91 vs 93 octane fuel

overdriv · 05-01-2022, 11:54 AM

I can't seem to find any 93 octane fuel in the south western states, but most every fuel stop has had 91 octane fuel. Was wondering if any one has done testing of both to see what the LT1 gives up, if anything, when using 91 octane fuel?
Does the computer actually know when a fuel less than 93 is being used or does it only know there is more pre-ignition, knock?
The car seems to run the same and seems to get decent MPG, just wondering how much timing is being pulled out using 91 octane fuel.

It seems to be compensating for the thin air very well. Still runs like a beast when needed, or wanted.

2SS Capt · 05-01-2022, 01:10 PM

Quote:

Originally Posted by overdriv

I can't seem to find any 93 octane fuel in the south western states, but most every fuel stop has had 91 octane fuel. Was wondering if any one has done testing of both to see what the LT1 gives up, if anything, when using 91 octane fuel?
Does the computer actually know when a fuel less than 93 is being used or does it only know there is more pre-ignition, knock?
The car seems to run the same and seems to get decent MPG, just wondering how much timing is being pulled out using 91 octane fuel.

It seems to be compensating for the thin air very well. Still runs like a beast when needed, or wanted.

All we can get is 91 octane out here in Kalifornia... I'm sure it pulls a little timing to avoid knock and detonation, guessing it gives up 20-30 HP...

khcoaching · 05-01-2022, 01:14 PM

I thought this was interesting and may help answer your question - though I hear our cars are pretty sensitive with the stock tune.

mariojas · 05-01-2022, 04:02 PM

LT4 is tuned on 91 from factory, isn't? Look into manual. I see 91, not 93.

WhiteMale · 05-02-2022, 09:43 AM

Ive run both extensively I can't from the seat really tell any difference if its there it's a little placebo maybe, I think it's one of those things that youd have to dyno and do data logging to see it otherwise it's only in your wallet.

*I do make it a point to run 93 myself but Ive really only got 2 stations that in my radius that are practical, one I drive right by it to/from work or I wouldn't be doing 93 most likely.

xplct · 05-02-2022, 10:23 AM

I run 93 all the time, the manual does state somewhere that you can run 100 also, or is that just for the ZL1?

*radz28* · 05-02-2022, 01:14 PM

The manual, if I recall, states ZL1s are tuned for 93.

Race Proven Motorsports, I think, AND Complete Street Performance, have BOTH done videos (at least segments, if not dedicated videos) on comparing dyno' numbers between 91 and 93 octane.

It seems running 93 over 91, on a tuned car, could be worth tens of WHP.

Joshinator99 · 05-02-2022, 02:27 PM

Quote:

Originally Posted by radz28

The manual, if I recall, states ZL1s are tuned for 93.

Race Proven Motorsports, I think, AND Complete Street Performance, have BOTH done videos (at least segments, if not dedicated videos) on comparing dyno' numbers between 91 and 93 octane.

It seems running 93 over 91, on a tuned car, could be worth tens of WHP.

LT4 is already octane limited running 93…91 will cause additional knock retard and power loss, especially in high temp/heavy load conditions. Probably another 20-30 WHP sitting there if you run 100 octane.

KingLT1 · 05-02-2022, 03:26 PM

Both the LT4 and LT1 are octane limited running 93. I am sure you can run 91 on either engine but you will get more KR and pull timing. The knock sensors are setup to be overly sensitive on both engines.

1badtie · 05-02-2022, 05:04 PM

I have 93 oct here where I live. Been trying to find ethanol free 93 as its not a daily driver but it's getting real hard to find.

overdriv · 05-02-2022, 05:21 PM

Will the LT1 drop a code if it senses knock?

arpad_m · 05-02-2022, 07:14 PM

Quote:

Originally Posted by 1badtie

I have 93 oct here where I live. Been trying to find ethanol free 93 as its not a daily driver but it's getting real hard to find.

Out of curiosity, what are you hoping to gain from ethanol free 93?

wnta1ss · 05-03-2022, 07:00 AM

Quote:

Originally Posted by 1badtie

I have 93 oct here where I live. Been trying to find ethanol free 93 as its not a daily driver but it's getting real hard to find.

Computer expects E10 gas, so putting ethanol-free in will make it run a little bit richer. Personally, I do not think that is a benefit. What I would do with a stock ZL1 if I was trying to perk it up a bit, would be to add some unleaded 100 gas that has a little ethanol in it.

xplct · 05-03-2022, 07:13 AM

Here is the 100 octane reference.

