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Old 07-05-2011, 05:50 PM   #1
DoggyB22's Avatar
Drives: 2001 Camaro Z28
Join Date: May 2010
Location: Bay Area/Santa Barbara, California
Posts: 215
Arrow Track and Dyno Tested: 750hp SLP ZL1 Camaro Convertible

Featured on Camaro5 HOMEPAGE.

Not bad at all..... Going that this is a convertible. I'm sure we would expect better times with a hard top. Cant wait for Chevy to release the ZL1 times.

That sound is just

Track Tested: 2011 SLP ZL1 Camaro Convertible

Dyno Tested: 2011 SLP ZL1 Camaro Convertible

When we posted our Track Tested results of the 2011 SLP ZL1 Camaro Convertible, a few of you cried foul. The trap speed, commenters opined, was too low to support the claim of 750 horsepower. Put it on the dyno, came the cries.
Ask and you shall receive. The result is across the jump.

Let's recap with what we're dealing. For their ZL1 package, the power brokers at SLP work up an LS7 block with a forged chromoly crank, a hotter cam, beefier rods and pistons, LS3 heads massaged with new valvetrain hardware, and then top the whole works with a TVS 2300 blower. They touch almost every other engine component, too, replacing the bearings, timing chain, oil pump, pushrods and head studs with racier stuff.

SLP then pop in a stouter clutch, a lighter flywheel, proper tubular headers and a big-bore exhaust. The result of all this work is 750 horsepower at the flywheel and a rip-snorting exhaust note.

In the confines of MD Automotive's Dynojet chassis dyno bay, the sound of seven liters of uncorked supercharged pushord V8 ricochets off the walls, positively pummeling your senses -- this is a convertible, after all, and so we just had to put the top down while on the dyno. The TVS blower is silent, too. You mostly hear exhaust, and lots of it.

What we measured can be seen below:

Its fat dome of a torque curve peaks at 610 lb-ft at 4200 rpm, and peak power of 617 horsepower arrives right at the fuel cut. That little blip in power right at the fuel cut was not repeatable, so the peak is realistically closer to 610 hp at the wheels.

If you're a fixed-percentage-driveline-loss kind of guy, it will help to get your bearings around what a stock Camaro SS puts to the ground. In our testing on this dyno, a stock Camaro SS loses to the driveline 13% of its total flywheel power. Most production RWD, normally aspirated cars exhibit roughly 10% reduction from flywheel to wheels on this particular dyno, so 13% is on the conservative end of the range. Apply this value to the SLP ZL1 and it appears to be shy of its 750 hp claim by a bit.

A big factor is playing into this, namely geography. SLP are based in Michigan. Michigan and much of the rest of this great nation enjoy the fruits of 93 (and in many cases 94) octane fuel. For a forced induction engine, octane does to power what catnip does to your tabby -- it really perks things up.

Now consider that we do all of our testing in California, and that California is not in Michigan, which means a) we don't point to our palms when describing our hometowns, and b) the highest octane premium fuel that's widely available is shitty 91 octane. Yes, 91 octane is completely lame.

You know where I'm going with this. SLP developed their 750-hp calibration on midwest fuel and not 91 octane. On the plus side, I didn't hear a single ping while on the dyno, which means their knock detection works very well. The downside is that the car simply won't make the same power on 91 as it does on 93 octane. SLP doesn't sell the ZL1 to California residents anyway, thanks to the draconian (and expensive) hoops that CARB requires companies to go through in order to do so. However, the CARB-free states of Arizona and Nevada also max out at 91 octane.

Thing is, SLP are their own competition. A while back we tested on this very dyno a Camaro equipped with the company's ZL575 package, which claims 575 hp at the flywheel. The ZL575 put down 558 horsepower and 513 lb-ft to the wheels on 91 octane, and it ran a 116.8 mph trap speed to the ZL1 'vert's 117.2. True, the ZL575 is lighter than the ZL1 (by about 240 lb) and has better aero, but the comparison of it to the ZL1 shows that making even more power on 91 octane quickly becomes a losing proposition.

But hey, the ZL1 still manages to out-sauce a freakin' 911 GT2 RS, which is no mean feat in its own right. Still, our advice for those perusing the SLP offerings is to stick with the ZL575 package.


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LT Pacesetter Headers, Moser 9" 3.89 Gears, FAST 90mm Intake & TB, 28" M/T Tires, Tune
Dyno'd 346 rwhp 354 lb tq
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