2-3mpg with K&N air filter and aftermarket muffler?
 

Hello all. I have a 2012 Cadilac Escalade Hybrid. For its age and mileage, it's running pretty well and getting decent fuel mileage. But I'd like more, of course. I have aftermarket wheels, not by choice, but they are stronger as we tow with this truck. My wife's commute is 7 miles one way and the stupid road she drives is mostly 45mph with maybe a dozen stoplights from here to there. I can take the truck on a loop through town then onto the interstate and back through town and average 21-22mpg. She's getting about 17mpg on this commute. One GM SUV hybrid owner has suggested that if I put a K&N filter and an Aftermarket muffler on it I could get 2-3mpg better. My mechanic brother says no, you'd need a cold air intake kit and full exhaust.

What do you guys think?

Thank you for your time.

If you were asking about a 36hp VW engine, I'd say yes; but I dunno.

What aftermarket muffler would it be? Lakes pipes? SuperTrapps?

Doesn't sound like good advice to me. An 18% improvement in fuel economy from an air filter and exhaust? The biggest restriction to airflow in an engine is the throttle, which is used every time it's not wide open. In other words, an air filter isn't going to magic more fuel economy. An exhaust could potentially, but that also needs to be tuned correctly, so some monkey in a shop isn't likely to get that right.

That short trip distance isn't helping economy because it's not enough time to warm up. Get an EV and it will efficiently cover those short distances.

Yup. Just because he's an owner doesn't mean he knows anything about the vehicle. I see a lot on forums or facebook groups where guys are preaching about plug wires and ground straps too. Doesn't mean they work though. lol
Your best bet will be to pump the tires up to 45+ and teach your wife how to drive without brakes (DWB). A lot of the time in the Prius i try to use neutral (you could just coast as well) instead of regening because its still only around 60% efficient.
Also as stated above you could look into the temperature of the car on her commute and look into grill blocks and redirecting the intake for warm air. Its about time for me to do this on the Prius again this year as well.

K&N filters are great... if you hate your engine.

Intake restrictions limit peak power in modern MAF/MAP sensored engines, similar to having the throttle butterfly in a partial restriction. But they don't affect your overall mileage. Your mechanic brother sounds like he learned on carbureted engines.

EDIT: Also, for partial loads like that, ecomodders generally recommend the reverse of a CAI, which is a warm air intake. https://en.wikipedia.org/wiki/Warm_air_intake

Her drive should be ideal for a hybrid. So I would say you need to adjust the nut behind the wheel. She needs to quit enjoying the rumble of that big v8 and the way she can out accelerate everyone around her. Anything that increases power wont help economy much if any, but will even further excite the nut behind the wheel and encourage even more spirited driving.

Please know, I'm not really calling your wife a nut, it's just an old saying that makes a great point.

Also know that if Cadillac could have achieved 2-3 mpg better EPA certification from a different muffler and air filter they would have done that in 2012.

1. Any somewhat modern car (read less than ~20 years old) has a cold air intake from the factory
2. The stock airfilter in any somewhat reasonably designed car does not obstruct airflow in any meaningfull degree unless it's clogged
3. Even if the airfilter was restricting airflow, your fuel efficiency wouldn't suffer in a fuel injected gasoiline car

To elaborate on 3:
The only time your air filters restriction becaomes significant is at WOT.
At less than WOT, airflow is restricted massively by the throttle body
If your air filter is clogged up, that results in you effectively not beeing able to reach WOT, meaning you lose a little bit of power.
However your engine doesn't get any less efficient from that.

And a muffler certainly hasn't any effect on your fuel efficiency unless swapping it reduces your cars weight significantly.
(I doubt that's the case here)

What would help your wife to get a better fuel economy on that short trip in winter would be a block heater.

I mean, a block heater in Florida? Certainly it will speed up the already short warm up cycle, but as others have stated, the low hanging fruit is tire pressure and adjustments to the way the vehicle is driven.

Good luck getting anybody, especially a woman to change driving behavior.

As I pointed out, the vehicle itself isn't very efficient, especially for a hybrid. It probably doesn't make sense to get a commuter car considering only 3,650 commute miles per year. You'd only be saving a couple hundred bucks a year in fuel.