93 octane gas stations?

[newbie911]

Does anyone know of any gas stations that have a "premium" with a 93 octane rating instead of the usual 91 octane rating in the Carson/Reno areas?

[sperry]

Don't think so. 91 is "premium" here because we get California gas.

Allied Washoe in Reno does have 100 unleaded however. $7.25/gal I think is the current price according to MikeK.

[Kevin M]

The VPRacing on Prater and Pyramid has 100, but I don't know the price.

[Braydog]

VP racing has 93 oct, and 100 oct from the pump. Current price for 100 octane pump is 6.99 per gallon. They also have leaded 110 octane for 53.95 per 5 gallon can. You have to ask the clerk for this though, since it is leaded they say they are not allowed to display it.

There is one on West 7th street, just west of Keystone, and as Kevin said, one on the corner of Pyramid and Prater. The 7th Street location does not offer the 93 or 100 octane though, only the 110 cans.

[newbie911]

Thanks guys, looks like I need to hit VP to get the good stuff!

[S2kreno]

Probably a stupid question. Does that stuff make everyone go faster or just modified cars?

[Kevin M]

Probably a stupid question. Does that stuff make everyone go faster or just modified cars?

Your engine needs some capacity to take advantage of higher octane. Generally that means higher compression, increased boost for FI, or advanced timing. Since 99% of us drive cars with engines meant for street use, longevity, emissions compliance, etc. we don't benefit from simply adding higher octane fuel. The only way you would is if your engine was already suffering performance losses on 91. Then 93+ would restore it to where it's supposed to be running.

[Braydog]

Probably a stupid question. Does that stuff make everyone go faster or just modified cars?

for Autocross? Not really. Keep in mind this is with my limited experience of just this season.

For those of us with forced induction, running a higher octane fuel allows the turbo's boost to be increased more safely, without the risk of damaging key parts.

With the autocross genre, I, so far have not seen a need for running a high boost/octane map, and for the unexperienced autocrosser such as myself, could see it hurting me more than helping me. I go into corners WAY too hot as it is, and would probably be "adopting" twice as many cones if I was running my race fuel map.

[Dean]

Unless your car is setup to use higher octane, it will REDUCE power VS. what the car is tuned/designed to run on. Whether that is high octane ECU MAP(s) or different Carb settings, that is the case.

Higher Octane in lay terms actually means a higher resistance to burn (due to being squished)!!! In a car not tuned for it, that resistance to burning will reduce power. At this altitude, it will be even worse. (Oooh, another variable to include in HAP. Octane):rolleyes:

[Cody]

I am tuned safely for 91 octane at this elevation, but on a hot day of racing, you bet I spike the octane a bit to prevent knock. I use Torco, mostly, though.

[Braydog]

I am tuned safely for 91 octane at this elevation, but on a hot day of racing, you bet I spike the octane a bit to prevent knock. I use Torco, mostly, though.

seems like a smart choice. I generally do the same. BUT, Nothin beats throwing some 110 in there, crankin up the boost and letting it fly. Cheapest aircraft carrier launch on earth :D

[Kevin M]

I am tuned safely for 91 octane at this elevation, but on a hot day of racing, you bet I spike the octane a bit to prevent knock. I use Torco, mostly, though.

That's a seperate issue from performance gains though, and unique to modified engines.

[Cody]

^You don't think stock FI cars will knock with a heat soaked IC Kev?

[Kevin M]

I said no such thing.

[sperry]

^You don't think stock FI cars will knock with a heat soaked IC Kev?
They won't knock much, because the ECU will (should) retard timing. So, higher octane gas won't make the car faster, it will just prevent the car from getting slower when the I/C heatsoaks.

That is assuming the 100 octane isn't already making the car slower to begin with as Dean mentioned. :p

[Cody]

Right, regardless of whether the engine is modified or not (mine is not), if the ECU senses knock, it pulls timing in response, reducing HP, end of story.

Yes, 100 octane would be overkill. I tend to run 93 or so on hot days at Autocross. It certainly does seem to help keep the car from losing power.

[sperry]

Right, regardless of whether the engine is modified or not (mine is not), if the ECU senses knock, it pulls timing in response, reducing HP, end of story.

Yes, 100 octane would be overkill. I tend to run 93 or so on hot days at Autocross. It certainly does seem to help keep the car from losing power.
I'm all for 93 octane in anything that requires 91... mostly because all the cars that require 91 are actually designed for 93 'cause that's what the rest of the country gets except for us poor shmoes on the west coast.

[S2kreno]

but we're supposed to need less because of our high altitude....but we're supposed to need more because of our low humidity....but....crap:(

[newbie911]

My car is rated for 93, with a "reduced performance" at a 91 min. rating. I should think about about going for more on hot days then, correct?

[Cody]

^I'd run 93 all day long if I were you. I'd keep a can of Torco in the car for long trips, emergencies, etc. The car will learn to take advantage of the 93 over time, increasing your available HP, on an ongoing basis.

But I'm sure it's safe to stick with 91. Alternating back and forth (unless using the 93 while racing) could actually be the worst thing. If the car learns to use the 93, it will knock when you go back to 91 and "get on it". It will of course "learn" to pull timing again, but this process isn't something you should attempt to repeat regularly.

[newbie911]

So the "ECU" can't adjust or re-learn that quickly to changes then? What about "re-setting" the "ECU" (disconnect the battery for extended period of time)?

[dsmith]

My RX7 Twin Turbo specifies "a minimum of 93 octane" (common stuff back in 1993), but of course I haven't been able to get that for quite a few years. Under normal conditions I don't notice any difference from the old days of better gas, but the last time I ran it at RFR, as the IC got heat soaked, I lost a ton of power and suspect it was from the ECU retarding timing to fight knock.

Where do you get the Torco?

[Braydog]

No, you would need to run 2 different maps in order to fully use the benefits of a higher octane fuel.

In your case I would suggest the APR ecu upgrade. APR is awesome in the sense that you can run multiple maps. I did this on my VW. I had a stock map, a 100 octane map, and a valet map (limited speed to 15 mph among other things), and it was loaded all at once. I could control which map I used with the cruise control buttons. 2bennett Audimotive is the closest place to Reno where you can get it installed (without mailing out your ecu and waiting for it to return). That is where I had mine installed, and they do awesome work. They are located in Davis, CA. http://www.2bennett.com is their website. If you're wanting to run multiple maps, an ECU upgrade is the way to go, in my opinion. It saves reflashing your ECU every time you want to change.

[Braydog]

Another option for you. I pulled this off another forum, and have tried the Toluene method myself. I had this tested at 107 octane, using 100 octane fuel as a base, and 30%. This is just up for debate, so please do not take any of these methods to heart unless you completely know what you're doing, or have alot of money to spend on new equipment, as I am in no way a chemist.

Here are some common ways to boost your octane using off the shelf products. I pulled this off another car site.

Formula #1 - Toluene
R+M/2.........114
Cost...........$2.50/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane
Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $3/gal at chemical supply houses or paint stores.
Formula #2 - Xylene
R+M/2.........117
Cost...........$2.75/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........97.0 Octane
30%...........99.5 Octane
Notes: Similar to Toluene. 12-16 ounces will only raise octane 2-3 *points*, ie. from 92 to 92.3. Usually mixed with Toluene and advertised as *race formula*.

Formula #3 - Methyl-tertiary-butyl-ether (MTBE)
R+M/2.........118
Cost...........$3.50/gal
Mixtures with 92 Octane Premium
10%...........94.6 Octane
20%...........97.2 Octane
30%...........99.8 Octane
Notes: Oxygenate. Very common in octane booster products. Has lower BTU ontent than toluene or xylene, but oxygenate effect makes the gasoline burn better and produce more energy.
Formula #4 - Methanol or Ethanol
R+M/2.........101
Cost...........$0.60 - $1.75/gal
Mixtures with 92 Octane Premium
10%...........94.3 Octane (Methanol)
10%...........94.7 Octane (Ethanol)
20%...........Not Recommended
Notes: Methanol is wood alcohol. Ethanol is grain alcohol and found in Gasohol in 10% ratios. Both alcohols are mildly corrosive and will eat gas tank linings, rubber and aluminum if used in excessive ratios. Main ingredient in "Gas Dryers", combine with water.

