JK 23112

Why is your 88 octane ten cents cheaper than 87 octane? That seems bizarre to me.

As for Murphy, I guess that must be a regional chain or something. We don't have them in Virginia.

Gearhead Jim

Joe-
My2017 manual says 93 is "highly recommended", it says lower grades can be used but with reduced performance, reduced mileage, and possible knocking that could lead to engine damage. That certainly would not be "recommended", and they don't use that word. It would be permissible, if you are willing to accept the penalties. Here's a cut and paste from my 2017 manual, pp. 213-214:


For the LT1 6.2L engine, premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 93 is highly recommended for best performance and fuel economy. Unleaded gasoline with an octane rated as low as 87 can be used. Using unleaded gasoline rated below 93 octane, however, will lead to reduced acceleration and fuel economy. If knocking occurs, use a gasoline rated at 93 octane as soon as possible, otherwise, the engine could be damaged.

JerryU

You are delusional or smoking something!

Try bottom of page 213 to top of page 214 of the 2017 Owner's manual, quoting that sentence exactly:

"For the LT1 6.2L engine, premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 93 is highly recommended for best performance and fuel economy."


That is from the published PDF version of the Owner's Manual, which is searchable and i can cut and paste! That is how I get this stuff so quickly! I don't type it!

Skid Row Joe

Apparently, it depends on which page(s) you're reading and quoting from then.

Jerry has made up so many BS quotes on fake fuel recommendations, he's probably delusional. His posts certainly are false op ed pieces.

The bottom line is that GM Chevrolet Corvette 2017 Owners Manual recommends using 87 octane.

You can't claim they don't. 87 is perfectly fine to use in your 2017 Corvette.

Skid Row Joe

I don't know, but my 2017 C7 runs perfectly fine on 87 or greater numbered gasoline. I posted exactly what I have available at the Murphy's Oil I routinely fill up at. 88 no problem. It passes GM's 2017 Corvette Owners Manual recommendation of 87.

Foosh

Sure, if you never rev the engine past 3K rpm or so, you'll be fine on 87 octane. The actual recommendation was, prior to the 18MY, 91 or greater, assuming some Corvette owners might actually use the entire rev range from time-to-time. However, for 2018, the manual language has changed on the identical engine. 93 is now "HIGHLY RECOMMENDED." 87 has never been recommended, but acceptable for gentle use.

Below is the language from the 2018 owner's manual.

For the LT1 6.2L engine, premium
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 93 is HIGHLY
recommended for best performance
and fuel economy. Unleaded
gasoline with an octane rated as low
as 87 can be used. Using unleaded
gasoline rated below 93 octane,
however, will lead to reduced
acceleration and fuel economy.
If knocking occurs, use a gasoline
rated at 93 octane as soon as
possible, otherwise, the engine
could be damaged. If heavy
knocking is heard when using
gasoline with a 93 octane rating, the
engine needs service.

Skid Row Joe

Not according to GM, and your own post below:

87 is still gold for 2018. Great to read.

JerryU

Jerry does't make up BS posts- he doesn't need to! He researches the issue and in this case used the search feature in the PDF of the 2017 Owner's Manual as he knew it said it somewhere. Took <1 minute to find the related pages! Then he just highlighted, copied and pasted in the post. NOT his words-GM's exactly! Yep unlike some others he took the short time format properly!

The fact that you cannot understand his simple explanations is not his fault!

Read The SIDE BAR in his post #28 on advice he gave to his friend with his turbo 4 cylinder in a large sedan that insisted on using regular in a car that needed high test! If you never want to accelerate fast and shift at low RPM you'll probably be OK. But why did you buy a Vette- to impress girls?

Jerry doesn't mine entertaining the Forum folks (~1400 of the silent majority have viewed this silly post versus the ~25 of us vocal minority who have posted) with his posts as it appears you do as well since he can't believe anyone is a foolish as your posts reflect!

Dave80C3

I posted a the quote out of the 18 manual.

Highly recommend is what it says about 93.

It no where recommends 87, it says it can be used. Big difference.

It also never said recommend in my 14 manual for 87, again it is can be used.

Can be used and recommended are not the same.

Try reading comprehension 101. Made them bold read so its easier to see.

1SG_Ret

I suppose if someone spends $60K or more for a car and wants to run the least expensive fuel in their car, it's their prerogative. Who am I to argue with them, anymore than telling them what they should eat, whether they should smoke or how much they should drink.

Time catches us all in the end and we just have to accept the consequences of our choices.

6spdC6

Roughly the equivalent of going to the best steak house and ordering a hot dog.

Foosh

You said 87 is "recommended". It is not recommended for any MY, and you are incorrect. The manual language says 87 "can be used" with caveats as the language clearly states.

There is a fundamental difference between recommending something vs. saying something can be used with care but that you will experience performance degradation.

If "good as gold" means the clearly stipulated performance degradation is OK with you, then that's just the way your brain is wired. I'm happy mine is NOT wired that way.

Reading comprehension certainly is fundamental!

PatternDayTrader

Lol ... yeah I love read comprehension.

turbota

Wow Its that high again in some areas.

PatternDayTrader

Holy flurking schnitt !!!!
You gotta be kidding me !

Gearhead Jim

Joe-
It's been many years since I added a CF member to my "Ignore" list, but you are now the one and only name there.

911Hunter

Maybe this practice could save you the GDI Induction service cost of $129 at the Dealership. Probably I should follow that good practice.

Patman

That induction service could possibly include cleaning the back of the intake valves though, and that's something that injector cleaner in the tank cannot do on a direct injection engine since fresh fuel does not wash over the intake valves like it does on a port injected engine.

911Hunter

My car is just 32,000 miles, and after a multipoint inspection dealer recommend it. Is that common with this Corvette engines? And how frequently needs to be performed?

JerryU

Would be interesting to see what their multipoint inspection is and showed. As noted by Patman adding "stuff" to the fuel does nothing for DI coking as there is no fuel passing over the intake valves.

There are some liquids that are put through the throttle body but somewhat similar to that BS test of Techron, once carbon has deposited, a fluid will not dissolve much carbon on pistons where it can accumulate. The use of Top Tier fuel can help the piston carbon accumulation before it occurs.

They key is to have as little deposit as possible in the first place!

GM via a Tadge old post said the coking in a C7 is a "cosmetic issue." Others have said it's more! I find it interesting that GM has improved the PCV system in newer dry sumps so less oil is sent into the intake. That was well after Tadge said it was cosmetic! Me thinks they spent that engineering time and cost for a reason!

However even the new PCV system does not stop all oil from entering the intake as I still collect some in my improved Grand Sport system with my "catch can" than I did in my Z51. Don't want to start a discussion if one is needed as don't know what percentage of oil and coking I stop but IMO ~$150 is worth catching some so it does not enter the intake to bake on my hot intake valves!

Ferrari was considering recommending a liquid cleaner system injected in the throttle body to be used by the dealer at each oil change. But I don't think that was every implemented. You can google there are systems sold that inject a "cleaner" and some YouTube videos showing it's effectiveness. Yep even Ferrari has coking in their DI engines!

BMW and others have used walnut shell blasting, which can remove the baked on carbon deposits, called coking. But that requires removing the intake manifold, blasting each intake valve and would cost more than $129!

Might ask the dealer what they will do for $129 but frankly doubt it is worth it! Some dealers claim they clean the throttle body but I don't see a need!

If you find out let us know.