IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: motorhead on November 15 2013, 10:08:59 AM
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http://speedtalk.com/forum/viewtopic.php?f=1&t=37811 (http://speedtalk.com/forum/viewtopic.php?f=1&t=37811)
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I can't believe I read that
I can't hardly read can't spell
I'm hoping the new Champion heads and intake make my car faster at the same boost
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I can't believe I read that
I can't hardly read can't spell
I'm hoping the new Champion heads and intake make my car faster at the same boost
It's is completely apples and oranges. If the heads and intake have less restriction, then the boost number is no longer related to your prior boost number. And, it gets further complicated in that aluminum is thermally less efficient than iron so it takes a higher level of heat within the combustion chamber to produce the same amount of power as the iron heads. That is why we raise the compression a point on average to try to make up for the thermal weakness of the aluminum head.
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will i read enough to get Irons
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I got 6 or 7 posts in before I was too stupid to work the mouse wheel and had to give up.
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I'm with Earl on this one. The more I read either I got a lot dumber or the posts did. Just couldn't tell which. :O
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LOL!!!
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I quit reading because I am usually in a state of confusion to begin with....I don't need any more
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Aluminum is a much better conductor than iron. Aluminum has a coefficient of thermal conductivity of 206 W/m'C (watts per meter celsius) compared to iron at 70 W/m'C.
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Aluminum is a much better conductor than iron. Aluminum has a coefficient of thermal conductivity of 206 W/m'C (watts per meter celsius) compared to iron at 70 W/m'C.
Thanks for verifying my statement.
Engines run on the heat from the combustion process. Aluminum bleeds more heat out of the combustion chamber than does iron. This reduces power and makes it more inefficient than iron when it comes to power production.
We raise the compression to build more heat during combustion to make up for the loss. We can also use thermal coatings on the piston tops and combustion chambers to keep the heat within the cylinder to drive the piston down harder and coat the inside of the exhaust port to try to keep the heat out of the coolant which may aggravate detonation
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I have to do a government exam on this stuff right away. One of the good things about aluminum being a good conductor is on the exhaust stroke it helps expel more heat so when the compression stroke occurs it is compressing denser gas because it isn't as hot. The down side is you don't want to dissipate the heat on the power stroke. You want to convert as much heat energy to mechanical energy as possible, ie. efficiency.
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Okay might not have come out right. I was kind of referring to the Carnot cycle, which is the ideal cycle. Replace the cylinder head with basically a hot body, non-conductor, and cold body. But you are correct we want to keep as much of the heat in the cylinder as possible and not reject it.
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I never had any doubt :)
The advantage that aluminum has over iron is that it is cheap to cast in smaller numbers, and it weighs a lot less. In a racing environment, it is also easy to repair. You have to look at the entire elephant and not just its ears or trunk. This topic is really relevant to performance and not general science. Else, we will soon be touting the wonders of electric power :D
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I read this thread and had to hurl! 1) In the specific case of aluminum heads for LC2 the valves and seats are larger, and unshrouded, therefore more charge air per intake stroke. The flow data from both Champion & TA support the fact that untouched Aluminums will out flow most (if not all ported irons). Since aluminum heads likely flow more air (at 28 inches on the water monometer) than iron, does boost (or unusable intake air quantity go down???) Yes if all other conditions are equal. If a greater amount of air by volume (aluminum) and a greater mass density due to cooler temperature (aluminum) makes it to the combustion chamber is more gas required to meet the commanded air/fuel ratio? YES!! Since the spark plug location (aluminum) is closer to the intake and exhaust valve might the thought occur that the chamber burn rate is faster?( Less octane req'd??). This is somewhat verifiable by the fact that aluminum head cars with higher static compression ratios run pump gas (without alky) at higher boost levels than iron head motors. Temperature is only one part of the Carnot cycle. You have mass density, potential energy/unit of mass and temperature. These factors combine uniquely in most situations. Folks with aluminum heads that I know without exception say they make better power and have better response than their irons. Is it more expensive to change over to aluminum? YES!!!! Do aluminums have different torque requirements for fasteners? Are aluminums good for newbies?? Probably not!
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I read this thread and had to hurl! 1) In the specific case of aluminum heads for LC2 the valves and seats are larger, and unshrouded, therefore more charge air per intake stroke. The flow data from both Champion & TA support the fact that untouched Aluminums will out flow most (if not all ported irons). Since aluminum heads likely flow more air (at 28 inches on the water monometer) than iron, does boost (or unusable intake air quantity go down???) Yes if all other conditions are equal. If a greater amount of air by volume (aluminum) and a greater mass density due to cooler temperature (aluminum) makes it to the combustion chamber is more gas required to meet the commanded air/fuel ratio? YES!! Since the spark plug location (aluminum) is closer to the intake and exhaust valve might the thought occur that the chamber burn rate is faster?( Less octane req'd??). This is somewhat verifiable by the fact that aluminum head cars with higher static compression ratios run pump gas (without alky) at higher boost levels than iron head motors. Temperature is only one part of the Carnot cycle. You have mass density, potential energy/unit of mass and temperature. These factors combine uniquely in most situations. Folks with aluminum heads that I know without exception say they make better power and have better response than their irons. Is it more expensive to change over to aluminum? YES!!!! Do aluminums have different torque requirements for fasteners? Are aluminums good for newbies?? Probably not!
