Do you use premium?

[cr0m3kid]

I say go with what the car's manufacterer says....

you can also make a leaded 100 octance fuel by putting regular in it and adding 1 oz or about a capful of rubbing alchohol per gallon.

Is this really true? just by adding rubbing alcohol

[southside]

I've heard of some stuff they sell at home depot you can mix to make race gas.But I have never heard of mixing rubbing alchol.

[Whiteboy572]

I believe that premium has a lower flash point and is able to burn faster than 87, if i remember correctly? My z has a 10.5:1 cr and i know if i run 87 it will knock, ive heard plenty of stories. You can run 87 or 93 if you have your car tuned for it, but you will make less hp i know the differance in a cobalt ss vary from 87-93 its like 15-20 whp differance. I know if your cars suppose to run premium the factory probly sets the timing tables as they were using premium and they have the knock tables put in at what a lesser premium would do and retard it to that. The knock sensor will probly go ape sh!t when you add 87 and dip below the factory tune and start trying to retard itself so much its starts sputtering, etc. 93 is a more refined fuel and will burn cleaner and get better gas mileage for a fact, but this is a high comp motor im talking about. You will probly have no prob running 87 as long as you keep the rpms low. As for low comp and 87 it probly wouldnt matter a whole lot until you started winding it out but then you would probly sacrafice some power.

[04LRGC]

Premium Mid-grade Unleaded
TEXACO - club drive & cruise rd intersection
678 380 3445

[Atlblkz06]

you can also make a leaded 100 octance fuel by putting regular in it and adding 1 oz or about a capful of rubbing alchohol per gallon.

I've heard of some stuff they sell at home depot you can mix to make race gas.But I have never heard of mixing rubbing alchol.

Thats probably Toulene: AKI (R+M)/2 = 114

A 10% mix will boost your octane by 3 points for 87 and 2 points for 93.
Remember that straight toulene does not have detergents. Though.

[SmackedInATL]

i wish my car took regular lol

+1 to that!!

[EmminoDaGreat]

I believe that premium has a lower flash point and is able to burn faster than 87, if i remember correctly? My z has a 10.5:1 cr and i know if i run 87 it will knock, ive heard plenty of stories. You can run 87 or 93 if you have your car tuned for it, but you will make less hp i know the differance in a cobalt ss vary from 87-93 its like 15-20 whp differance. I know if your cars suppose to run premium the factory probly sets the timing tables as they were using premium and they have the knock tables put in at what a lesser premium would do and retard it to that. The knock sensor will probly go ape sh!t when you add 87 and dip below the factory tune and start trying to retard itself so much its starts sputtering, etc. 93 is a more refined fuel and will burn cleaner and get better gas mileage for a fact, but this is a high comp motor im talking about. You will probly have no prob running 87 as long as you keep the rpms low. As for low comp and 87 it probly wouldnt matter a whole lot until you started winding it out but then you would probly sacrafice some power.

87 is more volatile, it will burn faster, which can cause preignition... 93 Burns slower, and so forth...

[Whiteboy572]

87 is more volatile, it will burn faster, which can cause preignition... 93 Burns slower, and so forth...

Yeh, i had it backwards. So basically you can get more timing out of 93 firing the plug b4 tdc getting a more complete burn and making more power.

[rrutter81]

I believe that premium has a lower flash point and is able to burn faster than 87, if i remember correctly? My z has a 10.5:1 cr and i know if i run 87 it will knock, ive heard plenty of stories. You can run 87 or 93 if you have your car tuned for it, but you will make less hp i know the differance in a cobalt ss vary from 87-93 its like 15-20 whp differance. I know if your cars suppose to run premium the factory probly sets the timing tables as they were using premium and they have the knock tables put in at what a lesser premium would do and retard it to that. The knock sensor will probly go ape sh!t when you add 87 and dip below the factory tune and start trying to retard itself so much its starts sputtering, etc. 93 is a more refined fuel and will burn cleaner and get better gas mileage for a fact, but this is a high comp motor im talking about. You will probly have no prob running 87 as long as you keep the rpms low. As for low comp and 87 it probly wouldnt matter a whole lot until you started winding it out but then you would probly sacrafice some power.

most intelligent post here.

however speaking from experience, I run BKR7E plugs and still got 4 degrees of KR on 93+octane booster. Im thinking they had a 97 Octane tune. It still drops to the lower octane table just incase.

Higher MAP will reduce the timing by default via the table so compression does have a little bit to do with it. However I would look at the problem, not the bandaid.

87 is more volatile, it will burn faster, which can cause preignition... 93 Burns slower, and so forth...

this is kind of right but also wrong. 93 octane can be compressed more before detonation. 87 is easier to cause detonation. If we were to take extremes like diesel it might become clearer?

I think a better way would be to say "which has a greater resistance" to detonation rather than saying something is more volatile under 0 psi.

What are you talking about?

it means that the timing map that is advanced 35+ (at least for me) degrees under normal driving was under the same octane rating as under WOT.

[Quicksilverado]

it means that the timing map that is advanced 35+ (at least for me) degrees under normal driving was under the same octane rating as under WOT.[/QUOTE]

I'm assuming you don't have a low and high octane table then. What is your c.r.? Most f/i motors have a fairly low c.r. which will allows the use of a lower octane gas as long as it is not seeing any boost.

[Got Milk?]

mm, my gas cap tells me i need to use premium. and it gotz boost, so im not using regular unless i really have no other choice.

[rrutter81]

I'm assuming you don't have a low and high octane table then. What is your c.r.? Most f/i motors have a fairly low c.r. which will allows the use of a lower octane gas as long as it is not seeing any boost.

I have both a high and low octane table.(hence why i mentioned it in the first place) Please dont try to educate me on octane ratings or my engine/pcm.

10.0:1 is my compression ratio

its an LSJ ecotec 2.0

[collins]

with an 11:1 cr daily driven car, it does not like 87... kinda sucks, as yesterday was the first time i found premium in a week and a half...

[DirtyMechanic]

with an 11:1 cr daily driven car, it does not like 87... kinda sucks, as yesterday was the first time i found premium in a week and a half...

[Mike Lowrey]

11.5:1 CR + 93 octane tune = Premium for me

[Kevykev]

One of my cars "requires" Premium so, for that reason ALONE, I use premium. The others get the regular stuff!

[slimm]

i have to run premium but couldnt find any. so, i put in regular and used the Lucas Octane Booster with the regular and had no problems. I recomend that if you are in dying need of gas. If you can hold out for premium, wait!

[1000cckiller]

PREMIUM IS AT THE PILOT GAS STATION ON BOULDERCREST.

[Member31410]

I just barely got some premium at the BP off GA 400 and Windward Pkwy by TopSpeed.

[Sport1.3]

I'm actually swapping my motor in a few weeks, so that i'm able to run regular again.......it will be my first MPG build. I'm shooting for 55mpg lol

[DerrickT]

oh, the OP already stated that. so... repost.

oh noez~!! I don't read every post I have better things to do.

[Shawna]

*waves hand* I do