Page 1 of 2 12 LastLast
Results 1 to 15 of 16

Thread: SC Boost?

  1. #1
    Join Date
    Feb 2003
    Location
    Houston, Republic of Texas
    Age
    67
    Posts
    2,475

    SC Boost?

    Okay, I know I'm not the only one on this board who wants to ask the question, so I'll show my ignorance and learn something. I hear a lot of talk about "boost" with regard to SC, and I assume that it must be one of the following:
    1. The AMOUNT of additional air supplied to the engine by the SC;
    or
    2. The Pressure at which the additional air is supplied.

    Am I close so far?

    Now, if I am correct on one of those, please answer this for me. It would seem that the more boost you have, the more power the engine would get from the SC, right? I understand that you might not want all of the boost and power you can get, because of the extra strain it would place on the engine and drive train, but in general, does more boost mean more added power?

    Thanks, as usual.
    2003 MM 300A
    Born June 18, 2002
    Adopted Christmas Eve, 2002
    First Factory Rebuilt Ford P.O.S. Engine at 81,000 miles
    Second Factory Rebuilt Ford P.O.S. Engine at 101,000 miles
    Ford Racing 4.10's
    Reinhart/XCal2 Custom Tune
    Reinhart Underdrive Pulleys
    K&N Conical Air Filter
    Reinhart Exhaust with 18" Magnaflows
    Silencer Removed
    Bosch Micro Edge Excel Wiper Blades
    Bob White Red Bumper Inserts
    Lone Star Beer in cup holder
    Fellowship of Christian Cowboys
    license plate bracket
    ****************************** *********

    God and the soldier we adore, In times of danger, not before.
    The danger gone, the trouble righted, God's forgotten, the soldier slighted.

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

    Cynicism is the smoke rising from the ashes of burned out dreams.

  2. #2
    Join Date
    May 2003
    Location
    Edmonton, Alberta
    Posts
    3,074
    Yes. More air = more oxygen = fuel burns better = more power.

    A NA (Normally Aspirated) engine sucks the air into the engine. A "Ram Air" setup uses the speed of the car to force more air into a NA engine.

    A SC or Turbo uses the engine itself to force pressurized air into the engine. A SC uses rotating force of the engine crank to turn a compressor to force the air. A turbo uses the exhaust gases to turn a compressor to force more air in.
    2003 Marauder 300eh - Stock

    Born: 12/03/2002
    Adopted 02/17/2003

    Trilogy #243

    AVIC D3
    SS Inserts.
    Metco Control arms and Watts link.
    QA1 8 way adjustable shocks and struts.
    Addco front and rear anti-roll bars.
    Wilwood front brakes.

    I can't drive 55. I'm looking forward to not being able to drive 75 ether.

  3. #3
    Join Date
    Sep 2002
    Location
    Cape Cod, MA
    Posts
    13,675
    Ross:

    On an N/A (Naturally Aspirated) motor, the pistons are always creating a vacuum in the intake manifold (except at WOT), which is measured in "inHg" (inches of mercury)...at WOT, the intake manifold is at normal atmospheric pressure (14.7 psi at sea level). On a pressure-fed engine, the supercharger or turbocharger adds to this pressure, forcing more air into the motor than normal atmospheric pressure can provide. This additional pressure is the "boost" rating...
    The Blackbird
    Trilogy #61
    Driveway Queen

    The Spruce Goose
    2004 Grand Marquis LS Limited Edition
    Daily Driver

  4. #4
    Join Date
    May 2003
    Location
    Edmonton, Alberta
    Posts
    3,074
    2003 Marauder 300eh - Stock

    Born: 12/03/2002
    Adopted 02/17/2003

    Trilogy #243

    AVIC D3
    SS Inserts.
    Metco Control arms and Watts link.
    QA1 8 way adjustable shocks and struts.
    Addco front and rear anti-roll bars.
    Wilwood front brakes.

    I can't drive 55. I'm looking forward to not being able to drive 75 ether.

  5. #5
    Join Date
    Sep 2002
    Location
    Cape Cod, MA
    Posts
    13,675
    Dr. Caleb:

    Those are excellent links...thanks!
    The Blackbird
    Trilogy #61
    Driveway Queen

    The Spruce Goose
    2004 Grand Marquis LS Limited Edition
    Daily Driver

  6. #6
    Billatpro Guest
    One way to look at "Boost" is to think of it in terms of an air compressor, like the one you may or may not have in your garage. As the blower spins up it begines to build a reserve of air "waiting" to get into the motor! it is this reserve that shows up on your "Boost gauge"
    In an ideal world the engine would use all the air the blower could pass through to it, at which point the blower would no longer be making "Boost" and the engine would be making "MAX" power.
    Did that make sense to anyone?

