144.56 mph vs. 147.54 mph in the 1/2 mile.
Stock 2015 Challenger SRT Hellcat, automatic. Independent test of the Legmaker vs. Stock Intake. 93 octane, 10% ethanol.
5th gear dyno from 2590 to 6100 rpm
Average total power under curve gain of 9.1 rwhp / 8.7 rwtq
The decision to purchase the modification depends on your goals:
- to pursue quicker 1/4mi times (+1 mph, 0.1 sec)
- to increase engine power (at least average +9 rwhp across the total RPM)
- to hear a louder whine from the engine
- to draw attention to your Hellcat (impressively loud on acceleration)
- to improve underhood appearance
- to subdue the "mod bug" bite
Stock with lower intake temperatures and higher coolant temperatures than Legmaker
1st-5th gear (calculated 1/4mi to ~125mph)
3.70% increase total rwhp / 3.25% increase total rwtq
Average total power under curve gain of 9.5 rwhp / 9.5 rwtq
Inlet Temperature Considerations (calculated stock to 95.0 deg F)
Average gain of the LMI could be calculated as 16.8 rwhp / 13.7 rwtq.
If the stock dyno inlet temperature was the same 95 deg F as the LMI testing temperature, the average gain of the LMI would be higher. The two dynos for stock show that, for every 3.6 deg F change in inlet temp, there is an average 5.2 rwhp / 3.3 rwtq difference.
This also shows that it only takes a 12.6 deg F difference to have a negative effect over stock.
Testing Standard Conditions (at the start of each dyno run):
- J1349 standard reference (1.1684 kg/m^3 air density; 29.53 inHg - 100 kPa; 77 deg F)
- J1349 standard reference Inlet Air Temp at 77 deg F with variance between 56 - 95 deg F
- J1349 standard reference coolant temp between 165.6 and 240.4 deg F (+/- 37.4 deg F of 203 deg F operating temperature value)
- Inlet Air Temperature (MAF sensor reading) was 89.6 deg F (stock) and 95.0 deg F (Legmaker)
- Coolant Temperature was 204.8 deg F (stock) and 203.0 deg F (Legmaker)
- Air Charge Temperature was 134.6 deg F (stock) and 132.8 deg F (Legmaker)
- Intercooler Temperature was 78 deg F for stock and 80 deg F (Legmaker)
- Oil Temperature was between 180-185 deg F.
- 5th gear for automatic Hellcat transmission (6th 1:1 runs the dyno too high)
- 0 graph smoothing for most accurate raw data results.
- SAE correction value applied to results.
Total Horsepower/torque area under the curve with gearing applied:
HP Total Area under curve: 2.9% increase
Stock 1710.584 vs. LMI HP Area: 1761.782 (+51.198)
TQ Total Area under curve: 2.5% increase
Stock 2094.184 vs. LMI TQ Area: 2148.579 (+54.395)
1st-5th gear (calculated 1/4mi to 125mph)
3.70% increase total RWHP / 3.25% increase total RWTQ
Increase total 9.48 RWHP / 9.54 RWTQ
Baseline drivetrain loss estimations:
HP to rwhp 0.9038; TQ to rwtq 0.9415
Dyno Measured / Rated Stock output
639 rwhp @ 6000 rpm / 707 hp @ 6000 rpm (0.9038 drivetrain loss)
612 rwtq @ 4800 rpm / 650 tq @ 4800 rpm (0.9415 drivetrain loss)
2015-2016 Legmaker Hellcat Intake. The pre-filter was not used during testing.
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