Clearance for the tall rocker...
Clearance for the tall rocker arms was achieved by using these Katechaluminum covers. LAPD had them powdercoated red to add some underhoodcolor. Katech coil relocation brackets were also installed to providebetter access to the valve-cover bolts, not a bad idea if you're doing alot of tuning and tweaking in search of power. In this photo, you canalso see the Kook's 17/8-inch custom headers.
Intake, Fuel, Exhaust & More
The combination of intake parts that the LAPD crew assembled for theengine has remained constant throughout--a FAST intake manifold, coupledwith a 90mm Nick Williams throttle body (up from the stock 80mm), andthe stock mass airflow sensor. Air comes into the system through aVaraRam intake. To make sure there's enough fuel for the increasedamounts of air, the original fuel injectors were swapped for 32-lb/hrunits. Custom tuning of the engine's air, fuel, and ignition was handledin-house using LAPD's DynoJet chassis dyno.
Induction is handled using...
Induction is handled using a FAST intake manifold, the stock MAF sensor,and a Nick Williams 90mm throttle body. Extra fuel comes from 32-lb/hrinjectors.
Exhaust leaves the engine through a set of Kook's 17/8-inch customheaders and an X-pipe, then back to an LAPD after-cat system.
"As you can see, this isn't your everyday 'head and cam' car," Alpointed out. "Those kinds of motors don't have some of these exoticparts, like the Meziere electric water pump, 160-degree thermostat, andASP underdrive pulleys. But it takes a lot of attention to detail tomake this much power." Money, too, as it turns out. Al figures he's gotsomewhere over $14,000 invested in this engine. "But remember, for halfthat price you can have 430 hp," he added.
So, how did the new combination perform?
At the leading edge of the...
At the leading edge of the induction system is this carbon-fiber VaraRamintake.
As you can see from the accompanying dyno charts, they got close--reallyclose. Horsepower peaked at 493 at 6,600 rpm, while torque topped out at445 lb-ft at 5,400 rpm. From a driveability standpoint, the torque curveis sweet--in excess of 400 lb-ft from 3,800 rpm all the way to 6,400.
Our experience in the car matches what we saw on paper. There's a littlelope to the idle, but nothing harsh. Below 3,500 rpm, the car is almostdocile. Kick it, though, and it literally screams up to its redline.Weaving in and out of traffic on a fast-moving L.A. freeway, theon-paper difference between 493 and 500 hp is moot. This Z06 easilyleaves other traffic like, well, like it's moving backwards, to use anold cliche. There is plenty of power here--more than enough to risk thewrath of the town's "other" LAPD.
Here's how the finished engine...
Here's how the finished engine looks under the Z06's hood. Nicely done,with few tip-offs as to what lurks beneath.
Out back, exhaust leaves the...
Out back, exhaust leaves the engine via this 3-inch LAPD after-catexhaust system.
|RPM||HP (stock)||HP (modified)||Torque (stock)||Torque (modified)|
= peak figures
Los Angeles Performance Division
10155 Canoga Ave.