  7. #7
    Join Date
    Jun 2003
    Location
    Arkansas
    Age
    58
    Posts
    20
    Dont Know if this will help, it may be easiest to look at your engine as an air pump, the more air you move through it the more power it makes. The only other concern is mixing enough fuel to burn with all of that air. The best thing about a supercharger/turbocharger is that it allows you to move more air through the engine without making the engine bigger physically- a bigger engine has more negative horsepower (more friction, heavier crank&rods=more reciprocating mass). So the SC engine is more efficient. WIth boost being the amount of "extra air" the limiting factor becomes the strength of the engine componants.

  8. #8
    Join Date
    May 2003
    Location
    Missouri Ozarks
    Posts
    270
    1. What are the factors governing 'how much' boost to provide??
    2. Is there a 'boost limit'??

    Open questions to anyone..........

  9. #9
    Billatpro Guest
    There many factors governing "How much boost" and all of the lay within your short block. Yes there is a Boost limit and this also lay within your short block.

  10. #10
    Join Date
    Jun 2003
    Location
    Arkansas
    Age
    58
    Posts
    20
    The amount of practical boost with a marauder is (my opinion) limited primarily by the stock compression ratio, which when combined with increased cylinder pressure and heat introduced by a SC will cause predetonation of the fuel (knock), and potentialy burn a hole in a piston. Also I have read about Cobra's breaking rings when the boost is increased over 12-15psi and the engine is pushed hard. Also the rods, crank and pistons (cast HE rather than forged) could fail with too much boost, not to mention the headgasket. If my MM gets a blower it will probably not make over 8psi, because that safety margin is important to me. BTW the info on Cobra's breaking rings is heresay not firsthand for me.

  11. #11
    looking97233 Guest
    Try this link:

    http://www.kennebell.net/techinfo/techinfo-home.htm

    This is the Kenne Bell site. There is a lot of good info there. Also this is the supercharger that dennis said he could make 600RWHP with. Just one thing though big $$$. You would have to either rebuild the lower end or buy an 03' Cobra short block to take the pressure and the strain.

  12. #12
    Join Date
    Jul 2002
    Location
    Rochester MN
    Age
    48
    Posts
    509
    The level of boost is a serious consideration, if it was me I would keep the boost under 7 or 8.... I am running 14 on my Mustang, but have forged internals and terrific heads.... It will be only a matter of time before someone toasts a shortblock with over 8 psi, mark my words...... The extra 30 horse you get from raising the boost a couple of lbs isn't worth the risk of blowing parts... although that sounds really cool at the track

    go to www.corral.net and do a search for maximum boost, boost, etc. etc. Tons of info there.
    2 shoes and a nice pair of comfy socks

  13. #13
    Join Date
    Feb 2003
    Location
    Motor City
    Posts
    940
    Boost is limited by the amount of fuel you can add too (in addition to what the engine can handle). You can add all the boost you want. But, if you can't get enough fuel to get the A/F ratio correct, you'll blow up the engine regardless of whether its got forged parts or not. Even at 8 psi of boost, you will have to upgrade the fuel system. Most blower kits include new fuel system components.

  14. #14
    Join Date
    Sep 2002
    Location
    Plano, TX
    Age
    49
    Posts
    2,271
    [
    One for Mad3R: http://travel.howstuffworks.com/turbine.htm

    Hope this helps! [/B]
    Darn it!! can't I have ANY secrets around here!!


    Gone, but not forgotten

    "I don't drink beer, I drink Guinness."

  15. #15
    Join Date
    May 2003
    Location
    Edmonton, Alberta
    Posts
    3,074
    Originally posted by MAD-3R
    Darn it!! can't I have ANY secrets around here!!


    When you get the evil red eye in the grill, and the "Turbo Boost" button, post the pictures
    2003 Marauder 300eh - Stock

    Born: 12/03/2002
    Adopted 02/17/2003

    Trilogy #243

    AVIC D3
    SS Inserts.
    Metco Control arms and Watts link.
    QA1 8 way adjustable shocks and struts.
    Addco front and rear anti-roll bars.
    Wilwood front brakes.

    I can't drive 55. I'm looking forward to not being able to drive 75 ether.

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •