What is the Best Octane?

**1TA LS1** · 05-15-2007, 11:07 AM

I've heard many different opinions on gasoline Octane levels for our LS1 engines. My local Pontiac dealership mechanic told me on my stock LS1 with minor bolt-ons (exhaust + Intake) the best performance and gas mileage octane is 90 to 93. My friend told me to use 91 octane (91 is the highest in California) and add an octane booster every fill-up since your car is a higher compression engine.

Who is right and what is the best performance octane level for our engines? What do you guys fill up?

**2000T/A Guru** · 05-15-2007, 11:22 AM

I use 92 or 93 sometimes i do use the race gas they sell around he its 110 octane.

**rajiv1998** · 05-15-2007, 11:49 AM

91+ is the best. Wut ever you do, please dont use regular. I use 110 when im at the track

**1TA LS1** · 05-15-2007, 12:25 PM

Originally Posted by rajiv1998

91+ is the best. Wut ever you do, please dont use regular. I use 110 when im at the track

Is there a difference in performance at higher octane levels above 91?

**2000T/A Guru** · 05-15-2007, 12:36 PM

Between 91, 92, 93 you really wont notice maybe just a little, but 110 its slightly noticeable, and between 87 and 93 im my jimmy i notice off the line i couldnt even chirp the tires with 87 but with 93 i can spin them a little, true story.

**SexyTransAm** · 05-15-2007, 01:17 PM

116 is the only way to go

**silverbullit1972** · 05-15-2007, 04:08 PM

91 octane v-power baby

**urstolendesire** · 05-15-2007, 04:56 PM

yeah dont even put regular in that tank!! that was a bad experiance. even the mid seems to knock. i've even tried mixing premium with mid and it still knocks...not good if your tryin to save on gas money...

**rajiv1998** · 05-15-2007, 05:01 PM

Originally Posted by urstolendesire

yeah dont even put regular in that tank!! that was a bad experiance. even the mid seems to knock. i've even tried mixing premium with mid and it still knocks...not good if your tryin to save on gas money...

yes. You have the money to buy the car and afford parts for it, so why try to save a few bucks on gas? I hate it when people are like "im looking into buying a ws6, but am worried about gas milage" Its not great, but its not bad either. The only downfall is u have to use premium and w/ a motor like the ls1 im not surprised. U dont buy an ls1 worrying about gas milage.

**urstolendesire** · 05-15-2007, 05:18 PM

agreed. that is one of the thinggs you take on, such as the insurance payments goin up...especially for an 18 yr. old...lol.

**joejenkinsglass** · 05-15-2007, 05:58 PM

the ls1/ls2 was designed for 92 I use 93 but its getting hard to find 91 seems to be the norm around here luckily my daily driver is diesel

**1TA LS1** · 05-15-2007, 10:52 PM

Originally Posted by joejenkinsglass

the ls1/ls2 was designed for 92 I use 93 but its getting hard to find 91 seems to be the norm around here luckily my daily driver is diesel

Thanks for the feedback. 91 is the highest in California as well.

Do you think it's worth dropping in Octane booster with every tank?

**Mike's TA** · 05-16-2007, 08:56 AM

Originally Posted by rajiv1998

Wut ever you do, please dont use regular. I

Regular throws a whole bunch of codes in my face. Tried it once and got some codes. Then accidentally put it in there and noticed after it was full. (they changed the color of the handles at my gas station, bastards

) Sure enough, more codes.

Only use 93

**NeeD4SpeeD** · 05-16-2007, 09:14 AM

Use the highest pump gas possible...Going 87 or 89 will do more harm then good and probably throw ur a/f mix off a bit cuz your giving a high perf engine shit gas....Not to mention some gas stations water down there gas a bit so if you go lower then 91-93 you could see ur whoel dash light up with codes lol

**Arrison24** · 05-16-2007, 09:16 AM

basically use the highest you see wherever you happen to be

**2000T/A Guru** · 05-16-2007, 09:25 AM

Im 19 my I have many tickets my insurance is high 3200 a year jsut for my T/A, i have this car and a beater, rent i have to pay and a kid that i have to feed, if i can do all that you better put some god damn 93 octane in your car.

**1TA LS1** · 05-16-2007, 01:23 PM

Originally Posted by 1TA LS1

Thanks for the feedback. 91 is the highest in California as well.

Do you think it's worth dropping in Octane booster with every tank?

WHY WOULD SOMEONE PUT REGULAR GAS?!?!

I would never do that and I am not going to try it......

I fill up 91 everytime, which is the highest in California, but I have been adding octane booster to my full tank of gas every time. The reason for adding an octane booster is so my Trans Am will have a higher octance to get better performance. - This was recommended to me by my friend who builds engines. He stated, "b/c of the compression ratio on your vehicle, you should put gas with a higher octane level than just putting 91 so you sould get the best/better performance." Is he right? Or am I wasting my time adding octane booster?

**intheclouds1977** · 05-16-2007, 01:29 PM

I'm not familiar with the computer tables on these cars yet. You need to find out the lowest octane that will put you in the top performance table without knocking. My guess is that's somewhere between 91-93 (depending on what altitude you're at). Less octane is needed the higher altitude you are at for the same detonation prevention. Once you find the lowest octane you can run and still be in the top performance table, increasing octane will do absolutely nothing for you. Octane is resistance to detonation...nothing more. So, if you're already in the top table without detonating, more octane does nothing but take up perfectly good space that mogas could be in for more power.

**1TA LS1** · 05-16-2007, 01:40 PM

I agree with that intheclouds1977. That makes more sense to me. Now I wonder how much higher of an octane I get when adding an octane booster to my full tank of 91 gasoline....