21sniper]

Originally posted by Mule
Sorry if you got your feathers ruffled Dangler. Sniper hit the bull's eye. My point is this. When you see claims that exceed this ratio, you are looking at claims, not reality. Sniper was also 100% correct in saying that there will always be some loss of efficiency so the best anyone will ever do is going to be less than 100% improvement.

Thanks Corky.

Glad me and Corky could help.

[Danglerb]

Nobody here does or has disagreed with your basic premise, just wondered what you were driving at in saying it, and questioned the terms you put it in. Pressure without temperature and other details doesn't define HP.

"Now I am really confused" I'd say that was the professor's goal. OTOH in a rules based competition the edge may be in something you would not expect.

[Mule]

Help Corky help!

[Danglerb]

Originally posted by Mule
Help Corky help!

Read his book, PV=nRT, its not just a good idea, its the law.

http://en.wikipedia.org/wiki/Ideal_gas_law

n is the item of interest, how many molecules of O2 per unit of time decides the HP.

n = (PV)/(RT)

[Mule]

Women say it's all about the o, you say it's all about the n.


WTF is Dangler trying to say?

[Danglerb]

Originally posted by Mule
Women say it's all about the o, you say it's all about the n.


WTF is Dangler trying to say?

That I prefer even an inane discussion about cars to cleaning my garage.

Its still mass and not just pressure. Pressure gauges as far as I am concerned are mostly useful so the customer has something to watch move after spending a load of money.

Garage cleaning is winning now, can't wait for the next episode.

[rhjames]

pressure gauges are an absolutely useful tool in monitoring a turbo/supercharged engine, not just an add-on toy for amusement.....

mule didn't get what I was saying either, but what the heck?

this discussion of atmospheres has gotten pretty much into the argument of semantics, until Sniper chimed in.

However, Sniper was off when he claimed tunnel ram intakes create forced induction. Having operated numerous tunnel ram equipped engines, both cast manifolds and fabbed sheetmetal t-rams, I have never found that the intake charge was under pressure. It was always under some amount of vacuum, even in the high-end ProStock engines I was privileged to run. I have never seen any tunnel ram create positive pressure (atmospheres as this discussion calls them) in any rpm range, regardless of load or not on the engine.

as for the issues of percentage of improvements, to be blown or not to be blown, the comment that 10% improvement is unattainable is false.

if you supercharge (or turbo for that matter) a given engine at an overdrive percentage, you can overcome the 100% increase in HP. My diesel engine example in my earlier comments demonstrate this example.

My diesel won't hardly run without the turbo, but makes 600 plus HP at only 2100 rpms. Take the turbo off, and you'll be lucky to get 100 HP at the same rpms.

this same example should be applicable to gas engines as well, although I have no actual number to back up this up. it is just a common sense approach to the question at hand.

Herr is on track with some very good numbers as well, but I have found holes in his R&D as well. His latest clutch issues will skew his dyno numbers, because there may have been slippage on the old clutch (before turbo), and now that he's got a non-slipping clutch (after turbo) the numbers may be skewed. His addition of bigger stickier tires will skew the numbers as well.....

Your discussion of facts and figures as they relate to dyno this and dyno that...... are dependent upon consistent conditions for comparison. ambient temps, barometric pressures, engine components, etc., all have bearing on hp and torque claims.

------

[Mule]

James, what Sniper was referring to was the effect of port tuning on the intake side which absolutely causes a slight increase in pressure. If I need to explain the principles of port tuning I will but this is how they produce increased power. If you don't believe me call the guy who built that sheet metal intake. I guarantee he can explain it.

Your diesel will produce power in the same ratio we are discussing as any other engine. Why? Cause diesel needs air to burn just like gas.

I'm still waiting for somebody to give me a real example of exceeding 100%. so's Corky.

[Danglerb]

http://www.bellengineering.net/

It seems kind of sad after all the stuff he has done for him to still be waiting.

[rhjames]

mule:

after running tunnel rams (both cast and sheetmetal fabbed up whatever's) on various ProStock/comp engines over the past thirty some odd years, I have yet to see one that creates "pressure" in the intake tubes as you describe.

following your example of 1st atmosphere this and 2nd atmosphere that, there is no positive pressure on naturally aspirated engines in the intake. just vacuum, and various amounts of it depending upon application and rpm. Vacuum is negative atmosphere, let's say, in your atmosphere speak, therefore is not positive pressure.

Put a pressure gauge on one of the intake runners on a tunnel ram and you'll see what I'm talking about-----only vacuum. Tunnel rammed engines usually have cam profiles which huge amounts of overlap, losing vacuum to the point that you can't use vacuum assisted power brakes (not that you would want PBs on a prostocker.)

Port tuning is a matter of making the air charge run into the Combustion chamber at a higher velocity for increased filling of the cylinder, to overcome inefficiencies of the port design(s). Again, it is not pressure as you assert.

