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Building a low cost 800 HP unblown engine tips
This is a reprint from RaceCarbooks.com – Alkydigger sells all their Books
Disclaimer: All of the following engine profiles cannot be guaranteed to work adequately right out of the box. In any of these engine profiles, jetting combinations were determined from similar running engine profiles previously analyzed with ProCalc. Spark plug readings and engine temperature measurements are needed from incremental runs. That is to determine if jetting adjustments may be further needed from these baseline profiles for your particular setup. Incremental runs are necessary, first with spark plug readings (such as described in our books and other sources) and second with temperature checking during or after a run. Appropriate adjustments to jetting or ignition advance are all needed before full power, full runs should be done. Adequate performance without engine failures is also dependent on appropriate engine assembly and parts selection not addressed by these descriptions. Additional qualified expert engine building / tuning skills and information is necessary.
Note: Many racing engines are available with higher horsepower levels, but look at the prices and shipping costs. Higher powered engines are quite costly. Shipping of complete engines can be an additional significant cost. In addition, high powered engines on gasoline can be more expensive to run because of more expensive $20+/gal high octane gasoline. Here is an alternative for the budget racer, especially one who may already have access to lower cost parts. More expensive components can be substituted especially if you already own them although changes in engine size affect the fuel injection setup.
Low Cost Injected Alcohol V-8 Description
The following is an example of a low cost engine combination for land or water racing. It starts with a low cost injected alcohol big block V-8 racing engine. Keys to low cost are the following:
>> factory cast iron block and square port heads such as BBC’s
>> mechanical fuel injection
>> methanol fuel.
This is a ‘high power per dollar’ engine that is based on a low cost block/cylinder head platform: big block GM, FoMoCo, or Mopar V-8; running on relatively low cost methanol fuel; with the following engine specs:
engine platform: 454 big block GM; 460 Ford, Ford FE bored / stroked to 440+ ci; 440 Mopar, or cast iron Early Hemi bored / stroked to 440+ ci; amount of overbore may be limited by cylinder wall thickness; (smaller displacement engines such as Ford FE or Early Hemi’s can be done, however the fuel injection jetting combinations featured below would need adjustment to smaller values; larger displacement engines such as stroker big blocks can be done also, however fuel injection jetting combos would need adjustment to larger values; our FI books and jetting calculator provide info for those changes)
engine RPM: not to exceed 8,000 RPM
displacement: 440-460
crankshaft: factory forging such as the GM steel crankshaft, FoMoCo steel truck/motor home crankshaft, Mopar steel truck/motor home crankshaft for 440; OEM crankshaft for early Hemi; or aftermarket low cost forging made by one of several crankshaft suppliers
rods: premium high strength steel
premium soft bearings: main & rod clearances approx. 0.003 inches for mostly OEM parts that may need this extra clearance for when they move around from more power
pistons: 12.5 to 1 compression ratio piston with piston-to-wall clearance as recommended by the piston manufacturer; typically 0.006 inches for forged pistons
steel top ring, cast iron 2nd, medium tension oil ring
wet sump oiling system with extra oil capacity
premium multi layer oil filter
premium multi viscosity engine oil such as 15w50; this higher viscosity is recommended for the increased bearing clearance
piston pins: premium steel
camshaft: roller tappet with 0.800 inch lift, about 275 deg intake duration, about 285 deg exhaust duration (hemi about 280 deg duration both intake & exhaust), lobe centers 106 to 109 for wedge / poly cylinder head; cam index usually about 4 deg advanced to line up the overlap centered around top-dead-center; 109-110 for hemi head; hemi cam index: straight up; run a steel camshaft core, not cast
premium high strength roller lifters, pushrods, rocker arms, rocker arm mounts
cylinder heads: hand ported cast iron BBC square port for GM engine; Max Wedge head for Mopar wedge; ported 331 or 354 head suggested for early Hemi
intake valves: 2.15 to 2.4 inches
exhaust valves: 1.75 to 2 inches
valve spring seat pressure: 250-300 pounds with premium valve retainers, keepers (check with camshaft supplier for more specifics)
ignition: 2 to 6 amp magneto: Vertex, Mallory, or SuperMag
spark advance: approximately 36 deg for 2 amp magneto; 34 deg. for 6 amp magneto ( reduce by 2-4 degrees for small combustion chambers like Early Hemi)
spark plug gap for magneto: 0.016-0.020 inches
headers: individual pipes where rules permit with a small reduction in mid range power; otherwise, four-into-one collector should increase mid range power with a small reduction in top end power; low restriction mufflers could be added for reduced noise although top end reduction estimate of about 50 horsepower may occur for any type of baffled mufflers
manifold:
>>> stack type: 2.75 dia. or more throttles, ram tube length for 5,000 to 8,000 RPM range
>>> tunnel ram with Enderle hat, Hilborn, or two Alkydigger Assassinator throttle bodies with an air scoop
>>> single plane, largest volume runners with Alkydigger throttle body with air scoop.
