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Which fuel is better for 2.5 Turbo engine longevity?

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2019 Mazda CX-5 Signature (Machine Gray)
Picked up a CX-5 Sig over the weekend. I understand using regular fuel (87 octane) will reduce the horsepower (I think to around 227HP) and using premium fuel (91-93 octane) will increase the horsepower up to 250.

My question is, what is the best fuel for the longevity of the engine?

My initial thought is premium gas optimizes the engine and ignites under less compression.
However, would this cause additional strain on the engine due to the output?

Is using regular fuel and reducing the HP output, and possibly reducing overall strain, on the engine the way to go?

I bought the Mazda because of the torque and lack of turbo lag (which is the same no matter what fuel is used; 300 ft lbs of torque @ ~2,000 RPMs). The overall horsepower isn't necessarily a big deal to me, as long as I have the power to get power at highway speeds, I'm happy. Overall, I want what is best for the engine's longevity.

Any info is appreciated, thanks!
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
:
Plano, Texas, USA
Mazda says in the official power curve, it's an "unnecessary spending on premium fuel" by 2.5T owners if they drive mostly under 4,000 rpm, because the power is exactly the same between 87 and 93 octan from 0~4,000 rpm. As long as you use Top-Tier gas such as Shell (I prefer) or Costco, that's the best you can do for engine longevity.

 

shadonoz

SkyActiv Member
Contributor
:
State of Jefferson
:
2017 CX-5 GT AWD+
My question is, what is the best fuel for the longevity of the engine?

My initial thought is premium gas optimizes the engine and ignites under less compression.
However, would this cause additional strain on the engine due to the output?

Is using regular fuel and reducing the HP output, and possibly reducing overall strain, on the engine the way to go?
Sounds like you're overthinking this. Use whichever suits your budget and your butt dyno.(drive2)

Any one of a million other things will probably cause you to replace the car before you could wear out the engine from the strain of too much power. It's made to take it.
 
:
CX5 GT-R
Picked up a CX-5 Sig over the weekend. I understand using regular fuel (87 octane) will reduce the horsepower (I think to around 227HP) and using premium fuel (91-93 octane) will increase the horsepower up to 250.

My question is, what is the best fuel for the longevity of the engine?

My initial thought is premium gas optimizes the engine and ignites under less compression.
However, would this cause additional strain on the engine due to the output?

Is using regular fuel and reducing the HP output, and possibly reducing overall strain, on the engine the way to go?

I bought the Mazda because of the torque and lack of turbo lag (which is the same no matter what fuel is used; 300 ft lbs of torque @ ~2,000 RPMs). The overall horsepower isn't necessarily a big deal to me, as long as I have the power to get power at highway speeds, I'm happy. Overall, I want what is best for the engine's longevity.

Any info is appreciated, thanks!
Top Tier fuel is best, regardless. I personally use 91 octane ethanol free Top Tier. It's a whopping 60 cents more per gallon, or $6-8 more per fill-up, so why not? 23hp extra, yo! I also notice a 1-3mpg gain using E-free gas.
 
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CX5 GT-R
Sounds like you're overthinking this. Use whichever suits your budget and your butt dyno.(drive2)

Any one of a million other things will probably cause you to replace the car before you could wear out the engine from the strain of too much power. It's made to take it.
The CX5 engine is stoopidly over-engineered. I am honestly astounded any company would dump this level of R&D into a CUV's drivetrain.
 
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2019 Mazda CX-5 Signature (Machine Gray)
Mazda says in the official power curve, it's an "unnecessary spending on premium fuel" by 2.5T owners if they drive mostly under 4,000 rpm, because the power is exactly the same between 87 and 93 octan from 0~4,000 rpm. As long as you use Top-Tier gas such as Shell (I prefer) or Costco, that's the best you can do for engine longevity.
Awesome! Premium is almost $1 more in Ohio (in my area) and they just introduced a gas tax to increase the price further. I'll likely stick to regular then since I don't plan on racing it all the time. I always purchase Shell gas (don't belong to Costco) since I've read it's better than most. Thanks!
 
