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Discussion Starter · #1 ·
i have read lots of people deciding to tune for 91 octane and then run 93 octane gas anyway for safety. but what about tuning for 93 octane then using octane booster with every tank to raise it to say 94 or 95? or higher? or even using a little just for piece of mind on the stock tune? does running higher octane have any negative long term effects aside from diminished bank account? also could running octane booster in an otherwise 100% stock car get warranty claims denied on the engine should anything happen? im talking about an fa20 if that helps.

these are the specific chemicals im referring to. if anyone has any other suggestions of experience with some other product im all ears.
toluene
xylene
https://www.amazon.com/Octane-Boost...98425023&sr=8-1&keywords=Klotz+Octane+Booster

i have heard that xylene can yellow your spark plugs is that a bad sign or just a fashion statement?
 

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Stanley Yahtzee said:
i have read lots of people deciding to tune for 91 octane and then run 93 octane gas anyway for safety. but what about tuning for 93 octane then using octane booster with every tank to raise it to say 94 or 95?
This is a band-aid fix for people running generic mapping who have trouble with the 93-octane version. Get a custom calibration for what gasoline you're going to be running and be done with it.

If you want to supplement the fuel for higher octane, look into a WMI kit. Pump gas when you are cruising, race gas when you're hammering it. WMI systems are becoming more obsolete and less desirable with the availability of E85, but they're still a valid option where E85 isn't readily available. If you want full-time option, convert to E85 and be done with it. Given the choice, I'd go E85 with flex-fuel capability (based on E%), but that's not feasible for everyone.

You don't have to use methanol in your WMI system; you can use something like isopropyl (rubbing) alcohol that you find in grocery stores / pharmacies in your system, so it's not like you have to deal with major vendors to supply your kit. You can get the isopropyl alcohol and distilled water in the same place.
 

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Stanley Yahtzee said:
i thought there was no perfect way to run a modern wrx on E85 yet? dosent it kill the HPFP?
Everything can be accomplished with money...if E85 conversion isn't feasible (e.g., E85-compatible pump is $$$), invest in a WMI setup.

I don't believe in gas tank additives in an attempt to increase octance.

I use dry-gas (HEET) during the winter months to try to prevent water in the fuel lines and keep them from freezing. I use Sea Foam in the fuel tank to help clean injectors once/year. Other than that, the gas in the tank is exactly what I've calibrated the car for.
 

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Discussion Starter · #5 ·
so just getting a protune for 93 octane will guarantee that 93 octane will be absolutely sufficient? there will be no added assurance from running any higher octane under any scenario?
 

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Stanley Yahtzee said:
so just getting a protune for 93 octane will guarantee that 93 octane will be absolutely sufficient? there will be no added assurance from running any higher octane under any scenario?
There are no guarantees in life, especially when modifying a car.

If you go to a competent tuner, they should have a sufficient safety margin built into the calibration to allow for fluctuations with fuel quality.
 

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Discussion Starter · #7 ·
your right there are no guarantees, perhaps i worded that incorrectly. the risk is exactly my point, higher octane=higher knock resistance=lower risk? yes?

also why dont you believe in fuel additive octane boosters?
 

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Stanley Yahtzee said:
your right there are no guarantees, perhaps i worded that incorrectly. the risk is exactly my point, higher octane=higher knock resistance=lower risk? yes?

also why dont you believe in fuel additive octane boosters?
If you want more "insurance", look into a WMI kit. It only sprays under certain parameters, so it won't be in use when you're cruising down the freeway (where a tank additive will be used all the time).

You shouldn't need octane boost under cruising conditions. The only time you should worry about octane it is under load. By installing an on-demand system like a WMI kit, you limit your "waste" while providing all the necessary insurance when you need it.
 

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Discussion Starter · #9 ·
it is something i may look into in the future, my wrx is going to remain almost entirely stock for the first 2 years of its life(at most a stage 1 protune and catback) another thread has my hopes up(probably far far too high up) for what the 2020 sti is going to be. so im not sure how long i will own this wrx. so i dont want to hurt re sale value by modding the hell out of it straight away.
 

