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Author Topic: Mixing Premium & Mid-Grade Back to Topics
Pucelle

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Rochester

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Message Posted: Mar 24, 2012 7:39:27 PM

Do you mix premium and mid-grade (or regular since these days the spread is sooo wide) to get the best price and octane to get to 91? Or do you just get Premium most of the time and maybe the occasional mid-grade?
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PatAZ
Champion Author Tucson

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Message Posted: Jan 7, 2013 10:29:57 AM

Just regular in the Toyota, always premium in the BMW.
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LauraLea5
All-Star Author Ontario

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Message Posted: Jan 7, 2013 6:30:14 AM

No
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medic6133
Champion Author New York

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Message Posted: Jan 7, 2013 5:36:32 AM

Premium only.
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dgsteven
Champion Author Los Angeles

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Message Posted: Jan 7, 2013 3:24:29 AM

no way
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Pucelle
Rookie Author Rochester

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Message Posted: Apr 12, 2012 1:07:57 PM

For those of you that didn't know, most cars that require "premium" gas actually require a minimum of 91 octane. Gas stations usually have 87, 89, and 93 for their gas with a spread of 10 cents between.

Now a days that spread is higher, especially between Regular & Mid-grade that mixing Reg & Premium can be more cost effective than Mid & Premium depending on price/station.

I have almost 18 gallons in my tank and so the 10+ cent spread is noticeable.

I do know that for Top Tier gas stations, I can use 89 (my manual even states it) but there have been times when it has been cheaper to do my own mix of premium & regular than just mid grade since regular was 40-50 cents cheaper.
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jimmy544
Champion Author Boston

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Message Posted: Apr 8, 2012 8:44:58 AM

It is true that it is an uncommon situation but I have seen at least one station in Eastern Nevada that had diesel and reg gas and that was all. Also it was really expensive and the only station open for about 100 miles. That was in 2009 in January. I So it does happen. I think I have seen this a couple of other times too since then but that particular experience sticks in my mind because I was really low on gas because the station 100 miles before had been closed. Eastern Nevada even in January is pretty barren and desolate.

Because this situation does happen occasionally the government mandates that all gasoline cars need to be able to run on regular gas without damage. It is true that some old cars from the 60's would likely not run well and might be damaged but cars from the late 70's on were supposed to be able to run on unleaded regular without damage. The engine will not develop max power if it needs premium to do so because the ignition system will retard as someone pointed out but this will not lead to damage because the damage comes from pre-ignition AKA knocking. It will just be down on power.
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BobSassafrass
Rookie Author Houston

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Message Posted: Apr 4, 2012 4:23:31 PM

The reason for using Premium is because high compression engines require it to prevent detonation. When you use 87 in these engines it detonates (knocks) then the engine compensates by retarding ignition timing. This is bad for the engine. The retarded ignition timing leads to less MPG as Sluggopyle said. But prolonged use can cause engine problems that will surely cost more than an extra 30 cents a gallon.
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alphanyr
Champion Author Connecticut

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Message Posted: Apr 3, 2012 7:16:22 PM

no
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sluggopyle
Champion Author North Carolina

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Message Posted: Apr 3, 2012 2:55:23 PM

Well Jimmy, I drive a lot all over the eastern US and Canada, and I have yet to see an area where you could only get regular or diesel. Anywhere. I do see plenty of stations where you can't get diesel but that's not the question.

The other point, yes the regular will burn, but at what price? How much is the mileage loss compared to the lower cost of the fuel? This is the question (I don't know the answer; haven't tried it yet). But if the loss in mpg translated to cost-per-mile is more than the gain in pump savings, then obviously it will be more expensive to run regular -- in the same way that running E10 costs more even if it's priced a dime lower than ethanol-free if the former creates a mileage loss greater than its own displacement.

Bottom line: price per gallon ain't the whole story.



