Presently I'm tuning for Premium (91 Octane in Colorado) on my Turbo'd project.
Is there some "rule of thumb" or calculation that I can use to estimate how much advance I can gain under boost (more advance = more power) when using a higher octane fuel like E85 (estimated at 105-114 octane) or Race Gas (i.e. 97, 104, or 110 Octane)?
Timing Advance vs Octane
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
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Southcross
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Timing Advance vs Octane
1979 Volkswagen Dasher MegaSquirted Turbo Drag Project a.k.a Mr Hanky
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devastator
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Re: Timing Advance vs Octane
I added 5 deg. advance across the board, except under boost, when I started using E85. This is not a fair example I suppose, since I'd ping without a high octane fuel. You do know that you have to pull advance out when under boost right?
Sandrail-ACVW 2276 cc, Turbo
MS-II W/spark burning E85
The sand must be punished.
MS-II W/spark burning E85
The sand must be punished.
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Southcross
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Re: Timing Advance vs Octane
sure do... 1.5 degrees retard per 10kpa (or 1 degree for 1 psi, 10kpa = 1.5psi)
you were able to add 5 degrees advance going from premium to E85? Theoretically you should be able to add almost that much to the Bins above 100kpa too. E85 is a finicky thing, it loves compression, makes it combust better... also will produce more power than gasoline when burned at Stoich.
you were able to add 5 degrees advance going from premium to E85? Theoretically you should be able to add almost that much to the Bins above 100kpa too. E85 is a finicky thing, it loves compression, makes it combust better... also will produce more power than gasoline when burned at Stoich.
1979 Volkswagen Dasher MegaSquirted Turbo Drag Project a.k.a Mr Hanky
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devastator
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Re: Timing Advance vs Octane
Yes, my timing under boost is approx. 5 deg. more with E85 than with Av gas. I've never been able to use premium. I'm pulling 1 deg per 1 lb of boost. I run a little more conservatively than I'd like because I don't trust the % of ethanol to gasoline in E85 to be consistent. It can vary from 65% to 80% depending on the time of the year. I plan to start checking my fuel with a hydrometer each time I buy it, (in a 55 gallon drum).
Sandrail-ACVW 2276 cc, Turbo
MS-II W/spark burning E85
The sand must be punished.
MS-II W/spark burning E85
The sand must be punished.