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Join Date: Jun 2006 Location: Naples, FL
Posts: 503
|  2 stroke faster than 4 stroke? Heres your proof, now shaddup :-)
Here is a reprint from Bass and Walleye Boat Magazine. They have a number of excellent tests, all very well and fairly done.
Even tho I am currently a Yamaha owner, I was very happy to see that the only 4 stroke that came close to the 2 stroke was the VERADO! Always glad to see the US companies do well.
Here's the full article.
Editor Steve Quinlan and I met with the very accommodating folks from Ranger Boats on Arkansas’ Bull Shoals Lake in mid-spring, and conducted a shootout between 250-horsepower offerings from all of the major players (sans Evinrude, who was invited but declined) on identical Ranger 620VS multispecies boats. We had at our disposal for the weekend four four-strokes (a Suzuki DF250, Yamaha F250, and Mercury 250 Verado) stacking the deck against a lone two-stroke DFI (Mercury 250XS). With four outboards comparing very closely in terms of weight, horsepower output, top-end rpm limits and torque, we expected the outcome to be pretty close. With the exception of the top speed and acceleration of the Mercury 250XS, it was.
THE SETUP
We chose Ranger’s 620VS as a test platform for several reasons. Since the Suzuki DF250 is not available in a 20-inch-shaft length version -- and we very much wanted to compare this engine against the other 250 offerings -- we had to select a hull with a minimum 25-inch-transom height. That excluded all of the bass boats, and moved us over to a walleye/multispecies design. Unfortunately, it also meant having to exclude Yamaha’s 250 HPDI, which beginning in 2006 is no longer available in a 25-inch-shaft version.
We also wanted to see how the torque and hull-lifting abilities of these big engines would fare when fitted to a heavier hull more suited for bigger waters and bigger payloads. Finally, we know and understand that the speeds we reached will certainly not be considered “sexy and exciting” by those who want to see just how fast these behemoths can push a lightweight boat. But, the Rangers provided a very stable platform, and stable means repeatable, which is of paramount importance in testing.
While I personally would have loved nothing more than to test on a bevy of flyweights designed to reach 90-mph speeds, we elected to go for stability and repeatability instead. It worked; our test was easier to conduct, the people at Ranger were a delight to work with, all of the hulls were as close to identical as possible, and we obtained very “real-world” results. Our weather at Bull Shoals was not perfect — we dodged clouds, rainstorms and by our last day, were blessed with 80-degree temperatures and bright sunshine — but we were able to complete all of the tests in roughly identical water, temperature and wind conditions. In all, it was a very fair comparison—exactly what /BWB/ readers look for.
GAME ON!
Our procedure was the same as in past /BWB/ tests. First, the factory reps are allowed time to set up and fine-tune the rigs to their liking. Ranger Boats’ test crew, however, did a lot of the work beforehand for the engine reps, and consequently a lot of the setups ended up the same after the engine men completed their testing. When we arrived, we performed dry-land inspections on all of the boats, engines, setups and props, and took careful notes on each. We then removed each engine and recorded the weights with our digital load-cell scale setup, noting that our figures of course contain oil and fuel in the engine, propeller installed, steering cylinder and hoses, and cowling. Hence, our figures reflect heavier weights than the factory brochures show, as the engine guys quote “dry weight.”
We then filled the 51-gallon fuel tank in each hull, and weighed the boats and trailers at a local scale. The empty trailers were weighed last, so that we could subtract those weights from the hull weights and arrive at a “hull only” figure (sans trailer, outboard and propeller but including fuel, rigging and accessories). In this case, the Verado-powered boat was the heaviest, so it was tested “as is.” The Yamaha boat was the lightest by 100 pounds, so we handicapped it with a 100-pound bag of lead shot. We fitted the 250XS boat with 17 pounds of shot, and the Suzuki boat with 65 pounds. We don’t handicap for outboard weights — only differences in hull weights.
After we recorded the weights, hull notes, engine notes, setup and propellers, we headed for the lake.
SPEED AND PUNCH: TWO-STROKE BRAGGING RIGHTS
No sense dancing around it, in terms of speed and acceleration, Mercury’s 250XS is clearly the champion of the 250-horsepower crowd -- and by a very significant margin. We hit a best average top speed of 64.5 mph spinning a 24-inch-pitch lab-worked Bravo I four-blade wheel right at the limiter (5850 rpm). We actually bumped the limiter a few times, trimming high into the wind while trying to eke out that last mph. The next closest speed was achieved by the Verado, at 63 mph even (turning a 23-inch lab-finished Tempest Plus propeller) at 6140 rpm. The Yamaha finished third with a solid 60-mph clocking, turning a stock 23-inch-pitch Yamaha VX-Max three-blade prop at 6000 rpm. In the top speed wars, the Suzuki came up fourth out of the four, pushing the Ranger to 58.6 mph at 6100 rpm turning a stock Suzuki 16x24.5-inch three-blade prop.
