The Case IH STX425QT Quadtrac tractor engine horsepower is 425 hp | 316.9 kW, and PTO horsepower is 370 hp | 275.9 kW.
Engine HP425 hp | 316.9 kW
PTO HP370 hp | 275.9 kW
PTO Transfer87.1%
Torque1594 lb-ft | 2161.5 Nm
Displacement915 ci | 15.0 L
Case IH STX425QT Quadtrac Horsepower Specs
Engine horsepower
425 hp | 316.9 kW
PTO horsepower claimed
370 hp | 275.9 kW
Case IH STX425QT Quadtrac Useful Horsepower Calculations
PTO-to-engine power transfer
87.1% of engine hp reaches the PTO
Engine size per PTO horsepower
2.5 ci per PTO hp
PTO horsepower per liter
24.7 PTO hp per L
Engine size per engine horsepower
2.2 ci per engine hp
Engine horsepower per liter
28.3 engine hp per L
Torque per PTO horsepower
4.3 lb-ft per PTO hp
Rated speed per PTO horsepower
5.4 rpm per PTO hp
Case IH STX425QT Quadtrac Engine Specs
Engine type
turbocharged aftercooled diesel
Displacement
915 ci | 15.0 L
Bore and stroke
5.39×6.65 inches | 137 x 169 mm
Rated RPM
2000
Torque
1594 lb-ft | 2161.5 Nm
Torque RPM
1400
Case IH STX425QT Quadtrac Fuel, Cooling, Starting & Service Specs
Starter volts
12
Battery volts
12
Case IH STX425QT Quadtrac Horsepower Comparison Charts
Engine horsepower comparison
This model
425 hp
Average
210 hp
Low
120 hp
High
380 hp
PTO horsepower comparison
This model
370 hp
Average
175 hp
Low
100 hp
High
320 hp
Displacement comparison
This model
915 ci
Average
520 ci
Low
360 ci
High
750 ci
Torque comparison
This model
1,594 lb-ft
Average
700 lb-ft
Low
350 lb-ft
High
1,250 lb-ft
Rated RPM comparison
This model
2,000 rpm
Average
2,100 rpm
Low
1,600 rpm
High
2,500 rpm
Engine size per PTO HP
This model
2.5 ci/hp
Average
3.3 ci/hp
Low
2 ci/hp
High
5.2 ci/hp
Benchmarks use practical low, average and high ranges for the large ag tractor category. Use the operator manual and actual engine/tractor configuration before sizing implements or judging working power.
Case IH STX425QT Quadtrac Horsepower FAQ
How much horsepower does the Case IH STX425QT Quadtrac have?
The listed engine output is 425 hp, above the 210 hp benchmark average. That is a higher-power result, so ballast, tire setup and implement width matter if you want to use the full 425 hp.
How much PTO horsepower does the Case IH STX425QT Quadtrac have?
The listed PTO output is 370 hp, above the 175 hp benchmark average. That is the number to use for mowers, balers, augers, pumps and other PTO tools that need up to about 370 hp.
How much engine power reaches the PTO on the Case IH STX425QT Quadtrac?
The PTO-to-engine transfer works out to 87.1%, from 425 engine hp to 370 PTO hp. That is a normal usable range for judging PTO implement fit.
How big is the Case IH STX425QT Quadtrac engine?
The engine displacement is 915 ci, above the 520 ci benchmark average. Bigger displacement can help low-rpm pull and load-holding feel.
Is the Case IH STX425QT Quadtrac engine stressed for its PTO horsepower?
The engine has about 2.5 cubic inches per PTO hp, using 915 ci and 370 PTO hp. That is a smaller-displacement, higher-output style result.
How much PTO horsepower per liter does the Case IH STX425QT Quadtrac make?
The output density is about 24.7 PTO hp per liter, using 370 PTO hp and 15 L of displacement. Higher hp/L means more output squeezed from each liter; lower hp/L usually means a more relaxed engine tune.
How much torque does the Case IH STX425QT Quadtrac have?
The listed torque is 1,594 lb-ft, above the 700 lb-ft benchmark average. The 1,594 lb-ft figure is useful for lugging, loader work and heavy PTO load recovery.
Does the Case IH STX425QT Quadtrac have good torque for its PTO horsepower?
The torque-to-PTO-power figure is about 4.3 lb-ft per PTO hp, using 1,594 lb-ft and 370 PTO hp. A higher number usually points to a slower, gruntier working feel.
What rpm is the Case IH STX425QT Quadtrac rated at?
The rated speed is 2,000 rpm, close to the 2,100 rpm benchmark average. The 2,000 rpm figure is around normal for this class.
Official information note
Horsepower and engine specs can vary by year, market, engine option, fuel system, test standard and tractor configuration. Check the operator manual, spec plate, parts book and official caseih.com website before buying parts, sizing implements or making repair decisions.
