Edmunds Inside Line - Full Test: 2008 Dodge Viper SRT-10 Coupe

Merc1 · 08-24-2007, 01:59 AM

Extreme Makeover: The 200-mph Edition

"Brute strength and awkwardness" is a phrase that we heard a lot while growing up at Dad's race shop. He used it to describe a powerful yet ill-handling machine; or, more often, the driving technique of a hero driver attempting to cope with one. Both definitions rattled around in our brain as we traveled to Virginia International Raceway (VIR) to drive the 2008 Dodge Viper SRT-10.

Consider the specifications: 600 horsepower (90 hp more than before) from an improved 8.4-liter V10; 200-mph top speed; and a front-engine, rear-wheel-drive chassis with no stability control.

My God, do they even make cars like that anymore?

Brute Strength? Check

The 2008 Dodge Viper SRT-10 isn't all-new, but the signature V10 lump under the hood is. Serious, meaningful changes have increased the V10's output and improved its fuel economy (and even its air emissions, too). And yes, it really is rated at 600 hp, which peaks at 6,100 rpm. Torque is up to 560 pound-feet at 5,000 rpm — as if this descendent of a truck engine didn't have enough torque already.

Stouter pistons and rods from Chrysler's popular 6.1-liter Hemi V8 have made possible a 1-millimeter increase in the V10's cylinder bore, swelling the displacement from 8.3 to 8.4 liters — a whopping 510 cubic inches.

A substantial increase in the compression ratio from 9.6:1 to 10.2:1 results from reworked combustion chambers. The fuel injectors now reside in the heads, close to the intake valves instead of farther upstream. Each spark plug now has its own coil. And a swinging pickup in the oil pan (borrowed from the Viper Competition Coupe) prevents oil starvation in the V10 during high-g driving.

Putting the increased muscle to the pavement requires a beefed-up Tremec TR6060 six-speed manual transmission with 10 percent wider gears and triple synchronizers. A stronger twin-plate clutch copes with the power increase.

A More Radical Cam

The biggest trick here is the 8.4-liter V10's variable cam-phasing device known as Cam-in-Cam. Variable valve timing is mechanically straightforward for DOHC applications, but an OHV engine with a single cam mounted within the block cam as found in the SRT-10 presents a challenge.

Here the hollow camshaft has fixed intake lobes on its outer circumference, while the exhaust lobes are attached to separate, movable inner shaft. A computer-controlled mechanism in the cam sprocket continuously adjusts the relative phasing between the two shafts. As a result, the valve overlap can be made radical enough for maximum power or conservative enough for a smooth and clean idle.

A surprising benefit is a 17 percent increase in fuel economy for this new V10. While the 2006 Viper was rated at 11 mpg city and 19 mpg highway (adjusted for 2008 equivalency), the 2008 Viper is good for 13 mpg city and 22 mpg highway. Plus a buyer of a 2008 Viper pockets a $1,700 savings in gas-guzzler tax.

Unleash the Beast Already

Once we take to the track at VIR, we soon find that the new engine's increased grunt flings the Viper out of the slowest hairpins with even greater authority. The absence of traction control proves of little concern thanks to accurate throttle response, wide Michelin R-compound rubber and a new GKN Visco-Lok speed-sensing limited-slip differential.

The acceleration down the long straights is simply crushing, and the V10's broad torque curve smothers the gaps between the six widely spaced ratios in the gearbox and overcomes the tall 3.07:1 axle ratio chosen to deliver a top speed of 200 mph. The engine's 6,250-rpm redline might seem a bit truckish for some, and the throaty thrash of the mighty V10 isn't exactly musical, but 8.4 liters of displacement and 10 pistons get the job done in a hurry.

Once we put the new Viper on our test track in California, we found that bursts to 60 mph can be accomplished entirely in 1st gear, and the mark comes up in 3.7 seconds, a full 1.2 seconds quicker than the 2006 Viper SRT-10 we tested. A couple of shifts later, the quarter-mile disappears in 11.8 seconds at 125.3 mph — a stunning 0.8 second and 7.9 mph better than the old car.

It Gets Better

Though the performance of the reworked engine grabs headlines (and the seat of your pants), the tweaks to the Viper's suspension are arguably more significant. They make the 2008 Dodge Viper SRT-10 simultaneously more livable on the street and more corner-capable on the track.

First and foremost, the former run-flat tires have been cast aside and replaced with Michelin Pilot Sport PS2 high-performance tires — and a sealant kit. Freed from the necessity to be stiff enough to bear the burden of running without any air pressure for support, the sidewalls of the PS2 tires are less rigid, improving compliance and suppressing skittishness over bumps and cracks in the pavement.

That said, the Viper is still all about fast driving on a track. Spring rates that are 5 percent firmer preserve the overall wheel rate of the previous suspension calibration, and shock damping has been adjusted to capitalize on the capability of the new rubber. This setup also allows increased negative camber in the static alignment (now negative 1.4 degrees at every wheel). The end result increases mechanical grip and improves poise from this very heavy, very powerful car with a very short 98.8-inch wheelbase.

These improvements have also allowed the SRT engineers to address the excessive understeer that has been dialed into the Viper over the years in an effort to control the beast in its nature. By simply replacing the previously hollow rear stabilizer bar with a solid one of the same diameter, rear roll stiffness has been increased.

Awkwardness? No, Not Really

At VIR, these tweaks allow us to stab the new Viper aggressively into low- and high-speed corners alike without speed-sapping understeer. The steering is sharp and direct, and you can use a quick lift of the throttle or trail braking to make a quick entry into a corner, as the 2008 Viper seems less likely to surprise you with snap oversteer.

Within a lap or two, the predictable responses of the 2008 Viper's new suspension tuning make fast driving almost effortless. Even with 600 ponies underfoot, this new Viper is far from being the handful we'd imagined on the way here. It just hauls butt and makes no excuses.

On our testing surface in California, the 2008 Dodge Viper SRT-10 scorches our skid pad with a 0.99g two-way effort. (The counterclockwise run was 1.02g.) Had conditions been less hot and slick, Dodge's own 1.05g "performance target" seems possible.

The Viper's 72.4-mph slalom speed places it near the top of the heap of front-engine machines. Weight distribution of 49.5 percent front/50.5 percent rear for the car's 3,437 pounds helps. None of the cars in our 2006 American Exotics test (Viper included) got close to the 70-mph mark.

Down to Business

We haven't said much about the rest of the Dodge Viper because not much has changed. It's still a tight squeeze in and out, and our tallest tester complained about seat travel. A navigation system is now available, though.

Perhaps the most striking attribute of the 2008 Dodge Viper SRT-10 is its price. Despite the extensive engine do-over and the chassis refinements, the as-tested price of our coupe is actually $945 lower than a similarly equipped 2006 model.

Including destination, a roadster costs $83,995, and a coupe like ours starts at $84,745. These figures are slightly higher than last year, but that $1,700 drop in gas-guzzler tax tips the scales the other way.

The 2008 Dodge Viper SRT-10 certainly ups the ante in the brute strength quotient, but it's anything but awkward. Even the most ham-fisted hero drivers among us can now wield it. Prepare to trade in your 2006 edition. It's the best negative $945 you'll ever spend.

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The real question is are you man enough to drive one of these? Really nothing else quite like it IMO. I love it!

M