[bignaz]

That moment when people realize that the tank of gas the dealership gave them was 87.


87 won't kill your car. It will run like shit you won't get the power you payed for. If it was required the sticker would say Premium fule only. Not premium fule recamended.


It won't kill your car. Could have issues with a warranty for the engine because they can void if if you do not follow there recommended service and premium is recamended.


87 is fine. But honestly the loss in power you will have and the shitty mpg you will get your not really saving that much going with premium. But 87 is good to go. Alot of people won't admit it but you would be surprised how many mustangs and Camaros go in say $40 on pump 5 premium. Then go out and put 87 in. I know a guy who works at a gas station and he told me it happens a lot. So there's more then a few people out there giving there car a steady flow of 87 and it's fine. Just expect a drop in mpg and it runs pretty dirty.

[KingLT1]

Originally Posted by wjones14

Yeah, I don't think that's true either. JCunningham, can you provide your source regarding the 2 tables?

I personally use TopTier 93 octane only in mine. It's a weekend and track car for me, driven maybe 3000 miles per year.

According to the owner's manual, however, you can use 87 and it will not hurt the car. Quote from page 25 of the 2018 manual:

"Use premium 93 octane unleaded gasoline in your vehicle. Unleaded gasoline with an octane rating as low as 87 may be used, but it will reduce performance and fuel economy."

GM EFI/GDI vehicles have had high and low octane tables since 1996 when obd2 was released. All of my Camaros 1996 Z28, 2002 Z28, and 2016 SS have high and low octane spark tables. If the ECU detects a persistent amount of spark knock it will default to the low octane table which pulls a bunch of timing advance.

Google will yield plenty of results proving this.

That being said 87 octane will not blow the engine up, but the LT1 will not tolerate much spark advance with that fuel. Too much compression.

[BlaqWhole]

So here is the deal. There is a lot of misinformation here. Either that or some people are not fully explaining things. So this is what you need to know.

If it is 2am and you're low on gas and you're out in the middle of nowhere and there is one gas station open and they only have 87 octane...then it is ok to use it. Your ECU will adjust for it provided you drive properly. No you can't go WOT or wring out the RPMs or go flying at 110 MPH. You use the gas to drive the car normally until you can put premium gas in it.

If you are driving across the country or to another state and you won't be flogging the car during the drive and you'll be driving a steady speed at low RPMs and granny shifting, then you can also use 87 octane and you'll be ok.

Now if you are using lower octane gas frequently and you're getting on the car and driving in a spirited manner, then you WILL suffer some mechanical issues. The degree to which you'll have mechanical failure can vary from minor to devastating.

These engines require premium gas for long term and extended use as well as for spirited driving. The ECU is able to compensate. But it's ability to compensate is very limited. It is not going to save you from catastrophic engine failure. With that said, although it requires premium gas, you can get away with using lower octane gas provided you don't use it habitually and you aren't beating on the car.

So again, in an emergency situation you will be ok. If you are going on a long trip and the car will be going at a steady pace in OD with the RPMs low then you will be ok. In both cases do not beat on the car. Outside of those two situations you should not use anything lower than 91 octane at all.

And remember, the ECU is RE-active...not PRO-active. It cannot know the octane level and adjust the tune accordingly...that is unless you have a low octane tune programmed into the ECU. It reacts based off of what the sensors send. So by the time the sensors send data and the ECU reacts and pulls timing or goes into limp mode, it could be that the damage has already occurred. So the ECU is not going to save your engine if something drastic happens. It can save it if something minor happens tho. You might get away with a ping. But if you hear a knock and then the car goes into limp mode...well the ECU did it's best...

Anyway, the point is...you are NOT fine if you use low octane fuel. You'll be "ok" at best if you use it and drive it like a wuss. Otherwise do not use low octane.

[hotlap]

Originally Posted by BlaqWhole

Question 1: Should I use premium gas?
Answer: Yes. The manufacturer recommends it and they know their shit.

