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Octane Ratings, when did they drop

Posted: Tue Oct 09, 2018 8:42 pm
by ClutchFork
In particular, when did regular pump gas drop to 87 octane?

My and ClutchDisc's '92 Mustang 5.0 LX is rated at 9:1 compression. My gearhead friend at work says 87 octane is fine. The guy who sold it to us said he always runs premium. He did not say there were any engine mods so I am thinking it is stock. I think premium is a waste but wondered if the octane of Regular was 89 in 1992, then it should be fed at least 89 octane, right?

Re: Octane Ratings, when did they drop

Posted: Tue Oct 09, 2018 9:48 pm
by Rope-Pusher
ClutchFork wrote: Tue Oct 09, 2018 8:42 pm In particular, when did regular pump gas drop to 87 octane?

My and ClutchDisk's '92 Mustang 5.0 LX is rated at 9:1 compression. My gearhead friend at work says 87 octane is fine. The guy who sold it to us said he always runs premium. He did not say there were any engine mods so I am thinking it is stock. I think premium is a waste but wondered if the octane of Regular was 89 in 1992, then it should be fed at least 89 octane, right?
What did Ford say you should be running it on?

Yanno, as the weather gets colder, you can get by on fuel with less octane than what you might want in the summertime.

Re: Octane Ratings, when did they drop

Posted: Tue Oct 09, 2018 9:56 pm
by tankinbeans
Can't answer the question aboot if or when octane ratings dropper since I'm still a spritely fella, but 9:1 seems low enough where regular is fine. Also, I've read that elevation plays a role in octane requirements. I just can't recall the relationship; higher elevations can take lower octane (I think) and in certain parts of Colorado 85 can be had.

Me Mazda runs fine on 87 and it's running 13:1. I use premium because there's no corn in it, at least from the stations I frequent.

Re: Octane Ratings, when did they drop

Posted: Tue Oct 09, 2018 10:57 pm
by ClutchFork
Thanks. Well my main concern is not to run too low an octane and make a hole in the nice forged aluminium pistons from spark knock. No idea what Ford calls for because we don't have an owner's manual with it, or if we do, I don't know where in the car it may be. You would think this is the basic Mustang, so regular fuel, whereas the sportier models might require premium.

First fuel mileage check. Came out to a respectable 9 mpg. Of course we have been hauling hard off most stop lights. ClutchDisc put it up on Fuelly.com:
http://www.fuelly.com/car/ford/mustang/ ... isc/824172

Re: Octane Ratings, when did they drop

Posted: Wed Oct 10, 2018 8:33 am
by watkins
I'm pretty sure 87 has been considered "regular" for about as long as gas hasn't had lead in it.

Re: Octane Ratings, when did they drop

Posted: Wed Oct 10, 2018 8:23 pm
by Rope-Pusher
watkins wrote: Wed Oct 10, 2018 8:33 am I'm pretty sure 87 has been considered "regular" for about as long as gas hasn't had lead in it.
I remember......what was it I remembered?....oh yeah.....I remember when they called it Ethyl and not lead. People knew lead could be poisonous, but Ethyl, why she was some girl your dad dated before he met Mom, right? You too could get lucky with Ethyl like dear old Dad prolly did.
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Re: Octane Ratings, when did they drop

Posted: Wed Oct 10, 2018 8:34 pm
by AHTOXA
Rope-Pusher wrote: Tue Oct 09, 2018 9:48 pm
ClutchFork wrote: Tue Oct 09, 2018 8:42 pm In particular, when did regular pump gas drop to 87 octane?

My and ClutchDisk's '92 Mustang 5.0 LX is rated at 9:1 compression. My gearhead friend at work says 87 octane is fine. The guy who sold it to us said he always runs premium. He did not say there were any engine mods so I am thinking it is stock. I think premium is a waste but wondered if the octane of Regular was 89 in 1992, then it should be fed at least 89 octane, right?
What did Ford say you should be running it on?

