My car makes 295 hp on a Dynojet, but I lose about 20 hp on a Mustang." How many times have we heard this one? Do you really think horses are falling off your power curve as you drive to the Mustang dyno? The engine is making the same power, no matter the dyno, but the different dynos just read the power differently.
The Mission
The "Dyno Dash-AWD" will illustrate the variances between different dyno brands. We ran the same car on four different types of dynos on the same day, and the Dash, conducted in the Seattle area, enlisted the following shop/dyno entities: Fame Auto Service/Mustang, Pina Motorsports/Dyno Dynamics, Drift-Office/Dynojet and Speed Factory/Dynapack. A run made on English Racing's Dynojet a few weeks prior to the dash has been included as well.
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Dyno Dash - AWD
We asked to be treated as a typical customer coming in for a baseline. All testing procedures were left to each shop's dyno operator's discretion, including which gear to make the pull in and the amount of cool-down time between pulls.
We have denoted the time of arrival, time of first and last pull as well as the mileage between dynos to provide a chronological picture of how this "Dawn of the Dyno" day unfolded.
The Car
The star of the show is an '06 Mitsubishi EVO IX SE. It has been modified with a Buschur cone intake, TiTek Innovations Power Pipe (an 02 housing downpipe combination), a GReddy Ti-C exhaust system and a Hallman manual boost controller set to spike the turbo to about 25 psi. We saw max boost readings from 24.6-25.8 psi during the dash. The variation was likely due to how quickly the engine was brought up to speed on the dyno.
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Dyno Dash - AWD
The EVO rolls on Bridgestone Potenza RE-11 and Rota G-Force wheels. While supremely grippy yet quiet, there is a degree of relevancy of the tires in dyno testing since different tire circumference can possibly skew the comparability of back to back results.
Ready, Set, Go!
The dash started with an early morning ferry ride across Puget Sound and wind around the Seattle area. Dyno weather stations pegged air temperature at 61 degrees Fahrenheit in the morning and 58 degrees at my last stop. Relative humidity was between 65.4 and 74.9-percent, and the barometer ranged from 29.88-29.53 in-Hg during the dash, which is quite consistent. It was raining. All runs were made using SAE J1349 correction factors.
The Mustang, Dyno Dynamics and Dynojet units are eddy-current dynos that provide load via magnetic resistance (like a giant electric motor). In most eddy-current setups, metal windings are subjected to magnetic fields generated by variable-strength electromagnets.
Dynapack dynos are hydraulic-load dynos that use a hydraulic pump and an adjustable valve to dictate the pressure, i.e. resistance or load of the dyno.
Mustang: 292.7 WHP
Under its "DE" designation, Fame's dyno has dual eddy-current absorbers, which allow it to handle more power. Options include an air clutch and cooling fan. The Mustang-spec fan is rated at 5,000 cfm, but Fame has a collection of additional fans that can provide up to 30,000 cfm.
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Dyno Dash - AWD
Fame's dyno operator, Tim Hadfield, knows his Mustang inside and out and was quick to say trust is a key issue in any tuner/customer relationship. He went on to illustrate how dirty dynoers can sandbag results by preloading the rollers and/or changing the load between before and after runs to show nonexistent gains.
Shop
Fame Automotive/Dyno Authority
425-502-5850
www.fameautomotive.com
Time in: 8:58 am
Time of first pull: 9:19 am
Time of last pull: 9:27 am
Mileage from last dyno: N/A
Dyno: Mustang
Model: AWD 500DE
Type: Eddy current
Age: 10 years
Purchased: New
Software: MD 7000 V2.39
Options: Dual eddy, clutch, 5,000-cfm fan
Run 1: 284.6
Run 2: 297.6
Run 3: 296.0
Average: 292.7
Variance: 13.0 whp
Test gear: Third
Dyno Dynamics: 318.6 WHP
Pina's Double D has no options and the shop employs a Patterson fan rated at 7,500 cfm. The strap-down procedure was unique. Pina uses a leverage bar at the rear that runs tie-down straps over the lower control arms, then secures to the dyno deck. Owner Andre Santoso said the DD's twin-roller design is more stable than a single-roller design and the leverage bar provides less suspension bind, which translates into smoother runs. It also makes getting vehicles on and off the dyno a snap.
Shop
Pina Motorsports
253-872-9495
www.pinamotorsports.com
Time in: 11:04 am
Time of first pull: 11:42 am
Time of last pull: 11:52 am
Mileage from last dyno: 57.1 miles
Dyno: Dyno Dynamics
Model: AWD 450DS
Type: Eddy current
Age: 2 years
Purchased: New
Software: 7.1.4 4WD Release
Options: N/A
Run 1: 318.2
Run 2: 319.7
Run 3: 318.1
Average: 318.6
Variance: 1.6 whp
Test gear: Fourth
Dynojet: 312.52 WHP
Wideband 02 monitoring to plot air-fuel ratio and an Analog Module that displays certain parameters in gauge format on the computer screen during a run are among the optional fare on Drift-Office's DJ. There are two 5,000-cfm fans at the ready.