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2019 Mazda CX-5 Signature (Machine Gray)
Sounds like you're overthinking this. Use whichever suits your budget and your butt dyno.(drive2)

Any one of a million other things will probably cause you to replace the car before you could wear out the engine from the strain of too much power. It's made to take it.
Probably am :) and I lol'd at butt dyno. Good points, thanks!
 
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2019 Mazda CX-5 Signature (Machine Gray)
Top Tier fuel is best, regardless. I personally use 91 octane ethanol free Top Tier. It's a whopping 60 cents more per gallon, or $6-8 more per fill-up, so why not? 23hp extra, yo! I also notice a 1-3mpg gain using E-free gas.
I'll have to check and see if I'm getting Top Tier, I think Shell is considered this? It's been awhile since I've had a car I didn't lease so I wasnt as concerned in the past 3 years. I'll have to double check if it's E-Free. Appreciate the feedback, thanks!
 
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CX5 GT-R
I'll have to check and see if I'm getting Top Tier, I think Shell is considered this? It's been awhile since I've had a car I didn't lease so I wasnt as concerned in the past 3 years. I'll have to double check if it's E-Free. Appreciate the feedback, thanks!
Shell is TT, but I'm 99.99% sure it's E10.

For reference, I am paying $2.8X/gal for 91 octane TT E0.
 

NelsonLewis

Banned
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16.5 CX-5 GT AWD w/Tech BRMica
87 octane on a stocker. Both are gonna be pulling timing and running rich as hell for a safety net anyways, so detonation chances are roughly the same with both.

The 93 octane may gain 23hp on the top end, but it's still held back by aforementioned safety net...A tuner's dream...
 
4

40752

I*ve been using 89 non ethanol, and it*s about .50 more a gallon than 87 ethanol.
 
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Ottawa, Ontario
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17 Mazda 6 GT
The CX5 engine is stoopidly over-engineered.
They can't afford to not have this engine work properly, considering it is used across the entire product line. It's their go to engine.
If it were a badly engineered engine, they'd be in deep doodoo.
I've driven Nissans over the years, and they're in the same situation with their VQ35 V6 engine.
It's been used in every Nissan and Infiniti since 2001, and thankfully for them, it's a good engine.
If it wasn't, Nissan would be up the creek.
That's why I've been interested in what happens with the 1.5l turbo engine from Honda.
It's going to be their go to engine for the next 10 years (probably), and if they can't sort out this gas in oil issue, then they're screwed.
 
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CX5 GT-R
87 octane on a stocker. Both are gonna be pulling timing and running rich as hell for a safety net anyways, so detonation chances are roughly the same with both.

The 93 octane may gain 23hp on the top end, but it's still held back by aforementioned safety net...A tuner's dream...
Given t he torque, I'd say the leash is as much for detonation control as it is drivetrain component longevity.
 
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CX5 GT-R
They can't afford to not have this engine work properly, considering it is used across the entire product line. It's their go to engine.
If it were a badly engineered engine, they'd be in deep doodoo.
I've driven Nissans over the years, and they're in the same situation with their VQ35 V6 engine.
It's been used in every Nissan and Infiniti since 2001, and thankfully for them, it's a good engine.
If it wasn't, Nissan would be up the creek.
That's why I've been interested in what happens with the 1.5l turbo engine from Honda.
It's going to be their go to engine for the next 10 years (probably), and if they can't sort out this gas in oil issue, then they're screwed.
Mazda did really well with SkyActiv, IMO. They really did. It reminds me of GM's LSX engine series. Infinitely modular, and damn well executed with more efficiency and performance than competing brands.
 

NelsonLewis

Banned
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16.5 CX-5 GT AWD w/Tech BRMica
Mazda did really well with SkyActiv, IMO. They really did. It reminds me of GM's LSX engine series. Infinitely modular, and damn well executed with more efficiency and performance than competing brands.
Performance? 187 hp out of a 2.5L in NA form is piss poor performance, especially running that much compression...
 
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CX5 GT-R
Performance? 187 hp out of a 2.5L in NA form is piss poor performance, especially running that much compression...
But it's in a 3500# vehicle, and it's about area under the curve and the torque curve. Find me another 2.5 NA motor that runs on 87 octane and provides such a meaty torque curve.
 
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