This engine can be assembled for around $6,000 to $11,000 with mostly new and premium used parts. It would be almost street-able with an automatic transmission & high stall speed torque converter. Although it would have very high fuel consumption and not emissions compliant in many parts of the world. The main bypass would need to be adjusted for different air densities.
Intake & Fuel System
Racing mechanical fuel injection ProCalc analysis for normally aspirated 450 ci V-8:
at 95% air density, about 800 HP at 7,500 RPM
fuel pump: approx 4.9 GPM at 4,000 pump RPM; 8,000 engine RPM; RONs, Enderle, or Hilborn -1/2 size fuel pump
nozzles: 0.030 inch dia; more nozzles size info in our Jetting Big Block book
main bypass at 0.085 inches for air density around 95%
torque peak at 5,000 RPM
volumetric efficiency at torque peak: 103%
air to fuel ratio at torque peak: approx. 4.8 to 1
fuel pressure at 5,000 launch RPM: approx. 55 psi
high speed bypass poppet or diaphragm valve recommended opening RPM: 5,800
fuel pressure at 5,800 RPM: 74 psi
high speed bypass poppet or diaphragm valve pressure setting: 74 psi
high speed bypass jet size: 0.060 inch dia
volumetric efficiency at horsepower peak: 90%
air to fuel ratio at horsepower peak: 5.2 to 1
horsepower peak: approx 7,500 RPM
fuel pressure at 7,500 RPM with high speed bypass open: 79 psi
fuel to the engine: 1.84 gallons per minute; 110 gal/hour; 729 #/hour (methanol) with above fuel pump and jetting combo for 95% air density
brake specific fuel consumption: 1.1 pounds per horsepower per hour
for dragster or altered weight: 1,750 pounds, 1/4 mile ET: 7.6 seconds; 1/8 mile ET: 4.86 seconds; quarter mile speed: 180 MPH; eighth mile speed: 144 MPH at 95% air density.
Same setup at lower air density; all the same except:
at 90% air density, about 760 HP at 7,500 RPM
main bypass: 0.090 inch dia
the high speed bypass poppet or diaphragm valve opening pressure: 66 psi to maintain a 5,800 RPM opening point
fuel to the engine: 1.75 gallons per minute; 105 gal/hour; 693 #/hour (methanol)
brake specific fuel consumption: 1.1 pounds per horsepower per hour
for dragster weight of 1,750 pounds, quarter mile ET: 7.7 seconds; eighth mile ET: 4.93 seconds; quarter mile speed: 177 MPH; eighth mile speed: 142 MPH at 90% air density.
Note the following recommendations for different conditions:
for higher air density, run a smaller main bypass to maintain the air to fuel ratio and brake specific fuel consumption for best power; however, that will raise the fuel pressure; without adjustment, that will cause the high speed bypass to open at a lower RPM; that will cause the engine go lean at the top end; engine damage could occur as a result; instead, the high speed bypass opening pressure needs to be adjusted to a higher value to maintain the same opening RPM.
for lower air density, run a larger main bypass to maintain the same air to fuel ratio and brake specific fuel consumption for best power; however, that will lower the fuel pressure; without adjustment, that will cause the high speed bypass to open at a higher RPM; that will cause the engine go rich at the top end; power may be way down as a result; instead, the high speed bypass opening pressure needs to be adjusted to a lower opening pressure to maintain the same opening RPM.
our ProCalc fuel injection jetting calculator can determine the appropriate pressure settings for different air densities and different main bypass jet sizes.
at high altitude race tracks, the nozzles need to be changed to smaller ones to keep fuel pressure up; with the appropriate main bypass, the same fuel curve can be maintained for any altitude; horsepower will be the best for that altitude, but it would be lower as the altitude goes up, decreasing the air density.
our ProCalc calculator can be used to determine the best nozzle size change for higher altitudes.
our ProTune and ProTune Advance services can provide further analysis and training for setting up the calculator for most specific fuel injection and engine combinations.
Ram Air Effects w/o High Speed Bypass
Add to that considerations for ram air effects at high speed. For racecars or boats that exceed 150 MPH with forward mounted hat throttle bodies or air scoops facing the air flow, ram air will add more air into the inlet. Jetting may need adjustment for ram air provisions such as a smaller high speed bypass for high speed operation. More information about ram air gains is in our High HP Tuning book.
