Inexpensive octane boosters from the local auto parts stores and Walmart

[y_p_w]

I’d like to bump it up 2 points for about 10 gallons. None of those boosters would work?

From 91 to 93? Can't really be done (legally) with anything from an auto parts store. Most have disclaimers saying that a "point" for them is less than (R+M)/2. Like 2 points equals 0.2 increase of (R+M)/2.

The only thing that really works is blending some fuel that has a higher octane rating. The octane boosters that work independently of bulk octane rating are tetraethyl lead and MMT. The former is not street-legal and the latter can't really be used that much.

Some mentioned toluene. Ethanol would also boost octane rating, but most fuel in California is already E10. I've seen some gas stations that sold 94 octane (R+M)/2, but that was usually from blended 100+ octane street-legal racing gas.

 

[pzev]

I used to own a supercharged 5.0 Coyote, 13lbs of boost, upwards of 25 degrees of timing. She was very sensitive to knock and would pull about 3-5 degrees of timing on even the best street 93 octane. This setup a perfect test bed to quantify the results of assorted Octane boosters. I wrote up a whole post on a few years back on the forum I was active on at the time, utilizing a somewhat standardized method and numerous data logs of assorted products. My study was cut short when I sold the truck, but here is the original post for anyone curious (long read).

Cliff notes version.

Anything containing MMT will be an effective knock suppressant, and quality products have tangible results with low dosage rates (as low as 2 ounces per tank of fuel). In the post I referenced above, one bottle of Lucas Octane Booster was equal to over 4 degrees of timing on my supercharged 5.0, which equated to about 60hp. The professional products could be dosed at a "daily" rate of about 2-3 ounces per tank of fuel for tangible benefits.

Products that I found effective were as follows.

Pro products:
Boostane Professional
Torco
VP Octanium

Consumer Products:
Lucas Octane Booster
Royal Purple Max Boost
STP Octane booster (the product with MMT on label)

Products without MMT are worthless for increasing octane. MMT degrades in light, so translucent packaging is the first red flag the product won't work. MMT is also on the SDS, so read that to verify its presence in a product. Long term use of MMT can impact catalytic converter and spark plug life.

 

[RazorsEdge]

I used to own a supercharged 5.0 Coyote, 13lbs of boost, upwards of 25 degrees of timing. She was very sensitive to knock and would pull about 3-5 degrees of timing on even the best street 93 octane. This setup a perfect test bed to quantify the results of assorted Octane boosters. I wrote up a whole post on a few years back on the forum I was active on at the time, utilizing a somewhat standardized method and numerous data logs of assorted products. My study was cut short when I sold the truck, but here is the original post for anyone curious (long read).

Cliff notes version.

Anything containing MMT will be an effective knock suppressant, and quality products have tangible results with low dosage rates (as low as 2 ounces per tank of fuel). In the post I referenced above, one bottle of Lucas Octane Booster was equal to over 4 degrees of timing on my supercharged 5.0, which equated to about 60hp. The professional products could be dosed at a "daily" rate of about 2-3 ounces per tank of fuel for tangible benefits.

Products that I found effective were as follows.

Pro products:
Boostane Professional
Torco
VP Octanium

Consumer Products:
Lucas Octane Booster
Royal Purple Max Boost
STP Octane booster (the product with MMT on label)

Products without MMT are worthless for increasing octane. MMT degrades in light, so translucent packaging is the first red flag the product won't work. MMT is also on the SDS, so read that to verify its presence in a product. Long term use of MMT can impact catalytic converter and spark plug life.

Thank you for the work you put into this. Alot of people anymore just go by opinions of a product instead of doing any sort of research.

 

[weaponoffreedom]

There isn't a benefit TO YOU.

The difference on my tune from 91 to 93 is 14 horsepower and 12lbft of torque across the entire rev range.

agreed, if the tune requires 93 and you give it 87, or 91, there is an issue.

 

[DGXR]

Most of the cheaper off the shelf octane boosters don't do much, while good octane boosters are expensive (Race Gas Ultra/Concentrate, etc). I suggest going to a station that sells race gas, add 2-3 gallons of 100 octane and then top off with 91 octane. That will give a serious octane boost and likely cheaper than most other options.
The Cougar looks awesome, show more pics of that please.

 

[nickaluch]

Will do!
View attachment 176261View attachment 176262View attachment 176263View attachment 176264View attachment 176265View attachment 176266

Let's see some pictures of that sweet cougar

 

[Nicasio]

Most of the cheaper off the shelf octane boosters don't do much, while good octane boosters are expensive (Race Gas Ultra/Concentrate, etc). I suggest going to a station that sells race gas, add 2-3 gallons of 100 octane and then top off with 91 octane. That will give a serious octane boost and likely cheaper than most other options.
The Cougar looks awesome, show more pics of that please.

Let's see some pictures of that sweet cougar

Here ya go!

 

[Chris142]

Toluene or Xylene.

Can we get that in California?

 

[Revving2Redline]

Try to buy toluene by the gallon.

it will definitely work.

 

[Revving2Redline]

Can we get that in California?

million dollar question!?!?

 

[meadows]

I would think you could. Look in paint supplies.

 

[Rogueman2016s]

I gas up all our cars at the nearby Costco. We only have 91 octane here in California. I’d like to bump it up to at least 93 octane for one of my cars. I see so many different brands on the shelves. Any recommendations?

Fleet mechanic at my last job gave us this to run in our work vans every now and then.

Octane Booster | STP®

Restore horsepower while reducing knocking and pinging with the Octane Booster from STP®. Find out more about this fuel additive here.

www.stp.com

But I’ll be honest I never felt any difference.

 

[Graham Piccinini]

Huge misconception is what octane boosters are "bringing to the table".
When an octane booster says it will raise octane by 5 points - it does not mean that your 87 just became 92. What it means is your 87 just became 87.5, at best.
EDIT: I see it mentioned in post #21.

 

[Rogueman2016s]

Yes I believe most consumers buying octane booster are expecting a kick in pants kind of experience

 

[Snagglefoot]

It does seem that Cali does not allow 93 octane. Is the some reason for it? The owners manual for the Chevy 6.2 engine specs 93 octane.

It looks like GM bent over for California and now their 2024 6.2 engine calls for 91 “ minimum “, instead of 93 “ Recommended “Here are the fuel recommendations from the 2020 and 2024 owners manuals. Enjoy.

 

[97prizm]

It does seem that Cali does not allow 93 octane. Is the some reason for it? The owners manual for the Chevy 6.2 engine specs 93 octane.

Yes The people's republic removed xylene from the gas which bumped up the octane. There are a couple of articles published on it.

 

[DGXR]

I'm pretty sure anything the factory built as "premium required" will do fine on 91 or 93 octane.