CelicaTech Main Page  CelicaTech Member List CelicaTech Image Gallery CelicaTech Data Garage Chatroom CelicaTech Forums Search CelicaTech Forums Contact CelicaTech
+ Reply to Thread
Results 1 to 9 of 9
  1. #1
    Ultimo Miembro Fantástico Gigantesco MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of MrWOT has much to be proud of
    MrWOT has donated to the forums! MrWOT helped get Luni's MR2 back on the road!

    Join Date
    Dec 2004
    Location
    Boulder Creek, California
    Posts
    2,827
    Images
    50

    Default Information on how turbos work, and how to pick the right one! READ ME!

    I really like the way aaawelder put it: "do not include yourself in this circuit"

  2. #2

    Default

    GOOD STUFF!!

    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
    click
    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
    for the specs of my 5sfte

  3. #3

    Default

    Good stuff WOT.
    2000 Absolute Red Celica GTS 6-Spd
    1991 Crimson Red MR2 Turbo


    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


    - Shadow's Army - Commander In Chief


    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
    Originally Posted by surfergravity
    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
    This thread is gayer than Richard Simmons singing a duet with Elton John in a bath house.

  4. #4

    Default

    Nice.

    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

    94 Celica ST
    1.8l stock 7A-FE, T3/T4

    04 Mazdaspeed Miata
    1.8l, Factory Turbo, Hard Dog DD Roll Bar, Custom TB inlet pipe, boost controller...it's teh faster

  5. #5
    Blowing Stereotypes, ya heard? Snafu Vanilla Ice gets more respect.. Snafu's Avatar
    Snafu has donated to the forums! Snafu helped get Luni's MR2 back on the road!

    Join Date
    Dec 2004
    Location
    Minneapolis, MN
    Posts
    1,255

    Default

    WOW, that's how they work?!?!?!?!
    1988 CRX DX - Drag Car
    Vitara/TT rod Z6 - Sinktrap Manifold - GM9 turbo

    www.mydragcar.com/snafu

  6. #6
    Ultimo Miembro Fantástico Gigantesco Mike431635 is on a distinguished road Mike431635's Avatar

    Join Date
    Dec 2004
    Location
    Tampa, FL
    Posts
    1,000

    Default

    I found out a T3 60 trim is in the highest efficiency island on my 4AFE. When I get home I'll post the figures I used in the calculations, but I am assuming they are pretty accurate. That should be just about right though since a Super 60 is often used on the 7AFE.

  7. #7
    Ultimo Miembro Fantástico Gigantesco Mike431635 is on a distinguished road Mike431635's Avatar

    Join Date
    Dec 2004
    Location
    Tampa, FL
    Posts
    1,000

    Default

    All of the math and a good portion of the other stuff is taken from the Garrett advanced site posted above. Some of the figures are estimated since I have no freaking idea what they could be. I based my estimates on information from the Garrett site.

    Max Torque - 5800rpm (from my dyno)
    Horsepower Target- 160
    Engine Displacement- 1.6L / 97.632 ci
    Max rpm- 6500 rpm
    Temperature- 75 F
    Barometric Pressure- 30.08 in / 14.77391 psi
    Volumetric Efficiency (VE)- 95% (usually between 90 and 98 on engines with 16V heads, so I just estimated)
    Intake Manifold Temperature- 120 F (again, just estimated. it's usually between 100 F and 130 F on most cars)
    Brake Specific Fuel Consumption (BSFC)- 58% (usually between 50% and 65% or so, so I picked a # in the middle)
    A/F- 12 (good target AF, right?)

