93 octane?
Thread Starter
Instructor
Joined: Feb 2021
Posts: 154
Likes: 138
From: Mohave Desert
93 octane?
The book says use 93 but I know of only 91 octane gas unless you go to AV gas which is too high.
Anyone have a solution? It says perf may be affected. Is anyone adding octane boost to each tank?
Anyone have a solution? It says perf may be affected. Is anyone adding octane boost to each tank?
Drifting
Joined: Mar 2020
Posts: 1,564
Likes: 1,014
From: 31 hours East of Peoria, AZ
If unavailable, unleaded gasoline with a posted octane rating of 91 may be used, but with reduced performance and fuel economy.
Page 227:
Fuel containing metals such as methylcyclopentadienyl manganese tricarbonyl (MMT), which can damage the emissions control system and spark plugs.
I use STP non MMT octane booster (do not use the STP MMT based octane booster - it has the MMT written right on the bottle).
Melting Slicks
Joined: Nov 2007
Posts: 2,269
Likes: 544
From: Pittsburgh PA
St. Jude Donor '10-'11-'12-'13-'14
Just be aware that many octane boosters that claim to raise octane by some number of "points", a point is 1/10 of, an octane number. Thus tend to be lots of money for not much increase.
Last edited by John Harry; Sep 17, 2021 at 01:55 PM.
Melting Slicks
Joined: Nov 2012
Posts: 3,159
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From: SUFFIELD CONNECTICUT
Hey Kracka, has there been anyone that you know of that has done a dyno pull to see if by adding E85 to 91 or 93 would net a power increase? that would be nice to know. I realize this would have to be done in small quantities like you say 2 gal per tank, because ya cannot run high concentrations of E85 with out a sensor and a tune.
Race Director
Joined: Jan 2014
Posts: 10,709
Likes: 7,094
From: Fulshear, TX
@Kracka but the book say no E85???? Cant anything just be simple..of course not. Then you gotta worry about MMT as well... may just end up using 91 octane and say F*** it.
It truly is that simple
I have a handy dandy spreadsheet to help you calculate it exactly down to the decimal places if anyone would like a copy of it.
Race Director
Joined: Jan 2014
Posts: 10,709
Likes: 7,094
From: Fulshear, TX
Hey Kracka, has there been anyone that you know of that has done a dyno pull to see if by adding E85 to 91 or 93 would net a power increase? that would be nice to know. I realize this would have to be done in small quantities like you say 2 gal per tank, because ya cannot run high concentrations of E85 with out a sensor and a tune.
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Melting Slicks
Joined: Nov 2012
Posts: 3,159
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From: SUFFIELD CONNECTICUT
I certainly believe you, I didnt know 91 octane had no E in it, Here in Connecticut the pumps just say contains 10 % ethanal and always thought that was for all the gas.. 87, 89, 91 and 93. What happens if you add a couple of gallons to a tank of 93 octane, I know it raises the octane, but does the extra E make more power? E alone makes more power as long as you have a sensor and the car is tuned for it.
Last edited by BJ67; Sep 17, 2021 at 09:31 PM.
Race Director
Joined: Jan 2014
Posts: 10,709
Likes: 7,094
From: Fulshear, TX
Most modern engines can handle about 40% ethanol before throwing a code due to running out of fuel injector. Will blending additional ethanol into 93 E10 made more power? Yes, IF the engine is tuned for it. Going above 93-octane in an engine designed for 93-octane will not have a benefit unless you're in high-temp conditions and you need the additional octane as a knock quench (which ethanol is very effective at). For street use, if you're already using 93 E10 there's no need to add additional ethanol/octane unless you just want the headroom because to plan to really beat on the car in high temps (in which case, splash blending in a gallon sure wouldn't hurt). I know when it's 100F+, car loaded down with luggage, AC blasting... I can feel the ECU pulling timing even with 93 E10 when I really start pushing the car. That's the time a little extra headroom is beneficial.
Melting Slicks
Joined: Nov 2012
Posts: 3,159
Likes: 686
From: SUFFIELD CONNECTICUT
Most modern engines can handle about 40% ethanol before throwing a code due to running out of fuel injector. Will blending additional ethanol into 93 E10 made more power? Yes, IF the engine is tuned for it. Going above 93-octane in an engine designed for 93-octane will not have a benefit unless you're in high-temp conditions and you need the additional octane as a knock quench (which ethanol is very effective at). For street use, if you're already using 93 E10 there's no need to add additional ethanol/octane unless you just want the headroom because to plan to really beat on the car in high temps (in which case, splash blending in a gallon sure wouldn't hurt). I know when it's 100F+, car loaded down with luggage, AC blasting... I can feel the ECU pulling timing even with 93 E10 when I really start pushing the car. That's the time a little extra headroom is beneficial.
Last edited by BJ67; Sep 18, 2021 at 08:22 AM.