We must note, however, that Suzukis traditionally like to be run high. After some preliminary prop testing, Senior Product Development Engineer David Greenwood raised the engine to the very top set of holes (3/4-inch higher than any of the other three engines) and said he was disappointed he couldn’t raise it any higher. He noted after his test runs that the engine never really felt like it had broken loose at that height.
Acceleration results put the two-stroke XS at the top of the pile, too. Merc’s raspy “race production” engine pushed the stout Ranger to 30 mph from a dead stop in 6.2 seconds, a full four-tenths of a second quicker than the second place finisher (again the Verado, at 6.6 seconds). The Suzuki came in a very close third this time, with a 6.7-second clocking, and the Yamaha pulled up fourth with a distant 7.7-second average.
Midrange punch (measured in seconds from a 30-mph cruise to 50-mph) told a slightly different story. Here’s where the XS really put the smackdown on the others; it romped from 30 to 50 in 6 seconds flat, where the next closest competitor (Verado) could only muster an 8.1-second clocking. The Yamaha’s midrange torque topped the Suzuki’s, as it finished a full second (8.3 vs. 9.3) ahead to finish third. To those doubting Thomases, we used no fewer than four (!) methods of speed measurement: two handheld Garmin GPS 12 units, a boat-mounted Lowrance GPS (which was a delight to use, by the way) and a calibrated Stalker Pro k-band handheld radar speed gun. For rpm readings, we used our own digital FloScan tach for all of the engines.
FUEL ECONOMY: SURPRISE!
No surprise to us at /BWB/ but probably a disappointment to tree-huggers everywhere, the two-stroke Mercury 250XS eked out a win in the fuel-economy challenge, too. With an average of 3.5 mpg across the entire rpm range, it bested the Suzuki by one-tenth of a gallon. The Yamaha came in a close third at 3.2 mpg, and the absolutely thirsty Verado finished a distant fourth with a 2.8 mpg average.
With today’s fuel prices, this is a critical part of the test. We ran these numbers several times to be sure, and came up with the same results each time. We also checked our results against Yamaha’s and Mercury’s factory digital fuel-flow meters.
While the 250XS took top honors for overall average fuel economy, the Suzuki 250 actually achieved the highest mpg recording at cruise speeds. With a 4.3 mpg recording at 24.7 mph and 3000 rpm, it bested Merc’s XS by a tenth of a mpg at the same rpm.
WHAT ABOUT THE NOISE?
Years ago, we used to record sound output as a regular part of these tests, and our sister publication, /Trailer Boats/, still does. Since the four-strokes in this test were so quiet, we broke out our digital decibel meter and went to work, checking decibel readings at idle, 3500-rpm cruise, and full throttle. We took readings at the transom and at the helm at both idle and 3500-rpm cruise speeds, and at the helm while running wide-open.
The Verado was the clear winner here. It is so quiet, it is literally impossible to tell if it’s running or not idling (especially if the wind is blowing or waves are slapping the hull). Though it’s a cliché by now, we actually had to check the “pee indicator” (overboard water indicator) to see if it was running at the dock and out on the lake. At idle, the Verado registered 64 dBa on our meter at the transom, and an even more silent 56 dBa at the helm. It was significantly quieter than any of the other engines, even by the “naked ear.” The power steering whine present in earlier Verados is gone, as promised by the Mercury engineers. It is just an amazingly quiet engine. When it’s hammered, the Verado gives off a very high-pitched, high-rpm whine that sounds almost like a jet engine. That’s partly due to the supercharger, and partly due to the Verado’s advanced crank-train design.
The Suzuki is almost as quiet, but it’s just not silent like the Verado. It has a very nice sound, however, and even when it’s leaned on, it doesn’t sound like it’s laboring. The Yamaha has the most “trucklike” (automotive) sound of the group. It is audible at idle, and when the throttle is dropped, sounds like a big-displacement diesel engine pulling.
As expected, the 250XS is the loudest of the group by far. It has the traditional two-stroke howl, even when only turning 5800 rpm at full bore. That’s exacerbated by the open exhaust outlets at the top of the gearcase, but even at idle when those are buried beneath the waterline, it’s loud.
