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Old 10-20-2015, 09:21 PM   #6
L99CAMA2011


 
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Drives: One of the baddest handling Gen 5s
Join Date: Feb 2011
Location: Masachusetts
Posts: 4,177
Quote:
Originally Posted by IOMZL1 View Post
http://wot.motortrend.com/dyno-battl...pr=18332466311

There ain't no replacement for displacement, and if you need proof, check out the dyno chart below. We threw a 2016 Ford Shelby GT350 Mustang on the dyno, followed by the hardcore GT350R, just to get a look at the torque curve from the highest-revving V-8 Ford has ever put in a car.

And then for fun, we brought along a 2015 Chevrolet Camaro Z/28.

The Ford Voodoo engine is a high-revving work of engineering art. 526 hp from just 5.2 liters of displacement thanks to a power peak at a lofty 7,500 rpm and an 8,250-rpm fuel-cut. A flat-plane crank helps take advantage of intake and exhaust resonances, and quad overhead cams operate 32 big valves with 14 mm of lift—about as much as you'll ever see.

And then, there's the General Motors LS7: 7,008 cc of big American muscle, with just 16 valves, all operated by pushrods. Somehow by the grace of god (and titanium con rods), GM got this 101.6-mm-bore monster to rev to 7,100 rpm. It's rated 505 hp and 481 lb-ft of torque — 21 hp fewer than the Ford, but 52 lb-ft more.

So what happens when you put them on the dyno?

Well, at 1.500 rpm, the GT350R makes 239 lb-ft of torque. The Z/28 makes 341, 102 lb-ft more (numbers taken from a different run in which recording was started earlier).

In fact, from idle to about 3400 rpm, the Z/28 produces between 100 and 120 lb-ft more torque than the Shelby does. Around town, this enormous torque advantage, combined with slightly shorter gears, makes the Z/28 feel immensely more powerful.

However, things look different higher in the rev range. At 3,600 rpm, the Z/28's advantage has dropped to just 46 lb-ft. And while the Z/28's torque continues to rise until just under 5,000 rpm, its advantage over the much smaller GT350's V-8 doesn't.

The high-revving (for a pushrod) LS7 peaks in power at 6,200 rpm, and it runs into its rev limiter at 7,100 rpm — at which point the GT350 still hasn't even hit peak power.

But look at how close those power peaks are:
Car Peak Dyno Power Peak Dyno Torque
Shelby GT350 467 hp 374 lb-ft
Camaro Z/28 469 hp 438 lb-ft
Shelby GT350R 471 hp 376 lb-ft

The curves may look entirely different, but the output is the same: the difference in peak output between the Shelby GT350, the GT350R, and the Camaro Z/28 is not significant.

But, you may point out, the GT350 has a 21-hp advantage in its power rating? Where did it go?

Well, it could be that our long-term Z/28 has an engine that's fully broken in (it has over 16,000 miles on its odometer, compared to just 3,000 miles on the Fords.) Or it could be that the Camaro's drivetrain is more efficient at getting power to its wheels. Also remember that this test was conducted in ambient air temperatures hovering around the 100-degree mark. And all cars were fueled with 91-octane gas, which is the best we can get in California.

With 13:1 compression and all those revs, the Mustang's engine seemed more sensitive to the heat. So these results might have been different on East-Coast 93-octane fuel or in cooler, more humid conditions.

Still, although it's fun to point out that the Z/28 and GT350 put the same exact amount of peak power to their wheels remember that the peak number is just one number. It's the shape of the curve that matters so much.

Despite the Z/28's massive torque advantage, it's no quicker than the GT350R. They're pretty close to even—which is exactly what you'd expect given their similar weight-to-power ratios.

And, since we're big fans of muscle-car rivalries, that's exactly how we'd like to see it.
I am yet to see a shop dyno a Z28 with that much power to the wheels especially on 91 octane.
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