[gibsonlp09]

So, I was just wondering what octane people have been using so far...? I know they say 91 is recommended because the engine's high compression rate, but it's not required...and with gas as expensive as ever, what have you been using?

 

[agirltrucker]

Now keep in mind I just picked mine up last nite, but I have been running 87. Meet up with some solstice owners today and they suggested 89 if I can afford it...:lol: But none of them are using 91 and Pontiac suggested it for them too. Hope this helps...:thumbs:

 

[C20LET_50]

You can use all the fuel qualities because the knock sensor will detect and the ECU will reduce the power when lower octane fuel is used. But I don't understand why you buy a strong horse and won't feed enough

 

[java43]

You can use all the fuel qualities because the knock sensor will detect and the ECU will reduce the power when lower octane fuel is used. But I don't understand why you buy a strong horse and won't feed enough

my question exactly ...if we can't afford a few more cents a gallon..maybe we over bought?

 

[Crimson Avenger]

Just buy premium, it's only about $9.20 per month for once a week fill-ups...

Difference in price:

Perhaps more interestingly, the delta between the low grade of fuel and the premium grade has been about 20 cents per gallon for the last 7 or more years.

Further, that price difference stays constant even though the overall price of gas fluctuates. For example, right now in California, 87 is about $3.27 and premium 91 is $3.50. Still ABOUT 20 cents. It's not always exactly 20 cents, but it's close.

Back in 2001, when gas was at a historic low, you paid 95 cents per gallon for 87 and $1.15 for premium.
​

Actual extended costs:

What this means is that for your 13 to 14 gallon tank you'll put about 10 to 13 gallons in it each time you fill up. That means between $2.00 and $2.60 per tankful.

If you then fill up twice a week (doing a lot of daily driving) you're looking at about 100 fill-ups per year, or about $200 to $260 PER YEAR!!! Is it really worth hobbling the engine for that?

Just cut out two lattes per week, and you've made up for your premium fuel. (one if you drive less and fill up only once a week....)
​

High compression engines work better (more fuel efficiency & power) with premium:

This one's pretty obvious: 10.4 to 1 compression is HIGH compression. It's almost the exact same compression that we had back in the 60's for "high compression" performance engines.

You may also have slightly better fuel economy, so the actual cost might be even lower due to lowered total fuel consumption. This is true because with the additional spark advance that the computer can use with the correct fuel for this high compression engine, the engine will have greater power conversion efficiency.
​

Just buy premium:

If you only fill the tank once per week, you're looking at about $9.20 PER MONTH to drive the premium fuel, and this is one car where it most definitely makes a difference. For less than $10 per month? SURE I'll take premium.
​

 

[REDSKY]

I Agree...

Just buy premium:

If you only fill the tank once per week, you're looking at about $9.20 PER MONTH to drive the premium fuel, and this is one car where it most definitely makes a difference. For less than $10 per month? SURE I'll take premium.
​

I agree...I run high octane in all my cars except my Sunfire...The price in the end is really no big difference...I think it's just the fact that regular gas looks so expensive in the first place....Like AV's statement above you are only paying about $10 bucks a month more for the top notch stuff plus it's going to give you more power etc. At the track I use 104 octane and higher and you CAN tell the difference...so going from 87 to 93 or higher you will notice a difference plus you can always add an octane booster to your full tank as well to give you added boost...If you choose to ReFlash (ReTune) your ECM(ECU) you will notice the most difference using the high octane fuel.

If you are buying a Sky...treat it right use the good <stuff>!

 

[C20LET_50]

.....
[/indent]High compression engines work better (more fuel efficiency & power) with premium:

This one's pretty obvious: 10.4 to 1 compression is HIGH compression. It's almost the exact same compression that we had back in the 60's for "high compression" performance engines.

You may also have slightly better fuel economy, so the actual cost might be even lower due to lowered total fuel consumption. This is true because with the additional spark advance that the computer can use with the correct fuel for this high compression engine, the engine will have greater power conversion efficiency.
.....
​

:agree: :agree:
For correct results you have to measure on the dyno:
First: what's the increase in maximum power and what's the influence on fuel consumption.
Second: what's the difference in fuel consumption at some destinated levels of power.

Power will increase and fuel consumption will decrease, so for normal drivers not all of the higher price are real costs - I think it's nearly the same.
It's worth it to use the highest available fuel qualitity just for better driving.
Octane boosters maybe not cost efficient, better take the highest premium.

For the Sky RL / Opel GT I estimate Opel will recommend premium (Super 95 oct) or even premium plus (Super plus 98 oct) for the european cars. Both qualities are available at every gas station in Europe, some even offer Super 100 but most engines can't handle that high power fuel, so the upgrade price isn't worth it.

 

[GodWhomIsMike]

I don't own a Sky (yet), but I only use 93 from reputible gas stations. I had a bad experience with bad gas from a mom and pop station - required my car to be towed to the dealership. N/A Skys will probably be ok with lower octane, but for those of you planning on getting the turbo redline, expect to use 93 only (or 91 in Cali).

 

[hayabusa]

Yes i agree 20 cents is not alot. since some of us will be spending 20g to 25g or 25g to 30g rl.

Maybe my car might see 189 but never if possiple 187
try to run 191 or better most of the time.

Take care of your car and your car will take care of you.

 

[hayabusa]

Also i thought the red line had lower compression then the std ?

 

[GMguy]

You may also have slightly better fuel economy, so the actual cost might be even lower due to lowered total fuel consumption. This is true because with the additional spark advance that the computer can use with the correct fuel for this high compression engine, the engine will have greater power conversion efficiency.

