Given that the compression of our2 engines choices are 9.7 and 9.8...

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palmerwmd
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Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby palmerwmd » Sun Jan 24, 2021 6:27 pm

Given that the compression of our 2 engines care 9.7 and 9.8... Should we be able to run regular to no ill effects?

I am running premium in my truck and I feel it likes it.. on the long delivery drive i believe I saw an improvement in mpg after the first tankful (I presume the ECU figuring out its on premium now)

I am not destittue but I am not made of money either.
Maybe mid range or regular should be another choice given our compression ratios for both the V6 and V8?

When these two engine designs originally came on the market the price difference between regular and premium was only 10% or so.. trivial.. and I would fuel up on premium all the time.
But now its 30% and more... :|


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Re: Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby smj999smj » Mon Jan 25, 2021 3:24 am

Look at what's on the inside of the gas filler cover. If it says that premium is recommended for maximum performance, than you can use 87 octane. If it say premium fuel is "required," then use premium fuel. That said, in my experience, VQ and VK engines tend to run a little smoother on premium.

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Re: Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby palmerwmd » Mon Jan 25, 2021 7:43 pm

smj999smj wrote:
Mon Jan 25, 2021 3:24 am
Look at what's on the inside of the gas filler cover. If it says that premium is recommended for maximum performance, than you can use 87 octane. If it say premium fuel is "required," then use premium fuel. That said, in my experience, VQ and VK engines tend to run a little smoother on premium.
That is what I was thinking but needed a 2nd opinion.

When I got this vehicle I did all premium.
but I been doing so much driving mostly gentle rural hiway driving, premium seems like a waste.
Topped off with 89 Octane midrange today.
So tank is about 55% midrange and 45% 93 Octane.
Still smooth.

Next step will keep running it on mid range until tank is all 89 and see if it affects anything.
Of course in cool weather with gentle hiway driving thats not a very tough test...

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Re: Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby palmerwmd » Sun Feb 07, 2021 8:54 pm

I just found out from a forum guy who has been a petroleum inspector who tests fuels at gas stations that he has never tested mid range at less than 90 Octane.
He also says there is a 50/50 chance that midrange will actually be that particular stations premium.

So I think my new fuel strategy is going to be centered on mid range.
(Unless I decide to tow heavy at sealevel in summer)

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Re: Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby silverarrow27 » Tue Feb 09, 2021 1:24 am

I knew a general manager of a local gas station. She said mid-grade, 89, is just a mixture of 87 & 91. There's is no mid-grade tank underground. Nonetheless, I've always done 91 octane on any car that recommends it, one of those things where you'll never know when you need that extra performance.

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Re: Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby smj999smj » Wed Feb 10, 2021 5:36 pm

silverarrow27 wrote:
Tue Feb 09, 2021 1:24 am
I knew a general manager of a local gas station. She said mid-grade, 89, is just a mixture of 87 & 91. There's is no mid-grade tank underground. Nonetheless, I've always done 91 octane on any car that recommends it, one of those things where you'll never know when you need that extra performance.
You're correct; there is no "mid-grade" tank in the ground. The "mid-grade" is made by a combination of the two at the pump. In the mid-80s when Sunoco Ultra Premium made its debut and was the highest octane available on the street (costing a "whopping" $1.32/gallon!), I was working for a Sunoco station and we had three tanks: one for regular leaded, one for unleaded "economy" and one for Ultra unleaded. The regular leaded had it's own pump. The unleaded grades were all pulled from the two, unleaded tanks in the ground.

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Re: Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby palmerwmd » Wed Feb 10, 2021 5:45 pm

Gents,

am well aware they are mixes :)

But alas in my area when u mix 93 w/ 87 we get a combined 90.
Which is consistent from what this petroleum tester claims.

Give that premium in much of the US is only 1 octane better (91) I feel pretty good about midrange now.
:wink:

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Re: Given that the compression of our2 engines choices are 9.7 and 9.8...

Postby smj999smj » Wed Feb 10, 2021 5:51 pm

Premium is 93 octane around me. Let's me use that Superchips 93 Performance tune on my Pathy and also keeps my 03 Frontier's supercharged 3.3L happy!


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