Disclaimer: All of the following engine profiles cannot be guaranteed to work adequately right out of the box. In any of these engine profiles, jetting combinations were determined from similar running engine profiles previously analyzed with ProCalc. Spark plug readings and engine temperature measurements are needed from incremental runs. That is to determine if jetting adjustments may be further needed from these baseline profiles for your particular setup. Incremental runs are necessary, first with spark plug readings (such as described in our books and other sources) and second with temperature checking during or after a run. Appropriate adjustments to jetting or ignition advance are all needed before full power, full runs should be done. Adequate performance without engine failures is also dependent on appropriate engine assembly and parts selection not addressed by these descriptions. Additional qualified expert engine building / tuning skills and information is necessary.
Note: Many racing engines are available with higher horsepower levels, but look at the prices and shipping costs. Higher powered engines are quite costly. Shipping of complete engines can be an additional significant cost. In addition, high powered engines on gasoline can be more expensive to run because of more expensive $20+/gal high octane gasoline. Here is an alternative for the budget racer, especially one who may already have access to lower cost parts. More expensive components can be substituted especially if you already own them although changes in engine size affect the fuel injection setup.
Low Cost Injected Alcohol V-8 Description
The following is an example of a low cost engine combination for land or water racing. It starts with a low cost injected alcohol big block V-8 racing engine. Keys to low cost are the following:
>> factory cast iron block and square port heads such as BBC’s
>> mechanical fuel injection
>> methanol fuel.
This is a ‘high power per dollar’ engine that is based on a low cost block/cylinder head platform: big block GM, FoMoCo, or Mopar V-8; running on relatively low cost methanol fuel; with the following engine specs:
engine platform: 454 big block GM; 460 Ford, Ford FE bored / stroked to 440+ ci; 440 Mopar, or cast iron Early Hemi bored / stroked to 440+ ci; amount of overbore may be limited by cylinder wall thickness; (smaller displacement engines such as Ford FE or Early Hemi’s can be done, however the fuel injection jetting combinations featured below would need adjustment to smaller values; larger displacement engines such as stroker big blocks can be done also, however fuel injection jetting combos would need adjustment to larger values; our FI books and jetting calculator provide info for those changes)
engine RPM: not to exceed 8,000 RPM
displacement: 440-460
crankshaft: factory forging such as the GM steel crankshaft, FoMoCo steel truck/motor home crankshaft, Mopar steel truck/motor home crankshaft for 440; OEM crankshaft for early Hemi; or aftermarket low cost forging made by one of several crankshaft suppliers
rods: premium high strength steel
premium soft bearings: main & rod clearances approx. 0.003 inches for mostly OEM parts that may need this extra clearance for when they move around from more power
pistons: 12.5 to 1 compression ratio piston with piston-to-wall clearance as recommended by the piston manufacturer; typically 0.006 inches for forged pistons
steel top ring, cast iron 2nd, medium tension oil ring
wet sump oiling system with extra oil capacity
premium multi layer oil filter
premium multi viscosity engine oil such as 15w50; this higher viscosity is recommended for the increased bearing clearance
piston pins: premium steel
camshaft: roller tappet with 0.800 inch lift, about 275 deg intake duration, about 285 deg exhaust duration (hemi about 280 deg duration both intake & exhaust), lobe centers 106 to 109 for wedge / poly cylinder head; cam index usually about 4 deg advanced to line up the overlap centered around top-dead-center; 109-110 for hemi head; hemi cam index: straight up; run a steel camshaft core, not cast
premium high strength roller lifters, pushrods, rocker arms, rocker arm mounts
cylinder heads: hand ported cast iron BBC square port for GM engine; Max Wedge head for Mopar wedge; ported 331 or 354 head suggested for early Hemi
intake valves: 2.15 to 2.4 inches
exhaust valves: 1.75 to 2 inches
valve spring seat pressure: 250-300 pounds with premium valve retainers, keepers (check with camshaft supplier for more specifics)
ignition: 2 to 6 amp magneto: Vertex, Mallory, or SuperMag
spark advance: approximately 36 deg for 2 amp magneto; 34 deg. for 6 amp magneto ( reduce by 2-4 degrees for small combustion chambers like Early Hemi)
spark plug gap for magneto: 0.016-0.020 inches
headers: individual pipes where rules permit with a small reduction in mid range power; otherwise, four-into-one collector should increase mid range power with a small reduction in top end power; low restriction mufflers could be added for reduced noise although top end reduction estimate of about 50 horsepower may occur for any type of baffled mufflers
manifold:
>>> stack type: 2.75 dia. or more throttles, ram tube length for 5,000 to 8,000 RPM range
>>> tunnel ram with Enderle hat, Hilborn, or two Alkydigger Assassinator throttle bodies with an air scoop
>>> single plane, largest volume runners with Alkydigger throttle body with air scoop.
