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[ANSWERED] 17 z06 running on 91 octane

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[ANSWERED] 17 z06 running on 91 octane

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Old 02-02-2018, 07:15 AM
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jvp
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Default [ANSWERED] 17 z06 running on 91 octane

The original question is here.

jgzo6 asked:
I have a 17 z06 and live in las vegas. I use chevron and the highest octane I can find is 91at any brand name gas. The local chev dealer told me 91 is fine I have read that the 17 z06 is tuned different than a 15or16 and that's why the owners states 93. I have called GM and was told it will have a slight impact on performance. What I am concerned about is the effect on engine life and no one has answered that question for me .. My z06 is driven on the street only and used for long trips Engine longevity is important to me.
Tadge answered:
The tuning change between model years 15/16 and 17 does not affect engine operation during typical street driving. If you are not working the engine hard, there is little to no difference between 91 and 93 octane fuels. Even in high torque/Hp operation, there will only be slight performance degradation and the ECM (engine control module) will protect the engine from damage over the life of the car. The bottom line is that you needn't worry at all about using 91 octane pump fuel.
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Old 02-02-2018, 12:34 PM
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Ugh, this question could have been asked so much better.

-what performance characteristics were changed in 2017 and what are the implications of 91 octane vs 93 in regards to daily driving, track usage, and maximal power output.
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Old 02-04-2018, 04:53 PM
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Originally Posted by Pacembellum View Post
Ugh, this question could have been asked so much better.

-what performance characteristics were changed in 2017 and what are the implications of 91 octane vs 93 in regards to daily driving, track usage, and maximal power output.
it could be the 2017ís have a more aggressive tune towards performance on the track in extreme conditions requiring 93 to exploit that tune along with enhancements to the supercharger which provided enhanced cooling. However Tadge is saying us owners of the 2017ís can get by with 91 on the street with spirited driving and it wonít hurt the car. In any event I am disappointed in the performance of my 2017z compared to my 2009 c6z. While the 2017z is good down low in first and 2nd gear On the upper rpm operation in 2nd , 3rd and 4th I think my stock 2009 c6z would walk away from my stock 2017z or for that matter any stock 2015, 16 or 17 c7z. (I test drove quite a few 2016 and 2017 c7zís and they all seemed to be dogs up high). But not having to worry about the ls7 dropping valves even after they are repaired being no guarantee that fixed the problem was the reason I chose to move into a c7z. The c7z is still pretty good bang for the buck and a removable roof and better interior with exception of the silly dashboard is a good conciliation prize for the c7zís lack of performance on the big end.

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Old 02-05-2018, 10:46 PM
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Originally Posted by Mr. Gizmo View Post


it could be the 2017ís have a more aggressive tune towards performance on the track in extreme conditions requiring 93 to exploit that tune along with enhancements to the supercharger which provided enhanced cooling. However Tadge is saying us owners of the 2017ís can get by with 91 on the street with spirited driving and it wonít hurt the car. In any event I am disappointed in the performance of my 2017z compared to my 2009 c6z. While the 2017z is good down low in first and 2nd gear On the upper rpm operation in 2nd , 3rd and 4th I think my stock 2009 c6z would walk away from my stock 2017z or for that matter any stock 2015, 16 or 17 c7z. (I test drove quite a few 2016 and 2017 c7zís and they all seemed to be dogs up high).
You think a stock C6Z with 505hp is going to walk away from a C7Z with 650hp? Ok.
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Old 02-05-2018, 11:04 PM
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Originally Posted by Patman View Post
You think a stock C6Z with 505hp is going to walk away from a C7Z with 650hp? Ok.
figure a c7z on 91 is only making 630 crank, now figure it's hot (abive 86 degrees) and pulling timing...down to 600 crank. C6z was underrated and not as temp sensitive and 275lb lighter, i could believe it at keast "feeling" close.
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Old 02-05-2018, 11:09 PM
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》》Engine longevity is important to me.

My 2017 z06 car knocks and pings on Shell 91. My opinion is this has to be hard on the engine so I mix it with some 100 unleaded from Rebel stations or torco/boostane. No more knock, ping, or excessive KR.
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Old 02-06-2018, 10:34 AM
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^^^^
If your engine is knocking on 91 octane, I would take it in to be checked. It should NOT be knocking on 91.
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Old 02-06-2018, 11:15 PM
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another thing people don't mention is altitude. the general rule of thumb is for every 2500' of elevation, you can go down a point of octane with minimal difference in performance due to the air density decrease.
granted, at 2000', las vegas ain't high enough to warrant 91, but other areas in the mountains do. that's how they try & make the argument for that trash 85. unfortunately, it seems tons of places west of the mississippi just don't want to source 93
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Old 02-07-2018, 05:36 AM
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Temperature also plays a factor in octane requirement. In cooler weather you can get away with lower octane, my wife's BMW calls for 91 octane but in the cold winter months I usually put in 89. And I recall with my old C5, which was tuned, it would audibly ping on 91 in the summer but it wouldn't ping at all in cooler weather (I mostly ran 94 octane in it during the hot months)
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Old 02-07-2018, 09:16 PM
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Default Poster Comments on Mixing Different Octane Fuels