Formula #5 - Isopropyl Alcohol and Tertiary Butyl Alcohol
R+M/2.........101
Cost...........$0.60-$1.50/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........Not Recommended
30%...........Not Recommended
Notes: Similar to Methanol/Ethanol. Isopropyl Alcohol is simply rubbing alcohol.

Sample Mixture
To make your own octane booster, it is easiest to make up a large batch, and then bottle it up in "dosage-size" uses. Below is the basic formula of one of the popular octane booster products. To make eight 16 ounce bottles (128 oz = 1 gal):
100 oz of toluene for octane boost
25 oz of mineral spirits (cleaning agent)
3 oz of transmission fluid (lubricating agent)

[MikeK]

My RX7 Twin Turbo specifies "a minimum of 93 octane" (common stuff back in 1993), but of course I haven't been able to get that for quite a few years. Under normal conditions I don't notice any difference from the old days of better gas, but the last time I ran it at RFR, as the IC got heat soaked, I lost a ton of power and suspect it was from the ECU retarding timing to fight knock.

Before I went to a front mounted intercooler I would get the same thing at RFR about 5 minutes into each session. I use 2 or 3 gallons of 100 in each tank of 91 to prevent this.

[Cody]

So the "ECU" can't adjust or re-learn that quickly to changes then? What about "re-setting" the "ECU" (disconnect the battery for extended period of time)?
If you were to switch from 91 octane to 93 or so, you might try resetting the ECU, but I would give it a couple days to re-learn before driving competitively. Usually after a reset, the ECU (in subarus anyway) makes things really safe, and then slowly tries it's luck at increasing timing.

Your milage may vary.


Where do you get the Torco?

http://www.need4speedpower.com/

[Dean]

Octane will not fix IC heatsoak.

At Reno altitude, 93 probably doesn't buy you anything over 91 without tuning. most UCEs only adjust timing and once it is at the maximum within the range which it likely is already, more octane just slows combustion.

Reseting your ECU is probably even worse as it probably has a "safe" starting position and learns more advance over time and as I said is probably already at maximum at this elevation even on 91.

There may be ECUs which can adjust fuel dynamically using o2 sensor and/or knock sensors(known as closed loop) all the way to red line , but I would doubt it. Subaru ECUs give up at about 4K RPM or 40% throttle. Above those ranges, things can happen too fast for the sensor and ECU to react to and things can go boom...

Oh, and higher altitude and lower humidity both mean you need less octane as the intake charge is less dense. (I think that is right.)

[Cody]

Octane can't "fix" heatsoak. Hot intake air will still reduce power output due to a less dense intake charge (regardless of octane), but it can allow the car to avoid knock, for reals. If that's not a concern to you, I feel sorry for your motor. If you're lucky you'll only lose power, if you're unlucky, your motor will suffer damage.

[Dean]

I don't think 2 octane is going to do enough in a heatsoak condition, the ECU is going to have to pull timing anyway.

The solutions to heatsoak are less boost, more cooling (larger IC, more airflow over IC, water spray on IC) higher flow rate turbo.

[Cody]

It depends on how much heatsoak we're talking about, but 2 octane certainly can be the difference between knock or no knock on a moderately heatsoaked IC.

The problem with Subaru's method of monitoring intake temp is that it's measured pre-IC. There's no way for the ECU to know that your car has just sat ideling for 5 minutes while the TMIC has absorbed heat from the engine, turbo, downpipe, and the radiator. You take off, full throttle, and the motor knocks since the IC didn't cool the intake charge adequately. The ECU doesn't notice any problems until the knock sensor hears the knock.