SUBJECTIVE JUDGEMENTS: RUNNING QUALITY
In this arena, it’s our opinion only. We can only report what we observe, and what we observed is that the Verado is the smoothest, best-running, best-operating and easiest-to-drive engine. It simply shines in all aspects. The fly-by-wire DTS throttle and shift is simply not going to be beat by traditional cable setups found on the other engines. Its integral power steering is smoother and easier to operate than the Teleflex SeaStar Pro setups on the others. It’s easier to shift, throttle, steer, start and drive. No doubt about it, this engine performs as Mercury advertises; it’s a true “outboard drive system” as opposed to a simple outboard engine.
The Suzuki comes in a close second. While it shifts, steers and throttles traditionally, it’s very smooth and predictable. The gearcase “snicks” into and out of gear, rather than clunks like the 250XS. The throttle response is smooth and linear. Overall, it was a genuine pleasure to drive the Ranger equipped with this engine.
The Yamaha and Mercury 250XS both had a lot of “traditional outboard heritage” in the way they operated. Their shifting was not nearly as smooth; in fact, while the Yamaha was fairly quiet, the Merc really banged into gear. Other than that, the Yamaha’s running quality was superior, just like anything else ever made by Yamaha; I just wish they could change the engine noise and exhaust note to a more pleasant, less-labored sound. Since it’s a Yamaha, you know it’s not going to hurt itself, but it sure could sound happier. The 250XS is just plain raspy, loud and rude; like most (if not all) Mercury Racing products, it lets you know it’s there, with authority.
It must be noted that the fit and finish on all four engines was just fantastic; though it’s expected of the Yamaha, the others met Yamaha’s standards easily. Even the 250XS was superb, and this is an engine that we had faulted for being a little rough around the edges in years past. I’m guessing that the Verado assembly guys rubbed off on the Racing crew a little.
FINAL OBSERVATIONS
Clearly, four-strokes have a long way to go yet in the top speed, acceleration and even the fuel-economy wars before they can catch a well-tuned DFI two-stroke like Mercury’s 250XS. It’s a shame we didn’t have Evinrude’s 250 E-Tec in the mix to compare — they were very conspicuous in their absence. In addition, Yamaha has since last season discontinued the 25-inch Saltwater Series version of their vaunted VMax 250 HPDI, so we sorely missed their two-stroke participation in this test. Perhaps in the future we’ll do another two-stroke/four-stroke 250 shootout — on a bass boat — among 20-inch-shaft engines.
We neither added nor deducted points for pricing, yet the results were a bit surprising. Based on 2006 model year MSRPs, the Verado was actually the least expensive of the bunch at $19,140, followed by the OptiMax XS at $19,688, the Yamaha F250 at $19,900 and the Suzuki DF250 at $20,182. We dinged the OptiMax XS for warranty, however, as it carries a two-year warranty while the other three engines all carry three-year warranties.
The clear winner in this test, for those who primarily care about speed, acceleration and fuel economy, is the Mercury 250XS. The Verado would have finished a close second if not for its last-place fuel finish, but we still rate it a solid — but distant — second place nonetheless. The Suzuki was not far behind, finishing neck-and-neck with the 250XS in terms of fuel economy, and right there with the Verado for second in holeshot. The Yamaha turned in a good performance in midrange punch and fuel economy. In reality, any one of these outboards would fit the bill for hulls like the Ranger 620VS. Top speed is only a few mph off the pace of the Merc two-stroker, and fuel economy is excellent with either engine.
If fishing, reliability, fuel economy and ease of operation were my primary concerns, I would be happy with any of these outboards. It’s when top speed, punch, and having the “big dog” are important (and I must ask, to what red-blooded American are these not priorities?) that the two-stroke Mercury 250XS becomes the standout. In my book, that makes it the winner of this test, and the engine I would choose if I were shopping for a 250.
RANGER 620VS
As an ultra-high performance boat aficionado, I’m not used to hulls like the 620VS. After a weekend spent with four of them, however, I know I wouldn’t mind owning one as a big-water, big-fish excursion hull. I get the impression that owning a Ranger is sort of like owning a BMW or a Mercedes; the level of fit and finish is just up there so high, it’s expected that the boat will perform and last for years to come. I’d suspect current Ranger owners would tell me I’m right.
These 620s ran well in calm and in chop, didn’t get us wet despite running them within 10 feet of each other (for the photo shoot), crossed broadside waves without jarring us to death and generally just performed like champs for our entire test.
What’s more, the professionalism and quality of workmanship was evident everywhere we looked. Our test hulls were nearly flawless, and everything worked on them as well. Will these boats win any speed records? Of course not, but they’ll get you there, and back, in good time and in dry clothes. I enjoyed my time spent in the Ranger 620VS. It’s a darn nice boat, and for the money, a great value.
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2008 SeaPro SV2400 bay boat with a 225 Verado. One sweet setup.
Ableinspector.com |
(One has a top speed of 38mph while the other has a top speed of 42mph - yes more than 10%)
