Luna

iTrader: (6)

Ok, I have finally gotten a chance to put premium in my car ( I have always forgotten since I am not used to it) and it seems like I might be getting less gas mileage. Maybe I am just more tempted to lay into it since it jumps a little harder but I don't know. Shouldn't I get better gas mileage on premium assuming I can control my right foot

SmokingWS6

iTrader: (1)

take the less milage even though it probably is the same.

87 = no motor

Sexyblu03

kinda sorta. people are very misled about higher octane gases. the higher the octane the more resistance it has to explode. all that means is it burns slower, smoother, and allows more timing advance and higher compression.

jimmyblue

iTrader: (11)

High octane blends have less energy content but can
let you tune to make more power. But for a given
efficiency in the engine itself you will burn more
premium to do the same work.

If you've been running around on low octane then it's
likely that the PCM has learned its way to reduced
spark, not something that helps when you put in
slower burning fuel later. Late spark = lower efficiency
again.

spy2520

iTrader: (3)

This is more fo a technical question and most ls1 owners probably dont really care, but wouldn't the emissions be higher with a higher octane fuel? CO would increase i believe since it is caused by incomplete burning of fuels especially in a combustion engine. Higher octane fuel burns slower and would have more of a chance of releasing CO. OR, maybe it is opposite, because since lower octane gas burns so easily, the brun must be inefficient and in that case it is guaranteed to release more emissions (or atleast CO).

Luna

iTrader: (6)

So you're saying my PCM has to learn that I am running premium ?

solocus

iTrader: (8)

Most definately!

Luna

iTrader: (6)

How long does that take?

demonspeed

iTrader: (7)

Don't worry about it. Just run premium and don't think twice. There is a reason why they say that's what you need from the factory. There is no reason to analyze.

yak

iTrader: (15)

It usually takes a tank of gas or so. the car will get better milage with premuim, especially in the hot weather. When I first bought my car the dealer put regular in it and it ran like ****, revs would bounce around when I was at a light. after a couple tanks of premium, it ran like a ****.

transamjunkie

I thought running anything less than premium in an LS1 would risk detonating a piston or some other engine damage? Was always told run premium in it at all times...and the "old school" tune port injected v8's I've owned always ran better with premium...lower grades had the motor pinging and valves clattering.

Martingale

If you've been running low octane fuel and now you're running premium I'd reset the PCM if it was my car. It will relearn itself on its own eventually but this would be quicker. After you reset the PCM the first time you start the car it will act really funny for a few minutes. Don't worry, that's normal...

http://www.ls1.com/link_ecm.html

FBDYLVR

iTrader: (14)

Reset and you should be good to go...

Martingale

A piston wont detonate literally but the air/fuel mixture will ignite too soon causing what's known as "detonation" or "pinging". Because the LS1 has knock sensors it will start pulling timing when it knows the motor is pinging and engine damage is not an immediate concern, but doing it over and over again over long periods of time isn't good at all for the motor. What you risk most is probably popping a head gasket.

Luna

iTrader: (6)

Thanks guys, the dealer put regular in it and I am not used to even thinking about putting premium in it so I always just hit the regular button out of habit and then went dammit!! half way through the fillup. I am already starting to see a little extra power and acceleration with the premium. BTW it did seem to run just fine on regular but my guess is the last owner always ran regular in it...