Motor work is terribly permanent. What if it turns out that you don’t like more horsepower? What if it makes your ATV harder to ride and less fun? Not only have you spend thousands to mess up your machine, you’ll have to spend more to go back.
That doesn’t happen often, but it’s worth thinking about. A far less drastic way of getting more power is VP U4.4 race fuel. This is the latest generation in VP’s line of affordable race fuel. The Pros usually burn more expensive versions of VP that provide something like a seven percent horsepower boost across the board. That’s the good news. The bad news is that stuff costs about $40 a gallon. U4.4 achieves almost the same advantage, but rather than using super expensive additives, it uses heavy oxygenation. It contains lead and MTBE, which is a form of alcohol that once came in pump gas. The motor octane rating is 103, which is good for high-compression motors. So if you have had motor work done, you probably need race fuel anyway.
THE FUEL ON THE HILL
One of the most important advantages of U4.4 is that it compensates for altitude. You’ve probably noticed that your quad doesn’t run the same when you take it into the mountains. Even EFI systems suffer at altitude. They compensate for the decrease in atmospheric pressure and correct the air-fuel ratio, but there’s still a horsepower loss and the bottom line that that a 450 can run like a 400. Having more oxygen in your fuel is the solution. We were big fans of U4 and U4.2, but one thing stopped us from using it all the time. The smell. We often transport quads in enclosed vans, and the fumes would make the driver a little barfy after a short trip. The latest version of the product still has a strong odor, but it doesn’t stay with you for days.
As far as performance goes, it’s still a great buy. A six-percent horsepower gain can be very expensive to achieve through hardware. A $1000 pipe might get you there or it might not. The boost you get with U4.4 can be felt through the seat of your pants, there’s no question about it. It generally is a very uniform increase, not changing the nature of the powerband anywhere.
REJET OR REMAP?
Theoretically, U4.4 can cause the need for a change in jetting or fuel mapping. More oxygen is more oxygen, whether it comes in the form of fuel intake or air intake. But in many cases, U4.4 is a pour-in replacement for pump gasoline with no other modifications required. We used it in a 2009 Suzuki R400 with the stock fuel map. That ATV was fitted with fuel injecting last year, and it comes somewhat lean to pass federal tests. We were afraid that the fuel would throw it over the edge. Not so. Even with aftermarket pipe, the Suzuki ran clean and strong. That isn‘t to say that more performance can‘t be had with remapping. With a little more fuel in the mix, we think there’s another 1 or 2 percent boost available. But as is, the Suzuki clearly gained about 3 hp. On a carbureted machine, we would bump up the main jet a size or two for kicks, but on an EFI motor, we don’t think the gain justifies the cost of a fuel-system modifier, which usually sells for over $300.
The exact price of U4.4 is hard to pin down because of the cost for shipping hazardous materials in different regions. We have seen it available for less than $15 a gallon. Yes, that’s over four times the price of pump gas, but it’s still a bargain compared to what race team managers have to pay for similar results. Those guys are prohibited from using heavily oxygenated fuel by AMA Pro racing rules–you aren’t. For more information, go to www.VPracingfuels.com or call (951) 696-5100.