Factory Hot Rods: SRT-4 Extreme Lightweight
November 2004

2004 Dodge Srt4 Rear Left View

After our test the SRT-4 Lightweight went back to Michigan, where DaimlerChrysler engineers slapped on drag slicks and ran one 11.83-second pass at 123 mph in 70-degree weather

This much power has no place driving the front wheels of anything on a road course. Was it impressive? Absolutely. Was it fast? Unquestionably. Was it balanced and predictable? Well, not really. But it was one hell of a lot of fun. Turn the Lightweight into a corner and it responds instantly--just like you'd expect of a car with this much rubber and significant spring rates.

Trouble is, when you get into the gas at corner exit, the Lightweight cooks both its front tires so severely it refuses to change direction at the next corner. It's entertaining and terrifying all at once, really. The only hope is to balance the throttle against the brakes with your left foot at corner exit to quell the Lightweight's instant boost response and keep power delivery to the front wheels in check. Luckily, there's a set of gigantic Stoptech brakes up front to handle the task.

Keep this brake/throttle tug of war up in the 100-degree heat of the California desert for very long and the Lightweight turns itself into a hugely destructive mass of thermal and kinetic energy, But still, it's a hugely entertaining mass of energy.

Not so surprisingly, driving the Lightweight is a lot of work. Both feet are constantly busy with the pedals, your arms are fighting against 383 lb-ft of torque fed through the Quaife limited-slip differential and your neck is balancing your head against the loads created by sticky Michelins and massive power. The only saving grace is there's not much shifting required to keep the beast on boil, as the Lightweight produces a minimum of 360 lb-ft of torque between 3000 and 5000 rpm. Still, its lap time of 1:30:35 was more than 6 seconds quicker than the stock SRT could manage and was by far the quickest of the day.


When it comes to driving there's really no similarity to the stock SRT-4. The Lightweight is in its own freakishly overpowered world. The stock SRT-4 is soft, quick and relatively civilized. The brakes on the stock SRT-4 are the first component to suffer on the track. Within a few laps, the pedal softens and the rear wheels begin to hop under heavy braking. The Stoptechs on the front of the Lightweight work flawlessly, producing consistent pedal feel stop after stop.

The Lightweight has impressive ride quality for a car this hard-core, but that's where the civility ends. It's brutally fast, smells of race fuel and feels like a submarine inside. And we really mean brutally fast. It recorded among the quickest zero-to-100 times we've ever seen at 9.6 seconds--beaten only by all-wheel-drive cars.


It's this straight-line acceleration where the Lightweight really shines. Obviously, it has difficulty putting power down off the line, but once it's hooked up we can't think of anything that crushed us into the seat with such authority. It took BFGoodrich drag radials to produce the 12.5-second quarter-mile time we mentioned earlier. They were used in conjunction with the dial-a-boost set to the second setting, which is designed for use with drag radials and limits boost in first gear.

Amazingly, all that power comes from a stock SRT-4 engine and cooling system fitted with Mopar's Stage 3R upgrade and utilizing the Stage 2 turbo toys. The only other engine mod is the side-exit 2.5-inch exhaust. That's it. Get yourself a Stage 3R, some 100-octane fuel and make 369 hp to the wheels. Don't expect the rest of the Lightweight to be so easy to duplicate.


A big part of the speed here is courtesy of the unobtainable Mopar diet. A small crew of fabricators and engineers were responsible for finishing this car for the SEMA show in 2003 and had plenty of DaimlerChrysler resources at their disposal. O.E. levels of refinement are obvious in the quality of the final product. The doors, for example, look exactly like the stock doors inside and out--until you try to shut one and it doesn't have enough momentum to compress the seal and engage the lock mechanism. Body panels of this weight and quality are rare in the aftermarket.

The fact that a car can be this focused and still be driven normally is amazing. In fact, there's no reason this car couldn't have all the comforts of a real car re-installed and be driven daily. It's that good

Acceleration Lightweight Stock
Quarter-Mile Time: 12.5 sec. 14.0 sec.
Quarter-Mile Speed: 119.2 mph 101.6 mph
0-30 mph: 2.2 sec. 2.7 sec
0-60 mph: 4.7 sec. 6.0 sec.
0-100 mph: 9.6 sec. 14.1 sec
Slalom Speed (700-ft. slalom): 1.01g .87g
Lateral Grip (200-ft. skidpad): 74.9 mph 71.7 mph
Lap time: 1:30.35 1:36.45
60-0 stopping distance: 109 ft. 116 ft.
70-0 stopping distance: 149 ft. 156 ft.
80-0 stopping distance: 192 ft. 204 ft.