Ford’s New 7.3-L Engine — Your Predictions?

[Luke D]

Nice video not sure about Newmar's releases. Saw A 2021 Thor at RV show in February. Messa AZ has some 2021's. Thor's as Lazy Days here in Tampa. I believe Jayco will be released soon if not already. Maybe my wife an I will take a trip to the Tampa dealer s . Outside should be safe. We got Lazy Days, camping world, General and RV world. Beats staying home all-day Sunday

[Pete'sMH]

“It’s natural and expected that present owners of V10 will be more critical of new V8 in order to make their engine seem better by comparison.”

It’s equally natural and expected that purchasers of the new engine will be somewhat blinded by their expectations and the newness. That said, I’m quite certain the new engine will have significant advantages or Ford wouldn’t have bothered. Point is that the old engine/chassis is very effective and well proven and, at least for the near future, people have a choice to buy the 2020 models at a very significant cost savings over the new one and for many people that is important. Or it can mean they are able to buy a nicer coach for the same money.

[Pete'sMH]

Originally Posted by Chance

Here’s another video that makes two important distinctions. One is that engine doghouse is smaller than previous motorhome with V10, and at end of video they take it out on road and claim that it’s significantly quieter.





https://youtu.be/YDWY2L_ke1w

Well, I’d take everything that particular dealership says with a sizable grain of salt.....

[Muggs]

We have the 2 valve v-10 in Vegas 24.1. Almost 4 years and 28,000 miles with 6 spd. Overall MPG is steady at 9.5 to 10.5. This is at 12,500 or 18,500 w/racecar trailer. It cruiies fine from 65 to 75 indicated. I find it odd that MPG seems identical within 5% In either configuration. Have had a couple 11 mpg trips but was flat back roads in 45 to 55 zones. In either trailer or no trailer, keeping up with traffic is zero issue. I did have an 8.8 mpg without trailer but that was a lot of time over 80 mph indicated. Wife did not like the wind noise.

We really cannot complain about chsssis/engine/trans combination. Its performance is like a lawnmower/generator engine designed to run within speed range seemingly forever. Many of buddies with e450 based machines see same MPG. Others with F53 based units report 6 to 8 towing and never more than 9.5 no trailer. I am fairly certain an enclosed trailer would hurt MPG on our unit.

Overall this is my first ever Ford product, I am very pleased. The Thor part has also not disappointed.

The V-8 would need to really bump MPG to justify change or I would need bigger unit (not likely).

[Chance]

Originally Posted by Muggs

......cut....

The V-8 would need to really bump MPG to justify change or I would need bigger unit (not likely).

That’s not ever going to happen in my opinion. The new V8 “may” get slightly greater fuel economy due to its higher compression ratio, lower friction, and improved breathing, but these can only be incremental improvements in the Premium “power” tune. The reasons large and heavy motorhomes get crappy fuel economy is mostly because of the amount of power it takes to move them, not because their engines are that inefficient.

As I’ve stated before, V10 technical data shows that the V10 engine is reasonably fuel efficient in the right power range. I’m certain Ford did not replace the V10 with the new V8 just to save fuel. There’s no way the new V8 can save enough fuel over a V10 to justify upgrading a motorhome solely for that purpose.

The new V8 has significant “potential” over the V10 which has nothing to do with fuel economy. I believe the driving force (no pun intended) behind the new V8 was to reduce costs. The new engine is simpler so should cost less to manufacture and repair/rebuild. It’s also physically smaller, so can fit in tighter spaces and/or have better cooling over the exterior of engine. A smaller RV doghouse should be a welcomed improvement.

What I like best about a V8 is that it’s not a V10. My V10 may have just over 200,000 miles now, but it’s never been smooth or quiet. A V10 is not inherently balanced, so requires a balance shaft. Beyond that, I have never driven a single Triton engine that wasn’t loud. Even a 4.6L V8 in an F-150 was louder than old OHV V8s from the past, particularly at higher RPMs.



P.S. — For the size RV I’m interested in, I still think the 7.3L is too large for optimum efficiency. A +/- 5-liter engine should have greater chance of 12 MPG at 60 MPH in a smaller motorhome.

[Chance]

A major question I had about power and torque peaking at 3,900 RPM on motorhome and large truck applications has been answered.

Based on dynamometer results done by 5-Star Tuning, it appears Ford electronically limits power and torque to 3,900 RPM, with a steep drop off above 3,900.

I though (guessed) the derated power numbers may have been on paper only, but it appears Ford has an electronic governor in place for these heavier-duty applications. The good news is that it’s easy to defeat if you’re into that kind of “upgrade”.

Personally, I’d leave the engine alone so I could feel completely comfortable putting my right foot to the floor and not worry at all about over-stressing the drivetrain.

Info came from The Fast Lane Truck. They plan to test motorhome in near future climbing up to Eisenhower Tunnel.

[Bob Denman]

You're right about potentially over-stressing other powertrain components.
When the old V-10 showed up in the F-350: we had four clients tear the transfer cases apart while plowing snow...
A heavy right foot, chains on all tires, and a blade-full of wet snow: was what it took!