[krw1103]

I would like to know if anyone has tried running 98 octane gas in their stock ZL1? Supposedly, NOLA motorsports park has 98 octane available but I did not know if it could cause any damage to the engine or valve train. Will the ECM sense the extra octane or is it just a waste of effort and money?

[SteveV]

Last time I was at VIR, I tried the different octane ratings they have there. VIR has like 4 different octanes at the onsite pumps. Above 98 gets really expensive too...

I did see a slight perf increase from 94 to 98 in stock tune. Seemed peppier. When I tried 102, I saw no difference. Was a complete waste of my money on a stock tune.

Hope this helps.

[Stephen12ZL1]

Same here seems like a waste and my straightaway speeds were no faster. I put 100 octane in my car at VIR and saw basically no difference except how much I spent at the pump.

[Markoz28]

I imagine mixing a few gallons of 98 to 93 would help with detonation. Won’t make more power but shouldn’t lose any either.

[krw1103]

Thanks guys for the helpful info. I don't want to just burn money up thinking there is a performance improvement but it sounds like what I would be doing if I went to the higher octane fuel.

[Juiced1]

Running added octane without a tune won't do much except help you keep lost HP. If you are getting any knock the octane will help eliminate it and get back any timing that was being pulled. We've ran into knock on stock LT4s more then you would think. So a little octane on a track day isn't a bad idea. We've done some 100 octane tunes and gains are usually around 30-35rwhp over 93.

[SteveV]

I never meant to imply my car felt stronger or more powerful. It just seem a tad more responsive with 98 vs 94. Didn't affect my lap times at all...

[Can'tHave2MuchHP]

Can't hurt. Adding true higher octane fuel is much better than adding one of those little bottles of octane booster too.

[ssmofo]

If you added more timing it might help.

[travislambert]

I've tried 100 octane on multiple occasions at PittRace during the summer, and I've yet to detect any meaningful difference in performance.

Without a tune to offset the timing normally lost due to higher air temperatures, race gas is a waste of money. The stock timing tables aren't aggressive enough to justify anything beyond 93.

[TJay74]

I would not run the whole tank full of 98/100/10/104 and so on. The higher the octane the slower the fuel burns, so there is a point of diminishing returns.

Best thing you can do is add some 98+ or higher to a tank of 91. Example, the 6th gen Camaro tank is 19.8 gallons. 10 gallons of 91 with 10 gallons of 98 will net you around 94.5 octane.

As said earlier, unless you modify the tune for more timing to take advantage of the extra octane, in stock form you really wont see much. Reality is you only want the most amount of octane needed to keep detonation from happening.

[Homeless Junkie]

I run and have run octane for the last four track days. I was told by an instructor that it's good for the longevity of the engine. He went on to tell me all the things Juiced posted up thread. I barely ever drive my car on the street. I don't feel any faster it's just a bit of insurance. Considering how much this hobby costs another $150/day in fuel is a drop in the bucket.

[Bow Tie Fanatic]

I’ve used 100 (not 98) and couldn’t tell 100 octane worked as far as seat of the pants but my PDR said otherwise. The only time I have run 158 mph on the front at VIR was with a 100 octane in the tank. That was with letting off 200-300 feet early because of massive brake shake. Normally in good air we are hitting around 156 down to the 6 marker. Anyway maybe it was just an unusually good day but it did make me think there could have been some performance gain.

[SJFGTO]

You only need enough octane to avoid detonation. After that, meaningless. Adding a little 98 may or may not help, depending on quality of gas already in the tank. It won’t hurt.