R6 gearing / shift points / top speed

Discussion in 'General' started by Gino230, Mar 24, 2019.

  1. Gino230

    Gino230 Well-Known Member

    After the D200 this really got my wheels turning. You have the top guys doing 180 MPH on SS legal R6's. My bike is no slouch, but the best I've ever seen on the GPS is 167. Top speed is free lap time at Daytona, and there's alot of it so tweaking things to get it right can pay big dividends. I recall @stangmx13 chiming in on another thread about shift points, and that got me thinking that maybe I need to put some more effort into getting this right.

    Yes, I'm bigger, 5'11" 190.

    Yes, they are getting a better drive. But with over a mile of track we are at terminal velocity.

    When I did the 200 in 2016 on my older R6, it was making 123 on MR-12 and I couldn't get more than 158 MPH. I was pretty new to the 4 cylinder thing and I think I was shifting at around 12-13K RPM. With this "short shift", the bike would fall into a range where it would not pull out of (below the torque peak?), thus I think my top speed and acceleration was hurt. Compounding that, the motor was very tired and although it made good peak HP, the midrange was weak.

    Fast forward to October- New engine build, same peak HP, but better midrange. I was winding it to death, sometimes not even using 6th if there was a headwind. She hangs around 15 or 15.5K RPM in 5th, so I assume I was geared correctly.

    Last weekend, I focused on tucking in tight, running the high line up by the wall, and winding it past 15K before shifting. Then I got the camera with the GPS speedometer and watched the footage. That showed something strange, past about 14.5 or 15K (can't see the tach in the video) the bike stops accelerating. Upshift and the acceleration starts again. So maybe my gearing is too short? Not sure how accurate the GPS in the camera is timewise. But it was within a MPH or so of the AIM SOLO for top speed.

    I spoke with @MELK-MAN on Saturday, and among other advice he's using taller gearing. We didn't discuss the top speed issue, just some infield stuff. I understand why he's using that gearing for the infield, but Greg, are you pulling 6th on the banking?

    I'm running 16/43 gearing and Dunlop 180 rear slick.
     
  2. metricdevilmoto

    metricdevilmoto Just forking around

    The biggest mistake I often see racers making is shifting at the wrong times coming off the banking and not being aware of how what part of the tire you are on effects rpm.
     
    MELK-MAN likes this.
  3. Gino230

    Gino230 Well-Known Member

    Yes, I don't know what part of the puzzle this fits in- I do know by observation, that when coming down off NASCAR 2 to the back straight, you stand up and the RPM drops as you get onto the fatter part of the tire. So if I upshift before that point, then I'm REALLY falling down in the RPM range. Similar effect on the front straight, and then there's the tri-oval where you pick up 500 RPM

    Is that what you mean by mistake?
     
    metricdevilmoto likes this.
  4. Gino230

    Gino230 Well-Known Member

    Also, at that same point on the banking (NASCAR 2), the bike is already into the overrev in 5th. So I'm not really accelerating until I stand it back up. Again, maybe a little taller gear would work better here timing wise.
     
  5. lightning97

    lightning97 Well-Known Member

    Try 17/42 next fall
     
    Gino230 likes this.
  6. -Eric-

    -Eric- Well-Known Member

    Where does your bike stop making power? R6s with stock cam timing fall over after 14k. Altered cam timing moves that closer to 16k. On my bike (stock) you can feel the acceleration stop after 14k
     
  7. Mongo

    Mongo Administrator

    Put an R1 engine in it :D
     
  8. TurboBlew

    TurboBlew Registers Abusers

    maybe I missed it... was there a trap speed area that confirmed 180mph? That seems pretty high considering the restraints of what kind of modifications can be done and the weight limits. For the sake of discussion... lets assume 140 rwhp on MR12 for a stock displacement R6. Not even discussing the perfect tuck required on the banking. It seemed like bikes were slower this year. Saw at least 5 guys going into turn 1 with their leathers "flapping" in the wind which can make a dramatic difference in terminal velocity.
     
    Sabre699 likes this.
  9. TurboBlew

    TurboBlew Registers Abusers

    you can try it but Im going to wager it wont work very well.
    2.47 final drive would work great if your 600 can make near 60 ft lbs of torque! :D
    2.65 or there abouts seems to be the sweet spot
     
  10. RM Racing

    RM Racing Tool user

    167 in the actual loop speed trap is good. Stop overthinking it.
     
    metricdevilmoto likes this.
  11. hayes131

    hayes131 Well-Known Member

    First, I would say you are overthinking all the strategy ON the banking. But people love talking tech. That being said, my big ass did 188mph drafting to the lead in the 4 lap restart, by gps speed. Most laps were mid to high 170’s, with some extra windscreen and good fuel.

    I had a pic of data on my phone, but don’t know how to shrink file to put on here.
     
    CR750, sbk1198, BigBird and 5 others like this.
  12. Prospect

    Prospect Hayai

    If I understand this correctly; if you can theoretically keep throttle input constant and simply lean the bike, the RPMs will continue to increase the more you lean the bike over.
     
    metricdevilmoto likes this.
  13. humblepie

    humblepie Well-Known Member

    I would be very surprised to see bikes in the Daytona 200 doing 180 mph, ALONE, on the banking.
    In a draft, or two bike draft, happens all the time.
     
    TurboBlew and metricdevilmoto like this.
  14. metricdevilmoto

    metricdevilmoto Just forking around

    A 140hp SS legal R6 isn't something I've seen.
     
  15. notbostrom

    notbostrom DaveK broke the interwebs

    Was nice seeing you again Josh.
     
  16. MELK-MAN

    MELK-MAN The Dude abides...

    I'm sure there are others that can offer better advice Gino, but my 2c.. Find a gearing that suits your strengths for now, as long as you are not on the rev limiter on the banking anywhere.. And I see gearing all over the place.. even among faster riders, not as fast riders.. it does tend to be a little bit of a trade off on how the bike works in the infield when you start varying the gearing greatly from stock. And you can find yourself "in-between" where it pulls great off corners in the infield, but revs out in 6th without a draft. Or, get a little closer to being able to not rev out on banking, but then 1st gear is tough in Int. