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Post by donpiontek on Apr 23, 2008 8:05:18 GMT -6
Hi All:
I've got a 2001 3.5 with over 150K on the clock. I've always used premium (92 octane) when filling up, even though the owner's manual says anything above 87 octane is fine. Now......with the price of 92 octane hitting $3.60 / gallon+ here in Minnesota, I'm wondering if I can switch to "Regular". Any consequences? Thanks!
Don P
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Post by Oldsnut on Apr 23, 2008 8:06:21 GMT -6
Change to 87 with confidence
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Post by JimW on Apr 23, 2008 8:10:59 GMT -6
Agreed. 2nd Gens can take 87.
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scottydl
Super Moderator 
There's nothin' like an American V-8...
Posts: 7,373
Staff Member
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Post by scottydl on Apr 23, 2008 8:14:05 GMT -6
This has been discussed ad nauseum in the past. Check out the search function and type in "octane" for all the opinions you could ever want on the topic.  Short version - in the 2nd-gen and most cars out there, you are wasting money on anything over 87. In the 95-99 4.0L, 91+ is recommended for best results (that engine has higher compression) but many of us do fine with 89 and/or the occasional 87. |
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Post by Marc on Apr 23, 2008 9:40:40 GMT -6
My .02.....I have driven 2 2001 4.0s. My own & a demo. The demo was running on regular (87) and mine on premium (93). My car felt like it had twice the HP of the demo.
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Post by Aurora40 on Apr 23, 2008 9:55:49 GMT -6
Dan did some testing while monitoring knock retard on the 3.5L V6. I believe he suggested 87 or 89 octane. Certainly it seemed premium was a waste.
The V6 has a fairly low compression ratio compared to the 4.0L V8, not that that is the only factor in octane requirement.
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Post by Wacko on Apr 23, 2008 10:09:57 GMT -6
I've said this before...
The odd thing about this is that the difference in price between the grades does not appear to be a fixed percentage but a fixed dollar value. I.e. when gas was $1.50 for regular, plus was maybe $1.62 and premium was maybe $1.75. Now that gas is approaching $4, I see the difference is about the same per gallon. That doesn't make sense to me. You mean to tell me it always costs only 25 cents more to make a gallon of premium than it does regular, regardless of the cost per gallon?
My point is, it is still only costing you an additional $3.75 per fillup (0.25 x ~15 gallons) for premium over regular. I understand that the $3.75 is more of an issue when you are paying $50 to fill the tank vs. $30 in the past.
But as a percentage, the premium is a better buy as the cost per gallon goes up, assuming you need it to prevent knocking.
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Post by RapMastaC1 on Apr 23, 2008 10:58:35 GMT -6
We don't need to prevent any knocking though. The engine's PCM does that all for us. I don't think this thread should go to far. The Octane wars are about to start and you have a front seat! I run Premium all the time, but now I'm running 87 and I'm doing just fine, plus I got more money in my pocket. You mention it's only a 3.75 difference PER FILL UP! I fill up 70 every week, with that, that is about a 4.25 difference every week. Four weeks in a month - 17.00. 12 months in a year - 204.00 a year. That is one months worth of insurance, or three free tanks of gas. All for some ghost myth...
I think we should just leave it at that though.
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Post by Wacko on Apr 23, 2008 13:06:52 GMT -6
Let me clarify about the knock thing. I should have said, "If you want to prevent a knock-sensed retard of the timing and hence a loss of power."
But you totally missed my point on the $$ thing. I'm saying you were spending the $204 bucks more per year in the past (regardless of the cost per gallon). Why was it worthwhile then and not now?
Can anyone make sense why the difference in grades does not appear to change?
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Post by latenight72 on Apr 23, 2008 15:34:46 GMT -6
Like Marc, I feel a huge difference in power between Regular (87) and Premium (93). Although I use regular on a fairly regular basis now, though.  |
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Post by Aurora40 on Apr 23, 2008 16:34:40 GMT -6
The odd thing about this is that the difference in price between the grades does not appear to be a fixed percentage but a fixed dollar value. I.e. when gas was $1.50 for regular, plus was maybe $1.62 and premium was maybe $1.75. Now that gas is approaching $4, I see the difference is about the same per gallon. That doesn't make sense to me. You mean to tell me it always costs only 25 cents more to make a gallon of premium than it does regular, regardless of the cost per gallon? It makes perfect sense to me. The cost of refining a gallon of gasoline is the same whether it ends up premium or regular. The cost of the additives should be pretty independent from the cost of gasoline. I'd actually feel ripped off if premium were much more expensive than regular, like they are just trying to sock it to guys with nicer cars (generally speaking nicer cars require premium). |
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Post by algonquin on Apr 23, 2008 20:09:32 GMT -6
You can use the 87 but for about 3-4 bucks more per fill up you can fill your tank with super !
