[mjmenke]

I'm going to get flammed for this but I'm from rural Iowa, sometimes you CAN'T get premium so you make due.

The LT1 will run just fine on 87 ethanol.

FYI the dyno numbers in my signature were made on 91 octane no ethanol.

[Drags1998]

The best I can buy is 91, NEVER had a problem. If You buy the best that you can find You'll be all set!!!! It will run just FINE!!!!

[CAM-FIFTY]

Ok so out of curiosity I looked in the manual that came with my 2016 2SS - it says the same thing as myChevrolet app does, 91 for v8.

Not sure why GM changed it in 2017 manual.

[TJay74]

Originally Posted by mjmenke

I'm going to get flammed for this but I'm from rural Iowa, sometimes you CAN'T get premium so you make due.

The LT1 will run just fine on 87 ethanol.

FYI the dyno numbers in my signature were made on 91 octane no ethanol.

Flamed yes, main because while the LT1 can "run" on 87 it states in the manual only to do it in emergencies and to fill back up with 91 or higher otherwise engine damage can occur. GM has gone as far as to say if you are caught running 87 octane and have engine damage they will not warranty the repairs if that is the case.

[Hawk397]

If you don't develop any knock or knock detection, then you are correct - no additional performance from a higher octane. However, if knock is detected the controller will drop to the "low octane" table. Resetting to the normal table used to require a full fuel fill-up - not sure if that is still the case.

Mark

Originally Posted by Zeke.Malvo

Are you sure about that? I haven't seen any dynos or data to support that 92 or 93 is any better for the stock calibration than 91.

[EFI Tuning]

Knock doesn't guarantee the use of the low octane table. If knock is detected it will pull timing immediately. If the knock retard exceeds a certain threshold it will start to increment the knock learn factor. Think of this factor as a slider between the low and high table. The higher the factor the more it biases towards the low octane table. If knock is not detected any longer the knock learn factor will start to decrement and will head back towards the high octane table. I've seen tunes where people raise the low octane table. Unless it is a track only car running known fuel this is bad practice.

Tim

[Zeke.Malvo]

Originally Posted by Hawk397

If you don't develop any knock or knock detection, then you are correct - no additional performance from a higher octane. However, if knock is detected the controller will drop to the "low octane" table. Resetting to the normal table used to require a full fuel fill-up - not sure if that is still the case.

Mark

Right. I just haven't seen any evidence of any knock being detected or the LT1 running on a different timing table with 91 vs 92/93.

[ctrlz]

Originally Posted by EFI Tuning

If the knock retard exceeds a certain threshold it will start to increment the knock learn factor.
Tim

Thanks for the informed comment.

Originally Posted by Evil-Bee-NH

91/93 you'll experience less timing and knock issues and slightly better MPG.

As to the LT1 getting better fuel economy on 93 vs 91... good luck measuring that. Theoretically that may be accurate, but the difference is going to be so small that it's probably not statistically significant.

[alexandre_baril]

Originally Posted by Kyokai

I understand that 93 octane fuel is recommended on the LT1 V-8. Only problem with that is most stations in my area only sell 92 octane. Granted I can search further outside my immediate area.

Question is...will the difference hurt the engine?

It won't hurt the engine and won't affect performance that much, especially for NA cars. High octane fuel is more resistant to detonation, so you can tune with a more aggressive timing with 93 vs 91. But how much performance would you lost on the 91 octane table? Timing will be adjusted if knock are detected and you will loss maybe 5-10 whp? Not sure how it works with the Camaro, but I doubt the entire power curve will be affected, but I do not know for sure.

Not sure anything else than a dyno can detect if the car is running 91 or 93 as far as performance goes.

As far as causing damage to the engine, it won't.

If you really care and want to feel the difference between 91 and 93, you can buy some Torco Accelerator and add to your tank to reach 93 octane or even higher level of octane. It works, many people are doing this as an inssurance when going to the track, especially tuned car. Just be aware if you use it on a regular basis, your exhaust will get a red tint because of the Torco. Same with your spark plugs and the inside of your motor.

[Kyokai]

Originally Posted by alexandre_baril

It won't hurt the engine and won't affect performance that much, especially for NA cars. High octane fuel is more resistant to detonation, so you can tune with a more aggressive timing with 93 vs 91. But how much performance would you lost on the 91 octane table? Timing will be adjusted if knock are detected and you will loss maybe 5-10 whp? Not sure how it works with the Camaro, but I doubt the entire power curve will be affected, but I do not know for sure.

Not sure anything else than a dyno can detect if the car is running 91 or 93 as far as performance goes.

As far as causing damage to the engine, it won't.

If you really care and want to feel the difference between 91 and 93, you can buy some Torco Accelerator and add to your tank to reach 93 octane or even higher level of octane. It works, many people are doing this as an inssurance when going to the track, especially tuned car. Just be aware if you use it on a regular basis, your exhaust will get a red tint because of the Torco. Same with your fuses and the inside of your motor.

Thanks everyone for all the great info. I've been filling up with 92 and no issues what so ever.