[OldFart]

Curious if the wide disparity of specific highway mileage experiences of the turbo (some mid 20s, some low 30s US gallons) is somehow related to the exhaust valve seal issue.

 

[Trickster]

Curious if the wide disparity of specific highway mileage experiences of the turbo (some mid 20s, some low 30s US gallons) is somehow related to the exhaust valve seal issue.

I am betting on driving styles, terrain, and traffic.

 

[30pilot]

Curious if the wide disparity of specific highway mileage experiences of the turbo (some mid 20s, some low 30s US gallons) is somehow related to the exhaust valve seal issue.

Maybe oil viscosity? aircraft turbos are very oil/viscosity specific with strict operating procedures.

 

[Trickster]

Maybe oil viscosity? aircraft turbos are very oil/viscosity specific with strict operating procedures.

Thinner oils being used now are for just that reason…..better fuel economy for the manufacturers overall ratings to meet governments criteria.
I can see maybe 1-3 mpg improvements with the thinner oils but that’s about it. IMO.

 

[Theturkeydancer]

Thanks for the replies everyone. I just got back from another highway trip where I achieved only 25.6mpg at 70mph cruise control, flat terrain, AC on. This was a longer trip so I'm more confident in the results, and I'm pretty disappointed.This car should be getting 31-32 under these conditions and we never would have bought it if we knew we'd have to be stopping for gas every 200-250 miles like a v8 sports car.

I still do suspect that something is wrong with the car because my mom's cx5 turbo gets 28mpg all day long and if anything it's a slightly bigger and heavier car that should be getting worse mpg not better. But I don't think these numbers are low enough for the dealer to actually do anything other than give me the standard speech about driving conditions etc.

@OldFart can you point me in the direction of the valve seal issue if you have a spare moment?

 

[KSEGG]

Curious if the wide disparity of specific highway mileage experiences of the turbo (some mid 20s, some low 30s US gallons) is somehow related to the exhaust valve seal issue.

Was this the issue that solved the oil leaking problem in all MY's under 2023?

Thanks for the replies everyone. I just got back from another highway trip where I achieved only 25.6mpg at 70mph cruise control, flat terrain, AC on. This was a longer trip so I'm more confident in the results, and I'm pretty disappointed.This car should be getting 31-32 under these conditions and we never would have bought it if we knew we'd have to be stopping for gas every 200-250 miles like a v8 sports car.

I still do suspect that something is wrong with the car because my mom's cx5 turbo gets 28mpg all day long and if anything it's a slightly bigger and heavier car that should be getting worse mpg not better. But I don't think these numbers are low enough for the dealer to actually do anything other than give me the standard speech about driving conditions etc.

@OldFart can you point me in the direction of the valve seal issue if you have a spare moment?

Had my Turbo for about 5 months and did a variety of driving conditions - my usual lead foot around town to cruising at 65-70 during road trips on open road with no traffic and undulating terrain.

IMO, the Turbo was never meant to achieve MPG beyond 30. The NA can do 30+ all day long in a road trip condition.

Also, are you resetting your average MPG counter every time you do a long distance bit? I noticed the computer sucks at doing actual averages. You need to reset it every time to get far more accurate results.

 

[OldFart]

Thanks for the replies everyone. I just got back from another highway trip where I achieved only 25.6mpg at 70mph cruise control, flat terrain, AC on. This was a longer trip so I'm more confident in the results, and I'm pretty disappointed.This car should be getting 31-32 under these conditions and we never would have bought it if we knew we'd have to be stopping for gas every 200-250 miles like a v8 sports car.

I still do suspect that something is wrong with the car because my mom's cx5 turbo gets 28mpg all day long and if anything it's a slightly bigger and heavier car that should be getting worse mpg not better. But I don't think these numbers are low enough for the dealer to actually do anything other than give me the standard speech about driving conditions etc.

@OldFart can you point me in the direction of the valve seal issue if you have a spare moment?

Is your result based on a manual calculation, or via the onboard system. May be worth doing a manual calc to see if the onboard system is merely off.

As for the Valve Seal Issue....
Here is the TSB https://static.nhtsa.gov/odi/tsbs/2023/MC-10230891-0001.pdf

Here is a thread (may want to skip to the later pages)... Oil Burning

 

[Theturkeydancer]

This is based on manual calculation, resetting the trip computer and then dividing the miles by how many gallons get pumped in at the gas station. Thanks for the links to the info I requested!

 

[Trickster]

Thanks for the replies everyone. I just got back from another highway trip where I achieved only 25.6mpg at 70mph cruise control, flat terrain, AC on. This was a longer trip so I'm more confident in the results, and I'm pretty disappointed.This car should be getting 31-32 under these conditions and we never would have bought it if we knew we'd have to be stopping for gas every 200-250 miles like a v8 sports car.

I still do suspect that something is wrong with the car because my mom's cx5 turbo gets 28mpg all day long and if anything it's a slightly bigger and heavier car that should be getting worse mpg not better. But I don't think these numbers are low enough for the dealer to actually do anything other than give me the standard speech about driving conditions etc.

@OldFart can you point me in the direction of the valve seal issue if you have a spare moment?

