Okay I live in California and we only get 87,89,91 octane. I want to get my turbo ls vtec tuned for daily driving and occasional highway runs. I have a greddy boost controller that i want set for low and high boost. With the high gas price I want to know if I can run 87 octane safely at low boost for dd or should I stick with 91 octane all the time? What is the max boost I can run on 87 octane for dd and max boost for 91 octane? Thanks in advance

Here is my setup:

built ls bottom 83 mm CP pistons and ring, Eagle rods, sleeved
mild built b16 head
1000cc inj (overkill but thinkin of future build)
Hondata s300
gt3076
FR mani
more stuff i dont remember

 

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A good rule of thumb is that whatever octane fuel you tune on, you should always run at least that octane rating to avoid detonation. If you want to run 87, the safest way to do it would be to tune on 87, or some EMS will let you switch between 2 maps with a toggle switch and you can have a "DD tune" with 87 and a "high boost" tune with 91+. It probably depends on how good your tuner is, but most people running any amount of boost will run the highest readily available octane of pump gas, and switch to racing fuels for higher boost levels. I'm not sure what gas prices are like in Santa Rosa, but in the South Bay, the difference between 87 and 91 at most stations is about $0.20-0.25. I would personally just bite the bullet and tune and drive on 91 for $2-3 more per tank. It seems like you have a lot into your build, and it doesn't really make sense to potentially jeopardize it by running 87, but again, it all depends on your tuner and how much power they can safely get out of whichever octane rating you decide to go with.