Intake Question...Gas mileage

S

SandMan2

Member
I just bought a grand touring AWD. I was torn between that and the new Mazda6 b/c of the gas mileage difference (17/25 vs 15/21). But there is only a 3 mpg difference between the two, so that doesn't seem to be a huge difference. I'm wondering if an intake will bridge the gap and give me an extra 2mpg or 3mpg??

Has anyone experimented with this?
 
Even a well designed true cold air intake that creates denser air will not provide a dramatic increase. You may notice a bit more zip when you accelerate, but very little increase in MPG. I've experienced real world examples of this in our '9. Quicker, but MPG was close to the same.

When someone builds a really effective intake for a CX9, I will be curious to see what it does, if anything. remember, the CX9 already has a CAI. Just not the straightest path.
 
No. I think the EPA rating now (after the revision) is fairly accurate.
I had K&N filter installed (and now it is off) for 1 year. I can tell you that it gave you more zip in accelerating, but unnoticeable change in MPG.
(I took if off because it was dirty, so I put back my OE filter for now)
 
Anything that will help improve the ability for the engine to make power without additional fuel will improve MPGs. Some things to consider:

- Less restrictive exhaust system
- Quality spark plugs (iridium)
- High power coil packs
- Use of quality synthetic oils (engine, trans, diff)
- Lighter wheel/tire combo
- Lighter brake rotors (2 piece rotors)
- Keeping injectors and combustion chambers clean of excessive carbon build up.
 
Last edited:
ceric said:
No. I think the EPA rating now (after the revision) is fairly accurate.
I had K&N filter installed (and now it is off) for 1 year. I can tell you that it gave you more zip in accelerating, but unnoticeable change in MPG.
(I took if off because it was dirty, so I put back my OE filter for now)
Click to expand...

We get right around the EPA rating, and I'm pleased to get that with a vehicle this size. I don't understand why these people think they should get the same mileage as a mid-sized sedan. They can bolt whatever crap you want onto a CX9, but they just wont get better mileage. These guys only getting 13 or so have to have something wrong with the car: VVT stuck, like a few have been, improper tire inflation, leaving the E-brake on (it happens), etc.

No amount of modifications will improve performance on this car more than I got when I drove to California for a week long trip. The mile drop in altitude from home made the car more zippy, but really didn't change the mileage. The increase in air density is considerably more than a CAI could ever achieve vs. the stock intake.

I'm curious why you removed your K&N, ceric. I put one on as soon as we bought our CX9, and clean it every 10k, with every other oil change. (we live in a dirty area). It didn't really increase mileage, but, as on our last vehicle, it seems to help slightly with the low end. I mainly use them for the longer life and less restriction as they get dirty.
 
I considered the K&N drop-in but instead put in the Amsoil drop in (no, I am not a dealer and no sales pitch to follow). I ordered 2 of them and then discovered that the filter has a 100,000 mile warranty (anyone want to buy the extra one...OK, so no "buy Amsoil oil from me" sales pitch).

That said, I have measured my mileage for the past 14,000 miles and have never dipped below 19, with most tanks at around 22mpg. I'm running synthetic oil and do mostly highway driving, about half urban with slowdown-speedup and slow moving parking lot and the other half at 78mph on cruise control.

So, I am not sure if my new coated air cleaner is making that much difference, and I am not that light-footed a driver, and now the AC is on all of the time....
 
I definitely can feel the difference w/ vs w/o K&N when accelerating.
I removed my K&N because it was dirty, and I really need to clean it.
Before that happens, I dropped in the OE one.

When I had a trip from San Jose to Sacramento, I got 22mpg with my GT AWD (averaging ~75mph). CX9 with tall 6th gear performs very well on highway (Cd=0.36)
It is the city stop-n-go driving that really kills the MPG.

I have ScanGaugeII mounted so I get to watch the MPG closely.
If I start the CX9, send my kids to school 1 mile away (1 light 4 stop signs) and back. I will get 11mpg. No kidding. That is the way it is.
 
Well from personal experience a KN CAI yes over time increased my MPG (not on this car). ABout a 10% increase.
But gas mileage is something that is affected by many factors and each car responds differently to mods.
If u bought a a 9 trying to get the same mileage of a 6 u are kinda dreaming and should have bought the 6 in first place.
 
SandMan2 said:
do you think the mpg in the 9 is much worse than the V6 sedan would be in daily driving?
Click to expand...


Regardless of the BS you read on this forum about MPG. You will not get 15 MPG around town. It will be more like 13.5 to 14.5.

Thats real life numbers not the inflated crap you read. (gun)
 
So far I'm with you o.c.cx9. I haven't gotten much better than 12.5 in the three tanks I've used so far. I'm not exactly a hypermiler and if I really cared about mpg's I wouldn't be driving it like I do, and probably wouldn't have even bought the thing.
 
I am avg about 16 right now commuting to work, errands, and kids to and from day care. I say we have a good 50/50 mix in Wash. DC traffic. Looking forward to the first oil change and see if the MPGs will improve. On a side note, our 08' Tahoe never avg above 13ish in the same commute.
 
I have ScanGauageII mounted in my CX9. Today, I set it to "gauge" mode so I could monitor IAT (intake air temperature) and compared that to the "outside temperature" displayed from exterior sensor. Guess what? They are almost the same (+/- 3F). In fact, the IAT is actually lower at higher speed.
In my view, the air into CX9's intake is already "cold" enough. Any CAI probably will not see any gain from colder and denser air. Better breathing? Maybe possible with the cone-shape intake, but I have no way to measure that myself.
Just an observation from today's trip (averaging around 60F in north California).
 
Looking at the airbox on the CX, it's pretty efficient. A K&N drop in will probabaly suffice in terms of bang for the buck. I remember there was a huge thread in the WRX/STi forum regarding CAIs. The airbox on the Subies are designed pretty well that most CAIs actually lost power with the exception of K&N Typhoon system.
 
benben01 said:
Looking at the airbox on the CX, it's pretty efficient. A K&N drop in will probabaly suffice in terms of bang for the buck. I remember there was a huge thread in the WRX/STi forum regarding CAIs. The airbox on the Subies are designed pretty well that most CAIs actually lost power with the exception of K&N Typhoon system.
Click to expand...

On my CX-7 I put in the K&N panel filter and took out the noise reduction baffle in the bottom of the air box. There was noticable difference in responsiveness and I doubt an actual CAI would do much more on this particular set-up.
 
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