300X vs. 300XS - Who is King?
The 300X is long gone from Mercury's line up and has been replaced by the direct inject 300XS. This is old news. It is also pretty common knowledge that when the 300X (3 liter) was bumped for the 300XS (3.2 liter)
performance may have dropped. They are both rated at 300 hp from Mercury so whats the deal?
Below are the results from our recent water test of both stock engines and our tests of back to back dyno pulls. They both make the claimed 300 hp. In fact they both make over 300 at the prop and both have at least 300 ft/lb of torque. Both are outstanding power plants stock. What is the most powerful? The 300X, by a long shot. They could have called it a 325X. The rev limit on the XS is 6400 while the X spins to 7000.
After testing, the 300X made exactly 326 hp stock with the XS making 306 hp. They both made over 300 ft lb of torque however the X rev'd to 7000 with more after peak power (over-rev) than the larger displacement XS. This explains the larger top speed numbers we have all seen from the X. The good news is the XS can be made to run with and beat up the X with bolt on parts. This is possible while still retaining the 4.5 gal per hour fuel savings enjoyed running the XS. You may wonder why the 3.2 is less powerful than the 3.0 liter? It is simple. The air pump. This air compressor pump is basically a dead single cylinder being drug along for the ride to push air and fuel into the direct inject chamber (also called parasitic drag). This is an awesome design however; nothing is free. It takes 20 hp to run that pump. Once the 3.2 XS is upgraded with level 1.1 spec, the XS becomes a contender to the X while still saving almost 5 gal per hour. The bottom line is both these engines are great and we encourage every one that can buy one do so because these great 2 strokes won't be around forever.
If you want to build hp at the expense of fuel mileage, the X is King. The XS at equal bore and stroke to the X will always be that 20hp or so behind with better fuel consumption. Below is a dyno curve of a bone stock 300X compared to our DBR Level 1.1 300XS. The X still pulls away a little after 6400 rpm, however, the L1.1XS would crush the stock X pulling a large prop.
performance may have dropped. They are both rated at 300 hp from Mercury so whats the deal?
Below are the results from our recent water test of both stock engines and our tests of back to back dyno pulls. They both make the claimed 300 hp. In fact they both make over 300 at the prop and both have at least 300 ft/lb of torque. Both are outstanding power plants stock. What is the most powerful? The 300X, by a long shot. They could have called it a 325X. The rev limit on the XS is 6400 while the X spins to 7000.
After testing, the 300X made exactly 326 hp stock with the XS making 306 hp. They both made over 300 ft lb of torque however the X rev'd to 7000 with more after peak power (over-rev) than the larger displacement XS. This explains the larger top speed numbers we have all seen from the X. The good news is the XS can be made to run with and beat up the X with bolt on parts. This is possible while still retaining the 4.5 gal per hour fuel savings enjoyed running the XS. You may wonder why the 3.2 is less powerful than the 3.0 liter? It is simple. The air pump. This air compressor pump is basically a dead single cylinder being drug along for the ride to push air and fuel into the direct inject chamber (also called parasitic drag). This is an awesome design however; nothing is free. It takes 20 hp to run that pump. Once the 3.2 XS is upgraded with level 1.1 spec, the XS becomes a contender to the X while still saving almost 5 gal per hour. The bottom line is both these engines are great and we encourage every one that can buy one do so because these great 2 strokes won't be around forever.
If you want to build hp at the expense of fuel mileage, the X is King. The XS at equal bore and stroke to the X will always be that 20hp or so behind with better fuel consumption. Below is a dyno curve of a bone stock 300X compared to our DBR Level 1.1 300XS. The X still pulls away a little after 6400 rpm, however, the L1.1XS would crush the stock X pulling a large prop.