[Edited by: sluggopyle at 4/3/2012 3:00:38 PM EST]
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jimmy544
Champion Author Boston

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Message Posted: Apr 3, 2012 1:43:41 PM

Even if your car manufacturer recommends that it be run on premium it will run on regular without any damage. It has to as per the government. The car may not be able to develop full power and performance may not be up to what it would be on the premium it will still run ok. It has to be that way as there are some places where you have a choice between diesel and regular gas and that is all you have to choose from. Run out of gas or run regular.
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sluggopyle
Champion Author North Carolina

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Message Posted: Apr 3, 2012 10:45:52 AM

=> Looks like most people don't understand the context here. <=

I dunno about "most people" but it does seem to be a trend. I tried three times to explain this to Forresj; he just posted on my whiteboard "Up yours" followed verbatim by the same pig-ignorant post he's been trashing this thread with ("up yours"?? what is it, 1962 again?) Then the coward finds a way to lock his whiteboard so I can't respond. Funny he can figure out how to do that, yet he can't read the thread.

I don't know why reading is so difficult for some, yet they think they're qualified to write. The OP is not rocket surgery; it says "to get to 91 (octane)". Nobody said squat about using MORE octane than you need; it assumes you already need the higher octane (why else would you be doing a mix like this -- duh).


My knowledge from gas station managers confirms what BobSassafrass said-- they'll get a stock of regular and premium and mix the two to get mid-grade.

One of my cars is designed for 93; on some future long trip I may try alternating grades to gauge the effects (presumably the fuel efficiency drops). But as BobSassafrass notes, the price differential may not justify it.

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BobSassafrass
Rookie Author Houston

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Message Posted: Apr 2, 2012 5:39:39 PM

Looks like most people don't understand the context here.

I drive a 2006 Civic Si. The high compression motor calls for 91 octane or higher. Here in Texas I have only ever seen 93 octane. The OP probably has a similar situation, why pay 10 cents extra for 93 when your car will run on 91? So they want to purchase 5 gallons 89 and 5 gallons 93 to create 91 octane in the tank.

We aren't trying to run lower grade the engine wants just get the slightly cheaper 91. I wasn't sure if mixing would actually be able to create 91 octane or just a mix of 89 and 93 but on the octane wiki page I found this:

"Purchasing 91 octane fuel (where offered) simply means that more fuel of higher octane is blended with commensurately less fuel of lower octane, than when purchasing a lower grade. The detergents and other additives in the fuel are often, but not always, identical."

So that said there should be no problem mixing to get 91. But like others have said this is penny pinching extreme. I get 10 gallons a week so this equates to a savings of $1 a week or $50 a year. While I most definitely make sure my phone, electricity, water, and food bills are as cheap as possible; saving a dollar a week is almost not worth the effort of having to put 2 different grades of gas in at one fill-up.
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gasmask78
Champion Author Virginia

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Message Posted: Apr 2, 2012 12:30:44 AM

Unless you drive a Mercedes or Rolls Royce...why get Premium?!!
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Jescareno22
Veteran Author Toms River

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Message Posted: Apr 1, 2012 7:30:52 PM

no
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sc331mustang
Champion Author South Carolina

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Message Posted: Apr 1, 2012 6:13:03 PM

I mostly buy mid-grade for my car that call for premium. As long as I am not flooring it and making the pistons rattle. For my motorcycle that also call for 93 octane I put 93 octane in it because of the high compression. 89 octane will make it spit and sputter. It is not worth damaging the motor when you can hear the difference.
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forresj
Champion Author Wilmington

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Message Posted: Apr 1, 2012 5:52:32 PM

it's a waste of money to mix fuel if your vehicle runs fine with just regular gas. you're paying extra to fund the CEO's mansion and hooker visits. you're also helping terrorists buy bombs to kill us.
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sluggopyle
Champion Author North Carolina

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Message Posted: Apr 1, 2012 4:15:12 PM

So Forresj, you're going to keep repeating the same ignorant post even after it's been explained that you have the question backwards? Nice.
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forresj
Champion Author Wilmington

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Message Posted: Apr 1, 2012 11:53:51 AM

it's a waste of money to mix fuel if your vehicle runs fine with just regular gas. you're paying extra to fund the CEO's mansion and hooker visits. you're also helping terrorists buy bombs to kill us.
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2011370Z
Champion Author Phoenix

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Message Posted: Apr 1, 2012 10:26:05 AM

My car calls for 91 but after talking with many mechanics I use 89. It works fine for my driving and saves me .10/gal.
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ricebike
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Message Posted: Mar 31, 2012 6:38:51 PM

..
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Jescareno22
Veteran Author Toms River

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Message Posted: Mar 31, 2012 4:36:55 PM

,
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sluggopyle
Champion Author North Carolina

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Message Posted: Mar 27, 2012 10:24:04 AM

Thanks Shock, perhaps it does. I am only the messenger, but the point was to counter the idea floated that "99%" of cars call for regular octane.

Here's a comedy of errors post:
=> it's a waste of money to mix fuel if your vehicle runs fine with just regular gas. you're paying extra to fund the CEO's mansion and hooker visits. you're also helping terrorists buy bombs to kill us. <=

You've assessed the point of the thread bass-ackwards. The idea is not to mix *higher* fuel than you need -- it's whether you can get away with *lower* than you need. And then the ridiculous end: terrorists and oil companies are in different businesses. Just because a terrorist comes from Saudi Arabia and so does oil doesn't mean they're the same people. Or do "they all look alike to you"?
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gazprize
Veteran Author Toronto

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Message Posted: Mar 27, 2012 10:14:41 AM

no, do not mix
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OceanArcher
Champion Author Mississippi

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Message Posted: Mar 27, 2012 10:06:16 AM

Fifty years ago, I did mix fuels - but not anymore
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forresj
Champion Author Wilmington

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Message Posted: Mar 27, 2012 9:43:27 AM

it's a waste of money to mix fuel if your vehicle runs fine with just regular gas. you're paying extra to fund the CEO's mansion and hooker visits. you're also helping terrorists buy bombs to kill us.

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Shockjock1961
Champion Author Illinois

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Message Posted: Mar 27, 2012 9:28:36 AM

I think that chart might have a few errors Sluggo. A vehicle I own is on that chart, just checked my owners manual, it states that my vehicle requires 87 Octane gasoline...
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Dennis783
Champion Author Des Moines

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Message Posted: Mar 27, 2012 9:21:54 AM

I just get regular in my car (premium in wife's car since that is what is recommended)
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sluggopyle
Champion Author North Carolina

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Message Posted: Mar 26, 2012 2:07:37 AM

=> 99% of the newer engine computers want, need low octane fuels. <=

uh, NINETY-NINE percent?? No, not even close, and it's irresponsible to post that.

Story
>> The number of new vehicle models that need — or at least run better on — the priciest gasoline has steadily risen from 166 in the 2002 model year to 282 this year <<
list of models requiring premium (high octane) fuel (as of 2004)

[Edited by: sluggopyle at 3/26/2012 2:15:11 AM EST]
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PaylessKY
Champion Author Kentucky

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Message Posted: Mar 26, 2012 12:45:23 AM

If it works for you, no problem.

[Edited by: PaylessKY at 3/26/2012 12:50:31 AM EST]
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CaptDave2012
All-Star Author Arkansas

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Message Posted: Mar 25, 2012 11:16:32 PM

99% of the newer engine computers want, need low octane fuels. Read your manual and ask your mechanic, car dealer.
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djdumlao
Rookie Author Chicago

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Message Posted: Mar 25, 2012 9:42:14 PM

will mxing grade improve mpg?
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plastic
Champion Author Virginia

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Message Posted: Mar 25, 2012 9:28:59 PM

I've done that since the 80s with one car. Low octane would work fine if I drove normally and didn't push it. If I wanted to drive it the way that it was designed then I had to use higher octane. Through trial and error I found that I could get by with less than 93 and worked out a ratio that worked great. The timing gears were set pretty advanced on that cam.

I mixed super with mid-grade.

[Edited by: plastic at 3/25/2012 9:33:34 PM EST]
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Shockjock1961
Champion Author Illinois

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Message Posted: Mar 25, 2012 8:24:52 PM

I make it a point not to buy a vehicle that needs to run on premium.