I guarantee that you will get no better mileage with high grade , for the simple fact that highgrade gas doesn't contain as much energy as lower octane gasoline. The reason is because the octane boosters in highgrade gas (which is what makes it a highgrade gas) don't have anywhere near the energy capacity of low octane gasoline. People eternally confuse higher power levels with high octane, when in fact, the higher octane gas is more difficult to ignite and burns more slowly than lower grades - this is what allows high compression engines to run without harmful detonation. Ethanol, for example is now used to increase octane and ethanol gives significantly lower fuel mileage than gasoline.
For example : flex fuel models that can burn both E85 and regular gas (85% ethanol - it can't be higher because it would be difficult to start the engine on pure ethanol) have their EPA econmy ratings published at www.fueleconomy.gov - a typical difference would be a vehicle
getting 21/28 MPG on gas, gets 15/20 when running E85.

 

[eldeeko]

I guarantee that you will get no better mileage with high grade , for the simple fact that highgrade gas doesn't contain as much energy as lower octane gasoline. The reason is because the octane boosters in highgrade gas (which is what makes it a highgrade gas) don't have anywhere near the energy capacity of low octane gasoline. People eternally confuse higher power levels with high octane, when in fact, the higher octane gas is more difficult to ignite and burns more slowly than lower grades - this is what allows high compression engines to run without harmful detonation. Ethanol, for example is now used to increase octane and ethanol gives significantly lower fuel mileage than gasoline.
For example : flex fuel models that can burn both E85 and regular gas (85% ethanol - it can't be higher because it would be difficult to start the engine on pure ethanol) have their EPA econmy ratings published at www.fueleconomy.gov - a typical difference would be a vehicle
getting 21/28 MPG on gas, gets 15/20 when running E85.

Not so sure about this statement "when in fact, the higher octane gas is more difficult to ignite" (I would say "slower to ignite") as it produces energy for a longer time on the pistons instead of one "big bang". Try this link: http://autorepair.about.com/od/enginefuelgasolines/a/highoctanegas.htm
If that doesn't do it, it has some very good links also.

 

[ggccg]

Not so sure about this statement "when in fact, the higher octane gas is more difficult to ignite" (I would say "slower to ignite") as it produces energy for a longer time on the pistons instead of one "big bang". Try this link: http://autorepair.about.com/od/enginefuelgasolines/a/highoctanegas.htm
If that doesn't do it, it has some very good links also.

But don't forget that this force over a longer period of time is not constant... it decreases over that longer period as the volume of the cylinder increases on the piston down-stroke.

 

[nighttamer]

I'll have to throw in my 2 cents. I started out using 87 when I first got my Sol then switched to 91. According to the DIC I did get better MPG, only about 1-2 but that is ok with me. The car also felt like it had a little more spunk. I don't worry about the technical stuff, gas spark/burn or Dyno's, I worry about what I see and what I feel.

 

[C20LET_50]

I'll have to throw in my 2 cents. I started out using 87 when I first got my Sol then switched to 91. According to the DIC I did get better MPG, only about 1-2 but that is ok with me. The car also felt like it had a little more spunk. I don't worry about the technical stuff, gas spark/burn or Dyno's, I worry about what I see and what I feel.

Theory and practice fit together, see above! :thumbs:
Try 95 if available maybe you feel another "little more spunk".

 

[nighttamer]

Theory and practice fit together, see above! :thumbs:
Try 95 if available maybe you feel another "little more spunk".

Or below, I'm set up for most recent thread at the top.
I would love some more spunk. :yesnod:
You get 98 great, 95 good but I get punked with 91. :lol:

 

[MCW Sky]

Mix and match

you could always half fill the tank with premium and half with regular and split the difference. my dad would alternate between regular and premium for his 59 Bonneville - but then with a 20 or so gallon tank and only about 16 mpg on the highway that is a bit diffent.

perhaps a better question woudl be what if any gasoline additives would be safe and or recommended for this engine? not to improve mpg or hp but to clean injectors and whatnot.

 

[dmbdlatc]

you could always half fill the tank with premium and half with regular and split the difference. my dad would alternate between regular and premium for his 59 Bonneville - but then with a 20 or so gallon tank and only about 16 mpg on the highway that is a bit diffent.

I don't know about that. It is my understanding that if the knock sensors detects and adjusts for engine knock, it will take a few tanks of high octane fuel to get the timing back to where it should be to take advantage of the higher octane fuel again. If true, switching back and forth would be a waste, just stick with the low octane.

Can anyone confirm this?

 

[azzhauler]

I don't know about that. It is my understanding that if the knock sensors detects and adjusts for engine knock, it will take a few tanks of high octane fuel to get the timing back to where it should be to take advantage of the higher octane fuel again. If true, switching back and forth would be a waste, just stick with the low octane.

Can anyone confirm this?

Based on LS1 programming, it won't matter. The system learns knock out very fast. It's also designed for if you get a lot of KR on an often basis. There is a parameter I scan on my TA sometimes that shows how close it is running to the optimum timing map in the pcm. This is almost always at 100%. When I get KR the humber decreases and then gradually comes back to 100%. Just driving to work is enough for it to get back up. GM programming may be radically different by now, but I'd bet its similar.

And just normal driving won't make a difference between 87-93 as far as KR. You almost never see it just driving like a good law-abiding citizen.

 

[Rick Tinley Park]

So, I was just wondering what octane people have been using so far...? I know they say 91 is recommended because the engine's high compression rate, but it's not required...and with gas as expensive as ever, what have you been using?

I will give it the oats it says to -- why starve a racehorse?? Face it -- the big put down is that @177 hp (Still more that Miata) she is under-powered. So I should take away power? -- No I will spend the extra 3 dollars A TANKFUL to feed her right.