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Discussion Starter #1 (Edited)
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Stock (White) vs. Stock w/ Legmaker (Red) Hellcats.
144.56 mph vs. 147.54 mph in the 1/2 mile.

Summary:

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

Your Goals
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

Smoothing 0
LMI vs. Stock - Final.png


Smoothing 5


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Stock with lower intake temperatures and higher coolant temperatures than Legmaker

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Calculated estimations:
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.

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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:
5th Gear:

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)
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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

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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)

Legmaker Product:

2015-2016 Legmaker Hellcat Intake. The pre-filter was not used during testing.

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References
Kenne Bell Air Temperature Testing - IAT's Air Temperature Testing Supercharger Kits. The 13 Variables | Kenne Bell
 

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DRIVESRT.COM
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Discussion Starter #3

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Great info, write-up, and thread, Ray!

I can't wait until we start using calculus to really understand the area under the curve how much much total HP we can gain/lose across the entire rpm range when we change our configurations. One day....
 

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DRIVESRT.COM
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Discussion Starter #7
Great info, write-up, and thread, Ray!

I can't wait until we start using calculus to really understand the area under the curve how much much total HP we can gain/lose across the entire rpm range when we change our configurations. One day....
Luckily, Excel has a way to calculate the area under the curve for each:

Stock HP Area: 1710.584
Stock TQ Area: 2094.184
LMI HP Area: 1761.782
LMI TQ Area: 2148.579

LMI vs Stock HP Area: 51.198
LMI vs Stock TQ Area: 54.395
 

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Premium Member
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Luckily, Excel has a way to calculate the area under the curve for each:

Stock HP Area: 1710.584
Stock TQ Area: 2094.184
LMI HP Area: 1761.782
LMI TQ Area: 2148.579

LMI vs Stock HP Area: 51.198
LMI vs Stock TQ Area: 54.395

It's a good thing too, I'd hate to derive the polynomial for a horsepower curve... :oops:
 

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Vendor
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What does, "The pre-filter was not used during testing". What's a pre-filter?
Thank you
LMI supplies a water repellent pre-filter "sock" that goes over the filter to keep any moisture off the filter pleats when driving in inclement weather. The rain shield that is also supplied with the kit keeps water from hitting the filter from the open hood vent, but when driving in the rain, water can still enter from the front inlet area. The pre filter will be a bit of a restriction that may or may not alter the data.
 

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Luckily, Excel has a way to calculate the area under the curve for each:

Stock HP Area: 1710.584
Stock TQ Area: 2094.184
LMI HP Area: 1761.782
LMI TQ Area: 2148.579

LMI vs Stock HP Area: 51.198
LMI vs Stock TQ Area: 54.395
Outstanding job of providing the board with great info, I am convinced it would be a good investment.
 

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DRIVESRT.COM
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Discussion Starter #20
Great info, write-up, and thread, Ray!

I can't wait until we start using calculus to really understand the area under the curve how much much total HP we can gain/lose across the entire rpm range when we change our configurations. One day....
PlumCrzyHellcat Thank you for mentioning this. It is much easier to see the total gain that way.
 
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