Yanno, as the weather gets colder, you can get by on fuel with less octane than what you might want in the summertime.
Yeah. I run 87 during the colder months here in TX but 93 during the blistering heat.

Re: Octane Ratings, when did they drop

Posted: Thu Oct 11, 2018 11:21 am
by watkins
AHTOXA wrote: Wed Oct 10, 2018 8:34 pmYeah. I run 87 during the colder months here in TX but 93 during the blistering heat.
"Colder"

I wish I could do that. I'm a 93 year round kind of guy. I don't even think about it any more honestly. Its honestly better not to when Im getting 20mpg out of a four cylinder station wagon.

Re: Octane Ratings, when did they drop

Posted: Thu Oct 11, 2018 8:07 pm
by Rope-Pusher
watkins wrote: Thu Oct 11, 2018 11:21 am
AHTOXA wrote: Wed Oct 10, 2018 8:34 pmYeah. I run 87 during the colder months here in TX but 93 during the blistering heat.
"Colder"

I wish I could do that. I'm a 93 year round kind of guy. I don't even think about it any more honestly. Its honestly better not to when Im getting 20mpg out of a four cylinder station wagon.
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Re: Octane Ratings, when did they drop

Posted: Fri Oct 12, 2018 12:03 pm
by watkins
Oh, I know. That's why I stopped caring so long ago.

Re: Octane Ratings, when did they drop

Posted: Sat Oct 13, 2018 9:31 pm
by AHTOXA
watkins wrote: Thu Oct 11, 2018 11:21 am
AHTOXA wrote: Wed Oct 10, 2018 8:34 pmYeah. I run 87 during the colder months here in TX but 93 during the blistering heat.
"Colder"

I wish I could do that. I'm a 93 year round kind of guy. I don't even think about it any more honestly. Its honestly better not to when Im getting 20mpg out of a four cylinder station wagon.
You're getting 0.5MPG more than me in my half ton truck with 375 ft-lbs of torque.

Re: Octane Ratings, when did they drop

Posted: Sun Oct 14, 2018 3:16 pm
by watkins
I should have around 310hp and 380 lb-ft from my little 2.3 that first debuted back in 1998. That makes your truck sound wimpy :lol:


My commute is nearly all stop and go for 18 miles each way. Id love to see what a reasonable drive cycle would mean for my fuel economy. Ive never really gotten a good highway economy test because Im either driving 80mph+, have an overloaded car, have some form of absurd thing on my roof racks (which never come off), or some combination of the aforementioned.

Re: Octane Ratings, when did they drop

Posted: Sun Oct 14, 2018 9:59 pm
by AHTOXA
watkins wrote: Sun Oct 14, 2018 3:16 pm I should have around 310hp and 380 lb-ft from my little 2.3 that first debuted back in 1998. That makes your truck sound wimpy :lol:


My commute is nearly all stop and go for 18 miles each way. Id love to see what a reasonable drive cycle would mean for my fuel economy. Ive never really gotten a good highway economy test because Im either driving 80mph+, have an overloaded car, have some form of absurd thing on my roof racks (which never come off), or some combination of the aforementioned.
Ya gotta admit that 325/375 from a 2.7 is far from wimpy. Then there are tunes, of course, and it's pretty much unnecessary at that point. I flip flop in regards to getting mine tuned now and again, but I'm probably not going to do it. Surprisingly, it hardly leaves me wanting more power.

Re: Octane Ratings, when did they drop

Posted: Mon Oct 15, 2018 8:45 am
by watkins
Absolutely. That's well within the safe power band for a long life span too.

I also fat fingered. Should be more like 350 lb-ft, not 380.

Re: Octane Ratings, when did they drop

Posted: Mon Oct 15, 2018 8:13 pm
by AHTOXA
I was really expecting GM to do better with they new 4-cyl 2.7 in the trucks, but it makes less power, less torque and gets less MPG than the 2.7 ecoboost in the Ford. I'm not sure what to make of that.