2018 GT MPG 87 vs. 93 octane

[michail71]

Given the ECU adjusts to the fuel does anyone know if the fuel efficiency is better on the higher octane for these cars?

I though I would be spending a great deal more on fuel for this car compared to my prior Turbo 4. But being able to run 87 octane actually brings the cost much closer.

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[millhouse]

Given the ECU adjusts to the fuel does anyone know if the fuel efficiency is better on the higher octane for these cars?

I though I would be spending a great deal more on fuel for this car compared to my prior Turbo 4. But being able to run 87 octane actually brings the cost much closer.

If it's anything like the 2015-2017....not much.

https://newsroom.aaa.com/wp-content...ium-Fuel-Phase-II-Research-Report-FINAL-2.pdf

 

[michail71]

If it's anything like the 2015-2017....not much.

https://newsroom.aaa.com/wp-content...ium-Fuel-Phase-II-Research-Report-FINAL-2.pdf

Interesting article.

They showed a 2.3% increase for the 2015-2017 GT. Considering the fuel cost difference of 20% it's rather obvious. Although I would be shocked to see a bump in economy by 20+%.

But my takeaway is if you are coming from a turbo 4 (which usually require 93 octane in many markets) the fuel cost isn't as bad as you may think going to a 5.0L GT.

 

[Loki-GT]

I know they found a way to make it possible to run 87 junktain in a 12.01 compression motor but that means the computer/knock sensors are working hard to keep knock down to make everything happy.

If people want to save money on gas they should buy a Prius.

 

[michail71]

I know they found a way to make it possible to run 87 junktain in a 12.01 compression motor but that means the computer/knock sensors are working hard to keep knock down to make everything happy.

If people want to save money on gas they should buy a Prius.

Has anyone run logging to see the difference in normal driving conditions? I'd be curios to see hard data on timing and knock sensors.

 

[millhouse]

I know they found a way to make it possible to run 87 junktain in a 12.01 compression motor but that means the computer/knock sensors are working hard to keep knock down to make everything happy.

If people want to save money on gas they should buy a Prius.

If 87 is the minimum recommended fuel, there is nothing wrong in being frugal on somethtine that makes virtually no difference for a daily driver. I’ve discussed this before, driving 18k miles a year makes it a no brained for me to run 87 octane. I don’t race it on the steet and as such, wont notice a difference.

 

[Loki-GT]

Has anyone run logging to see the difference in normal driving conditions? I'd be curios to see hard data on timing and knock sensors.

Agreed, I would too, I'm old school so its hard to sell me on it being just fine to run 87 on a daily basis in a 12.01 motor knowing how much work the computer/sensors have to be cutting back to keep knock at bay.

I'd love to be proved wrong but they did add 2 knock sensors to the 2018.

 

[michail71]

I may try that out. I've been looking at some Forscan adapters.

I'm still in the break in period so I've been easy in the throttle so far.

 

[growler]

3.5 ecoboost in a pickup gained 1 mpg 93 over 87 high speed driving over 6 months..you gain... but it aint worth it

 

[Kansas GT]

I ran 92 octane for the first 1000 miles and switched to 87 octane after that. Fuel economy was not impacted according to the onboard, and I haven't experienced a noticeable decrease in power. I know the power loss is probably there, but I don't track my car. Mine's a daily with occasional spirited driving.

I'm curious to see hard data on timing and knock sensors as well. I ran 87 from the start with my 3.5 EB F-150 and had no ill effects. If the manual says a minimum of 87 is recommended, I don't mind running that. I'm also not overly concerned about long-term reliability since I rarely keep new vehicles out of warranty.

 

[Mr. Met]

I always use 93 now. When I first got the car I was using 87 but I wanted to see if I could feel any difference between it and 93 and I certainly can (performance not mpg). Also according to the 0 to 60 timer my best on 93 was 1/5 of a second quicker. Even if I assume I am not getting any better mpg, if I averaged 20mpg and drove 15,000 miles it would cost me $270 a year or $.74 a day to use 93 over 87. Not really that costly.

 

[millhouse]

I always use 93 now. When I first got the car I was using 87 but I wanted to see if I could feel any difference between it and 93 and I certainly can (performance not mpg). Also according to the 0 to 60 timer my best on 93 was 1/5 of a second quicker. Even if I assume I am not getting any better mpg, if I averaged 20mpg and drove 15,000 miles it would cost me $270 a year or $.74 a day to use 93 over 87. Not really that costly.

Most people can absorb $270/year, but the question for most is...is it worth it? I can't fault anyone that says yes...but most people would flip their shit if their insurance went up $270/year...or if their phone bill went up $270/year.

It's all in the value of what the $270 gives you. For me, it's closer to $500. ;)...and it's a no-brainier.

Again, I don't have any data for the MY18....but the link I posted shows the dyno for the MY17, and the difference is so insignificant that it can't be felt but only measured.

I've said it before...using Top Tier fuel is far more important for these cars than running premium.

 

[Zelek]

The stock tune doesn't have much timing advance that I'm sure it can run on 87 octane just fine. Once you're tuned, you'll notice the real difference in using 93 octane instead of 87.

How some people can drive this car without giving it some throttle is beyond me.

 

[ctandc72]

I know they found a way to make it possible to run 87 junktain in a 12.01 compression motor but that means the computer/knock sensors are working hard to keep knock down to make everything happy.

If people want to save money on gas they should buy a Prius.

Not saying I don't agree with your post - but using the compression ratio isn't a great way to get it across. Comparing compression ratio to octane / knock retard / spark knock in Direct Injected engine is a lot different than a conventional engine. Would I run 87 in a GT? No - I don't even run it in my V6. I've seen valve and internals after running 87 octane versus 91/93. But that's just my personal opinion.

 

[wireeater]

The whole anti 87 crap in a sports car is about as dumb as the not having a V8 in a Mustang argument. I'm almost certain that if you put a tank of 87 in your GT you will have just as much fun as you did when you put a tank of 93 in it. It just means you can have just as much fun for a little cheaper.

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