The building of knuckles

LoPo said:
What are you talking about? Just about every gas station has 87 around here.

BTW Galena Market isn't a Chevron anymore. I think it's a 76 now. ;)
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Really? When did it change? :cheesy:

Now I'm going I have to look next time I stop for gas. Which one of the following octanes is not normal? I just assumed 87 was some shit gas Mavrick was pimpin.

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Two things I confirmed today:
1) I've been working too much and need more sleep
2) I don't know much about gas

Wait, was that three?
 
I do notice when I run the premium my rig does not ping like it does when I run 87. I do believe manual does say 87 though.
 
I've never seen a gas station by me have 90... That seems kinda stupid to have lol

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catahoula said:
I do notice when I run the premium my rig does not ping like it does when I run 87. I do believe manual does say 87 though.
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for a 2007-2011 the compression ratio is 9.6:1 with that you should be running 89-91 octane fuel or else it will ping and run like crap and get worse fuel mileage 2012-2014 is 10.2:1 and you should run 91 no less. and as always if i am wrong just give me the info in a non flaming manor and ill gladly listen :yup:
 
GCM 2 said:
I say let him try.....I want to see if he can fit that much nozzle girth in to his jeeps orifice.


Authors note; first time in forum history the words "nozzle, girth, and orifice" have been used in one sentence.
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:cheesy::cheesy::cheesy::cheesy::cheesy: man i love gregs humor!!!
 
I've been told the way it works is the station gets only two different octanes, the 87 and the 91. They then blend them in the pump to make a mid grade.

You should always run the lowest octane that your vehicle runs properly on. My 2012 runs fine on 87 so it would be a waste of money to run higher. My motorcycle needs premium in the summer but can run on 89 when they switch to the winter blend. Unless you get knocking, pinging or run on I would stick with the 87.
 
Tigrcky said:
for a 2007-2011 the compression ratio is 9.6:1.....
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I have a limited edition 2009 Rubicon, it came with the 3.8L High Output. These highly sought after motors had the 9.6352:1 compression ratios. Had my salesman not walked me to a special place at the back of the dealer lot and not set this particular Rubi aside while I waited for special pricing, I would have missed a great purchase.
 
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GCM 2 said:
I have a limited edition 2009 Rubicon, it came with the 3.8L High Output. These highly sought after motors had the 9.6352:1 compression ratios. Had my salesman walked me to a special place at the back of the dealer lot and not set this particular Rubi aside while I waited for special pricing, I would have missed a great purchase.
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Not to mention the sweet undercoating.:rock:
 
Tigrcky said:
for a 2007-2011 the compression ratio is 9.6:1 with that you should be running 89-91 octane fuel or else it will ping and run like crap and get worse fuel mileage 2012-2014 is 10.2:1 and you should run 91 no less. and as always if i am wrong just give me the info in a non flaming manor and ill gladly listen :yup:
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There are other things in to determine the required octane of fuel. Almost all engines today are manufactured to run on 87. Even my Mazda which has the new Skyactiv engine that has over 12:1 runs well on 87 and this is what the manual suggests.

I run 87 most of the time in our 13' JK and there is never any ping. This said, today's fuel has a precentage of ethanol in it. Ethanol loses it's octane very quickly. So I put higher octane in when I know I will not run through a full tank in a month. (Not a daily driver and in winter)


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jnabird333 said:
There are other things in to determine the required octane of fuel. Almost all engines today are manufactured to run on 87. Even my Mazda which has the new Skyactiv engine that has over 12:1 runs well on 87 and this is what the manual suggests.

I run 87 most of the time in our 13' JK and there is never any ping. This said, today's fuel has a precentage of ethanol in it. Ethanol loses it's octane very quickly. So I put higher octane in when I know I will not run through a full tank in a month. (Not a daily driver and in winter)


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interesting new info on the ethanol... another reason to hate that crap but i have built up many engines and i know personally that running to low of octane in an engine can cause predetonation to occur and takes the bang out of the compressed air fuel mixture in the cylinder, but lets just put it to real world testing run either and which ever gives you the best power and fuel mileage just run that :thumb:

edit- with the constant computer controlled timing it is very possible that they are adjusting for the predetonation by retarding the spark thus proving your point!!!
 
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GCM 2 said:
I have a limited edition 2009 Rubicon, it came with the 3.8L High Output. These highly sought after motors had the 9.6352:1 compression ratios. Had my salesman not walked me to a special place at the back of the dealer lot and not set this particular Rubi aside while I waited for special pricing, I would have missed a great purchase.
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by high output did they mean engine assembled sans headgasket? :cheesy:
 
Tigrcky said:
interesting new info on the ethanol... another reason to hate that crap but i have built up many engines and i know personally that running to low of octane in an engine can cause predetonation to occur and takes the bang out of the compressed air fuel mixture in the cylinder, but lets just put it to real world testing run either and which ever gives you the best power and fuel mileage just run that :thumb:

edit- with the constant computer controlled timing it is very possible that they are adjusting for the predetonation by retarding the spark thus proving your point!!!
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Yep... Older (non computer controlled engines) absolutely need the right octane for their compression. On these engines your suggested octanes are spot on. But on today's engines the computer plays all sorts a tricks to get the most bang for the cheapest buck.

One other adder though is running too high of an octane can be bad on the engine. Since you've built several engines I'm sure you've seen burnt valves from this.

Luckily the ECUs that control today's engines measure everything coming in and out and then make adjustments for changes, fuel octane being one of them. So, it is likely that the lack of ping you detect when running higher octane is a placebo effect. The ECU tunes the difference out by adjusting the injector pulse width. You would have to run extremely high octane to overcome the tune. When this occurs a code will most likely be thrown.


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jnabird333 said:
Yep... Older (non computer controlled engines) absolutely need the right octane for their compression. On these engines your suggested octanes are spot on. But on today's engines the computer plays all sorts a tricks to get the most bang for the cheapest buck.

One other adder though is running too high of an octane can be bad on the engine. Since you've built several engines I'm sure you've seen burnt valves from this.

Luckily the ECUs that control today's engines measure everything coming in and out and then make adjustments for changes, fuel octane being one of them. So, it is likely that the lack of ping you detect when running higher octane is a placebo effect. The ECU tunes the difference out by adjusting the injector pulse width. You would have to run extremely high octane to overcome the tune. When this occurs a code will most likely be thrown.


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you sir deserve a beer!!! :beer:
 
Wasn't paying attention on the way home last night.

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30K on the clock in a little over 2 years.
 
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