Suzuki GSV-R990 – MotoGP Suzuki -Testing The Waters Sport Blog

17 Mar 2015 | Author: | Comments Off on Suzuki GSV-R990 – MotoGP Suzuki -Testing The Waters Sport Blog
Suzuki GSV-R

Suzuki GSV-R990 – MotoGP Suzuki -Testing The Waters

Suzuki GSV-R990 – MotoGP Suzuki -Testing The Waters

As the Rizla Suzuki MotoGP mechanic warms up the GSV-R990 belonging to rider Chris Vermeulen just outside the pit garage at the Valencia circuit in Spain, I stand ready and waiting, thinking about my experience with the bike in ‘05 at this same racetrack. I am first on the long list of journalists to ride Suzuki’s Grand Prix machine this time, and all I can think about is how it seemed that the bike was neutered when I rode it the year before.

The ‘05 machine belonging to John Hopkins just had felt a little flat compared with the Ducati Desmosedici I had ridden the previous day back in November of that same year and the Suzuki MotoGP GSV-R test-team bike I rode in ‘04. I can’t help wondering if the Suzuki team is going to give me the same ultrasoft engine mapping this time around as well.

The Rizla Suzuki mechanic motions that everything is ready, so I shut my helmet shield and climb aboard, very conscious of the fact that Vermeulen rides with a conventional shift pattern (one down for first gear and five up for the rest of the gearbox ratios) rather than the reversed race pattern (one up, five down) used for most racing machines. A mistaken backshift on this racebike would obviously be disastrous, for my physical well-being as well as the GSV-R’s.

I head down pit lane making sure my leathers are comfortable and positioned correctly, and as I head out onto the racetrack after checking to ensure no one is on a flying lap behind me, I hope and pray that I got the “full monty” engine mapping this time.

Going Pneumatic

The biggest changes in ‘06 to the Suzuki GSV-R990’s all-new engine were the move to a wider 75-degree angle in the V-4 powerplant and the switch to pneumatic valve springs. Now commonplace in Formula One auto racing engines, a pneumatic valve spring replaces a conventional metal coil spring with what basically amounts to a miniature piston and cylinder in its place.

By highly pressurizing the cylinder with a gas (usually nitrogen, due to its temperature-inert qualities), an “air spring” is created with numerous advantages over a coil spring. The biggest benefits are that reciprocating weight and internal friction losses are substantially reduced (no springs and retainers mean less moving parts, and air-spring pressure remains fairly constant for the initial movement, meaning that ultrastiff springs-which create friction-are unnecessary to ward off valve float).

And valve float itself (where the valve follower fails to maintain contact with the camshaft at high rpm) with aggressive cams is basically eliminated. The downsides are some additional weight and complexity due to the need for a pressure storage tank and the various regulators and pneumatic hard lines.

“We had a lot of trouble and the year before with valve-spring reliability,” recalls Kunio Arase, project leader for the GSV-R. “At high rpm, the harmonics created in the valve springs were causing metal fatigue that resulted in several failures,” so Suzuki developed the latest GSV-R990 with a pneumatic valve train. “This allowed us to easily raise the maximum rpm level with the new engine 1000 rpm higher, without so much concern for reliability.” What about maintenance, since the system’s high pressure is crucial to its performance? “Maintenance has been very easy,” he continues. “We only have to perform basic maintenance every two or so races, whereas before it was after every race.”

It’s notable that the latest GSV-R800 uses a pneumatic valve train as well (and to apparently good effect-both Rizla Suzuki MotoGP riders John Hopkins and Vermeulen have been at or near the top of the time charts at the first two preseason tests of the ‘07 season). Was this a sort of trial run for the 800’s pneumatic valve system? “Yes,” reveals Arase, “although it had been developed and tested prior to using it on the 990 this season. The system used on the 800 is not much different than the one used on the 990.”

The use of pneumatics in the valve train enabled Suzuki engineers to fit slightly more aggressive cams, although it’s not just a simple matter of slipping in racier cams and getting more power. A lot of R-D time was spent massaging the power delivery so that the extra power wasn’t more of a hindrance than a help. “We changed power delivery through refining engine management,” says Arase, “paying special attention to engine-torque character, to make it easier for the rider to accelerate out of the turn. The technical application here was very difficult, but we were able to manage it properly after some refinement.”

Arase is naturally very coy about revealing any peak power figures, saying only that the GSV-R990 has “over 240 horsepower.” Bore and stroke, as well as crankshaft firing order, were supposedly unchanged from the ‘05 model.