    To plot compressor operating point:
    Wa= HP*(A/F)*(BSFC/60)
    Where:
    · Wa = Airflowactual (lb/min)
    · HP = Horsepower Target (flywheel)
    · (A/F)= Air/Fuel Ratio
    · (BSFC)= Brake Specific Fuel Consumption ÷ 60 (to convert from hours to minutes)

    Wa= 160*12*(.55/60)= 17.6 lb/min of air needed for 160hp

    Calculate required manifold pressure required to meet the horsepower, or flow target:
    MAPreq= [Wa*R*(460+Tm)]/[VE*(N/2)*Vd]
    Where:
    · MAPreq = Manifold Absolute Pressure (psia) required to meet the horsepower target
    · Wa = Airflowactual(lb/min)
    · R = Gas Constant = 639.6
    · Tm = Intake Manifold Temperature (degrees F)
    · VE = Volumetric Efficiency
    · N = Engine speed (RPM)
    · Vd = engine displacement (Cubic Inches, convert from liters to CI by multiplying by 61.02, ex. 2.0 liters * 61.02 = 122 CI)

    MAPreq= [17.6*639.6*(460+120)]/[.95*(6500/2)*97.632]= 21.659 psia

    Subtract atmospheric pressure to get gauge pressure (aka boost):
    21.659 psia - 14.774 psi= 6.885 psig

    I then had to account for pressure loss, which I did not know. I just estimated 2 psi To determine the Compressor Discharge Pressure (P2c), 2 psi will be added to the manifold pressure calculated above.

    P2c= MAP+Ploss
    Where:
    · P2c = Compressor Discharge Pressure (psia)
    · MAP = Manifold Absolute Pressure (psia)
    · Ploss = Pressure Loss Between the Compressor and the Manifold (psi)

    P2c= 21.659+2= 23.659 psi

    This is taken directly from Garret:
    Remember our discussion on inlet depression in the Pressure Ratio discussion earlier, we said that a typical value might be 1 psi, so that is what will be used in this calculation. For this example, assume that we are at sea level, so ambient pressure is 14.7 psia.

    We will need to subtract the 1 psi pressure loss from the ambient pressure to determine the Compressor Inlet Pressure (P1).

    P1c= Pamb-Ploss
    Where:
    · P1c = Compressor Inlet Pressure (psia)
    · Pamb = Ambient Air pressure (psia)
    · Ploss = Pressure Loss due to Air Filter/Piping (psi)

    P1c=14.77-1= 13.77 psia

    With this, we can calculate Pressure Ratio (PIc) using the equation PIc=P2c/P1c

    PIc=23.659/13.77= 1.718

    -----------
    In the end, I got these two numbers which will be needed for plotting on the compressor maps:

    Corrected Air Flow = 17.6 lb/min / 232.8 CFM
    Pressure Ratio= 1.718

    Now, some of the maps (for Mitsubishi turbos especially) use CFM instead of lb/min so I had to do some searching to find out how to convert the figures. I came up with this:

    Mass Air Flow vs. Volume Air Flow conversion:
    Mass Flow(lb/min) = 0.0756 x Volume Flow(cfm) IF the volume flow is measured at standard temperature and pressure (STP). Otherwise the Ideal Gas Law must be used to first convert the measured volume flow to STP.

    Just the math:
    lb/min = .0756xCFM
    CFM= [lb/min]/.0756

    For anyone with a 4AFE, there's all the math and numbers. You can plug in your own numbers and stuff, and I might even make a spreadsheet that will do all this math for us. It'll be a good tool to put on the site.

    Now you just go and plot You just need to find a good site that teaches you how to read compressor maps. I had a few but can't remember them right now. Basically, if you're farther left than the left-most line on the compressor map, you won't produce enough exhaust gas to spool the turbo. If you're too far off the right of the map, the compressor is going to be way too small. Instant boost, but it won't be efficient at all or produce enough power to reach your hp goal. You want to be close to the center of the greatest efficiency island as you can possibly be. That's the best balance between spool and top-end. Again, don't take this as the gospel because I'm not an expert at this by any means. But it is a good start

  8. #8
    Member ROME is on a distinguished road ROME's Avatar

    Join Date
    Dec 2004
    Location
    Melbourne, Australia
    Posts
    104

    Default


    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

    If it can break, I broke it

  9. #9

    Default

    I didn't write this, but some of you might find it helpful. It's pretty neat to play with.

    Right-Click > Save As

    To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

    94 Celica ST
    1.8l stock 7A-FE, T3/T4

    04 Mazdaspeed Miata
    1.8l, Factory Turbo, Hard Dog DD Roll Bar, Custom TB inlet pipe, boost controller...it's teh faster

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
Top Member List Chat Forum Search Contact Top