D14HUGGER.ORANGE

I have a 99SS with bolt ons and I normally run 93 octane in it at all times. The guy that had it before me ran 93 octane in it as well. Well my girlfriend accidentally filled her up with 87 octane and its been running like ****. Bogging down and idling like ****. Any one have the same problem? I figured the motor aint used of it?

79ChevyGuy

iTrader: (2)

The LS1 cars come factory with a high compression ratio, somewhere in the neighborhood of 10:1 if I'm not mistaken. It was never designed to run on 87 octane, but it has safeguards in case a situation like yours arises. The engine has knock sensors that will detect pre-detonation or "pinging" due to the low octane fuel detonating from compression rather than by the spark as it is intended. Detonation will destroy your engine, so to avoid that the PCM will compensate by retarding the spark advance, which in turn will cut power and in other words make it run like SH**. I would probably siphon some of the fuel out, or if there is already room in the tank, top it off with as much high octane as you can, or perhaps you could try the supposed magic of a bottle of octane booster. This is my 2 cents, if anyone else wishes to add to this or correct me feel free!

Brandon331

iTrader: (9)

mine hates anything less than 93 lol would I did when my dad put 87 in it one day was mix some 120 in it and fixed the problem

Latch

iTrader: (8)

I work at a car dealership and we put 87 octane in everything, even Z06s. It shouldn't cause your car to run like ****, it'll just be slow.

CHADsterss

Car should idle/run fine. Like said above it pulls timing, you won't really notice it in the low-end but your top end will be complete sh*t.

RevGTO

iTrader: (12)

The stock tune actually has a low octane timing table, so when the knock sensors indicate low octane fuel is being used, it switches to that table, pulling timing and reducing power. The car shouldn't run rough or anything. Could be just bad gas or if the car has a modified tune.

RPM WS6

iTrader: (3)

I8UR4RD

iTrader: (16)

i can tell even when the 93 from a shitty station is in it. the car would act different. pop in some shell....lit up like a christmas tree. my supercharged sts-v will throw and engine light on bad gas.

its running 15lbs of boost stock. again. go to shell. fire it back up on there 93. goes away. alot of times i will just throw in a fuel gallons of 110 with it. when the pcm sees some **** it does not like it will basically pull timing and all kinds of **** from the tune and the car will run a bit worse. most people dont even notice without a good bit of seat time.


e85 is the way.

ULTIMATEORANGESS

iTrader: (4)

if youre not on a stock tune id be careful. dont run it hard and maybe put in some octane booster.

buddhaz06

iTrader: (8)

All I run is 87 in my stock 98 t/a. Never had a problem and avg 19-21mpg. Any reason I should switch over to 91?

redbird555

iTrader: (14)

^ yes you would benefit from 91 or even 93 if its available... you may pick up a little fuel mpg but you will notice it in terms of power because the pcm as state will pull timing for 87. I've filled mine up with 87 before on accident and I could tell the difference immediately. and as others have said here it doesnt even like bad 93. I got gas from a ractrac a few weeks back and the car felt sluggish and ping like hell, put chevron 93 in it and all is well.

Jays_SSZ28

iTrader: (2)

This came out of a running bone stock '98 TA, the PO used to run 87 octane. Not saying if thats what caused this.


I've used 87 and 89 in both of my camaro's. It never made them run bad or slow, but it'll cause detonation with hard throttle, high rpm. I'd say it's ok to run 89 if you're going to drive like an old lady. Other than that run 92 or 93.

KingJacobo

Just don't rag on it with the 87 octane in the tank. You should be fine because as already stated it'll just retard timing and prevent pinging and bad stuff.

I would be scared to step on it if you didn't have a factory tune. Unless you know exactly what your tunes specs are..proceed with caution.

buddhaz06

iTrader: (8)

Hm I might start running 91 then. No 93 close to me. Shell ok?

redbird555

iTrader: (14)

ya 91 is fine. premium is only 4 bucks or so more per fill up so who cares lol for the added benefit and peace of min its worth it. i can never figure out why states in the midwest where oil is mined and refined only get 91 premium while here in fl premium is 93 or even sometimes 94

slikrider20

iTrader: (9)

I would look into not letting your g/f drive or fill up your car

reinhardt02

The owners manual for my 02 z28 recommends 91 octane at a minimum. Read your manual, it probably says the same thing. My manual states the car will run on 87 but will be sluggish. Use 91 or better for best performance.

Reminds me of a joke:
What do you tell a woman with two black eyes?
Nothing, you already told her twice.



Kidding, don't dot the g/f's eye. 87 won't hurt the car any.

D14HUGGER.ORANGE

Thanks for the input now I understand why its running like ****! Got about quarter of a tank left of it anyways. I heard the affes gas on base is bad too because the mililtary buys from the lowest bidder and it has lots of water.

joshua.lacy

I know, never let her drive it again. Problem Solved.

73CamaroLT

iTrader: (8)

Yea i recently started running 93 in my car. I was messing with my buddy after work in a new 5.0 and the car just didnt seem right. Then i remembered i have only put 87. So i switched and now it pulls hard like it should.