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how much power difference with different Octan fuel?

577 Views 4 Replies 2 Participants Last post by  2JZGTE
as all of you know, California only has 91 oct now. how much would our turbo cars suffer from lack of octan? I know heat would definitely play an important factor here.

how much power does the car usually gain on a dyno running 110 race fuel than 91 street pump fuel?
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I think I'm slightly outside the norm, but my car seems to pick up between 40 and 50 hp when going from 93 to 104. I've gone from 112 to 116~117 mph trap speeds when adding 104.
were you on the dyno when you discover the 40-50 pwer gain? that is quite alot for 11 octan boost...amazing actually!

anybody else have the same power gain?
My car does the same thing. With only 93 octane, I can only get 110 mph. When I add 104 I can hit 117 sometimes.

It's pretty simple. A good running BPU should make 400 rwhp and run 115-118 traps. When running too low of octane, and one of the knock sensors detects even a little knock, your timing gets retarded bigtime. I have seen it happen many times, on the dyno. 40-50 rwhp loss is standard, thus the low trap speeds. It can even happen with 92 and 93 octane when there is enough heat soak. Resetting the ECU and adding high octane gas will solve this. My advice for you guys stuck with 91 octane:

Get some Toulene or Xylene (octane enhancers)and figure out how much you need to add per tank to equal 93 octane. Shouldn't be too much. If you buy in bulk, it will probably increase price per gallon by only a dime or so.
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