What about using traction control to smooth out the power delivery on corner exit? “Our traction control has been refined quite a bit,” answers Arase, “but we still have a lot of room to improve in this area. Wheelie control has also been developed, but we only use it at circuits where wheelies are a problem.” Although Hopkins had informed me in ‘05 that the team would be using Magneti Marelli engine management for the next season, apparently that didn’t happen. The GSV-R’s engine-management system appeared to be a more advanced version of the same Mitsubishi EMS of ‘05, not the Marelli system as used by most of Suzuki’s competitors.

According to Arase, there have been minor refinements in materials and construction of the chassis, but the geometry measurements were basically the same as ‘05: “The chassis worked pretty well last year and the riders have not had any complaints, so we haven’t changed much on the chassis. Just very small refinements to construction of both the frame and swingarm to give better cornering feel for the rider. Hopkins and Vermeulen’s basic chassis specifications are the same.”

The most noticeable external chassis change was to the swingarm, which now sports all of its bracing underneath the main spars and no longer makes room for the rear bank of exhausts to exit next to the swingarm and out the left side; the rear cylinders’ exhausts now route up underneath the seat and exit out the tailpiece.

A Major Improvement

Accelerating out along the short straight between Turns 1 and 2 at Valencia, I decide to “give ‘er the berries” and see if the team has given me a map more closely approximating what Vermeulen uses during a race weekend. Lo and behold, the GSV-R hunkers down and launches down the straight with a verve that the ‘05 model could never have matched, lazily lofting the front wheel in third gear as it hurtles down toward Turn 2. Yeah, baby! Now we’re talkin’!

Suzuki GSV-R

Thankfully, I remember that even though the tires are already nearly up to temp from the tire warmers, the carbon brakes are not, so I shut off early and apply the brakes. As expected, the response is pretty dull, and I have to give them a pretty good squeeze for a longer period to get any stopping power. I drag the brakes at every opportunity on my first lap to get some heat into them, all while making sure to run into the right-hand corners at a decent speed to scrub in that side of the tires, since Valencia is made up of mostly left-hand turns.

There is no doubt that the Suzuki has a much stronger motor this time around, whatever engine maps it might be running. While the throttle still has that smooth yet crisp initial response that allows you to apply it earlier and more aggressively in the corner for a better drive out, the midrange acceleration is much improved. The GSV-R pulls much harder and gobbles up the short straights fiercely enough that I find myself having to control wheelies off many of the medium-speed corners in Valencia’s infield, something I never had to be concerned with before.

In fact, that more aggressive engine is almost a liability in some spots. The Suzuki’s steeper torque curve makes it a bit more difficult to control the bike in the tighter sections because of the extra care required with throttle inputs, and short-shifting to keep the power from ramping up too quickly is necessary in a few areas. If the wheelie control was activated, it isn’t very effective, as I have to fight to keep the front end down accelerating in third gear at a little over 120 mph as I crest the small rise on the front straight.

Top-end power is worlds better than with the ‘05 GSV-R, with none of the noticeable tapering off of acceleration past 14,000 rpm, and a much better overrev as it approaches the 16,500-rpm rev limiter. Nonetheless, I’m still wishing for a bit more on top, as acceleration feels like it is flattening out a little too prematurely compared with some of the other MotoGP machines.

Overall handling continues to be a strong point with the GSV-R, and it’s easy to see why the team was loath to change anything with the previous frame geometry. While not the nimblest or smallest-feeling bike in the MotoGP field, the Suzuki has an agile yet stable character that makes you feel as if you can do no wrong. Initial turn-in effort is a tad higher than most, but the payoff is superb stability and front-end feedback entering corners.

The GSV-R chassis has a well-balanced and communicative feel that promotes high corner speeds (which has obviously paid dividends with the new 800), and the Bridgestone tires contribute to the bike’s agility while offering up loads of grip and feedback at all lean angles.

I obviously wasn’t going fast enough to find any fault with the hlins GP suspension, but even at my slower speeds, their action and feedback seemed flawless. And once they had some heat into them, the Brembo carbon brakes provided the necessary stopping power to shed the speed this bike is capable of generating.

A New Beginning

While the Rizla Suzuki team was finally starting to see some positive results to its hard work in ‘06 (Vermeulen led most of the USGP until Hayden took over and then scored a podium finish in his home Grand Prix at Phillip Island), that development work has apparently transferred over and paid off in spades with the 800. Judging by Hopkins’ and Vermeulen’s performance during preseason testing, the Rizla Suzuki team finally has some well-deserved (and long-overdue) confidence heading into this year. Here’s hoping that hard work is rewarded with major results-the GSV-R has most of the assets necessary to win and just needs to put all of the parts together.

Photo Gallery: Suzuki GSV-R990 – MotoGP Suzuki – Sport Rider Magazine

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