KJ Jonesx
February 21, 2014

On the Dyno

Nothing beats doubling a Fox ‘Stang's 200 baseline horsepower, especially with a power-adder that looks as sexy as CXRacing's twin-turbo package!

Greg Montoya's EFI'd '84 coupe came to us with a fairly fresh 306 that put out 215 horses in its baseline evaluation on the chassis dyno. After installing CX's twin turbos, peak power climbed to more than 402 horsepower, with just as much torque (in lb-ft) at the rear wheels, with boost limited to only 8 psi.

"This combination can definitely make 30-40 more horsepower with a lock-up torque converter and bigger fuel injectors," said Addiction Motorsports tuner Eddie Rios. "We would see even more if the kit was installed on a Mustang with a manual transmission. So much more, we would have to consider where to limit power because the engine is based on a stock block. I like the way this turbo system is made, its price is perfect, and it definitely makes good boost."

We agree with Eddie's sentiments, especially when the overall price is taken into account. The total for a CXRacing twin-turbo kit and Holley's Dominator EFI is roughly the same price as many other Fox turbo systems—single or twins—by themselves. However, we must note, using Dominator actually is a bit of overkill—Holley's HP EFI is a perfect alternative to the big ECU, as it has many of the same features and capabilities [datalogger, boost controller], yet is priced approximately $750 cheaper because it does not control electronic transmissions and only has one wideband O2 input.

Baseline CXRacing Difference
RPM Power Torque Power Torque Power Torque
3,800 122.90 170.40 168.65 233.03 45.75 62.63
3,900 142.40 192.30 183.46 247.01 41.06 54.71
4,000 167.50 219.30 198.49 260.57 30.99 41.27
4,100 177.80 227.10 213.66 273.64 35.86 46.54
4,200 182.60 227.90 229.96 287.49 47.36 59.59
4,300 186.60 227.90 247.28 301.94 60.68 74.04
4,400 189.20 225.20 264.76 315.92 75.56 90.72
4,500 192.00 223.20 282.69 329.82 90.69 106.62
4,600 193.60 220.60 301.11 343.70 107.51 123.10
4,700 195.80 218.00 319.16 356.57 123.36 138.57
4,800 200.70 218.00 336.93 368.61 136.23 150.61
4,900 204.10 218.10 355.28 380.77 151.18 162.67
5,000 208.50 217.80 374.46 393.33 165.96 175.53
5,100 210.50 216.70 391.41 403.08 180.91 186.38
5,200 212.50 214.10 397.36 401.34 184.86 187.24
5,300 213.70 210.90 400.07 396.46 186.37 185.56
5,400 215.00 208.10 402.77 391.74 187.77 183.64
5,500 215.60 204.70 399.76 381.74 184.16 177.04
5,600 214.10 199.80 393.27 368.84 179.17 169.04
5,700 211.90 194.40 390.99 360.26 179.09 165.86
5,800 209.90 189.60 393.32 356.17 183.42 166.57
5,900 202.10 180.10 390.50 347.62 188.40 167.52
6,000 198.20 175.90 376.37 329.45 178.17 153.55

Our friend Eddie Rios of Addiction Motorsports is well-versed in tuning blown and turbocharged Mustangs with stand-alone engine-management systems. In a short time, Eddie has become quite proficient with Holley’s new Dominator EFI. After strapping Greg’s ’84 coupe on the Dynojet chassis dyno, Eddie took a moment to survey CXRacing’s twin-turbo layout.
Greg installed the Dominator ECU (PN 554-114; $1,744), as well as its associated harnesses (main power, universal main MPFI, V-8 injector and Ford TFI ignition), sensors, and such right in his driveway. Using the system’s pre-programmed calibration for a 5.0/turbo combination as a baseline, Greg had the engine fired and running well enough for moderate-throttle and light-boost drives around his neighborhood shortly after wiring the ECU, programming target air/fuel parameters, and allowing Dominator’s self-learning function to do its thing.
Fine-tuning the 306 involved Eddie shutting off the self-learn function, transferring its calibration data to the main fuel table, and then modifying fuel settings in stages, to eventually achieve a safe air/fuel ratio at WOT. The program’s base timing advance is 20 degrees, which actually proved to be a bit too much for our setup. By taking 4 degrees of timing out of the low range and 2 at the top of the rpm window, Eddie was able to achieve air/fuel ratios of 13.5 at idle, 12.0 at 2 psi, and the desired 11.5-11.7 from 4-to-8 psi of boost.
“The Dominator EFI’s self-learning actually does a great job,” Eddie says. “I really like the system’s 3D function, which allows fuel-table changes to be made directly from the grid and on the fly. I didn’t really have to do a lot of building off of the baseline for the WOT tune, but the system is really intuitive and does cover every area associated with tuning a boosted application and making it run well.”
With engine temps anticipated to be higher than normal with the turbos, Greg added a Flex-a-lite 180 Black Magic Xtreme Series electric fan that blows at a rate of 3,300 cfm.
The fan proved to be a perfect upgrade, as the Pony’s coolant remained at a steady 190 degrees throughout the dyno session.
And here is the fully completed turbo project, with the EFI system’s harnesses and sensors installed, and completed with Kevlar covers for the turbochargers’ turbine housings and K&N filters to protect the compressor wheels.
We really like the stealthiness of this setup, which only emits a low murmur when the engine is at idle or low, street-cruising rpm.
The fuel-injector dilemma answered our question as to why we did not see more power from, and a higher rpm plateau for the twin-turbocharged engine. A fix is in the works; exchanging the 42-pounders for 60-lb/hr squirters, which we’re sure will then make being mindful of the stock block a bigger concern.
You can’t beat a dyno graph that looks like this, with rear-wheel horsepower and torque practically mirroring each other throughout the entire run. We attribute the breakup at the top of the run to two things—the coupe’s loose, non-lock-up torque converter, and also the fact that the engine is equipped with only 42-lb/hr fuel injectors. While we don’t have the graph, the 400 horsepower and 403 lb-ft of torque are considerably more than the engine pumped out in its naturally aspirated form (215.6 hp at 5,500/227.9 lb-ft at 4,300).