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How many pounds of boost can you run on the 8.5:1 compression ratio before haveing to use above 91 octane.

you should always use 91 or above no matter how many psi you run, My car only drinks 93.5 :)

It all depends on your car and modifications. Do you have an upgraded fuel pump and injectors? do you have a way of controlling those injectors? What turbo are you running? you should have your mod list in your signature. we need a little more info before we can answer that.

8.5 isn't too high. I would say a few psi less than if you were on stock compression, but the only way to find out it to actually test it man. Most people that do it say it's completely worth it though.

92-93 FTW. I wouldnt run anything less. $3 more per fill up is way cheaper than rebuilding your engine because you knocked like hell on 87.

Some areas only get up to 91 octane.

Unfortunately, it is completely impossible to answer the question in the original post. The only way to know how much max boost you can safely run is to datalog the car while raising boost and watching knock (and AFR if you can afford it).

yea and thhat is cali for you, 91 is our premium :thumbsdown: