Can I run 87 octane or lower on your tune?
In nearly all cases, the answer is "yes, but...". 87 octane CAN be run in most vehicles, however it cannot be run efficiently in quite a few. Due to GM's choice of compression ratios, combustion chamber design, etc. 87 octane is a poor choice both in terms of engine power output as well as fuel efficiency. In those cases, it only makes sense to run a higher octane, as the performance benefits and increased fuel efficiency will outweigh the per-unit cost of that fuel.
For an inclusive (but not fully-encompassing) list of all vehicles that can run 87 but should not (under any circumstances), see below:
For an inclusive (but not fully-encompassing) list of all vehicles that can run 87 but should not (under any circumstances), see below:
- All LS1, LS2, LS3, L99, LS7, LSA, LS9 equipped vehicles. 91+ octane required.
- 2005+ L33 "B" engine silverado/sierra models. With a higher compression ratio than the standard 5.3L for those years, 89 octane or better is recommended for both fuel efficiency and power output.
- 2007+ 5.3L engines. At 10:1 compression, this engine (all variants) cannot run efficiently on 87 octane. Power output and mileage will be noticably better in 95%+ vehicles simply by switching from 87 to 89 octane. 91+ preffered.
- 2001-2007 LQ9 vehicles (AWD Cadillac Escalade, Silverado SS, Sierra Denali, Vortec Max). Compression ratios (and owners manual) dictate that premium fuel should be used at all times.
- 2007+ 6.2L L92 (and variant) vehicles. All 6.2L truck/SUV engines have a 10.5:1 compression ratio and as a result, require premium. Most of these vehicles will have a note in the owners manual as well as a decal on the gas door stating a recommendation to that effect.
- All 2014+ direct injected vehicles. Compression ratio is simply too high to efficiently burn 87 octane.