The ECU pulls timing until the knock is reduced and you may not see full power again for days or even weeks while the ECU slowly experiments with increased timing.

[Dean]

It depends on how much heat soak we're talking about, but 2 octane certainly can be the difference between knock or no knock on a moderately heatsoaked IC.Don was talking about track conditions. 2 octane is not going to help under those conditions. That is just too much heat for the system.

Standing heat soak of a TMIC is entirely different and 2 octane is not going to change that on a hard launch from a long stop like at an autocross on grid with hood closed and no additional cooling. If it is soaked, a hard launch at full boast is not going to have enough airflow over the IC before the temps climb and timing gets pulled.

2 Octane might be enough to handle some stop and go and stoplight type situations on the street.

The right IC, Turbo, etc are still the right solution to heat soak, not just throwing octane at the problem. Octane does not stop knock in real heat soak conditions, only delay it. Avoiding heat soak is the best option.

[Cody]

I'll take my chances.

[sperry]

Dean, there's no way you know one way or the other how much help 2 octane is going to give you.

On the other hand, the STI is tuned from the factory for 93 octane and is known to ping on 91 straight from Subaru. Frankly, if you're driving the car hard and have the money to spend on 93, I can't see one reason not to use it. A few points above what you're tuned for is always a good idea at the track, and the autocross course as it's a margin of safety for the motor.

Sure a new I/C, turbo, radiator, oil cooler, water injection, water spray, and tuning can help with fighting heat soak, but that's a little bit more cost and work than just pumping in some higher octane fuel to help. Hell, do all that work and the 93 would *still* be a good idea.

[newbie911]

I'm a little confused now, so what's the verdict/consensus here (not just for Subarus too)? Also, for me living in Carson, getting to the one station with 93 octane will be difficult on a regular basis to keep the ECU "programmed" for it. Thoughts???????

[Cody]

Without knowing specific details about your car's software and hardware, it's going to be hard to say what you should do definitively. Your best bet may be a good Porsche forum, in my opinion.

[Dean]

Sure a new I/C, turbo, radiator, oil cooler, water injection, water spray, and tuning can help with fighting heat soak, but that's a little bit more cost and work than just pumping in some higher octane fuel to help. Hell, do all that work and the 93 would *still* be a good idea.All I am trying to say is that heat soak is not a "Lack of Octane" problem.

[newbie911]

Thanks, and yes, I just raised the question on 6speedonline.com so we'll see what comes of that!

[Cody]

All I am trying to say is that heat soak is not a "Lack of Octane" problem.

LOL, I'll admit it's a bandaid solution, but for weekend warriors like myself, it's a damn good one. :)

That said, I'd have an IC sprayer in a minute if the stupid ass rules of ESP didn't prevent me from doing so. I can't even put a taller scoop on. :rolleyes:

[Kevin M]

LOL, I'll admit it's a bandaid solution, but for weekend warriors like myself, it's a damn good one. :)

That said, I'd have an IC sprayer in a minute if the stupid ass rules of ESP didn't prevent me from doing so. I can't even put a taller scoop on. :rolleyes:

STX/STU would permit the STi scoop Cody. AFAIK you're legal for those classes if you haven't changed your flywheel or clutch.

[Kevin M]

Also, I keep forgetting to tell you- debadging is now SP legal, so you don't have to run your badge/lettering magnets if you don't want to.

[Cody]

Thank god! (on the badges)

I'll have to look into STX as I'm still on the stock clutch and flywheel.

[Kevin M]

Thank god! (on the badges)

I'll have to look into STX as I'm still on the stock clutch and flywheel.

As long as your wheels are 7.5" wide or less, you're okay in STX. STU for 17x8s. You're also limited to 245s in either class.

[Cody]

I'm good in that regard too. But I thought you couldn't modify boost in ST?

[Kevin M]

Dammit, knew I was forgetting something. :( Of course, stock boost would help that knock problem in the heat too. :lol:

[Cody]

Ha, yah, but I won't give up the MBC (coupled with the apropriate tune of course). :)

["A" Stocker]

Don't think so. 91 is "premium" here because we get California gas.