Safety Car
Joined: Nov 2011
Posts: 3,712
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From: Norman OK
Some of you are confusing octanes. Depending on where in the USA you are you will have 91 E0 or 93 E0, or 91 E10 or 93 E10. There can be some fuel contamination with even 91/93 E0 to where it shows to have Ethanol in it.
With that the C8 and C7 fuel tank is 18.5 gallons, you can run up to E15 (15% Ethanol) easily with no issues, so on the ninitial fill add 2-3 gallons of E85 to the tank of 91 or even 93 and fill the rest up with 100 E0 gasoline. From there you just need to adjust how much Ethanol you add back in at each fill up. I always put Ethanol in 1st, then add the Ethanol fuel 1st, then add the gasoline to help mix it inside of the tank.
With that the C8 and C7 fuel tank is 18.5 gallons, you can run up to E15 (15% Ethanol) easily with no issues, so on the ninitial fill add 2-3 gallons of E85 to the tank of 91 or even 93 and fill the rest up with 100 E0 gasoline. From there you just need to adjust how much Ethanol you add back in at each fill up. I always put Ethanol in 1st, then add the Ethanol fuel 1st, then add the gasoline to help mix it inside of the tank.
Race Director
Joined: Nov 2000
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From: CA
2017 C5 of the Year Finalist
St. Jude Donor '08
OK, Yada Yada Yada on the no MMT in your car, been running it from almost day one in my bolt on 17 C7 Z06, purchased November of 2016. I get plenty of life out of my spark plugs, and after 5 years of running Torco in EVERY single tankfull, pretty sure I'm on the original O2s...
I don't give a hoot about the Naysayers, I've been running Torco for almost 15 years, not a single issue! If running MMT concerns you, please do what makes you comfortable, and I'll continue to do what works for me...
https://youtu.be/q2n88MjiGpM
https://youtu.be/qyEQxighdco
I don't give a hoot about the Naysayers, I've been running Torco for almost 15 years, not a single issue! If running MMT concerns you, please do what makes you comfortable, and I'll continue to do what works for me...
https://youtu.be/q2n88MjiGpM
https://youtu.be/qyEQxighdco
Last edited by jbsblownc5; Sep 19, 2021 at 03:03 PM.
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
OK, Yada Yada Yada on the no MMT in your car, been running it from almost day one in my bolt on 17 C7 Z06, purchased November of 2016. I get plenty of life out of my spark plugs, and after 5 years of running Torco in EVERY single tankfull, pretty sure I'm on the original O2s...
I don't give a hoot about the Naysayers, I've been running Torco for almost 15 years, not a single issue! If running MMT concerns you, please do what makes you comfortable, and I'll continue to do what works for me...
I don't give a hoot about the Naysayers, I've been running Torco for almost 15 years, not a single issue! If running MMT concerns you, please do what makes you comfortable, and I'll continue to do what works for me...
Race Director
Joined: Nov 2000
Posts: 11,221
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From: CA
2017 C5 of the Year Finalist
St. Jude Donor '08
Thread Starter
Instructor
Joined: Feb 2021
Posts: 154
Likes: 138
From: Mohave Desert
E85 mix
"No E85" as in straight E85 since that's [up to] 85% ethanol and 15% gasoline (you need a FlexFuel vehicle to run straight E85), rather than the standard fuel with is 85-90% gasoline and 10-15% ethanol. Blending 2 gals of E85 into a tank of 91 (which is an E0 product ) makes the equivalent of 93 (which is E10). Adding 10% ethanol to 91 E0 is how 93 E10 is created. Depending on the region, this is done at the rack or blender level, and again depending on the region, is sometimes unavailable to local retailers and C-stores.
It truly is that simple
I have a handy dandy spreadsheet to help you calculate it exactly down to the decimal places if anyone would like a copy of it.
It truly is that simple
I have a handy dandy spreadsheet to help you calculate it exactly down to the decimal places if anyone would like a copy of it.
Race Director
Joined: Jan 2014
Posts: 10,709
Likes: 7,094
From: Fulshear, TX
@Kracka Thanks for the help brother... I'll look around for E85 fuel and try your mix solution.. Where I live, only 91 is available so looks like it would be my only option. I have a tank of 91 in now with 370 miles on my car. I noticed a little pinging yesterday, very slight but I could hear it. Also have noticed the ticking sound some owners have described prior to an engine failure. Mine seems to go away once I get about 30-40 mph so hopefully it is normal. The car seems to run awesome so fingers crossed I got a good one! Thanks again for your insight - I saw some of the engine mods you did, impressive stuff.
Last edited by Kracka; Sep 20, 2021 at 11:49 AM.
Race Director
Joined: Aug 2016
Posts: 12,528
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From: Garden Valley CA
It's interesting that the 2022 owner's manual now calls out the minimum octane as 91 with no mention about 93 octane.
The direct injection was tweaked for 2022 but it was stated that was for better mileage and smoother idle.
The direct injection was tweaked for 2022 but it was stated that was for better mileage and smoother idle.
Last edited by RKCRLR; Sep 27, 2021 at 01:34 PM.