This engine can be assembled for around $6,000 to $11,000 with mostly new and premium used parts. It would be almost street-able with an automatic transmission & high stall speed torque converter. Although it would have very high fuel consumption and not emissions compliant in many parts of the world. The main bypass would need to be adjusted for different air densities.
Intake & Fuel System
Racing mechanical fuel injection ProCalc analysis for normally aspirated 450 ci V-8:
at 95% air density, about 800 HP at 7,500 RPM
fuel pump: approx 4.9 GPM at 4,000 pump RPM; 8,000 engine RPM; RONs, Enderle, or Hilborn -1/2 size fuel pump
nozzles: 0.030 inch dia; more nozzles size info in our Jetting Big Block book
main bypass at 0.085 inches for air density around 95%
torque peak at 5,000 RPM
volumetric efficiency at torque peak: 103%
air to fuel ratio at torque peak: approx. 4.8 to 1
fuel pressure at 5,000 launch RPM: approx. 55 psi
high speed bypass poppet or diaphragm valve recommended opening RPM: 5,800
fuel pressure at 5,800 RPM: 74 psi
high speed bypass poppet or diaphragm valve pressure setting: 74 psi
high speed bypass jet size: 0.060 inch dia
volumetric efficiency at horsepower peak: 90%
air to fuel ratio at horsepower peak: 5.2 to 1
horsepower peak: approx 7,500 RPM
fuel pressure at 7,500 RPM with high speed bypass open: 79 psi
fuel to the engine: 1.84 gallons per minute; 110 gal/hour; 729 #/hour (methanol) with above fuel pump and jetting combo for 95% air density
brake specific fuel consumption: 1.1 pounds per horsepower per hour
for dragster or altered weight: 1,750 pounds, 1/4 mile ET: 7.6 seconds; 1/8 mile ET: 4.86 seconds; quarter mile speed: 180 MPH; eighth mile speed: 144 MPH at 95% air density.
Same setup at lower air density; all the same except:
at 90% air density, about 760 HP at 7,500 RPM
main bypass: 0.090 inch dia
the high speed bypass poppet or diaphragm valve opening pressure: 66 psi to maintain a 5,800 RPM opening point
fuel to the engine: 1.75 gallons per minute; 105 gal/hour; 693 #/hour (methanol)
brake specific fuel consumption: 1.1 pounds per horsepower per hour
for dragster weight of 1,750 pounds, quarter mile ET: 7.7 seconds; eighth mile ET: 4.93 seconds; quarter mile speed: 177 MPH; eighth mile speed: 142 MPH at 90% air density.
Note the following recommendations for different conditions:
for higher air density, run a smaller main bypass to maintain the air to fuel ratio and brake specific fuel consumption for best power; however, that will raise the fuel pressure; without adjustment, that will cause the high speed bypass to open at a lower RPM; that will cause the engine go lean at the top end; engine damage could occur as a result; instead, the high speed bypass opening pressure needs to be adjusted to a higher value to maintain the same opening RPM.
for lower air density, run a larger main bypass to maintain the same air to fuel ratio and brake specific fuel consumption for best power; however, that will lower the fuel pressure; without adjustment, that will cause the high speed bypass to open at a higher RPM; that will cause the engine go rich at the top end; power may be way down as a result; instead, the high speed bypass opening pressure needs to be adjusted to a lower opening pressure to maintain the same opening RPM.
our ProCalc fuel injection jetting calculator can determine the appropriate pressure settings for different air densities and different main bypass jet sizes.
at high altitude race tracks, the nozzles need to be changed to smaller ones to keep fuel pressure up; with the appropriate main bypass, the same fuel curve can be maintained for any altitude; horsepower will be the best for that altitude, but it would be lower as the altitude goes up, decreasing the air density.
our ProCalc calculator can be used to determine the best nozzle size change for higher altitudes.
our ProTune and ProTune Advance services can provide further analysis and training for setting up the calculator for most specific fuel injection and engine combinations.
Ram Air Effects w/o High Speed Bypass
Add to that considerations for ram air effects at high speed. For racecars or boats that exceed 150 MPH with forward mounted hat throttle bodies or air scoops facing the air flow, ram air will add more air into the inlet. Jetting may need adjustment for ram air provisions such as a smaller high speed bypass for high speed operation. More information about ram air gains is in our High HP Tuning book.