Allied Washoe in Reno does have 100 unleaded however. $7.25/gal I think is the current price according to MikeK.

I work for the Petroleum Pipeline that supplies all the Gas and Diesel for Nevada. You guys don't get California Blends on either one (I'll check and see the difference). Your diesel is specific to Nevada and so is your gas. The Octane rating of fuel is just like the PAX an arbitrary number they come up with.

[Cody]

Fill 'er up with Fiction!

[Kevin M]

I work for the Petroleum Pipeline that supplies all the Gas and Diesel for Nevada. You guys don't get California Blends on either one (I'll check and see the difference). Your diesel is specific to Nevada and so is your gas. The Octane rating of fuel is just like the PAX an arbitrary number they come up with.

My understanding was that our gas starts with the CA blends than gets some volatility adjustments for altitude.

[sperry]

I work for the Petroleum Pipeline that supplies all the Gas and Diesel for Nevada. You guys don't get California Blends on either one (I'll check and see the difference). Your diesel is specific to Nevada and so is your gas. The Octane rating of fuel is just like the PAX an arbitrary number they come up with.
Well, we're certainly not getting the 93 octane the east coast gets. :mad:

[Dean]

As far as I know, the pipelines carry standardized RBOB, Reformulated Blendstock for Oxygenate Blending (gasoline production). Octane as well as other additives like "Techron" are controlled and added locally.

All the refiners RBOB goes in one end of the pipe and out the other. There are not separate pipes for Shell vs. Chevron much less 87 vs. 91...

["A" Stocker]

As far as I know, the pipelines carry standardized RBOB, Reformulated Blendstock for Oxygenate Blending (gasoline production). Octane as well as other additives like "Techron" are controlled and added locally.

All the refiners RBOB goes in one end of the pipe and out the other. There are not separate pipes for Shell vs. Chevron much less 87 vs. 91...

We ship EPA Gasoline and EPA Diesel to Reno, California has CARB Gas and Diesel. The Octane is already in the gas from the refineries, the additives like "Techron" are added at the loading racks. The only oxgenate used now is Ethanol and that is added at the racks also. There is only one pipeline for all these products and 87 octane is a different batch from 91 octane.

[Cody]

We ship EPA Gasoline and EPA Diesel to Reno, California has CARB Gas and Diesel. The Octane is already in the gas from the refineries, the additives like "Techron" are added at the loading racks. The only oxgenate used now is Ethanol and that is added at the racks also. There is only one pipeline for all these products and 87 octane is a different batch from 91 octane.

Do they use "pigs" to seperate the different octanes then?

And what's the difference between the EPA gas and CARB gas?

[newbie911]

More importantly, how do I safely get 93 octane into my car without having to drive to Sparks for the one station that has it???

["A" Stocker]

Do they use "pigs" to seperate the different octanes then?

And what's the difference between the EPA gas and CARB gas?

No we usually have a diesel batch between them,

one is regulated by the EPA and One is regulated by the California Air Resources Board.

[Cody]

No we usually have a diesel batch between them,

one is regulated by the EPA and One is regulated by the California Air Resources Board.

Let me try this a different way. What's the difference in them in terms of octane? Any other important differences as it relates to the way a car would run on one as apposed to the other?

[solonut]

Boy Doug you know alot about "gas"....

on the 91 Miata I set the timing at factory specs and ran the car for 2 weeks like that....mpg was 31.....bumped timing to 14degrees and ran premium for 2 weeks and the car got 33-34 mpg....for our running we actually save $ running 91 octane...

[Kevin M]

More importantly, how do I safely get 93 octane into my car without having to drive to Sparks for the one station that has it???

Dean, I would recommend getting a small drum or large gas can and keeping 100 octane int hat. Then add the correct number of gallons into your tank to bump the mix to 93 when you need or want it.