SUCCESS! I hope you puked on yourself. :icon_lol:
My buddy's Stage II heads, have a 10' valve, flow 335 cfm@.5 lift, he runs a .680 lift cam. What aluminum heads will out flow these? Yes I know your talking LC2, but what aluminum head matches the Stage II? The car ran a 7.9@179 with 24psi of boost on an old T-88 and not on alcohol. Yet you have to listen to all these pros chirp about how that isn't even possible to run. The funny part was the car was built by turbo pros and kept blowing up, because they messed up in a few areas which they never should have. He laughed when he fixed it, but he got the car at a good price.
I don't claim to be an expert, like yourself. I have friend that works for a top NHRA team that does heads. They do things that defy logic all the time, but if they go fast that is the only thing that matters.
I knew with "Volumetric Efficiency Nut" you'd chirp in! :rock:
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I'm also surprised at just how rarely people mention that head flow really means dick on a turbo engine. Granted, anything you do to decrease restriction is a net positive... but there's no need to spend $1000s when a simple 1/2 turn will do the same thing. (until the combo is maxxxed out)
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I'm also surprised at just how rarely people mention that head flow really means dick on a turbo engine. Granted, anything you do to decrease restriction is a net positive... but there's no need to spend $1000s when a simple 1/2 turn will do the same thing. (until the combo is maxxxed out)
I believe the point of the thread was to indicate a correlation between building the best, most efficient, naturally aspirated engine possible so as to prove to make it a better engine with boost. Not just using boost as a performance band-aid as the Turbo Buick does.
We (the hobbiest) should be focusing on air flow (in and out) and not just some random number that is a function of a restriction.
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Please understand I AM NO EXPERT. I will drive my T Type into the pond when I start thinking like I'm some hot shot that knows all of this. My reason for an aluminum head is driven by being able to run pump gas on the street. I go crazy watching people follow the leader without considering the facts, not mine or someone else's opinion. I like it when folks go to other sites (Speed Talk, Yellow Bullet etc.) to snoop around and learn. Bring what you have learned back here to teach a nut case like me.
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Many people tend to stick with what they know and never experiment. I have friends that have PHd's in their field, and one that is currently working on his PHd. I've been to the labs to see what he was working on. His advisor told him what he was doing will never work, even though it wasn't his field. He proved him wrong and reminded him of his comments, the guy did apologize. He was telling me how pissed off he was.
I did mention to a few people what he was working on and I got responds of, "That can't work! That defies the science behind it."
But when your going for a PHd, you're in the research and development game. You are the guy, it's not like you can ask someone. There is a reason you're making $90-$120/hr or even more. And he is one of the most grounded people I know, doesn't wear an engineering ring. But he does have colleagues that resemble the Big Bang Theory.
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I'm also surprised at just how rarely people mention that head flow really means dick on a turbo engine. Granted, anything you do to decrease restriction is a net positive... but there's no need to spend $1000s when a simple 1/2 turn will do the same thing. (until the combo is maxxxed out)
True dat!
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I did mention to a few people what he was working on and I got responds of, "That can't work! That defies the science behind it."
That just means they didn't consider ALL the science.
After I started playing with solar heating and intermingling it with electronics you'd be amazed how many times I had to walk away, look at porn, and wait until all the data could swirl around and homogenize. There are quite a few things that just don't make sense until you fully understand all the factors.
One thing I have noticed about the engineering types. When they find something that works for them, they'd rather get hit in the head with a hammer than change the way they do things.
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That just means you didn't consider ALL the science.
True, and thing get more subtle the deeper you delve.
One thing I have noticed about the engineering types. When they find something that works for them, they'd rather get hit in the head with a hammer than change the way they do things.
Yep.
I work with rocket scientists (actually).
I often have to bring them back to earth (not literally)
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I'm also surprised at just how rarely people mention that head flow really means dick on a turbo engine. Granted, anything you do to decrease restriction is a net positive... but there's no need to spend $1000s when a simple 1/2 turn will do the same thing. (until the combo is maxxxed out)
True dat! Be advised that turning up the wick may increase air volume but probably reduces mass density (how tightly packed the air molecules are per unit of volume) since the air friction goes up so air temperature goes up. It's not just the amount of air you pump into the chamber but it's how easy you pump it in (larger unshrouded valves) and the efficiency of the burn process (chamber shape and position of spark plug within the chamber) and how much you reduce the tendency to knock (spark plug location within the cylinder & relational position to the valves).
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This popped up today:
http://speedtalk.com/forum/viewtopic.php?f=1&t=744 (http://speedtalk.com/forum/viewtopic.php?f=1&t=744)
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Ditto Ditto Ditto!!!! If you have a thumpin' little 6 without a turbo can you imagine what you have with a turbo!
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This popped up today:
http://speedtalk.com/forum/viewtopic.php?f=1&t=744 (http://speedtalk.com/forum/viewtopic.php?f=1&t=744)
Like I've mentioned in the past, my buddy's is friends with Kieth Wilson( Wilson Manifolds). He would never make a manifold or modify one for a customer without the heads. Kieth showed me a stage II manifold he made for PTE, with a price tag of $8k. Just because your heads flow good doesn't mean your getting all the air in where it should be. Isn't that the reason Jason made the power plate? Because the factory setup flows a lot more air to the back cylinders.