I recently moved to Texas where they use 91 octane I was using 93 I have a tune on the car will this hurt my car should I get a retune. I can not hear any knocking but not sure what it sound like anyway
change of octane
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joshheat25
Member
From what I hear Predetonation what is caused by not using high enough octane can be harmful to your engine. It sounds like a pinging/tapping sound. Here is how you can tell. Cruise at about 60 in 5th gear and just give it about half throttle and if it makes a weird Pinging/tapping noise then you aren't using a high enough octane. Well if it is a custom tune to 93 octane then It will probobly ping using 87 and 91. So get it retuned!
Crzyhrse
Active Member
91 is still considered Premium fuel. You don't need to do anything to your Predator tune if your not experiencing any engine problems.
shotime
Founding Member
helty
some Ukrainian's enjoying a handjob via my credit
i just noticed this happening to my car on the way back from a road trip. just cruising along in 5th, (or 3rd/4th) and when i give it a little throttle i hear a tapping/rattling noise coming from under the hood. now, my car is bone stock except for and slp cat-back and k&n drop in with removed silencer. i use 87 octane, i believe thats what the owners manual calls for right? the car has never been tuned and has 32K. any ideas? should i try a few tanks of 91 octane or just take it to the dealer and have them fix it? i have an extended bumper to bumper warranty so im not worried about $$$. i know a rattling sound coming from under the hood cant be good, but its been like that for the last 2K miles, and still runs like a champ, and i havent had the CEL come on. suggestions?joshheat25 said:
umm, i just had my car tuned for 93 octane and thats what ive been using, ever since if im in 5th and i step on the gas it makes a noise, but it doesn't sound like a tapping.. sounds more like stuff rattleling coming from around the transmission.. maybe its cuz of the o/r xpipe and if im in a low rpm theres hardly no backpressure and it has no power there... what do you guys think? my dad didnt think it was pinging but ive never heard pinging so i dunno. is it distinctly heard from the engine? cuz this sounds like its coming from underneath
helty
some Ukrainian's enjoying a handjob via my credit
anybody?helty said:i just noticed this happening to my car on the way back from a road trip. just cruising along in 5th, (or 3rd/4th) and when i give it a little throttle i hear a tapping/rattling noise coming from under the hood. now, my car is bone stock except for and slp cat-back and k&n drop in with removed silencer. i use 87 octane, i believe thats what the owners manual calls for right? the car has never been tuned and has 32K. any ideas? should i try a few tanks of 91 octane or just take it to the dealer and have them fix it? i have an extended bumper to bumper warranty so im not worried about $$$. i know a rattling sound coming from under the hood cant be good, but its been like that for the last 2K miles, and still runs like a champ, and i havent had the CEL come on. suggestions?
helty said:
i know they say sometimes when putting in cai it can make the car ping, but with it just being a drop in that's kinda weird
AmBo
Active Member
What's the difference of octanes? What if you DON'T have a tune? Can you pick and choose your octance and not care???
96WhiteNight
New Member
Octane ratings are at what rate the gas is ignitable or at what temp it ignites. An 87 octane ignitites at a lower temp or a lower combustion then a 92 does. When it ignities at a lower rate you don't get that duration of time the gas and air combust. With 92 it can with stand more temp and pressure so that it doesn't ignite till it hits that later point which prevents detination
AmBo
Active Member
in Lamens (sp) terms? whats the benefits?
only reason i care is cuz i always use 93 octance, but yesterday i filled with 87
only reason i care is cuz i always use 93 octance, but yesterday i filled with 87
you're suppose to be using 87, that's what Ford had in mind when they built these cars. Now people, like me, use 93 because our cars have been tuned to use that, we needed it for timing reasons and such.
AmBo
Active Member
Black Stang 97
the guy on top of me is funny
well i live in south cali and ive never seen anything higher then 91 octane, does it make a difference lets say i use 87 then i switch to 93 on a stock motor?? my friend has an 05 3.5z altima and he swears that with the 93 octane he gets alot more power, ive been wanting to try it but: 1. cant find it anywhere 2.I dont now if it will harm my motor using a higher octane.
there's always been rumors floating around about higher octane will make your car run better.. at some drag strips they sell 100+ octane. I always went by what Ford recommended for the car
hotmustang331
Active Member
Nope, it will do nothing for the GTs. Going from 87-93 in a GT is pointless. So why do the 05GT guys feel a difference and some of these other cars? Simple, they have what is called a knock sensor, it can tell when the engine is pinging, and on 87 when it detects engine knock then it will remove some timing until it stops, but when you fill with 93 in those cars, it no longer pings and the computer slowly adds in some more timeing. For us GT guys, we have to manually up timing by means of a T/A or chip when we fill with 93 to take advantage of it. Hope that helps. Oh and the machs and 99-01 cobras also got a knock sensor, as well as the mightly LS1s.
96WhiteNight
New Member
9646gt
Member
if you run 93 octane on such low copression with out more added timing wont this cause the car to get worse gas mileage as well as develop carbon fast as the fuel isn't completely burnt ?
02davestang said:i've never heard of someone not being able to get 93 octane. every where i go in texas, i see gas stations all the time with premium 93 octane. weird!
Not in El Paso, TX 91 is the best you can get here
