What mods are needed to make running 100octane useful? Or would 100octane help a stock engine with CAI, 180tstat respond better? Or would I be paying more for gas just to enjoyl the swwwweeeettt high octane smell? Its not much more $ than 93 premium around here, where I can find it. A LOT of crotch rockets around here run it, but I know those things can spin upwards of 10,000 rpm. Just thinkin....

I can also find CAM 2 but no way am I putting that in my car, 110octane is just insane...its only 4.40/gal, though.

Some 00+ SSEi'* have seen KR in stock form so running 100 especially at the track won't hurt IMO. I run it from time to time and it seems like you run through it alot faster than 93 but besides that i have seen no ill effects.

Keep your money in your pocket. 100 octane fuel (or higher) is wasted on the car. It will suppress knock on high compression motors, that'* it sole use. Until you jack the compression up high enough, you have no use for it.

Ok, using the local crotch-rocket set as an example is a tad foolish. The mentallity of the crowd is as mixed up as most ricers. (I ride rice too...also raced them for years, so I know what goes through the mind of newbie sport-bike pilot..I used to be one ) Your typical 4 cycle, 4 cylinder, sportbike runs a compression ratio of 10:1. But it'* a small chamber and spins very fast. 12000 rpm redlines are pretty common. Even then, the motor will run fine on 87 octane gas. I had one bike with a Wiseco over-bore kit in it to take it to 637cc. Also raised the compression to 12:1. It ran on 93 octane. I only *needed* 100 octane race gas when that was combined with advacing the cams as well as increasing the ignition timing.

I don't even run straight 100 at the track. It'* pointless. I mix it with 92 up to about 95/96 octane for the most effect. A little more timing, no more octane over that. There is no POWER in higher octane fuel. That'* a myth.

It'* a hard myth to dispell. For years marketing of "Hi Test" fuels sold the public on the idea that Octane = Power.

Adding some more to my earlier reply...

Reality is just the reverse. Octane'* evil twin Heptane is the power source in gasoline. The higher the octane rating, the less volatile the fuel is. It has more octane molecules compared to heptane. (or, in modern fuels, it has enough of other chemicals added to simulate having higher concentrations of Octane vs. Heptane.) High octane only helps support other modifications that do add power by supressing the nature of the fuel to detonate on it'* own before the spark commands it to.

Even high boost pressures can be hacked on pump gas, provided it is applied at a high enough rpm. (in other words, light the mixture off via spark before it has a chance to detonate on it'* own.)

The most powerfull engines that need octane rating in excess of 100... Aircraft engines. Huge pistons, long strokes, and big power outputs at low rpm.

My main reason for asking had to do with KR, and gaining more power from getting less KR, not necessarily dumping a whole bunch of *high test* to try and up the HPs. Im an "carb/open header/no replacement for displacement/RWD/bang my own gears" kinda guy so I know all about the high compression motors. Even though Ive had my Bonne for a year, still learning about "tuning" a force induced gas engine.
And what willwren stated about mixing was what I was planning on doing. I did think that mixing would get me between 92 and 100. I was only gonna drop in a couple gallons with about 5 gallons of 92 to get me to the track and through the day.

I'll save the CAM2 110 octane for when I put a Mercury 410 (a 390 with a 428 crank) in my 64 Mercury Comet MoreDoor (4 doors)

Good luck. My last stroker motor (a 420 sbc) is getting new open-chamber heads to dump it'* compression ratio. Quality of pump gas just sucks and I can't afford to run the race gas it needs to keep knock from tearing it apart.

I'm building a stock 305 TBI as a backup motor...if fuel gets any worse I may re-engine the car down to the 305. The extra cubes will be useless if I can't run enough ignition timing to take advantage of the displacement.

I've even put installing the L67 in the '90 Bonneville on hold. If things stabilize a bit on the fuel cost/quality front, I might still do it, but for the moment having a 3800 that runs well on cheap gas has it'* advantages.

The CAM2 around here is $4.57/gal and thats only like $0.50 more than I am paying for premuim for the Bonne, the DD. I would totally run the engine "detuned" so to speak for street use. And I could save for a few weeks between strip times. Its mostly gonna be a toy anyways, cruise nights and such. The Bonne is what gets me around.

this is very true you wont gain any power from octane alone you gain power from more timing you can run whit the higher octane whitout knock

on youre L67 you will see gain if you have kr but 100 octane is racing fuel and harder to ignite

http://www.rockettbrand.com/technica...olineMyths.pdf