---

---

---

---

---

Submitted by Chris Sunkin
There are many factors to consider when selecting a fuel. Most of them would require a chemist experienced in hydrocarbon fuels to help you decipher In short, there are many ways to formulate a fuel through selection of base product to a whole catalog of additives and processes that enhance certain attributes The easiest way is to select the right fuel is to visit the VP fuels website No other fuel provider has focused more energy on the 2-stroke motorcycle community than VP They have some new, oxygenated fuels that really add performance.

Octane is just one measure of how a fuel will behave Too much octane without adequate compression will definitely hurt performance Octane is the fuel's resistance to combustion. Compression of the fuel/air mixture reduces a fuel's resistance to combustion and given enough pressure, the resultant heat will cause combustion on its own That's the principle behind a Diesel engine as well as the root cause of detonation Detonation is sometimes helped along by deposits in the combustion chamber Anyway, back to octane- if your octane rating is too high, your compressed fuel/air mixture is going to be harder to light via the spark plug That means that your effective ignition timing- that is, the point not where the spark hits but where the mixture ignites, will be retarded Simply advancing the ignition point in a fixed timing engine will compensate at high RPM but will kill the lower RPM power.

As far as changing fuel/air ratios with race gas- you'd probably see a minor change depending on the fuel you used It could go either way, richer or leaner, depending on the fuel It wouldn't be anywhere near as pronounced as if you went from 32:1 pre-mix to 40:1, maybe a couple percent.

In the end, there are only a few choices- make a compromise and use a fuel that's formulated for a high-efficiency 4-stroke that is required to meet your local emissions regulations (local pump gas) or use a fuel specifically formulated for your exact application (VP or other 2-stroke specific fuel. Home-brew fuel blends are likely to do more harm than good It's unlikely you'll get the best results through random experimentation.

---

---

Re: Looking for a 6.5L Diesel 2-Door Tahoe/Yukon...

--------------------------------------------------------------------------------
I have a black '96 Sport exactly as you describe- it's now my son's. I wasn't aware that it was available with a diesel- I've certainly never seen one, other than a military CutV

---

---

---