What a waste...
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Jmac2008
Champion Author Missouri

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Message Posted: Mar 25, 2012 7:40:24 PM

I just run 87
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Gas_Buddy
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Message Posted: Mar 25, 2012 6:39:37 PM

sluggopyle:

"No no GB, I see what he means. He's supposed to be running premium, but wants to cheat in some mid-grade now and then so as to save money by 'diluting' his fuel without sacrificing too much octane."

I know what I think he might have meant, but I try to give the person credit by assuming they know what they're asking. In this case the member asked if anyone mixes premium and mid-grade...

Is it too much to expect the question asked to be what they want to know, or is it too much to expect what they say to be what they mean?
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tdioiler
All-Star Author Detroit

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Message Posted: Mar 25, 2012 4:06:21 PM

Any car that says they 'have' to use premium isn't worth it since:

A) If I'm cruising around town without racing, who cares
B) My MPG won't be what I was told at the dealer but I'm saving money anyway??
C) A bike is way cheaper and more fun to ride !!
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chemist74
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Message Posted: Mar 25, 2012 1:35:51 PM

No - I have always been smart enough to only buy vehicles that run onregular gasoline.
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kxy4fw
Champion Author Denver

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Message Posted: Mar 25, 2012 12:25:52 PM

Mid-grade only.
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PatAZ
Champion Author Tucson

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Message Posted: Mar 25, 2012 11:46:34 AM

When I get gas I buy premium as the manual says.
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sluggopyle
Champion Author North Carolina

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Message Posted: Mar 25, 2012 10:32:00 AM

=> I will not buy a vehicle that is supposed to run on premium. <=

You can't always git what you want. Some cars are just not made that way, even if we want them to be.

<< this one f'rinstance.

Is it worth it to have the car?

Oooooh yeah!


Another thing to keep in mind: with the different grades being priced a dime apart, the more the general price of fuel goes up, the less significant that difference is- consequently premium becomes less and less relatively expensive. When gas is one dollar a gallon, a dime difference is 10% -- when it's $4 a gallon, that dime difference is 2.5%. And it means 2.5% of a dollar that's worth less too.

In the big picture with neighboring gas stations pricing themselves even less than a dime apart, the savings from one station to the next become less and less significant. In other words, ironically the more fuel prices go up in general, the less relevant this website's purpose is.


[Edited by: sluggopyle at 3/25/2012 10:37:46 AM EST]
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ricebike
Champion Author New Jersey

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Message Posted: Mar 25, 2012 10:13:51 AM

if you just have a high compression eninge and not turbo, you MAY get away with going lower than what's recommended

just have to accept that your knock sensor is going to work overtime and then you'll lose some HP and mpg
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jes
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Message Posted: Mar 25, 2012 7:41:10 AM

No. My vehicles are made to run on regular and they do so just fine. I will not buy a vehicle that is supposed to run on premium.
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GBHUGVA
Champion Author Virginia Beach

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Message Posted: Mar 25, 2012 7:23:53 AM

only when driving in the mountains other wise just use reg.
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bonbNJ
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Message Posted: Mar 25, 2012 5:50:18 AM

desperation
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sluggopyle
Champion Author North Carolina

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Message Posted: Mar 25, 2012 12:33:15 AM

No no GB, I see what he means. He's supposed to be running premium, but wants to cheat in some mid-grade now and then so as to save money by 'diluting' his fuel without sacrificing too much octane.

<< this car is supposed to be sipping premium, and I've thought about that, but haven't tried it (yet).
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Gas_Buddy
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Message Posted: Mar 24, 2012 10:38:58 PM

That makes absolutely no sense. Why would you go through the trouble of mixing premium and mid-grade to get the mid-grade octane? And then essentially write "mix premium and regular, rather than mix premium and mid-grade, because of the pripce difference".

That makes no sense.

Of course I have no idea why you'd even wonder about whether people "just get Premium and the occasional mid-grade" when gas prices, at least form the perspective of price posting, doesn't seem to be of any concern. Not being cynical, but with about one gas price every other month for the past ten years, are you really interested in if people mix grades of gas to get a different grade? Just asking; that's all. Just asking.

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