Airflow Bickering / butt hurt thread #2
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Airflow Bickering / butt hurt thread #2

  1. #1
    Senior Member Hass828's Avatar
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    Default Airflow Bickering / butt hurt thread #2

    Since we have been having so much fun as of lately, I thought I might as well bring this subject back to the top.
    I found a link I would like you guys to check out. It makes some of the "pro's" on the #1 thread look kinda silly.
    Cams for Turbocharged Engines - Hot Rod Magazine

    heres a copy & paste from the link that I really enjoyed-

    "Another factor influencing cam design for a turbocharger is charge density. Because turbo applications make such dramatic power, the common misconception is that the intake and exhaust port velocities need to be quite high, in turn mandating very large-duration camshafts to make a given amount of power. Actually, the exact opposite is true. Because of the increased pressure along with a corresponding increase in oxygen and fuel density, more fuel and air are moving into the chamber, but the velocity is actually lower. The combustion chamber pressure therefore rises more quickly, and filling occurs earlier in the stroke compared with a similar NA application."

    I have my flame/BS resistant suit on, so fire away.
    Last edited by Hass828; 01-15-2014 at 06:10 PM.
    "if we keep doing it the same way we always do..we will always get the same results"
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    LP-25.com Infomaniac's Avatar
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    Sounds reasonable to me. My cam is tiny.
    If For Some Reason I Do Something Worthy Of Recognition. God Provided The Ability And Deserves The Credit.


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    Senior Member bp298's Avatar
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    you sure you want to do this???

    here's a "copy/paste" from your same article.

    On the other hand, Roots blowers make boost immediately off idle, so they don't need exhaust help to pull the charge out of the cylinder. A cam optimized for a Roots supercharger can have higher intake duration (at 0.050) than equivalent-duration-operating-range cams for other applications. For example, a beltdriven centrifugal blower or a turbo would have a smaller intake to trap cylinder pressure during the intake stroke because they take longer to get up to peak boost

    I guess the "discussion" is now over...

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    Senior Member Hass828's Avatar
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    Quote Originally Posted by bp298 View Post
    you sure you want to do this???

    here's a "copy/paste" from your same article.

    On the other hand, Roots blowers make boost immediately off idle, so they don't need exhaust help to pull the charge out of the cylinder. A cam optimized for a Roots supercharger can have higher intake duration (at 0.050) than equivalent-duration-operating-range cams for other applications. For example, a beltdriven centrifugal blower or a turbo would have a smaller intake to trap cylinder pressure during the intake stroke because they take longer to get up to peak boost

    I guess the "discussion" is now over...
    You two Boobs are very much the same. I have never one time insinuated that a turbo makes boost as quickly as a blower. As a matter of fact, if the turbo deal has a fault at all, it is the SLIGHT hesitation at the hit. And things can be done to help with that. And I will state once again that it isn't an issue at all with boat drags. You have have posted before about how Bob Fry's boat, or how Info's boat leaves. So is it an issue?
    Seems to me I have heard that the blower guys have much more of an issue trying to deal with getting the hit softened up enough that they don't blow the pump away. Sometimes that advantage you guys keep wanting to claim is actually a disadvantage.
    "if we keep doing it the same way we always do..we will always get the same results"
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  7. #5
    steelcomp was here
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    Quote Originally Posted by bp298 View Post
    you sure you want to do this???

    here's a "copy/paste" from your same article.

    On the other hand, Roots blowers make boost immediately off idle, so they don't need exhaust help to pull the charge out of the cylinder. A cam optimized for a Roots supercharger can have higher intake duration (at 0.050) than equivalent-duration-operating-range cams for other applications. For example, a beltdriven centrifugal blower or a turbo would have a smaller intake to trap cylinder pressure during the intake stroke because they take longer to get up to peak boost

    I guess the "discussion" is now over...
    ...next...
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  8. #6
    steelcomp was here
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    Quote Originally Posted by Hass828 View Post
    You two Boobs are very much the same. I have never one time insinuated that a turbo makes boost as quickly as a blower. As a matter of fact, if the turbo deal has a fault at all, it is the SLIGHT hesitation at the hit. And things can be done to help with that. And I will state once again that it isn't an issue at all with boat drags. You have have posted before about how Bob Fry's boat, or how Info's boat leaves. So is it an issue?
    Seems to me I have heard that the blower guys have much more of an issue trying to deal with getting the hit softened up enough that they don't blow the pump away. Sometimes that advantage you guys keep wanting to claim is actually a disadvantage.
    So are we back to you making the rules for the discussion by limiting this to jet boats only?
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    Senior Member Hass828's Avatar
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    This thread and that link was actually more about cylinder head flow. I have said before that "its not how much the head is flowing but WHAT is flowing through the head". That extra dense, compressed charge will make a very mediocre set of stock style heads perform , and do it with a very mild camshaft.
    I believe that there are many-many boaters out there that have a good stout forged bottom end with low compression and mild heads that would like to increase their performance. I would like to point out that they would get way more for their money to consider turbocharging what they currently have instead of trying to change/port heads, camshaft, compression, ect. you know, the usual routine.
    Then they would have a variable power output that can still burn the same pump gas they are used to. And if they decide to poor some good fuel and boost to it once in a while will make more power than most other more expensive routes.
    "if we keep doing it the same way we always do..we will always get the same results"
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  10. #8
    Senior Member Hass828's Avatar
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    Quote Originally Posted by steelcomp View Post
    So are we back to you making the rules for the discussion by limiting this to jet boats only?
    Why , have you come up with an application where physics don't apply? What is it this time? Airplanes? Tractor puller? Snowmobile? Land speed racer? Top fuel car?

