Fuel suggestions on a stock motor for racing?

[cornerslider]

I have little bit of knowledge about fueling, and that probably makes me more dangerous than most .... I know our bikes were designed to run on 87 octane "pump gas". I also know the ethanol added to fuel, as a bit harder on the fuel system itself- especially when a bike may be in" storage" for several months in some climates. I own several bikes, and always run non-oxygenated/non-ethanol 93 octane. I know that it burns at a slower rate, and the compression in a stock motor isn't really high enough to warrant 93 octane. On my street bikes, I'm not too concerned with running peak performance/efficiency. I'm more after the non-ethanol portion of this equation... I used to have a fuel station by my house that sold non-ethanol 87 octane (they recently went out of business). I started racing my "07" this year, and it seems like I should have a bit more on top end (compared to other 07's). Would I gain anything by going back to 87 octane (even if it has ethanol)?

As far as my motor, it's bone stock (internally). I run an Akrapovic Ti exhaust, Hordpower intake, and ECU flashed by 2WDW. Unfortunately, the lack of OEM airbox doesn't make it super-sport legal. I'm running lightweight super-bike, which is pretty "challenging" on stock motor-

[M. Hausknecht]

4 hours ago, cornerslider said:

I have little bit of knowledge about fueling, and that probably makes me more dangerous than most ">.... I know our bikes were designed to run on 87 octane "pump gas". I also know the ethanol added to fuel, as a bit harder on the fuel system itself- especially when a bike may be in" storage" for several months in some climates. I own several bikes, and always run non-oxygenated/non-ethanol 93 octane. I know that it burns at a slower rate, and the compression in a stock motor isn't really high enough to warrant 93 octane. On my street bikes, I'm not too concerned with running peak performance/efficiency. I'm more after the non-ethanol portion of this equation... I used to have a fuel station by my house that sold non-ethanol 87 octane (they recently went out of business). I started racing my "07" this year, and it seems like I should have a bit more on top end (compared to other 07's). Would I gain anything by going back to 87 octane (even if it has ethanol)?

As far as my motor, it's bone stock (internally). I run an Akrapovic Ti exhaust, Hordpower intake, and ECU flashed by 2WDW. Unfortunately, the lack of OEM airbox doesn't make it super-sport legal. I'm running lightweight super-bike, which is pretty "challenging" on stock motor-

Yeah, I bet its tough in lightweight superbike with a stock motor.

Now to your question. The characteristics of your flash should determine what fuel you use. I "think" 2WDW adds timing to the spark maps, which adds a bit of power but also requires higher than 87 oct gas. Did they specify a minimum recommended octane rating? If they didn't add timing, there is no benefit to running more than 87 oct and, because the burn is slower with higher octane, there could be a slight detriment (to go with the higher cost). As for ethanol versus non-ethanol, again, I'd look again to the assumptions used by 2WDW. Do they tune for alky-free gas or 10% ethanol? You need more fuel with 10% ethanol gas and less without ethanol. The difference isn't enormous, about 5%.   

When I set about tuning my ecu, I first decided what fuel (brand, octane, specific gravity, and percent added oxygen) I'd run and then tuned both my fuel and spark maps for that specific fuel. Because the fuel I chose contains ethanol, I don't leave it in the bike for more than a few days at a time, and I run the motor briefly on ethanol-free gas to get the water-absorbing ethanol out of the fuel injection system when I leave it to sit for awhile. I live on the coast in North Carolina, so ethanol-free gas is widely available to keep the boaters happy. I decided against pump gas as much as anything to assure greater consistency in the fuel; with pump gas, the characteristics change with the seasons and you never really know what you're getting.  Whatever fuel you use, be consistent about it and check your spark plugs periodically for evidence of detonation if your timing has been bumped.

Even with stock internals, since you've improved your intake airflow capacity with the Hordpower, have you considered adjusting your cam timing?

Tech Article - Cam timing explained

You can do it without pulling the head, and with the stock pistons and an unshaved head, needn't worry about valve to piston clearance (there is plenty).

 

 

[cornerslider]

I think I had them tune it for 93 non-oygenated.... I'm going to shoot them an email though. I'd think they keep records of that sort of thing? Thanks for the input -

 

[fzar]

Just now, cornerslider said:

I think I had them tune it for 93 non-oygenated.... I'm going to shoot them an email though. I'd think they keep records of that sort of thing? Thanks for the input -

 

I have the same mod's done to my bike @2wheeldynoworks recommend 91 octane to me for my akra-ti, @hordboy intake, stock motor.