Premium gas or regular

[TommyTheCat]

Originally Posted by SSammy

Not here to argue, only attempting to help. Unfortunately, I’ve had to rebuild several direct injected engines, some of my family members insist on buying VW/Audi (yuck). The cylinders/pistons in those hold up very well and are fairly clean even after 100,000 miles plus, it’s the valve train that suffers, the valves are always filthy (I have several pics of some tear downs and them going back together if you’re interested). If you’re looking to reduce carbon deposits, Seafoam treatment through a vacuum line to the intake before every oil change keeps the valves much cleaner. The inherent problem is the fuel not getting to the back side of the valves.

Yeah this is why Ford/GM/ everyone is going to a blend of direct injection and port injection

[StingrayblueSS]

Originally Posted by ChibiBlackSheep

Sorry, what I said could be read wrong. It doesn't always go to the high-octane table on every key-on condition. I just meant that on reconnect of the battery it will always start at the high-octane, I kind of split my thought between 2 quote posts and could see where it comes off wrong.

Yeah it seemed like you were contradicting youself.

[xstuntman]

Of course the car will perform better on 91 octane - this isn't someone low compression tank from the late 70s/early 80s. High compression motors always run better on more octane.
Will at Overkill says his tune on 91 octane will get 15 to 30 hp but the same mods on 87 octane amount to 10 to 15 hp.

[ElderJ]

We need a forum specifically for octane discussions.


And yes, I'm joking, but on the real, this seems to be a VERY common topic. The decision is easy for me. My annual miles are incredibly low due to the blessing of working from home (I clock in about 3-4k miles per year on average). As such, it's a no-brainer for me to switch to 93 octane once I empty my tank. The minimal cost increase is well worth it for the peace of mind and any little bit of performance/reliability increase.


2014 LT V6 Automatic for the record. No tune. Stock everything. Well, I added an oil catch can, but that shouldn't have jack squat to do with this discussion I wouldn't think.

[Greenhornet2]

Originally Posted by xstuntman

Of course the car will perform better on 91 octane - this isn't someone low compression tank from the late 70s/early 80s. High compression motors always run better on more octane.
Will at Overkill says his tune on 91 octane will get 15 to 30 hp but the same mods on 87 octane amount to 10 to 15 hp.

Yes, but the discussion is based on the fact that if you are tuned for 87 octane, you will not have any positive effect from running more octane, in order to take advantage of the higher octane you would have to tune for it, as in advancing the timing.

[xstuntman]

Originally Posted by CamaroBarb

Back when compression ratio's were 8.5 to 1 yes but the fact is if you put regular in your v6 or v8 11 to 1 compression ratio engine the computer pulls timing so it doesn't ping detonate and destroy itself. AND GDI engiines are prone to Low Speed Pre Ignition. So at low engine speeds using regular the computer actually pulls the timing NEGATIVE to try and prevent it.

Correct.

Until the KR (knock retard) does it's thing more timing equals more power. On 87 you will get horrendous retard in the negative numbers as Barb has experienced. It's even worse cruising in warm weather btw. On 91 or 93 you will have much less KR and a tune seriously limits KR. I ran 87 and saw for myself how badly the exhaust tips carboned up. On 91 there's much less carbon since it pulls timing less often.

[HeyZeus]

Man that was a lot of information to read through... I got my 2SS about a month ago, the dealer I’m guessing put in premium, but ever since, I have put in 93 and the instant I did, got a huge boost in power and performance and it felt like a completely different car. Would this be the car switching tables? Or would I still potentially benefit from doing the fuse pull?

[Sxren_Camaro'13]

Originally Posted by ChibiBlackSheep

I always recommend people run 91 or 93 in their v6. The high-octane map is much better tuned to that car. But run regular if you want.

Regardless of the octane you run, frequent oil changes are good since it's a direct-injection and fuel dilution of the oil is a concern.

i always run 91

[lbls1]

I just realized it; All of my current rides take premium gas. I haven't bought regular in years!

[ZED SLED]

Originally Posted by HeyZeus

Man that was a lot of information to read through... I got my 2SS about a month ago, the dealer I’m guessing put in premium, but ever since, I have put in 93 and the instant I did, got a huge boost in power and performance and it felt like a completely different car. Would this be the car switching tables? Or would I still potentially benefit from doing the fuse pull?

the early 5th gen SS suffered from a software bug in that if the ecu started using the lower table, it would not switch back to the higher table after running premium. The only way to switch it back is via the full pull or disconnecting the battery. Your instant boost of power is likely placebo effect from spending an extra 40 cents/gallon. I would do the fuse pull and always run premium.

[HeyZeus]

Yeah I only put 93 in my car. I did the fuse pull last night and it definitely feels like a different car again. Just feels more aggressive, not necessarily more powerful