Please help me figure out what turbo is the best to suite my current application and future needs, I am on the learning curve so please be considerate of my ignorance. I want to learn and experiment with a turbo on my stock setup but spend money once in the proper direction for a built motor if possible.
stock 200ci out of a 1978 fairmont with the flat log head (roughly 60K miles)
or I could swap the head from the above motor to my
stock 200ci out of a 1966 mercury comet (125K miles), I think it might be better to just swap the fairmont motor in completely.
Below I followed the example on Garret Turbos website (http://www.turbobygarrett.com/turbobyga ... ch103.html) on how to calculate Air Flow Actual and Pressure Ratio to find the proper turbo using the turbo map. Do the following calculations look right? Is my volumetric efficiency even 85%? This all seems like a huge guess. To be honest since I am boosting my stock motor for now I only expect 180-200HP flywheel at best but I want to buy a turbo that I could use down the road in a few years when I do a full motor build. Am I wrong in doing this, how will this affect my performance only using 1/3 of the potential of the turbo (probably 6-8psi)?
Volumetric Efficiency 0.85 %
Horsepower Target (flywheel) 460 HP
Engine Displacement 200 CI
Maximum RPM 5000 RPM
Temperature
Barometric Pressure
Intake Manifold Temperature 130 F (100-130 average)
Brake Specific Fuel Consumption (BSFC) 0.55 (0.50-0.60 or higher)
Air/Fuel Ratio 11
Wa = HP * A/F * BSFC/60
Wa = 46.383
Wa = Airflow actual (lb/min)
HP = Horsepower Target (flywheel)
A/F = Air/Fuel Ratio
BSFC/60 = conversion to minutes
MAPreq = (Wa * R * (HP + Tm))/(VE * N/2 * Vd)
MAPreq = 41.184 psia
Boost = MAPreq - 14.7 psia (at sea level)
Boost = 26.484 psig
MAPreq = Manifold Absolute Pressure (psia) required to meet the horsepower target
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)
P2c = MAP + delta P loss
P2c = 43.184 psia
P2c = Compressor Discharge Pressure (psia)
MAP = Manifold Absolute Pressure (psia)
delta P loss = Pressure loss between the compressor and the manifold (psi) (avg 2psi)
P1c = Pamb - Delta P loss
P1c = 13.7 psia (at sea level)
P1c = Compressor inlet pressure (psia)
Pamb = Ambient air pressure (psia)
delta P loss = Pressure loss due to air filter/piping (psi) (avg 2psi)
Pressure Ratio = P2c / P1c
Pressure Ratio = 3.152
Also I notice that if I had a 250ci motor like the others it tremendously drops my boost down to 18psi which sounds right according to the results we have seen by others. But if I punch in 200HP in the formula with my 200ci motor I get negative boost and the only way I see to correct this is to drop by efficiency down to 40% (0.40)? Maybe the 200 motor is just not feasably going to work with 460hp and I should be aiming at building a 250ci block for the future motor swap which then makes buying the proper turbo now not possible with the CI change. Possibly a cheap $180 ebay turbo for now if this is the case, let me know what you guys think.
stock 200ci out of a 1978 fairmont with the flat log head (roughly 60K miles)
or I could swap the head from the above motor to my
stock 200ci out of a 1966 mercury comet (125K miles), I think it might be better to just swap the fairmont motor in completely.
Below I followed the example on Garret Turbos website (http://www.turbobygarrett.com/turbobyga ... ch103.html) on how to calculate Air Flow Actual and Pressure Ratio to find the proper turbo using the turbo map. Do the following calculations look right? Is my volumetric efficiency even 85%? This all seems like a huge guess. To be honest since I am boosting my stock motor for now I only expect 180-200HP flywheel at best but I want to buy a turbo that I could use down the road in a few years when I do a full motor build. Am I wrong in doing this, how will this affect my performance only using 1/3 of the potential of the turbo (probably 6-8psi)?
Volumetric Efficiency 0.85 %
Horsepower Target (flywheel) 460 HP
Engine Displacement 200 CI
Maximum RPM 5000 RPM
Temperature
Barometric Pressure
Intake Manifold Temperature 130 F (100-130 average)
Brake Specific Fuel Consumption (BSFC) 0.55 (0.50-0.60 or higher)
Air/Fuel Ratio 11
Wa = HP * A/F * BSFC/60
Wa = 46.383
Wa = Airflow actual (lb/min)
HP = Horsepower Target (flywheel)
A/F = Air/Fuel Ratio
BSFC/60 = conversion to minutes
MAPreq = (Wa * R * (HP + Tm))/(VE * N/2 * Vd)
MAPreq = 41.184 psia
Boost = MAPreq - 14.7 psia (at sea level)
Boost = 26.484 psig
MAPreq = Manifold Absolute Pressure (psia) required to meet the horsepower target
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)
P2c = MAP + delta P loss
P2c = 43.184 psia
P2c = Compressor Discharge Pressure (psia)
MAP = Manifold Absolute Pressure (psia)
delta P loss = Pressure loss between the compressor and the manifold (psi) (avg 2psi)
P1c = Pamb - Delta P loss
P1c = 13.7 psia (at sea level)
P1c = Compressor inlet pressure (psia)
Pamb = Ambient air pressure (psia)
delta P loss = Pressure loss due to air filter/piping (psi) (avg 2psi)
Pressure Ratio = P2c / P1c
Pressure Ratio = 3.152
Also I notice that if I had a 250ci motor like the others it tremendously drops my boost down to 18psi which sounds right according to the results we have seen by others. But if I punch in 200HP in the formula with my 200ci motor I get negative boost and the only way I see to correct this is to drop by efficiency down to 40% (0.40)? Maybe the 200 motor is just not feasably going to work with 460hp and I should be aiming at building a 250ci block for the future motor swap which then makes buying the proper turbo now not possible with the CI change. Possibly a cheap $180 ebay turbo for now if this is the case, let me know what you guys think.