I was taught in my engineering classes (both shade tree and classroom) that different octane fuels do not mix. I.E.: if you mix 10 gallons of 91 octane and 10 gallons of 93 octane in the same tank (I know, will not fit in a C7 fuel tank, thank you) you don't get 20 gallons of 92 octane fuel - you still have 10 gallons of 91 and 10 gallons of 93. https://www.corvetteforum.com/forums...withstupid.gif
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Old 02-08-2018, 02:02 PM
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Originally Posted by Tom's '07 Monty View Post
I was taught in my engineering classes (both shade tree and classroom) that different octane fuels do not mix. I.E.: if you mix 10 gallons of 91 octane and 10 gallons of 93 octane in the same tank (I know, will not fit in a C7 fuel tank, thank you) you don't get 20 gallons of 92 octane fuel - you still have 10 gallons of 91 and 10 gallons of 93. https://www.corvetteforum.com/forums...withstupid.gif

Interesting. I'm not a fuels engineer, but I understand that stations pumping 89 octane midgrade fuel produce it at the pump by simply mixing regular and premium fuels.
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Old 02-08-2018, 10:56 PM
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From what I have read and been told by local oil producers (I am located in North Central Texas) that most refined oil - fuel is shipped to distribution centers and the distribution centers add additives from the different brands of gasoline. Then the distribution center delivers it to the appropriate retail outlet. When is the last time you saw an EXXon or Phillips tanker at a gas station (i.e. convenience store)?
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Old 02-09-2018, 01:53 AM
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Originally Posted by Mr. Gizmo View Post


it could be the 2017ís have a more aggressive tune towards performance on the track in extreme conditions requiring 93 to exploit that tune along with enhancements to the supercharger which provided enhanced cooling. However Tadge is saying us owners of the 2017ís can get by with 91 on the street with spirited driving and it wonít hurt the car. In any event I am disappointed in the performance of my 2017z compared to my 2009 c6z. While the 2017z is good down low in first and 2nd gear On the upper rpm operation in 2nd , 3rd and 4th I think my stock 2009 c6z would walk away from my stock 2017z or for that matter any stock 2015, 16 or 17 c7z. (I test drove quite a few 2016 and 2017 c7zís and they all seemed to be dogs up high). But not having to worry about the ls7 dropping valves even after they are repaired being no guarantee that fixed the problem was the reason I chose to move into a c7z. The c7z is still pretty good bang for the buck and a removable roof and better interior with exception of the silly dashboard is a good conciliation prize for the c7zís lack of performance on the big end.
I bought my 2016 ZO7 M7 in Missouri where you can get 93 Octane. In the winter months the car was super fast. When I took the car home to Calif and used the worst 91 on the planet the car did not pull as hard. It was still fast but not fierce.
I track my car at least twice a month. When GM offered the 100 Octane Calibration it changed the entire feel of my car. With 100 Octane gas and the new calibration the car pulls hard all the way to 6000 RPM. Even in 90 degree temp. I will buy 100 Octane at the track. During highway driving I am forced to use 91 and I throw a can of Torco or Boostane in and the acceleration remains pretty strong. But all of this is a pain in the *** & expensive. 100 Octane at the track is $10 per gal. A can of Boostane is $30. One can should raise the Octane to about 96 or 97. To get to a hundred or 102 it will require a second can for a total of $60 per 15 gal
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Old 02-09-2018, 08:08 PM
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Originally Posted by Duck916 View Post
Interesting. I'm not a fuels engineer, but I understand that stations pumping 89 octane midgrade fuel produce it at the pump by simply mixing regular and premium fuels.
this is correct!
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Old 02-11-2018, 11:35 AM
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Originally Posted by Patman View Post
Temperature also plays a factor in octane requirement. In cooler weather you can get away with lower octane, my wife's BMW calls for 91 octane but in the cold winter months I usually put in 89. And I recall with my old C5, which was tuned, it would audibly ping on 91 in the summer but it wouldn't ping at all in cooler weather (I mostly ran 94 octane in it during the hot months)
you could probably run any non M bmw on 87. AAA just did a huge gas test 87 vs 93 and very little difference on most cars.
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Old 02-13-2018, 01:51 AM
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Originally Posted by Z06_BluByU View Post
this is correct!
where did you hear that? I donít think this is correct in all cases. I work for a major oil and gas company and we Have mid grade available in our terminals.

Last edited by sromley; 02-13-2018 at 01:59 AM.
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Old 02-13-2018, 04:24 PM
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Originally Posted by sromley View Post
where did you hear that? I donít think this is correct in all cases. I work for a major oil and gas company and we Have mid grade available in our terminals.
That's interesting, because I had always thought (taught) there were two large tanks for the 3 blends: 87 and 91. To get 89 is a blend of both 87 and 91.

"Internerd Source" One pump, three grades: How does it know?
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Old 02-14-2018, 10:42 AM
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Originally Posted by Patman View Post
You think a stock C6Z with 505hp is going to walk away from a C7Z with 650hp? Ok.
Uhh...yeah.

2006 Z06 can do easily 11.5 sec @ 127.1 mph. Some have even hit 10s. Even a C6 ZR1 will out muscle a C7 Z06. Weight and parasitic heat losses with the blower really hurt the new generation. The ZR1 coming out should have been the Z06. The current Z06 is a let down.

http://www.motortrend.com/cars/chevr...-corvette-z06/

http://www.corvetteblog.com/2007/12/...econd-14-mile/
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Old 02-14-2018, 10:46 PM
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Originally Posted by sromley View Post


where did you hear that? I donít think this is correct in all cases. I work for a major oil and gas company and we Have mid grade available in our terminals.
i was a mechanic at a shell in my younger years... tankers had two compartments that filled two tanks in the ground which we had to Ďstickí ea morning.. but we had three grades of gas.... the blend 89
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Old 02-20-2018, 11:18 PM
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Going back to the original question and Tadge's answer, it isn't clear whether his answer applies only to the Z06 or to all 2017 & later Corvettes.
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