Mixing 91+100 to get 93 in California

[ISaltMySaltedButter]

Hi y'all!
Long time lurker, first time poster here. I recently picked up my DE5, and noticed that 93 is the recommended octane. However, I live in California and 93 octane is basically nonexistent.

So my area actually has a 100 octane station nearby, and I've heard it mentioned you can achieve 93 by mixing the proper amount of 100 into 91. (Found plenty of fuel mixing calculators that all report the same ratios)

Question being: Has anyone actually done this to their DE5? I would like to put the proper octane in my car, but a little hesitant to go around mixing fuels when the only evidence i seem to be able to find about this practice appears to very anecdotal.

Appreciate any help! Thanks.

 

[ender_ong]

I do this, I mix 91 with 101 to get 93 at the Sunol Super Stop gas station in NorCal. I use this website to determine how much to mix: 93 Octane Mix Calculator

I checked with the attendant to make sure that the 101 is unleaded, make sure you do the same (pretty sure it will be unleaded though). From my calculations mixing it this way is actually cheaper than pumping the 94 octane available. I err on the side of getting slightly over 93, because it’s an estimate of how much gas is left in the tank on refill

 

[jayy_swish]

Using 91 octane is fine both stock and tuned off the shelf options. Unless you get a custom tune for 93 but that would make no sense in CA lol since there is none. You can also mix about 1.5 gallons of E85 to get you to 93 octane which would be cheaper than using 100 octane

 

[Frenzal]

I've run 91 since the beginning because 93 is not available. No problem yet.

 

[SocalDE5]

91 here. No issues. Car runs great.

 

[ZeroGSR]

Just because you aren't noticing things doesn't mean your car isn't pulling timing, it most certainly is. Whether or not that's a problem long term for the car is a different story, but at the very least you are leaving some hp on the table, multiple dyno plots and Hondata logs can confirm that.

If you have access to 100, mixing it to 93 is your best bet. E85 works also, but just know your power will likely dip as it has less energy density than standard fuel. 2 ounces of Boostane Pro also works and is cheap and easy, but does leave some orange residue and can clog cats with long term use. At only 2oz it's probably fine though. You can also do a meth setup, but that's likely a little overkill for this conversation.

When I drive past the same station as Ender, I do the same mix, I am on a "91" tune but I can definitely feel it when running 93. With it starting to warm up, knock is going to get worse.

 

[SocalDE5]

Just because you aren't noticing things doesn't mean your car isn't pulling timing, it most certainly is. Whether or not that's a problem long term for the car is a different story, but at the very least you are leaving some hp on the table, multiple dyno plots and Hondata logs can confirm that.

If you have access to 100, mixing it to 93 is your best bet. E85 works also, but just know your power will likely dip as it has less energy density than standard fuel. 2 ounces of Boostane Pro also works and is cheap and easy, but does leave some orange residue and can clog cats with long term use. At only 2oz it's probably fine though. You can also do a meth setup, but that's likely a little overkill for this conversation.

When I drive past the same station as Ender, I do the same mix, I am on a "91" tune but I can definitely feel it when running 93. With it starting to warm up, knock is going to get worse.

I concur with the fuel mix & timing.....
but the difference from 91 to 93 in power performance is minimal. Too minimal for road driving to notice. ignition timing is based off 93 but it will run and perform on 91.

If there is knock..... the knock sensor should remedy that. We would notice the car acting sluggish when accelerating.


Side fuel topic discussion.....
Since I this is a fuel thread.....I have read humans who track typeS deal with overheating issues. Aftermarket oil coolers, reverse rad hoses and improved coolant helps........
But
running LEADED race fuel would also be a big help. The lead fuel burns cooler in the engine. Cooler engine under hard rpms is a happy engine. And it is good for keeping valves clean.
I ran leaded fuel (100 & 110) in my race/track bikes with noticible lower temps.

Just a suggestion for you track guys. 2 5gal drums (fit in the trunk space) get you a full tank AND....it smells sooooo good when it burns through exhaust.

 

[ISaltMySaltedButter]

Hey thanks y'all! That's super helpful

 

[Fred 930]

..... But running LEADED race fuel would also be a big help. The lead fuel burns cooler in the engine. Cooler engine under hard rpms is a happy engine. And it is good for keeping valves clean.
I ran leaded fuel (100 & 110) in my race/track bikes with noticible lower temps .....

Will be interested if the poor sots who chose to live in California (without 93 octane fuel and many other conveniences) have any local access to leaded 110 octane race gas?? We can still buy it here in the midwest at a few stations, but I'd be very surprised if it can be found in CA! Perhaps a local airport or marina will have it, but it's not legal for highway use.

Also be aware, LEADED fuel will harm your catalytic converter. A little might be tolerated, but using it long term will damage the cat and possibly O2 sensors. So it might be OK for an occasional track day, but not all the time.

 

[ZeroGSR]

Will be interested if the poor sots who chose to live in California (without 93 octane fuel and many other conveniences) have any local access to leaded 110 octane race gas?? We can still buy it here in the midwest at a few stations, but I'd be very surprised if it can be found in CA! Perhaps a local airport or marina will have it, but it's not legal for highway use.

Also be aware, LEADED fuel will harm your catalytic converter. A little might be tolerated, but using it long term will damage the cat and possibly O2 sensors. So it might be OK for an occasional track day, but not all the time.

I wouldn't chance running any leaded gas in these cars at all. It only took a few gallons to ruin the O2 sensor and hi-flow cat in my car in the 90s. Idiot at the track put the wrong gas in my car. I did hit a great 1/4 mile time though, LOL.

But yes, we have race gas in CA including leaded, but as you stated primarily found at tracks, airports, or marinas, or places adjacent to them.

 

[SocalDE5]

Will be interested if the poor sots who chose to live in California (without 93 octane fuel and many other conveniences) have any local access to leaded 110 octane race gas?? We can still buy it here in the midwest at a few stations, but I'd be very surprised if it can be found in CA! Perhaps a local airport or marina will have it, but it's not legal for highway use.

Also be aware, LEADED fuel will harm your catalytic converter. A little might be tolerated, but using it long term will damage the cat and possibly O2 sensors. So it might be OK for an occasional track day, but not all the time.

Hey. I Love to hate CA.
I get my fuel from dealers who sell it. A F&L vendor is near me in Long Beach. I get it there. But the CA offroad tax for fuel is crap.

There are places with 100 at the pump........near small municiple airports. I know of a 76 that pumps it close to me.

Correct with LEAD. It can cause issues cats/sensors if prolonged use. Once in a while is good for offroad events.

 

[SocalDE5]

I wouldn't chance running any leaded gas in these cars at all. It only took a few gallons to ruin the O2 sensor and hi-flow cat in my car in the 90s. Idiot at the track put the wrong gas in my car. I did hit a great 1/4 mile time though, LOL.

But yes, we have race gas in CA including leaded, but as you stated primarily found at tracks, airports, or marinas, or places adjacent to them.

No way.... why you running a dodge neon at the track?

Lol. I just joshin'

 

[ZeroGSR]

No way.... why you running a dodge neon at the track?

Lol. I just joshin'

95 Turbo GSR running 12s, which was fast back then, LOL.

 

[tallboi]

Speaking of fuel, In my part of the country I have multiple fuel options. I can easily buy:

93 octane with 10% ethanol, not Top Tier
91 octane with 10% ethanol, Top Tier
91 octane ethanol-free, not Top Tier

I tend to run the ethanol-free 91 most of the time and sprinkle in an occasional tankful of the Top Tier 91 octane stuff containing 10% ethanol.

My rationale for prioritizing the ethanol-free is that it theoretically contains more "energy" than the ethanol blend and therefore *should* give me slightly better mpg, and it doesn't suck up as much moisture as an ethanol-blend.

What do others think/do if you have multiple options available?

 

[Fred 930]

Guess I'd run the 93 octane ..... but that said, I sure hate ethanol fuel and won't use it in any power equipment, like mowers, snowblowers, etc. And regarding "Top Tier", I suspect that's mostly a marketing term attempting to differentiate between commodity products from different vendors. If the price is identical, then Top Tier for sure - but I wouldn't pay 1 cent per gallon more for it.