    I'm aware that there are some applications that turbos may not be the perfect fit for. For jet boats I think they are a great fit. And I'm still not convinced that they wouldn't work for the V-drive crowd, but don't care if they give it a try or not.
    "if we keep doing it the same way we always do..we will always get the same results"
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    Senior Member GT Jets's Avatar
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    I will never forget the words that came out of my grandfather's mouth over 30 years ago... I keep going back to this every time I hear someone compare a roots blower with a turbo.

    "Turbos are great, except, the bigger the instantaneous demand on the engine, the more time you have to wait to have your ass pulled into the seat."

    Keep in mind he raced buggies at Baja, drag raced in Pomona in the '60's and flew gyro copters in WWII with the Screaming Eagles in the 101st Airborne and built/flew his own planes until he passed at the age of 89 years old. RIP pops...

    They definitely have a place in the performance world, there is no arguing that, in fact, they're awesome, but that was never really the argument, the argument always was, there are less tricky ways of getting the same result power wise, but having it at your fingertips.

    You just cannot deny the fact that a roots blower just is far superior and making the stump pulling grunt from standstill to scary much quicker.

    I really do believe a jet is quite literally the only real good place for turbos, basically because they have a stall converter built into them that lets them spin 3000 plus RPM from the opening of an anemic bottom end of a turbo deal.

    I have no dog in this fight (can't afford either) but I can tell you what I would install in either the I/O or the jet if I had the opportunity... It wont say Vidal Sassoon on the side...

    Carry on...
    Last edited by GT Jets; 01-15-2014 at 07:49 PM.
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    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    Quote Originally Posted by Hass828 View Post
    This thread and that link was actually more about cylinder head flow. I have said before that "its not how much the head is flowing but WHAT is flowing through the head". That extra dense, compressed charge will make a very mediocre set of stock style heads perform , and do it with a very mild camshaft.
    I believe that there are many-many boaters out there that have a good stout forged bottom end with low compression and mild heads that would like to increase their performance. I would like to point out that they would get way more for their money to consider turbocharging what they currently have instead of trying to change/port heads, camshaft, compression, ect. you know, the usual routine.
    Then they would have a variable power output that can still burn the same pump gas they are used to. And if they decide to poor some good fuel and boost to it once in a while will make more power than most other more expensive routes.
    Dollar for dollar, supercharging is one of the best deals around, regardless of how it's done.
    For those going low budget, the old draw through Rajays are still hard to beat.
    For more money, the blow through injected deals are hard to beat.
    For looks, nothing beats a polished roots blower for the wow factor.

  13. #11
    Senior Member Hass828's Avatar
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    Quote Originally Posted by jimsplace View Post
    Dollar for dollar, supercharging is one of the best deals around, regardless of how it's done.
    A pair of turbos capable of 2000hp when put on any common flat top 540+-~cid engine, can be had for $1300 brand new and will last for hundreds of hrs of abuse. How much would a supercharger capable of same cost$ and how long would it last before needing restripped?
    Last edited by Hass828; 01-15-2014 at 08:02 PM.
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    Senior Member GT Jets's Avatar
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    Quote Originally Posted by Hass828 View Post
    A pair of turbos capable of 2000hp on a flat top 540cid can be had for $1300 brand new and will last for hundreds of hrs of abuse. How much would a supercharger capable of same cost$ and how long would it last before needing restripped?

    So all you need is two turbos and no ducting, exhaust work, special tuning tools... Hmmmm...

    I always heard that the costs for each were comparable. The turbos being more involved and more odds and ends.
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  15. #13
    Senior Member Hass828's Avatar
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    Quote Originally Posted by GT Jets View Post
    So all you need is two turbos and no ducting, exhaust work, special tuning tools... Hmmmm...

    I always heard that the costs for each were comparable. The turbos being more involved and more odds and ends.
    Turbo needs headers, supercharger needs headers, turbo needs intercooler, supercharger needs intercooler, either one needs some form of fueler(carb-efi), The aluminum ducting is cheap, the additional expense will be the wastegates and BOV, but its a wash when compared to the blower intake and drive hardware, not to mention a good intercooler for a supercharger is much more expensive than one can be had for a blowthrough.
    How much did you say that 2000hp capable blower costs? And how long between rebuilds?
    "if we keep doing it the same way we always do..we will always get the same results"
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    Quote Originally Posted by jimsplace View Post
    Dollar for dollar, supercharging is one of the best deals around, regardless of how it's done.
    For those going low budget, the old draw through Rajays are still hard to beat.
    For more money, the blow through injected deals are hard to beat.
    For looks, nothing beats a polished roots blower for the wow factor.
    I beg to differ...
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