Piston Slap: Pushrod Prattle Edition

TTAC commentator edgett writes:

Since the current pushrod LS-X engines reportedly offers a better power-to-weight ratio than an equivalent Porsche engine, and returns excellent fuel economy, why aren’t other manufacturers emulating the same kinds of evolutionary upgrades which GM applied to their small-block V8?

Sajeev answers:

Naturally aspirated Porsche boxers may be lighter than an LS-X, but don’t bother comparing their power bands (i.e., area under the curve). The Porsche turbos are comparable, but weight is not their friend.

But your question is kinda wrong: all manufacturers apply evolutionary upgrades to their motors. It is do or die, even if GM Powertrain couldn’t save the Mothership from bankruptcy. But I digress. The LS-X thrives with fewer and lighter materials, lower center of gravity and abundant torque from a physically simple design with massive displacement: even with (fuel economy) taller gearing. Plus, they are cheap to make and getting more common in junkyards.

Which makes for a great power/economy combination in Frankenstein heart transplants. [If the Houstonian who owns the LS-6 powered Porsche 914 is reading: I want a ride in your car. E-mail me.] Speaking of evolution, wait until the LS-X gets direct injection and/or variable valve timing like its competition. They could be unstoppable, if GM Powertrain gets the money to make it happen. Start holding your breath . . . NOW!

Bonus! A Piston Slap Nugget of Wisdom:

The LS-X’s modern OHV architecture is the key to its success. Yes, I said “modern.” The 1949 Kettering/Oldsmobile OHV V8 is some 50 years newer than Karl Benz’s Boxer, 30-ish years newer than the first OHC motors. Just remember that when someone says that Detroit V8s are ancient dinosaurs.

[Send your technical queries to mehta@ttac.com]