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Off-Road Insider - Vortec I-5 Engines

Posted in How To on January 1, 2003 Comment (0)
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Off-Road Insider - Vortec I-5 Engines
0301 OFRP 02 z (010 14) insider

Inline Fever: GM Introduces Two New Inline Truck EnginesFollowing the lead of the successful Vortec inline-six engine that powers Chevrolet's TrailBlazer, General Motors has developed two additional engines based on the six-in-a-row Vortec. The Vortec 3500 inline five and the Vortec 2800 inline four are, in essence, scaled-down versions of the Vortec I-6 and are slated to power the new Chevrolet Colorado and GMC Canyon midsize trucks, which will be introduced later this year as '04 models.

The new Vortec I-5 and I-4 engines share common design elements, such as all-aluminum construction, dual overhead camshafts, and four valves per cylinder. The smaller siblings share the big VortecI-6's 10:1 compression ratio, electronic throttle control, coil-on-plug ignition, and adjustable exhaust cam phasing.

GM was able to rapidly develop the new four- and five-cylinder engines by employing 75 percent of the parts used to build the Vortec I-6 engine, with obvious savings in development costs. Similar to the big I-6, the I-4 and I-5 are stout performers: the 3500 I-5 is targeted to produce 215 hp and 225 lb-ft of torque, and the I-4 will be tuned to deliver 170 hp and 175 ft-lb of torque.

While the I-6 design effectively cancels out engine vibrations through its crankshaft layout and ignition firing order, the I-5 and I-4 engines must be balanced via add-on balancing shafts. Both new engines were designed to operate with dual balance shafts that are incorporated into housings on each side of the engine block. The balance shafts rotate at twice the engine speed and in opposite directions, thereby counteracting the natural rotational vibrations created by the I-4 and I-5 design.

To keep the exhaust of the Vortec I-4 and I-5 engines as clean as possible using today's technology, each engine's exhaust manifold uses an integral three-way catalytic converter. Making the cat a part of the manifold results in a quicker light-off time, which rapidly oxidizes hydrocarbons and carbon monoxide. Any pollutants that get past the initial catalytic converter are burned off inside a secondary cat mounted in the traditional location. The results are impressive: both new Vortec engines are able to meet California's Low Emission Vehicle standards.

As with the I-6, the I-4 and I-5 engines boast variable valve timing. Simply stated, the valve timing of the exhaust cam is electronically regulated (advanced and retarded) through a sophisticated program designed to enhance torque and overall drivability, deliver a smooth idle, and reduce emissions. Retarding the exhaust cam increases the overlap of the intake and exhaust valves, which increases the amount of exhaust gas recirculation within the combustion chambers, and thus creates the aforementioned performance benefits. A high-energy ignition spark is delivered by the coil-on-plug ignition system, which is electronically controlled, has no moving parts, never requires timing adjustments, and eliminates the need for spark plug wires.

Although these new GM engines are only now reaching the market, GM has looked far ahead to future development. In the works are full variable valve timing (adjustable intake and exhaust camshafts), turbo charging, direct-injection fuel systems, and models with larger-displacement. With the Vortec I-6, I-5, I-4 and V-8, GM certainly has an enviable lineup of powerplants for its midsize trucks and SUVs.

V-8 TrailBlazer A RealityOne of the worst kept secrets last year was the existence - in prototype form - of a V-8-powered TrailBlazer. Now, those test mules that were spied undergoing testing from Detroit to the deserts of the Southwest have finally sired a production V-8 TrailBlazer, and it's available at GM dealerships.

The TrailBlazer EXT (extended-length) will be available with an optional Vortec 5300 5.3L V-8 engine, the same great small-block that powers GM's fullsize Silverado and Sierra trucks and the Yukon SUV, but with one important difference: the TrailBlazer's Vortec is all aluminum. That's right, the Vortec cylinder block and heads are both manufactured from aluminum alloy. The TrailBlazer's lightweight, multi-port fuel-injected V-8 improves its power-to-weight ratio, and the alloy Vortec's thermal efficiency enhances both performance and fuel efficiency when compared with a cast-iron engine. Impressively, the pushrod, two-valve-per-cylinder Vortec V-8 allows the TrailBlazer to meet federal and California standards for Ultra Low Emissions Vehicles.

The V-8 TrailBlazer EXT will exhibit strong performance, thanks to 290 hp at 5,200 rpm and 325 lb-ft of torque at 4,000 rpm - enough power for a 2WD TrailBlazer to tow as much as 7,200 pounds. The TrailBlazer's transmission is GM's tried-and-true 4L60-E four-speed Overdrive, and the V-8 option will be available on 2WD and 4WD models.

Jeep's New Steeped-In-Heritage LogoDaimlerChrysler has announced a new Jeep logo to go along with a new Jeep image. The new logo is a silhouette of the original Jeep folding windshield, grille, and headlights set against an olive-colored background. Why the new logo? It's DaimlerChrysler's response to a recent court decision.

Last year, DaimlerChrysler sued General Motors and American General (builder of the Hummer H1 and H2) because of the grille design of the new Hummer H2, claiming the H2's design infringed on the trademarked appearance of the Jeep grille. DaimlerChrysler lost that one in court, so there is renewed focus on Jeep's storied military history as a way to separate Jeep vehicles from the every-expanding number of entries in the four-wheel-drive SUV market.

DaimlerChrysler is also reviving a Jeep slogan used during the '80s, "Only in a Jeep," as part of a push to double Jeep sales from 400,000 to 800,000 this decade, with the ultimate sales goal of 1,000,000 targeted at decade's end.

Fomoco Invests Heavily In Super Duty FuturesFord Motor Company recently announced a $50 million investment - in itself. Ford will invest the sizeable amount in its Kentucky Truck Plant in order to upgrade operations and increase production of its strong-selling F-Series Super Duty trucks.

The investment breaks down like this: $25.2 million will go toward a paint shop expansion; $12 million is slated for an overhaul of the body shop; and $8 million will provide for a thorough renovation of the plant's chassis production line. The Kentucky Truck Plant, which has been in operation since 1969 and currently employs 6,000 workers, will make good use of the upgrades: Ford plans to increase the annual production of F-Series Super Duty trucks from the previous pace of 348,000 units, in large part because Super Duty trucks (F-250, F-350, F-450, and F-550) account for approximately 40 percent of total F-Series sales, and Ford feels there are plenty of buyers for increased Super Duty production.

New Isuzu Truck Sets Sales Pace In Asia And AustraliaLast month, we showed artist's concept drawings of the two new compact trucks from GM: Chevrolet's Colorado and GMC's Canyon. This month, let's take a look at those trucks' fraternal twin, the Isuzu D-Max. This time, however, we have an actual photo of the real deal, thanks to Brenda Priddy & Company. News reports out of Asia and Australia, where the D-Max is sold, has the new, Thailand-built Isuzu truck selling at record pace: more than 8,000 trucks were sold during the first six weeks after its introduction.

Interestingly, this photo was captured when the D-Max was undergoing testing in the scorching California desert. Sharing much of the fundamental architecture with the Colorado and Canyon, there is speculation that Isuzu may officially introduce the D-Max to the American market, where Isuzu lacks a pickup. There's also talk the D-Max may be the platform for the next-generation Rodeo SUV.

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