[newbie911]

I like the idea of mixing in the 100 octane to achieve the 93 that I want, but will the "computer" react to the new mixture on an occasional basis (say, for a SCCA weekend) and take advantage of it? I thought that these "computers" needed time (months?) to learn and change to different octanes, among other conditions? Or do I need to calculate out a certain mixture and constantly do this all the time for the "computer" to adapt on a full time basis .......... make sense?

[sperry]

I like the idea of mixing in the 100 octane to achieve the 93 that I want, but will the "computer" react to the new mixture on an occasional basis (say, for a SCCA weekend) and take advantage of it? I thought that these "computers" needed time (months?) to learn and change to different octanes, among other conditions? Or do I need to calculate out a certain mixture and constantly do this all the time for the "computer" to adapt on a full time basis .......... make sense?
It shouldn't take months.

For a Subaru, all it takes is dragging the brakes to generate mid-level boost down a decent length straightaway and the car will advance right to the most aggressive setting in a few seconds.

For your car, there may not be a shortcut like that.

[Cody]

Yick, I'm not a fan of the Vishnu Reset Trick, Scott. Unless of course you know that your tune is super safe and there are no hardware issues.

[sperry]

Yick, I'm not a fan of the Vishnu Reset Trick, Scott. Unless of course you know that your tune is super safe and there's hardware issues.
All that "trick" does is put the car into the condition that triggers the multiplier advance. It's the same condition that during normal driving allows the multiplier to advance, all you're doing is forcing the situation. So, if your car has a problem with the trick, you have a problem in general!

Any tuned Subaru should be tuned w/ the multiplier maxed out so it doesn't try to advance beyond the programmed in advance. So after resetting the ECU, using the trick to jump right back up to the max multiplier should have zero risk.

[Cody]

"Should" being the operative term. I think this is kind of like the Octane debate with Dean. I just suggest you error on the side of caution unless you're in a huge hurry to get to the max IAM (16) for a race or something...and you trust that your tune is indeed safe at an IAM of 16 (which, if you're tuned, should be the case, as you said).

["A" Stocker]

Let me try this a different way. What's the difference in them in terms of octane? Any other important differences as it relates to the way a car would run on one as apposed to the other?

Nope.... If your car runs good on 91 octane it will run just as good on 93 and vice versa, if your car knocks going from 93 to 91 something is out of whack, there's not enough of a difference between the two. And who knows Shells 93 octane might just be Chevrons 91 again vice versa. The companies come up with the number. Back in the late 80's 76 stations all changed their octane for Premium to 95 octane up from 92 octane as a selling point, the deal was there was no change it was still 92 octane by their standards they just changed the number to a higher octane rating to beat Chevrons 93 octane.

["A" Stocker]

I like the idea of mixing in the 100 octane to achieve the 93 that I want, but will the "computer" react to the new mixture on an occasional basis (say, for a SCCA weekend) and take advantage of it? I thought that these "computers" needed time (months?) to learn and change to different octanes, among other conditions? Or do I need to calculate out a certain mixture and constantly do this all the time for the "computer" to adapt on a full time basis .......... make sense?

How does your car run on 91 octane?

[Kevin M]

Nope.... If your car runs good on 91 octane it will run just as good on 93 and vice versa, if your car knocks going from 93 to 91 something is out of whack, there's not enough of a difference between the two. And who knows Shells 93 octane might just be Chevrons 91 again vice versa. The companies come up with the number. Back in the late 80's 76 stations all changed their octane for Premium to 95 octane up from 92 octane as a selling point, the deal was there was no change it was still 92 octane by their standards they just changed the number to a higher octane rating to beat Chevrons 93 octane.

Doug, current FI engines are so highly tuned and well-designed that they most definitely can dance between a sweet spot at 93 octane and knocking at 91. Additionally, what you're saying is that all of the turboharged cars up here would run on 89 as well as on 91... you will be assured momentarily that's very very wrong. ;)

[newbie911]

I'm sure with the "computer" adjusting for it (91 octane), the car is running normally without knocking, but not with full power as it could with 93 octane.