Back in the early '70s, we experimented with individual runner sheetmetal intakes (no plenum chambers), coupled with 1150 cfm dominators individually tuned per port, trying to simulate fuel injection (which is illegal in all prostock racing), but had greater success with tunnel rams that had plenum chambers above the actual tubes. that research has lead to very shallow plenum chambers that you see on every prostock engine in competition today.

And yes, I still have the last tunnel ram/1150 Dominator package I ran, sitting on my garage shelf.....Two very rare Holley Dominators, originally given to Ronnie Sox by Chrysler Performance in late '69 (engraved part/serial numbers). the air horns are still intact-the meter blocks, accelerator pumps/squirters, throttle bodies are heavily modified-and they will out flow anything short of current use prostock technology.

Been there, done that, got the tee-shirt two and a half decades ago.

The exhaust side of things is no different as well, as there are now header collectors (comp eliminator) that actually promote cylinder scavenging, making the exhaust run out of the engine faster (creating vacuum on the exhaust side). Again, vacuum instead of pressure. In fact, race engines with these collectors won't hardly idle, as they are designed to operate efficiently at high rpms.


as for the diesel discussion, I pretty well covered it in my post as it relates to your atmosphere speak.....

Your original assertion about higher altitudes, barometric pressures and their relationships to power production was incorrect as well, and you didn't clarify your statements about it in your further argument.....

your original discussion about 100% volumetric efficiency and the multiplying affect of turbo/supercharging was well intended, but not very well articulated.....not surprising that the Danglerb character didn't quite get it, as he is still on a very long learning curve------Sniper was much closer in his writings-


all of this stuff is very argue-mentive, but does nothing to educate the masses when you have folks writing opinions and not facts.



Next we'll be arguing again about which dyno is better than which dyno.......again.


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[Mule]

Rh said:
Port tuning is a matter of making the air charge run into the Combustion chamber at a higher velocity for increased filling of the cylinder, to overcome inefficiencies of the port design(s). Again, it is not pressure as you assert.

Let me attempt to step up my articulation.

Is it suction? Let me save you some work. No it's not.

I guess I have to try to explain the principle of port tuning (which is totally unaffected by valve overlap). If you have a tube filled with a gas (air) and that gas is moving in the tube. If you close the tube at one end the gas near the closure stops immediately, however the gas at the other end of the tube continues to move, effectively compressing the gas in the tube. Compress = increase in pressure. If the tube we are referring to is an intake port on an engine, the goal is to have the valve re-open at the maximum increase in pressure (compression) thereby more fully filling the cylinder. This is why, suck as the engine might, ram type manifolds make more power than others. The effect of intake port tuning is to increase the pressure (compression) in the intake port near the valve. This is how under certain circumstances a N/A engine can exceed 100% volumetric efficiency.

You covered the diesel discussion? How by stating that in your opinion (with no supporting facts) that your diesel is different? Not exactly.

As for altitude, this effect is constant at whatever altitude.

Air density is determined by 2 factors BAROMETRIC PRESSURE and temperature and it ABSOLUTELY affects power production.

My original statement still has yet to be challenged by any FACT, or even a credible opinion showing that that a second, third or fourth atmosphere of pressure will support more combustion than the first.

If you know all these race car types give somebody a call. I guarantee that Jason Line, Warren Johnson, Larry Morgan or even a backyard engine builder with even a rudimentary understanding of port tuning can explain it.

Here's a link that may articulate it more effectively. I hope this will help you get your helmholtz resonator in order.


http://www.grapeaperacing.com/GrapeApeRacing/tech/inductionsystems.pdf

[Mule]

Here is a statement from ATI Procharger on how much power can be expected from boost. Maybe Dan Jones & Jim Summers need to contact some of our crowd to find out how to get it right.

How much horsepower will a supercharger add to my engine?

Although some manufacturers claim a specific horsepower increase, superchargers actually add horsepower as a percentage gain (percentage of an atmosphere). Assuming an engine with a compression ratio of around 9:1 running pump gas,if a supercharger gives your engine 14.7 psi of boost (another atmosphere) that will essentially double the output of your engine, everything else being equal. After adjusting for thermal and mechanical energy transfer, if an efficient centrifugal supercharger is generating 7.5 psi (approx. 1/2 an atmosphere), you will see around a 35-40% gain in horsepower and torque at your non-supercharged maximum horsepower rpm. If detonation forces you to use an ignition/timing retard system, you will of course see less of a gain because backing off several degrees of timing will greatly reduce an engine's power output. At higher boost levels, the heat generated by compressing air will produce diminishing returns as the boost is increased, although the use of intercooling or racing fuel can avoid this scenario of diminishing returns. Assuming the use of intercooling to run higher boost levels while maintaining reliability, a 100% increase can generally be achieved at around 17 psi on an engine with 9:1 compression running pump gas. The gains in horsepower and torque delivered by each ProCharger system can be found on the price list as well as on the "ProCharger Systems" page within this site

[Danglerb]

The original Grape Ape drag car was in the same body shop as my car getting restored before hitting the nostalgia tour this summer.