Question 2: Should I follow break-in procedure like the manufacturer recommends?
Answer: No. Do a burnout at first startup. The manufacturer don't know shit.

Question 3: Should I add a catch can ...if I run 87 octane and do a burnout at first start up?
Answer:

[LT4Greg]

Run whatever octane you want to use in your Camaro is what I say! It’s your car. Case closed.

[Spanky1]

Why is 93 octane available in some states but only 91 in other states?

[KingLT1]

Originally Posted by BlaqWhole

So here is the deal. There is a lot of misinformation here. Either that or some people are not fully explaining things. So this is what you need to know.

If it is 2am and you're low on gas and you're out in the middle of nowhere and there is one gas station open and they only have 87 octane...then it is ok to use it. Your ECU will adjust for it provided you drive properly. No you can't go WOT or wring out the RPMs or go flying at 110 MPH. You use the gas to drive the car normally until you can put premium gas in it.

If you are driving across the country or to another state and you won't be flogging the car during the drive and you'll be driving a steady speed at low RPMs and granny shifting, then you can also use 87 octane and you'll be ok.

Now if you are using lower octane gas frequently and you're getting on the car and driving in a spirited manner, then you WILL suffer some mechanical issues. The degree to which you'll have mechanical failure can vary from minor to devastating.

These engines require premium gas for long term and extended use as well as for spirited driving. The ECU is able to compensate. But it's ability to compensate is very limited. It is not going to save you from catastrophic engine failure. With that said, although it requires premium gas, you can get away with using lower octane gas provided you don't use it habitually and you aren't beating on the car.

So again, in an emergency situation you will be ok. If you are going on a long trip and the car will be going at a steady pace in OD with the RPMs low then you will be ok. In both cases do not beat on the car. Outside of those two situations you should not use anything lower than 91 octane at all.

And remember, the ECU is RE-active...not PRO-active. It cannot know the octane level and adjust the tune accordingly...that is unless you have a low octane tune programmed into the ECU. It reacts based off of what the sensors send. So by the time the sensors send data and the ECU reacts and pulls timing or goes into limp mode, it could be that the damage has already occurred. So the ECU is not going to save your engine if something drastic happens. It can save it if something minor happens tho. You might get away with a ping. But if you hear a knock and then the car goes into limp mode...well the ECU did it's best...

Anyway, the point is...you are NOT fine if you use low octane fuel. You'll be "ok" at best if you use it and drive it like a wuss. Otherwise do not use low octane.

Actually GM does have a tune for low octane and its the Main spark vs Air mass vs rpm low octane table. They set this table up for bad or low octane fuel. Look at the timing map compared to high octane. They have to do this because people run low octane fuel in vehicles all the time that are rated premium fuel only. If it wasn't for this there would be a lot of blown up engines.

If you look at the graph a stock LT1 at wot generally is in the .52g airmass range. So at 6400 rpm they see 21-22 degrees timing on good fuel. Now look at the low octane table which is what the engine would default to on 87 octane, you can see that the timing advance is only 7 degrees. That is probably 80hp minimum difference.

[JCunningham]

manual still says knocking may be heard. what BlaqWhole said is spot on.

[Ten4Lou]

Originally Posted by JCunningham

manual still says knocking may be heard. what BlaqWhole said is spot on.

Yep, spot on!!! If you use 87 gas, you WILL get knock with heavy acceleration!! When I picked up my ZL1, the dealer filled the car with 87. I heard engine knock as I was driving away. I immediately turned around and went back to the dealer. They admitted to using 87, apologized and then pumped all of the fuel out and replaced with 93.

These engines and factory ECU programming CANNOT fully compensate for 87 octane!! You WILL get knocking at spirited throttle and cause damage to your pistons if you continue the practice of using 87.

