January 15, 2010

Horse Sense:
Paul Svinicki reports that swapping on the CMRC delete kit without making the necessary revisions to Spanish Oak programming will cause an immediate 22 to 24hp loss at the wheels. By any name, the CMRC contraption consists of what looks like partial throttle plates stuck in each intake runner path. The pivoting flappers are processor-controlled, closing off all but a small portal to accelerate and tumble incoming air at low rpm, and then swinging wide open as the engine's demand for oxygen increases. The problem is they seem to block ultimate airflow and therefore rob power, much as the similar functioning Intake Manifold Runner Control plates did on Four-Valve Cobra engines

Among the new bells and whistles appended to every Three-Valve modular are Charge-Motion Runner Controls wedged between the '05 GT's intake manifold and cylinder heads, you may also hear them generically described as "tumble plates" in recognition of their job of speeding up and inducing a tumbling motion into air bound for the combustion chambers at light throttle openings. This is said to help homogenize the air/fuel mixture for thorough and squeaky-clean combustion at idle and just off-idle.

By any name, the CMRC contraption consists of what looks like partial throttle plates stuck in each intake runner path. The pivoting flappers are processor-controlled, closing off all but a small portal to accelerate and tumble incoming air at low rpm, and then swinging wide open as the engine's demand for oxygen increases. That's the theory anyway. The problem is they seem to block ultimate airflow and therefore rob power, much as the similar functioning Intake Manifold Runner Control plates did on Four-Valve Cobra engines.

The aftermarket solution is also the same as in the case of the IMRCs: Get rid of 'em. The Paul's High Performance CMRC-delete kit we're installing here is affordable, produces a generous horsepower and torque boost on the PHP Dynojet, and is straightforward to install, as will be seen via the accompanying photos. Beware, however, that the GT's super-sensitive Spanish Oak processor must be recalibrated to take advantage of the revised airflow characteristics, and to avoid the pesky old Check Engine light, driveability hiccups, a significant power loss and, says Paul, the eventual decision by the all-powerful Spanish Oak to go into "fail-safe" mode wherein the engine will spin no higher than 3,800 rpm.

Paul developed a specific tune to accompany the CMRC delete kit and strongly recommends you get both as a package deal, but will sell the delete hardware alone for those who have a qualified tuner in the neighborhood.

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Tales from the Dyno

  Baseline CMRC Eliminators Difference
RPM POWER TORQUE POWER TORQUE POWER TORQUE
2,500 126.8 266.4 132.3 278.0 5.5 11.6
2,600 133.6 269.9 139.6 281.9 6.0 12.0
2,700 140.8 273.8 146.5 285.0 5.7 11.2
2,800 146.3 274.4 151.7 284.6 5.4 10.2
2,900 150.5 272.6 155.9 282.3 5.4 9.7
3,000 155.3 271.9 160.8 281.5 5.5 9.6
3,100 160.4 271.8 166.3 281.8 5.9 10.0
3,200 166.0 272.5 172.9 283.7 6.9 11.2
3,300 172.2 274.0 181.6 289.0 9.4 15.0
3,400 180.1 278.3 191.5 295.8 11.4 17.5
3,500 189.3 284.1 200.2 300.5 10.9 16.4
3,600 197.1 287.5 207.0 302.0 9.9 14.5
3,700 204.3 290.1 214.6 304.6 10.3 14.5
3,800 213.5 295.1 223.3 308.6 9.8 13.5
3,900 221.4 298.1 231.1 311.2 9.7 13.1
4,000 229.7 301.6 239.8 314.9 10.1 13.3
4,100 239.3 306.5 249.0 318.9 9.7 12.4
4,200 248.1 310.2 257.3 321.7 9.2 11.5
4,300 255.1 311.6 263.4 321.8 8.3 10.2
4,400 260.1 310.5 268.2 320.2 8.1 9.7
4,500 264.5 308.7 272.8 318.4 8.3 9.7
4,600 269.2 307.4 277.5 316.8 8.3 9.4
4,700 274.2 306.5 282.6 315.8 8.4 9.3

4,800 279.3 305.6 288.1 315.2 8.8 9.6
4,900 284.4 304.8 292.8 313.9 8.4 9.1
5,000 288.2 302.8 296.5 311.4 8.3 8.6
5,100 290.3 299.0 297.9 306.8 7.6 7.8
5,200 291.1 294.1 298.1 301.1 7.0 7.0
5,300 290.6 288.0 297.4 294.7 6.8 6.7
5,400 289.9 282.0 297.3 289.2 7.4 7.2
5,500 288.6 275.6 296.9 283.5 8.3 7.9
5,600 287.0 269.2 296.1 277.7 9.1 8.5
5,700 285.9 263.4 295.8 272.6 9.9 9.2
5,800 287.1 260.0 296.6 268.6 9.5 8.6
5,900 289.1 257.4 299.0 266.1 9.9 8.7
6,000 290.8 254.5 301.0 263.5 10.2 9.0
6,100 291.4 250.9 301.4 259.5 10.0 8.6
6,200 291.7 247.1 300.1 254.2 8.4 7.1
6,300 289.7 241.5 297.1 247.7 7.4 6.2
6,400 285.7 234.4 292.9 240.4 7.2 6.0
6,500 280.3 226.5 287.3 232.1 7.0 5.6
6,600 274.7 218.6 281.7 224.2 7.0 5.6
6,700 268.3 210.3 275.6 216.0 7.3 5.7
6,800 264.4 204.2 269.8 208.4 5.4 4.2

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