Forum Discussion
Turtle_n_Peeps
Sep 03, 2019Explorer
ShinerBock wrote:
Let me first state that I am a big fan of the 3.5L Ecoboost engine. I had on in both my personal F150HD and F150 work truck putting over 250k miles combined on with the 3.5L Ecoboost.
The main problem with putting a gasoline turbocharged engine into an SD is heat. Gasoline turbocharged engines create a lot of it when worked hard for a sustained period of time. This is why the 3.5L Ecoboost has an open deck block even though most turbocharged gasoline engines put in cars are closed or semi-closed such as the infamous Supra 2JZ block which is known for handling high psi and over a thousand horsepower. This is needed to carry away the cylinder heat when you are under a sustained high load such as towing. Most gasoline turbocharged engines in cars are not under high loads for a long duration of time like a truck is when towing so a closed or semi-closed will offer enough cooling in these applications.
Most HD/SD V8 gas are iron closed deck designs for a reason. This aides in long term durability in their duty cycle. These engines can have a closed deck block and still remain cool because they are generally at high rpm when under load which is moving air in and out of the cylinders at a high rate which aides in cooling. While turbocharged engines move a lot of air into the cylinder to compress it(which creates more heat), they generally operate at much lower rpm which causing more heat buildup in the cylinders and block.
Diesels are an iron(CGI) closed deck design, but even though diesels are turbocharged like the Ecoboost they retain a lot less heat within their blocks due to their higher thermal efficiency. It is much more efficient at converting thermal energy into mechanical energy so an open/semi-closed deck is not needed to keep them cool under high constant load.
There is much more to it than slapping any ole engine into an SD/HD truck application and calling it good. Many things would have to be considered. I am not saying it will never be done(especially with the new cooling tech that was just discovered) or that the Ecoboost is not a long lasting durable engine. I am just saying that the cooling requirements of an SD/HD duty cycle is probably the reason why Ford has not put a small 4.X V8 Ecoboost in an SD.
Boom! Nailed it!
Let me also say anybody that says a turbo gas engine will get close in fuel mileage HP to HP does not know what they are talking about. The difference is going to be between 25 to 30% and that's a BUNCH! Just the BTU difference is a bunch and the gasoline engine can't make that up. The diesel is at WOT air wise and the gasoline engine can't make that up.
The gasoline engine makes more power and the diesel is way more efficient. That's just the way it is. That's why my race car has a gas engine in it but it is towed to the track with a diesel engine. :)
About Travel Trailer Group
44,052 PostsLatest Activity: Oct 29, 2025