Best advice is not to go driving all around town to save yourself a couple cents per gallon.
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Post by shrek on Apr 23, 2008 20:58:33 GMT -6
I've been using 87 octane in my 02 3.5 it seems to run ok.
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rschoyen
Aurora Groupie
"Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup."
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Post by rschoyen on Apr 23, 2008 23:38:19 GMT -6
I'm just gonna sit on the fence and say I use plus (or mid-grade) and always have.
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Post by Superdemon on Apr 23, 2008 23:42:11 GMT -6
No less then the best for my baby.
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Post by cubbiefan on Apr 24, 2008 0:16:30 GMT -6
I used premium since Ive had my car and it runs has loads of power but I have noticed slight shaking. What do you think guys do you think its because I put so many dang city miles or because Im using gas thats too good?
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scottydl
Super Moderator
There's nothin' like an American V-8...
Posts: 7,373
Staff Member
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Post by scottydl on Apr 24, 2008 7:28:15 GMT -6
do you think its because I put so many dang city miles or because Im using gas thats too good? Neither. Those things alone do not cause poor performance. There is some other mechanical issue. Post more details in a new thread in the 2nd-gen Maintenance area if you want some ideas. |
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Post by Rocketv8 on Apr 24, 2008 9:59:32 GMT -6
I used premium since Ive had my car and it runs has loads of power but I have noticed slight shaking. What do you think guys do you think its because I put so many dang city miles or because Im using gas thats too good? you can never use a "gas that's too good" i always use the Sunoco Ultra, which has 94 octane....only 2 cents more a gallon than the next grade down...cost me $3.55 a gallon yesterday...the extra octane probably has no effect whatsoever, but, i feel better using it in my car she has been good to me |
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Post by lanceslambos on Apr 24, 2008 10:14:29 GMT -6
i can't find 94 octane anymore  |
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Post by Marc on Apr 24, 2008 12:09:12 GMT -6
Sunoco Ultra 94 used to be available in NYS some years ago, but has since been downgraded to 93.
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Post by cubbiefan on Apr 24, 2008 13:48:15 GMT -6
My sister had a kia rio that shaked like a mofo with premium so she put regular like they told here it should have had since she bought it and it was goo plus i only feel the shaking when im stopped. Maby I should downgrade to regular? I have a v6
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Post by austinator on Apr 24, 2008 14:56:49 GMT -6
do you have a service engine light? Premium is not going to make your car shake
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Post by BlackButy on Apr 24, 2008 15:32:44 GMT -6
A healthy diet of Shell 93 and a bottle of Techron. This is when it needs to be filled up, which isnt very often.
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Post by cubbiefan on Apr 25, 2008 6:01:59 GMT -6
Never got a check engine light ever and I do use techron and lucas every now and then.
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Post by Marc on Apr 25, 2008 7:49:46 GMT -6
According to the 2001 owner's manual..........................................  |
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Post by aldrichd on Apr 25, 2008 9:58:02 GMT -6
93 octane in my 1999.
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Post by jason on Apr 25, 2008 10:01:27 GMT -6
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Post by aurorabrain on Apr 25, 2008 10:41:17 GMT -6
89 in my 1997. I have seen no performance improvement at the track, or any KR on a scantool in up to 80 degree weather. However, there is little to no carbon in my engine, which can explain why this works for me. I may have a factory freak i suppose, although the engine is about to die any day now. My 4.0 has the same crankshaft end play that speedneon was talking about, except i noticed mine about 50k miles ago.
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Post by aarcuda on Apr 25, 2008 13:39:56 GMT -6
93 in bth my '99 and my '02
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Post by youngin86 on Apr 25, 2008 16:29:29 GMT -6
91 octane premium for my car only. i dont put any thing else in. (96 4.0L, 78k) keeps her happy
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