While at the "office," we decided to explore the difference between the two most popular correction factors: SAE versus STD (standard). The SAE factor uses an ambient temp of 77 degrees versus 60 for STD. Barometric pressure is rated at 29.23 in-Hg for SAE correction and 29.92 in-Hg for STD. Both assume dry air. Drift-Office's Bob W. related the biggest difference is the assumed air temperature, hence with its cooler temp STD-corrected runs plot power higher. In the case of our EVO IX, the STD runs returned 320.9, 320.3 and 322.3 whp while the SAE corrected runs showed 312.2, 311.7 and 313.7 whp, about eight more horsepower. It's worthwhile to note that some Dynojets can be operated in inertial mode as well as eddy-current mode, which might give different results. Inertial mode is where power is measured by calculating how fast a car can accelerate the roller drums, which are of a known mass. Some feel that power pulls in inertial mode are a better representation of real-world conditions in terms of how the engine is loaded. Older Dynojets and two-wheel-drive units are typically inertial dynos only and had been the aftermarket standard for measuring power in the old days.
Shop
Drift-Office
253-288-3888
www.drift-office.com
Time in: 12:31 pm
Time of first pull: 1:07 pm
Time of last pull: 1:26 pm
Mileage from last dyno: 11.4 miles
Dyno: Dynojet
Model: 424xLC2
Type: Eddy current
Age: 2 years
Purchased: New
Software: WinPEP-7
Run 1: 312.2
Run 2: 311.7
Run 3: 313.7
Average: 312.5
Variance: 2.0 whp
Test gear: Third
Dynapack: 324.4 WHP
Dynapack dynos are unique. Their power absorbers are hydraulic systems that are self contained in cabinets. They have no rollers, instead the vehicle is jacked up with its wheels removed and its hubs are fitted with an adapter that joins the car to each cabinet. The cabinets or pods can be easily wheeled around, making the Dynapack great for space-limited shops and a supremely portable dyno that can be taken trackside. An external water source is needed for keeping the hydraulics cool.
Speed Factory's James Kemps says his Dynapack 4022 is basically two sets of 2,000 pods joined at the hip, if you will, enabling all-wheel readouts. Two Dayton portable blowers, rated at 2,870-3,500 cfm, are on call to chill the radiator and FMIC.
Shop
Speed Factory
253-566-4331
www.speedfactory.com
Time in: 2:18 pm
Time of first pull: 2:36 pm
Time of last pull: 3:04 pm
Mileage from last dyno: 22.3 miles
Dyno: Dynapack
Model: 4022
Type: Hydraulic
Age: 6 years
Purchased: Used 1.5 years ago
Software: RAH-SP V1.3-02
Run 1: 324.9
Run 2: 327.1
Run 3: 321.4
Average: 324.4
Variance: 5.7 whp
Test gear: Fourth
Conclusion
All too often, ego is the driving force for those who strap their ride down on the rollers. Dynos are not about bragging rights, they're tools used to optimize the engine's performance and verify the effectiveness of parts that are added to the mix. Like a piece of lab equipment, the dyno allows precise monitoring of vital operating parameters to ensure proper air-fuel ratios and ignition timing.
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Dyno Dash - AWD
No matter what you do, variables are in play. The dyno operator can unknowingly affect the outcome. The abruptness of initial throttle input, how the dyno applies and ramps up resistance, and the gear used in our EVO can all affect how high the boost will spike, which in turn impacts how much it falls off later in the run. Our manual boost controller may also play a role in the run-to-run boost variance.
There is no right or wrong, no winners or losers to be named. The bottom line is to find a good tuner and use the same dyno as your project progresses. If you change dynos, re-baseline your car and focus on the improvements from that point on-not on the numeric differences between the dynos. The power number is not critical, it's the realized gains that are the pearl in the oyster.
Control Group Dyno
Our test car was flash-tuned by English Racing about two weeks before the dash. It was a hot, sunny day compared to the rainy dash day. To illustrate the variation from Dynojet to Dynojet, the last tuning run of the session is presented here with both SAE and STD correction factors.
Shop
English Racing
360-210-7484
www.englishracing.net
Dyno: Dynojet
Model: 424 LC
Type: Eddy current
Age: 1 month
Purchased: New
Software: WinPEP7
Options: Linx system that physically joins both rollers to better simulate load
SAE Run: 315.9
STD Run: 324.0
Test gear: Third
