The Buick Grand National: What’s in an engine?

Excitement resigned among enthusiasts when GM applied to renew the trademarks on the Grand National and GNX badges which have not been used since the 1987 Buick Regal Grand  National was produced. The 547 1987 GNXs originally produced have recently generated occasional auction sales in excess of $100,000.

Now, rumors may turn into reality as the Grand National may be introduced at the 2014 Detroit Auto Show. The stunning resurgence of the Buick brand, especially in the United States and China, suggested that it was just a matter of time before Buick’s migration back to performance cars would accelerate.

So, what might we see when the new Grand National (GN) is unveiled? Two key components will be the rear-wheel-drive Alpha platform and a new twin-turbocharged V-6, the LF3, that GM suggests will be utterly free of turbo lag. It should also generate in excess of 400-horsepower in the new GN.

It is likely that this new feat of GM engineering will be used in a new 2014 CTS-VSport and a 2014 XTS-V. Engineer the traditional drawback of turbo lag out of the engine while bestowing it with in excess of 400 horses, and the new 3.6L V-6 should be a big hit. Cadillac will officially launch its “first ever” twin turbo V-6 later in 2013.

The theory, and the reality, is that two smaller turbochargers will create less lag than one large one. Add in a top-mounted throttle body and shorter air pathways, and that nemesis called turbo lag becomes nothing more than a distant memory. The old concept that used circuitous tubing in a heat exchanger has been eliminated, thus improving air flow. In fact, air flow routing volume has been reduced by in excess of 60-percent. The water-to-air intercooler produces 80-percent cooling efficiency, but with only one-psi of flow restriction, even when peak power is achieved. The big winner in this re-design is torque response.

Finally, the use of twin turbochargers makes the use of a centrally situated throttle body atop the powerful V-6 a logical, and effective, concept. Collectively, these engineering breakthroughs will allow the engine to sustain peak torque from 1,900 to 5,600 rpm.

Although exact engine performance data for the Grand National is still unknown, the numbers for the 2014 CTS-VSport are — 420 horsepower and 430 lb-ft of torque. In the slightly heavier XTS-V, the numbers will still be impressive for a V-6 — 410 horsepower and 369 lb-ft of torque.

Both the Grand National and the GNX are expected back in the Buick lineup during calendar year 2014. Performance will likely be a hallmark of the new GN, but color will not. The much-anticipated Buick Grand National should be a study in black. The lightweight, rear-wheel-drive Alpha platform should offer rear-wheel-drive optimized balance that should further enhance performance. After the Alpha is used in both of the new Cadillacs and the new Buicks, it is likely that it will also appear in a 2015 or 2016 “sixth-gen” Chevy Camaro.