05-01-2022, 11:54 AM	#1
overdriv Drives: 1969 Chevelle SS 2019 2SS Camaro Join Date: Jul 2018 Location: IL Posts: 246 View My Garage	91 vs 93 octane fuel I can't seem to find any 93 octane fuel in the south western states, but most every fuel stop has had 91 octane fuel. Was wondering if any one has done testing of both to see what the LT1 gives up, if anything, when using 91 octane fuel? Does the computer actually know when a fuel less than 93 is being used or does it only know there is more pre-ignition, knock? The car seems to run the same and seems to get decent MPG, just wondering how much timing is being pulled out using 91 octane fuel. It seems to be compensating for the thin air very well. Still runs like a beast when needed, or wanted.

05-01-2022, 04:02 PM	#4
mariojas Drives: 2022 ZL1 M6 & 2023 Stinger GT AWD Join Date: Nov 2021 Location: Detroit Metro, MI Posts: 452	LT4 is tuned on 91 from factory, isn't? Look into manual. I see 91, not 93. __________________ 2023 Kia Stinger GT AWD - as a family car... 2022 ZL1, M6 as daddy's ass mover Charger sold! Better to sell, than waiting to be stolen...

05-02-2022, 10:23 AM	#6
xplct Drives: 2022 camaro 2ss 1LE Join Date: Dec 2021 Location: FL Posts: 213	I run 93 all the time, the manual does state somewhere that you can run 100 also, or is that just for the ZL1? __________________

05-02-2022, 01:14 PM	#7
radz28 Petro-sexual Drives: Ultra-Grin Join Date: Oct 2006 Location: Crazy Coast Posts: 15,188 View My Garage	The manual, if I recall, states ZL1s are tuned for 93. Race Proven Motorsports, I think, AND Complete Street Performance, have BOTH done videos (at least segments, if not dedicated videos) on comparing dyno' numbers between 91 and 93 octane. It seems running 93 over 91, on a tuned car, could be worth tens of WHP. __________________ '20 ZL1 Black "Fury" A10, PDR, Exposed CF Extractor Magnuson Magnum DI TVS2650R // RFBG // Soler 103 // TooHighPSI Port Injection // THPSI Billet Lid // FF // Katech Drop-In // PLM Heat Exchanger // ZLE Cradle bushings // BMR Chassis-Suspension Stuff // aFe Bars // Diode Dynamics LEDs // ACS Composites Guards // CF Dash // Aeroforce // tint // other stuffs

05-02-2022, 03:26 PM	#9
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,793	Both the LT4 and LT1 are octane limited running 93. I am sure you can run 91 on either engine but you will get more KR and pull timing. The knock sensors are setup to be overly sensitive on both engines. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

05-02-2022, 09:43 AM	#5
WhiteMale Drives: 23 ZL1 A10 Rapid Blue Join Date: Aug 2020 Location: MO Posts: 1,983	Ive run both extensively I can't from the seat really tell any difference if its there it's a little placebo maybe, I think it's one of those things that youd have to dyno and do data logging to see it otherwise it's only in your wallet. *I do make it a point to run 93 myself but Ive really only got 2 stations that in my radius that are practical, one I drive right by it to/from work or I wouldn't be doing 93 most likely.

05-02-2022, 05:04 PM	#10
1badtie Drives: 2018 Camaro ZL1 Join Date: Nov 2009 Location: Central Arkansas Posts: 1,214	I have 93 oct here where I live. Been trying to find ethanol free 93 as its not a daily driver but it's getting real hard to find. __________________ 2018 ZL1 M6 NGM PPF and Ceramic coating IG: NGMZL1 2010 2SS RS --- SOLD MODS- Performance: BMR trailing arms & bushings \| BMR Toe links \| X-pipe \| Muffler delete \| Vmax ported throttle body \| Apex "strong" MAS \| Vararam CAI \| Apex catch can \| Kooks Headers \| Kooks HF Cats \| Dyno tuned by GPI 417 RWHP 409 FT-Lb Cosmetic: painted Zl1 rockers \| Zl1 grill \| AAC side markers \| AAC LED backup lights \| windows tint \| taillight tint \| JDP tow hook \| all emblems blacked out \| LED fogs

05-02-2022, 05:21 PM	#11
overdriv Drives: 1969 Chevelle SS 2019 2SS Camaro Join Date: Jul 2018 Location: IL Posts: 246 View My Garage	Will the LT1 drop a code if it senses knock?

05-03-2022, 07:13 AM	#14
xplct Drives: 2022 camaro 2ss 1LE Join Date: Dec 2021 Location: FL Posts: 213	Here is the 100 octane reference. Attached Images __________________

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