How do our A.C. systems work on these 2015 to present models? I can't find a straight answer. They aren't belt driven are they?

My real question is does my 2.7 or any newer motor still use extra gas and do I still lose power when my A.C. is on. I skipped a gen as I last owned an 07 so I don't know what if anything changed, people used to use underdrive pulleys to counter the power loss.

Any fleet managers or mechanics here know this?

 

The old mechanics used to say it took 10 ponies to turn the compressor.

So yes, the AC would have to "task" the engine and require more fuel.

Perhaps newer vehicle compressors are a bit more efficient.

 

Yeah, my old 150 you really felt it when you hit the switch. And gas mileage suffered for it, I don't feel any power loss. So yeah is it more efficient or does it work difderenrly?

 

Although the type of refrigerant has changed from R12 to R134a and next will likely be R1234yf, the theory is still the same. All of these refrigerants require a compressor and a means to turn said compressor. In the majority of cases it is indeed a belt driven A/C compressor and it still is in almost all modern vehicles, the exclusion being hybrid or electric powered vehicles where an electric powered A/C compressor is utilized.

So the answer is yes. Power is still borrowed from the engine to run the air conditioner. And yes, sort of, these systems are becoming more efficient. In general you might only notice the power loss on initial take off but it should be minimal if any. Also, at cruising highway speeds your fuel economy will suffer less with the A/C on then it would with the A/C off and the windows down.

 

So you said in a way they are getting more efficient. Does that mean it isn't borrowing from the engine as much?

As SPOAT said about 10hp. I always heard 10 to 15. Or is it roughly the same?

Also, I have a boost, so I'm wandering if any of you V8 guys "feel" any difference.

 

I put that "sort of" in there for a reason. A/C compressors have to operate under ever varying conditions and RPM's and are inherently not very efficient as far as compressors are concerned. What is making modern systems more efficient is the way the cool air is routed and how the cabins are insulated and designed. And most noticeably, the almost complete demise of engine mounted cooling fans as they are now all electric. Because of this A/C systems have gotten slightly smaller. Smaller condensors, smaller evaporators, shorter and less hoses, etc. all add up to the typical system using 1-1.5lbs of refrigerant versus the 4lbs Dad's Lincoln used.

The amount of horsepower required to run the system is hard to gauge but I would guestimate it to be around 4hp or so turn the compressor and move the gas/liquid through the system.

"Feel" the A/C? Maybe. That subjective "feeling" is also difficult to gauge. If the system is borrowing 4hp from your engine, it is doing so at all RPM's. Hypothetically you ~might~ feel those HP's more depending on the engines torque curve, especially the torque it's making right off of an idle when leaving the stop light. But does that minor draw on your engine make a difference once your rolling along? I doubt it.

Think of it this way. If you ADDED 4-10hp to your engine (across the entire torque curve) would you notice it? Maybe but not likely. If you did feel that extra power it would be at lower RPM and when accelerating from slow speeds. Tip in throttle at cruising speed would make little difference.

So, do 5.0 engines feel the A/C more? I can't answer specifically as I've never made the comparison. However, if you compared engine torque curves in lower RPM's you might find the answer. Again, I doubt there is much if any noticeable seat of the pants difference.

Edit: Should also point out that there are many vehicles on the road today that run the compressor continuously, regardless of whether or not you are running the A/C. Also, all vehicles run the A/C anytime you have the HVAC system set to defrost. This is done to dehumidify the air which makes defrosting the windshield easier.

 

Just fyi - if anyone is experiencing intermittent A/C issues, there is a new calibration that resolves this issue

 

Thank you for the very detailed answer I was looking for..

 

There's no such thing as a free lunch. The compressor consumes power... it has to come from somewhere, and the only source on your truck is the engine.

 

As far as being able to 'feel' it. I definitely would notice the compressor kicking on with my Civic & TL. In my 2.7, I don't notice it at all, and so far my MPG hasn't deviated much from running with no A/C in cooler months.