Gas prices suck now, especially on rip off long island where i live. I always got 93 for my car even though the engine is completely stock besides having headers. I never changed the timing or anything like that either. Can I run 87, or will i get knocking? If it is the least bad for my car I wont run 87, however at this point, if im buying 93 for nothing im sure as hell gonna stop. Thanks.
What Octane Does Manual for 5.0 Call For?
- Thread starter rseifert
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Michael Yount
Mustang Master
Yup - in fact, you may notice a slight increase in gas mileage running 87 octane; the lower the octane, the easier it is to ignite and it burns slightly quicker. I've dropped mine back from 93 to 87 (I've got a mild heads/cam/intake/exhaust combo) with no detonation at all and it appears (2 tanks checked) I've picked up about 1 mpg on city and hwy.
axeman
Founding Member
i run 87. i have since last summer when the gas prices went up a little. if you go to the track, you may even notice a little bump in performance since you are running 93 without advancing your timing.
i checked my gas milage the other day, even though it was almost all highway miles, i got 23.7mpg with 4.30 gears.
i checked my gas milage the other day, even though it was almost all highway miles, i got 23.7mpg with 4.30 gears.
YardSpecial
New Member
My god, i dont know what my timing is because i dont have a light, but if i run anything less than 93 i get the pinger.
YardSpecial
New Member
Um, just retard the timing till the ping goes away...........
Chevy SB trick for years, tune to the gas octane.
Chevy SB trick for years, tune to the gas octane.
Yup, ever since gas prices went way up, i backed timing down to 10 degrees so i could run 87 again
TRWXXA
Member
85_SS_302_Coupe said:
Your timing is not the only thing that could cause pinging.
You may have carbon buildup in the cylinders. This buildup can artificially increase your compression ratio.
Small carbon deposits in the cylinder can also cause it. The deposits heat up red hot, where they can ignite the fuel/air mixture prematurely.
Check the timing. If it's ok, you might want to try some kind of engine cleaner.
True. The best I have gotten away with is 12 degrees with a "healthy" engine. 14 is about as high as i'de go with stock form. Basically though it's just trial and error. Keep backing your timing down unil the pinging ceases. But, if you have to go below 10 degrees timing, than you've got an issue that needs attention seriously. Oh yeah, 87 is what most every non-overhead cammed engine comes built to run on.
i run 89 on 16* timing.... i could probably run 87 on her, but i noticed i get horrible gas mileage on 87. and i can get about 15-20 more miles on 93....89 being in the middle.... its kinda odd. then again getting 180 miles to a tank on a stock motor isn't great....
siege
New Member
iwashmycar said:87 all the way. I usually get 300 miles to the tank here.
300? are you serious? man, I only get about 180, that sucks.
I, too, recently bumped the timing back to 10 and switched to 87 from 91 (we don't have 93 here)...got tired of spending $35 to fill the tank
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