So two weeks ago you were getting 22 mpg, now close 26 mpg.
What changed?
It’s a turbo correct?
Top tier fuel?
Try a higher octane, although it defeats the economics you may find it gets better fuel economy.
The 30 has a small tank for sure, but it is a sub compact, so stop will more frequent.
I just returned from an extended road trip in my Turbo 50 and was getting 30mpg on premium Mobil fuel.
I am a coaster to red lights and easy off the line, so maybe it is driving style.
I would be a great chauffeur, the passengers could cut diamonds in the back I am so smooth.🤣

 

[IDD]

Temperature, humidity, gasoline octane, wind, etc. all significantly affect mpg and you need to be very discerning when performing your tests if you want to take the results seriously. Some days I get 26mpg, some days I get 30mpg on the same route at the same avg. speed of 75mph. It's just how it is.

 

[Zepharus]

Hi forum,, this is my first post. My dad has a 2021 turbo with 8k miles on it. I realize the fuel economy of the turbo isn't stellar but we're really getting crappy mileage. The trip computer says 22mpg in mixed driving, and the miles to empty indicator is only 230 on a full tank. I went on a short road trip last weekend and I achieved 25mpg doing steady state 65-70mph on the highway for about 3 hours with AC on, 87 octane. I feel like we should be getting at least 3mpg higher, if not more.

I've checked all the basics. Tire pressure is good, no warning lights, engine feels very strong.

Is anyone else getting numbers like these? Anything else I should check?

My milage didn't improve until about 15k miles on it honestly. getting 25-27 now in mixed

 

[speedmaster]

I don't have a CX-30 but a 2023 Mazda3 Turbo Premium Plus. In Miami, heavy traffic, and the best I could do was 19.9mpg (2000 miles on odometer, still very new). Miami Orlando via Florida's Turnpike, easy traffic, at night, 80mph average I've got 28.2 mpg (90% of the time with cruise control on)

 

[Yellowlt4]

I don't consider 27mpg average over 5k miles with 32mpg on highway trips terrible, especially on 87 octane.

 

[30pilot]

So two weeks ago you were getting 22 mpg, now close 26 mpg.
What changed?
It’s a turbo correct?
Top tier fuel?
Try a higher octane, although it defeats the economics you may find it gets better fuel economy.
The 30 has a small tank for sure, but it is a sub compact, so stop will more frequent.
I just returned from an extended road trip in my Turbo 50 and was getting 30mpg on premium Mobil fuel.
I am a coaster to red lights and easy off the line, so maybe it is driving style.
I would be a great chauffeur, the passengers could cut diamonds in the back I am so smooth.🤣

The size of the tank makes little difference if you have a 200-250 mile bladder in the passenger seat. When the indicator drops below 1/2, It's time to be looking for gas.

 

[Theturkeydancer]

Just last year I was driving a vehicle that had a 225-250 highway range (a moving truck) and I very nearly ran out of gas when one station was closed and the next one was 30-something miles away. I was at 3/8 tank when I started looking.

My dad's cx30, the subject of this thread, is fortunately not as bad as the moving truck. The useful range is about 250 miles, not the total range. Total range 25.6 * 12.7 = 325 miles to empty.

 

[30pilot]

Just last year I was driving a vehicle that had a 225-250 highway range (a moving truck) and I very nearly ran out of gas when one station was closed and the next one was 30-something miles away. I was at 3/8 tank when I started looking.

My dad's cx30, the subject of this thread, is fortunately not as bad as the moving truck. The useful range is about 250 miles, not the total range. Total range 25.6 * 12.7 = 325 miles to empty.

Our 2022 NA 30 has averaged 29.2 mpg, all miles since new, mostly trip miles, cruising at 72 mph on the interstates. Figuring 12 gal capacity in tank, that's 350 range at 29.2 mpg. The most I have seen is 364 miles before the low fuel indicator came on driving alone, lightly loaded, one stop, turn around and return, in dash info indicated 33.2 mpg.

 

[30pilot]

Just last year I was driving a vehicle that had a 225-250 highway range (a moving truck) and I very nearly ran out of gas when one station was closed and the next one was 30-something miles away. I was at 3/8 tank when I started looking.

My dad's cx30, the subject of this thread, is fortunately not as bad as the moving truck. The useful range is about 250 miles, not the total range. Total range 25.6 * 12.7 = 325 miles to empty.

I seem to remember a post about turning off the traction control, drive the car and turning the control back on to help cure this problem, possibly multiple times. I may have this confused with something else, a search may find that post.

 

[KSEGG]

I seem to remember a post about turning off the traction control, drive the car and turning the control back on to help cure this problem, possibly multiple times. I may have this confused with something else, a search may find that post.

I keep forgetting we can turn TCS off. Now I'm curious how it handles without it, lol.

 

[Trickster]

I keep forgetting we can turn TCS off. Now I'm curious how it handles without it, lol.

Unless you are on really slippery surfaces, I doubt you will even notice it off.

 

[30pilot]

I keep forgetting we can turn TCS off. Now I'm curious how it handles without it, lol.

Fun, select manual, use paddle shifters.

Unless you are on really slippery surfaces, I doubt you will even notice it off.

It wont try to correct with throttle or brake inputs. Turn it off, put it in manual, sport mode, and use the paddle shifters, try it, push it, 4k rpm and up.