falling Octane (AKI) ratings

[robbobster]

With the Torco Accelerator, we were able to add 4 degrees more advance which netted approximately 10 rwhp on the boosted trucks we were tuning on a dyno.

Your mileage may vary

EDIT: I should add that these were all 5.4L Ford modular V8 with either a centrifugal, roots or twin-screw supercharger, with anywhere from 9spi to 20+ psi of boost.

[ June 10, 2005, 07:10 PM: Message edited by: robbobster ]

 

[robbobster]

quote:

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Originally posted by 55:
Highest octane fuel we can get in atlantic Canada is 91. Regular is 87, midgrade is 89.

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Same here in CA. Tough to run a boosted/modified motor on 91 - we really had to pull a lot of timing out. I run FP with just about every tank, but I can't see running octane boost all the time.

 

[cit1991]

There are really no "additives" that raise octane anymore. Lead is out, and MMT cannot be used in the US. All the other compounds are blendstocks. I call an additive something that works at a few grams per gallon.

If you need 2 or 3% to get an effect, then it's a blendstock. The stuff they sell in stores is overpriced toluene or MTBE. Both raise octane, but you need gallons of it to boost 3 or 4 octane numbers.

California has lots of specific fuel specs that make blending of high octane fuel very difficult. The MTBE ban just makes it that much harder. They regulate aromatics and olefins to a much lower level than federal RFG calls for. They get tighter in 06. Look for 91 to drop or go away all together.

 

[Win]

A quickie store a few blocks from my house has a racing fuel sign on the price reader board and a pump that is marked for 101 AKI fuel.

I have thought about blending it with some 93 or 91 AKI, but am a little apprehensive that it could have some components that might be harmful to the 02 sensors, cats, etc.