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Stanley Yahtzee said:
yes i read that months ago back when i first decided not only that a wrx would be my next car but that it would be turned to stage 2 before 2000 miles lol.
If E85 is available to you and feasible, go that route. With the addition of flex-fuel systems in recent times, it's even more of a reason to go this route.

As I mentioned in that thread, a WMI system is a point of failure, which is why so many tuners shy away from them.

If you're looking for insurance, your mixture will be mostly water and the ECU calibration won't be so heavily reliant on the alcohol/methanol in the system, so a system failure wouldn't be catastrophic. The catastrophic failures is when you're tuning for race gas and the system fails and all you have is pump gas.
 

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Discussion Starter · #13 ·
e85 conversion=tune=warranty claim denial right? and yes adding points of failure to an already fairly complex(and cheap, lets be honest here) car is not appealing to me, im not looking to make a rocket i just want a little more than 265 hp. if i wanted a rocket id buy a used srt8 or something.
 

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e85 conversion=tune=warranty claim denial right? and yes adding points of failure to an already fairly complex(and cheap, lets be honest here) car is not appealing to me, im not looking to make a rocket i just want a little more than 265 hp. if i wanted a rocket id buy a used srt8 or something.

There is no more liability in E85 conversion, tune, etc. than simply tuning. If you have an accessport on your car currently, youre just as likely to have a claim denied. I get what you're saying, though, and yes, it would add a bit of complexity. Most notably new injectors and fuel pump
 

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also why dont you believe in fuel additive octane boosters?
The original octane booster was tetraethyl lead. You can't get it any more. At least not OTC. I liked this for my old farm tractor. It would also not be good for cats.
I don't like running additives either. I am paranoid and am always afraid such additives are snake oil and a waste of money.
 

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There is no more liability in E85 conversion, tune, etc. than simply tuning. If you have an accessport on your car currently, youre just as likely to have a claim denied. I get what you're saying, though, and yes, it would add a bit of complexity. Most notably new injectors and fuel pump
There is.

Unless you run an ethanol-compliant pump and lines (lines are mostly OK these days), there is additional potential for failure of OEM equipment when running high-ethanol percentages.
 

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Discussion Starter · #17 ·
The original octane booster was tetraethyl lead. You can't get it any more. At least not OTC. I liked this for my old farm tractor. It would also not be good for cats.
I don't like running additives either. I am paranoid and am always afraid such additives are snake oil and a waste of money.
ive already seen enough data to be pretty confidant these chemicals work, i just haven't seen anyone talk about what these chemicals do to an engine long term. i cant help but think most people who are crafting their own home-brew octane boosters are serious track nuts and maybe they dont do this witchcraft on their dailies.
 

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Stanley Yahtzee said:
ive already seen enough data to be pretty confidant these chemicals work, i just haven't seen anyone talk about what these chemicals do to an engine long term. i cant help but think most people who are crafting their own home-brew octane boosters are serious track nuts and maybe they dont do this witchcraft on their dailies.
If you're not modifying the tune on your car, there is NO benefit to adding any kind of additive to your tank. There is such a safety margin built-in that you're not even benefiting from using the 93 you have available (vs ACN91).

When you get to tuning the car, it becomes a different story (at which point, warranty is out the window, because the ECU was reflashed with a non-OE mapping)...

If your car fails at S1/S2 power levels, it would've failed stock. If you're worried about engine longevity, a good S1/S2 tune will probably be safer than OE tune with tank additives. That said, the remapping is grounds for a warranty claim denial, so you have to be willing to pay to play.
 

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Discussion Starter · #19 ·
If you're not modifying the tune on your car, there is NO benefit to adding any kind of additive to your tank. There is such a safety margin built-in that you're not even benefiting from using the 93 you have available (vs ACN91).

When you get to tuning the car, it becomes a different story (at which point, warranty is out the window, because the ECU was reflashed with a non-OE mapping)...

If your car fails at S1/S2 power levels, it would've failed stock. If you're worried about engine longevity, a good S1/S2 tune will probably be safer than OE tune with tank additives. That said, the remapping is grounds for a warranty claim denial, so you have to be willing to pay to play.
well i guess case closed then, thanks for the input.
 
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