***edit***
Just realized that this discussion was for “non-ZL1” camaros. I switch back and forth between the ZL1 forum and this forum so much that I forgot which one I was reading
The regular LT1 engines may have mapping to better compensate for the 87 gas However I can tell you that this LT4 cannot tolerate it. Even slightly spirited throttle causes constant detonation. Apologies for any mixup

[6sigma]

I'm curious how direct injection influences the spark timing. There is no fuel in the cylinder until DI injects it, so think of fuel injection timing almost like spark timing. The LGX V6 has 11.5 compression (same as the LT1) and recommends only 87 octane. I've run a lot of 93 and also 87 in mine and I really can't tell much difference. In fact, it seems to get a little better MPG on 87. The only way I can see how they make 11.5 compression work with 87 octane is to use DI to inject right at spark event. I've wondered why the LGX can run 87 with 11.5 compression bu the LT1 can't with the same compression. It isn't like the LGX is detuned, it has 93 hp/liter which is more than the LT1.

[BlaqWhole]

Originally Posted by KingLT1

Actually GM does have a tune for low octane and its the Main spark vs Air mass vs rpm low octane table. They set this table up for bad or low octane fuel. Look at the timing map compared to high octane. They have to do this because people run low octane fuel in vehicles all the time that are rated premium fuel only. If it wasn't for this there would be a lot of blown up engines.

If you look at the graph a stock LT1 at wot generally is in the .52g airmass range. So at 6400 rpm they see 21-22 degrees timing on good fuel. Now look at the low octane table which is what the engine would default to on 87 octane, you can see that the timing advance is only 7 degrees. That is probably 80hp minimum difference.

That is good info and thanks for posting it. However it is still based on reaction. So the ECU would react when it senses ping or knock. I'm talking about when the ECU is specifically tuned for low octane gas. As an example, a tuner can write a tune for low octane gas in which case you could get away with spirited driving. However in the case you mentioned damage could already have been done by the time the ECU makes adjustments.

[Frankie18SS]

Originally Posted by Spanky1

Why is 93 octane available in some states but only 91 in other states?

Altitude. Detonation is less likely to occur at higher altitude so high compression engines can run lower octane with no ill effects. All engines can run lower octane at higher altitude. I believe "Regular" in Colorado is 85 octane.

[SSDan]

Originally Posted by Spanky1

Why is 93 octane available in some states but only 91 in other states?

Originally Posted by Frankie18SS

Altitude. Detonation is less likely to occur at higher altitude so high compression engines can run lower octane with no ill effects. All engines can run lower octane at higher altitude. I believe "Regular" in Colorado is 85 octane.

In order to hit the EPA emissions requirements for several of the western states (especially CA) the gas has to be refined with less benzene. Benzene in gas helps boost octane but it also "off gasses" at fill up more (contributing to smog). By refining with less benzene the highest octane the refineries can produce is 91. The higher altitude contributes to the decision as well since refining with less benzene has less affect on performance since detonation (knock) is less of an issue.

[SSDan]

My take is that BlaqWhole gives us good practical advice on why you need to run the highest octane available at the pump and then what to do if you have to use a lower octane in an emergency. Or you can be cheap by using 87 octane all the time and are willing to granny drive your car to stay out of knock situations and take your chances.

KingLT1 gives us the technical details on how the engine's ECU manages excessive knock. The default setting is the high octane table. If the ECU records a sequence of knock events (as fed by the knock sensors) that exceeds the preset threshold then it switches to the low octane table. This reduces the amount of advance timing and thus reduces the opportunity for knock. The ECU is indeed reactive. It drops to the lower table after excessive knock is detected. The ECU will move back to the higher octane table after a preset threshold of engine cycles have recorded an acceptable level of knock. So, the ECU will move back and forth between the two tables as dictated by the readings coming from the knock sensors.


The fifth Gen Camaro's LS3 ECU had the issue that it would get stuck in the low octane table and stay there if low octane fuel was used. It often would not reset to the high octane table after going back to high octane fuel. It required a hard reset (disconnect the battery) to force the ECU to default back to the high octane table. That is why when I had mine tuned - the tuner over-wrote the low table with the high table's values and I then I never ran lower than 93 octane.