Project Dodge SRT-4 - Tech Project

Nineteen sixty-four Pontiac GTO, 1962 Chevy Impala SS 409, 1969 Chevy Camaro, 1970 Plymouth AAR Cuda, 2003 Dodge SRT-4-musclecars, every one.

Dodge reinvented the classic formula for performance last year when it crammed a huge engine in a small body and created the SRT-4-the baddest, boosted, burnout machine to be had under 20 large. It handily won our Tough Crowd comparison test (January 2003) with its combination of huge power, admirable handling and stop-right-now brakes, and when the contest was over, we knew we had to have one.

Then we figured if we were going to be driving around in the modern incarnation of a classic musclecar, it might as well look the part. Enter Santini Paint and Body in Westminster, Calif., known to street rod and musclecar goofs across So.Cal. as the place to find flames for their Mustang or pinstripes for their GTO. Turns out, Pete Santini does a pretty good job turning the Neon's modern soap bar styling into a tribute to the 1970 Plymouth AAR Cuda. Santini and the vinyl artists at Permanent Impressions in Huntington Beach, Calif., are responsible for our little homage to Dan Gurney's '70s repli-racer.

For those of you born after Elvis got really fat and really dead, the AAR Cuda was a production-car version of the Cuda Dan Gurney and his All-American Racer team raced in the SCCA Trans Am series. Built to compete with the Z28 Camaro and Boss 302 Mustang on the street and on the track, the AAR Cuda and its basic twin, the Dodge Challenger T/A, were built and sold only one year, 1970. They each had a unique look that included a black hood with hoodscoop, multiple spoilers, side exhaust and striping. And both were the only Mopars ever powered by the 340 cubic inch Six Pack engine-which means it had three two-barrel carburetors. In 1970, the AAR Cuda was as close to a Trans Am racer as you could get without actually being Dan Gurney.

The SRT-4's newfound styling sets the direction for this project: Fast and cheap. The SRT-4 will follow a straightforward upgrade path made available through Mopar. Divided into three stages of engine mods, Mopar's designs on making the SRT-4 more powerful are easy. Mopar also offers a coil-over kit and a few other gizmos we'll install throughout the project. But the in-house Dodge shop certainly isn't the only company interested in the SRT-4's potential. We'll test multiple wheel and tire packages, as well as at least one aftermarket brake kit.

Mopar Stage One
There are few other places in the aftermarket where you'll find this much power and torque for this little money. The Stage One retail price is $399, but we're told the street price is closer to $330. Mopar rates the Stage One kit at 240 hp and 260 lb-ft of torque. However, as we've already experienced with the SRT-4, these are conservative numbers. With Stage One installed, our car made exactly those numbers at the wheels. The peak torque increase isn't huge; however, there is a 10 lb-ft gain throughout most of the midrange.

Our project car in stock form was slightly stronger than previous SRT-4s we've tested, making 227 hp and 256 lb-ft of torque right out of the box. This dyno test was performed with the car still full of Michigan fuel. All other SRT-4s we've tested have used California's notoriously low-octane fuel.

The Stage One ECU includes several unusual calibration changes. Along with the usual higher boost at partial and wide-open throttle, the calibration geeks at Mopar programmed in a boost hold feature during wide-open throttle shifts. This allows the wastegate duty cycle to remain constant while the clutch is depressed as long as the engine isn't on the rev limiter, maintaining boost into the next gear. Boost is also higher in first gear for harder launches and the deceleration exhaust note is more aggressive.

Perhaps the most obvious change in driving the car comes from improved boost response, thanks to a slightly higher overrun of the boost target. This translates to less throttle opening for more boost relative to the stock calibration.

It took only a few hours to install the Stage One kit, which consists of four 577 cc/min. (at 58 psi) fuel injectors and an upgraded ECU. PVO engineers tell us it can be done in half an hour, but we suspect they've done it a few more times than we have. Regardless, it's simple. We also installed the Mopar's blow-off valve spacer, which isn't included with the other Stage One goodies. The spacer turns the stock compressor bypass valve, which reroutes discharged boost back into the turbo, into a blow-off valve that dumps it out into the world. This gives the characteristic purge sound sought after by so many rice boys. We like it. But installing it isn't easy and it added significantly to the install time.

The instructions for Stage One installation weren't yet written when we put the kit on our car, but it's simple enough that we managed the job without problems. Still, following the directions in the kit is advisable. After removing the plastic engine cover, the first step is to bleed the pressure in the fuel system through the valve at the end of the fuel rail. We did this with a screwdriver. To remove the rail from the injectors, you must remove the retaining clips, which hold them together.

Be careful when removing and replacing the injectors to not drop anything into the open hole in the intake manifold. We found that the shape of the manifold causes debris to build near the hole, making it easy to push gunk into the engine when installing the new injectors. The instructions, if we had them, would have told us to blow this debris away before removing the injectors. Instead, we removed the debris by fishing around the hole with some grease on the end of a welding rod.

Before removing the ECU, be sure to disconnect the battery. This will ensure that any errant electrons are stopped before they destroy the ECU's sensitive electronics. Swapping ECUs is simple as long as the harness plugs go back in the same location they were in from the factory. That's pretty tough to screw up, but we found ourselves trying to do it at least once. The only other tricky part of this operation is re-installing the ECU with the self-tapping screws that hold it to its mounting bracket. Seeing that the ECU's mounting holes weren't tapped, we stopped to buy a tap. Only later did we find out the fasteners are designed to thread their way through the soft metal of ECU casing without damage. Oh, well.

With the ECU installed, it was a simple matter of reconnecting the battery, building fuel pressure and firing up the engine. If only every mod were this simple.