![]() ![]() The EPA doesn't require automakers to report fuel-economy figures for pickups with a GWVR of over 8500 pounds, so these trucks can be as efficient or inefficient as the automakers like. It should help boost fuel-economy, too.Īutomakers talk about fuel-economy and how it impacts engine design a lot, but what's interesting here is that at least in the US, trucks like the Super Duty don't have any standards to meet. It's Ford's now-familiar 10-speed, though one that's been optimized for big truck usage. The transmission it's paired to isn't old-school, either. Stick with the Coyote, kids.īeltramo said that there aren't any plans on sticking this engine in an F-150 either, but it will eventually find a home in medium-duty trucks like the F-650 and F-750. ![]() And even if you could wedge this motor into a Mustang, it wouldn't be very good, because of its heavy cast iron block and low-revving nature. It's possible then, but good luck doing so without having to cut into the firewall. This compactness means there'll be lots of room in the engine bays in which the 7.3-liter finds a home, which Beltramo said helps with cooling.Īnd if you're wondering if it'll fit in a Mustang, Beltramo told us it's actually shorter in height and narrower than a Coyote V-8, but quite a bit longer thanks to much increased bore centers. Beltramo said the 7.3-liter is quite a bit shorter in height than the 6.8-liter overhead-cam V-10 it replaces, and not too different in any other dimension. There's also the relative compactness of an engine without overhead camshafts. Generally speaking, pushrod engines are a lot simpler than their overhead-cam counterparts, so there's a lot less stuff to break. This 7.3-liter should be pretty durable, too, thanks to a cast-iron block, a forged steel crankshaft, and oil jets to cool the pistons. Then there's serviceability-in a number of ways, the 7.3 is similar to the 6.7-liter Power Stroke, so technicians won't have a totally new engine they'll need to learn. For one, it'll be cheaper than the 6.7-liter Power Stroke diesel V8, which should appeal to fleet buyers, and to those in areas where gas prices are especially cheap (fuel economy for the diesel should still be better, though Ford doesn't have numbers). But when you start talking about running day-in day-out, at high weights.the displacement brings a big fuel-economy benefit."įord thinks there'll be other benefits brought by the 7.3. "There would be a hit for the displacement. "If you used in an F-150 or something, it would not return the kind of fuel economy at light load as some of our other engine offerings that we deploy in that vehicle," Beltramo said. When towing/hauling a big load, a truck's engine needs to be making peak power, and if it's doing so at relatively low RPM, it won't use a ton of gas Typically, a pushrod engine makes lots of torque at low RPM, while an overhead-cam engine-like the 5.0-liter Coyote in the Mustang-does its best work from the middle to the top of the rev range. It really is the optimum solution for the over 14,000-pound. ![]() "That's what led us to a pushrod two-valve. "That led us to a torque-per-liter value and a power-per-liter value, knowing that, boxed us to 7.3 liters."įor fuel efficiency's sake, Ford engineers determined they wanted the engine to generate peak power at what Beltramo considers "relatively low" RPM. "We built a map of where an engine, can run stoichiometric air-fuel without a bunch of spark retard," Beltramo said. In vehicles with 14,000-plus-pound GVWRs-like the Ford Super Duty-Beltramo told us its critical for an engine to operate at peak power with an optimal air-fuel ratio (stoichiometric combustion). By contrast, vehicles with a GVWR over 8500 pounds tend to tow and haul a lot, which means they're using a lot of their horsepower a lot of the time. That means they don't use much sustained horsepower. We talked to Joel Beltramo, manager for V-8 gas engines at Ford, about why a big pushrod motor makes sense here.īeltramo pointed out that most vehicles with a gross vehicle weight rating (GVWR) of under 8500 pounds cruise around without carrying or towing much weight at all. A new pushrod V-8, let alone one displacing a hearty 7.3 liters, might seem backwards to you. ![]()
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