The Dyno

On the COBB Tuning SoCal Mustang dynamometer, we established the EVO’s baseline horsepower figures at 335 horsepower and 337 lb-ft of torque. With the COBB AP taking control over the factory boost solenoid, maximum boost pressure reached was 27 psi.

335 WHP
337 LB-FT TQ

Test 1: Cosworth Intercooler Kit + Pipe Kit

After a cool-down period, we installed the Cosworth front-mount intercooler and intercooler piping kit. We opted to install both systems at the same time as either half of the upgraded intercooler system tested separately might not show any significant changes in power production or reveal any shifting of the powerband. In spite of having to remove the front bumper to install the front-mounted intercooler, the installation went without a hitch as described in the instructions. The intercooler hard pipes were also constructed in such a manner as to be direct replacements for the factory rubber units. After some tuning by John Drenas, the complete Cosworth intercooler core and pipe kits demonstrated healthy power increases in the lower RPM range and nominal increases at the upper end of the spectrum. Maximum changes in torque occurred at the start of the powerband, increasing as much as 10-to- 12 lb-ft that slowly tapered to redline. Maximum boost level was still held at 27 psi, making the peak 337 horsepower and 346 lb-ft of torque a direct result of the intercooler and piping.

337 WHP
346 LB-FT TQ

The larger intercooler core and pipe diameters allow a greater amount of flow without boost pressure loss or excessive turbo lag. At a constant 27 psi of boost, the intercooler upgrade was good for 9 lb-ft of torque and a peak increase of 2 horsepower.

Test 2: TOMEI Powered Downpipe

With the EVO back on the lift, we then installed the TOMEI Powered 3-inch downpipe. Thanks to the design of the outlet flange and collector bowl, the TOMEI Powered unit was also relatively easy to install. Back on the Mustang dynamometer, we took great care to re-tune the car with the downpipe in place. As large-diameter aftermarket downpipes tend to promote excessive boost levels by simply being installed, Drenas carefully re-tuned the fuel and ignition maps through the COBB AP while eyeing peak boost levels. After ensuring that peak boost pressures never surpassed the 27psi mark, the maps were finalized and the downpipe turned in peak numbers of 344 horsepower and 375 lb-ft of torque. What’s more important is the upward shift of the powerband on the order of 20-to-25 horsepower and the corresponding torque increases as much as 30 lb-ft. The bulk of the increased torque occurs in the low-to-mid range of the powerband indicating the car will feel much faster than the numbers alone would indicate.

344 WHP
375 LB-FT TQ

The stainless steel TOMEI POWERED downpipe offered a peak increase of 7 horsepower and almost 30 lb-ft of torque. Additionally, the COBB AccessPort was called upon to ensure boost levels didn’t creep past the 27 psi limit.