The Pewter Rocket's new LS2 heart is pumping strong! The change in thecar's personality is pretty amazing. In its former life the '00 FRC wasa quiet, comfortable cruiser. Minor changes to the intake and theaddition of after-cat exhausts produced 331 rwhp and 333.3 lb-ft oftorque. The car was no slouch, but a good-running Z06 would put two carlengths on it anytime it wanted. Next, the car went through an MTIRacing head-and-cam conversion (Read "Tuning In," Dec. '04 and Jan.'05). This change produced a nice bump in horsepower and torque (410rwhp and 378.9 lb-ft of torque). We continued to fine-tune the car byadding a Callaway 78mm big-bore throttle body and after-cat exhaust.This produced 436.8 rwhp and 414.5 lb-ft of torque. Overall, we werevery happy with the new personality of our C5. We now waved bye-bye tostock Z06s. The lumpy cam and teeth-rattling performance above 3,000 rpmmade the car exceptionally fun to drive. It gave us a 10 on ourgrin-factor meter! But, as we asked in our "Have a Heart" story (Sept.'05): "Can we ever get enough performance?" The answer is no!
Team VETTE returned to MTI Racing to have its new 6.6L LS2 engineinstalled in place of the hot rod LS1. You know the old saying: "Thereis no substitute for cubic inches." MTI Racing's new 6.6 LS2 enginepackage retails for $15,990, which includes a core credit for acustomer's reusable LS1 or LS6 engine. It also includes a one-yearunlimited mileage warranty. Since our LS1 benefited from many MTIRacing upgrades, we decided to reuse some of our previously installedparts. This included our modified heads, Z06 intake, and 78mm throttlebody. We also reused our MTI Racing long-tube headers, Callaway exhaustsystem, Fidanza flywheel, and SPEC pressure plate and clutch. (MTIRacing's production 6.6L package will include modified AFR heads, acustom intake, and a 90mm LS2 throttle body.)
MTI elected to remove our LS1 engine from the top rather than thebottom. Both methods take about the same amount of time, but removalfrom the top allows the car to move around the shop easier. Reese Cox,Jesus Garcia, and Chris Ivester quickly took the usable parts from theold engine. The team installed a Callies 4340 Racemaster crank, Mahle F1pistons, and CompStar connecting rods in the new LS2 block. All of theseparts were secured from Callies Performance Products. The block has a4.010-inch bore and 4.000 stroke, which make it 404.1 ci or 6.6 liters.Once the lower end was assembled, the pan and oil pump were installed.Next, an MTI custom hydraulic roller cam was installed along with thetiming chain and sprockets. New for the '06 LS2 engines is a plastictiming-chain tensioner Reese was able to secure and install. Thetiming-chain cover and external cam-sensor wiring connector were alsoinstalled. Next, the cam buckets, intake-valley pan, head-bolt studs,and gaskets finished off the short-block assembly. The heads,valvesprings, and crank pulley completed the engine. The team thenmounted the Fidanza flywheel and SPEC pressure plate and clutch. Theengine was now ready for installation.
During installation, it was discovered the LS2 had one extra stud on theright side of the block that interfered with the C5 motor mount. Partof the stud had to be removed to clear the motor mount. Everything elsefit perfectly. The two knock sensors in the intake valley on the C5 havebeen relocated to each side of the LS2 block. Also, the LS2 cam sensoris now located on the front instead of the back of the block. Reesebuilt new wiring harnesses to accommodate these changes. New 32mminjectors were installed to feed the increased cubic inches. Thefinishing touches included adding the headers, intake, radiator, coolingfans, and hood. The car was now ready for its first startup. Reesechecked the computer with his laptop and the car started the first time.After we completed a trouble-free 500-mile break-in run, we returned toMTI Racing and hooked up the Rocket to the dyno. Our best pull was 477rwhp and 464 lb-ft of torque on a 100-degree day.
On the road, the Rocket is very docile; the car lopes along with nostumbles or bad manners. It even has power in Sixth gear. We no longerhave to watch the tach to make sure the motor is turning above 3,500 rpmto get maximum performance. Now you can punch it at 2,500 rpm and haveall the power you need. This is not a cam motor--it's a torque motor. Weeven averaged 28.6 mpg on a 7-hour trip with the A/C running. But theremarkable thing is, even at 2,000 rpm the LS2 produces well over 350lb-ft of torque. When you punch it, hang on; it turns from a kitten intoa tiger! We think MTI Racing has a winner with this new 6.6 package. Ifyou install this LS2 into your C5, it might make you want to hold offbuying that new Z06!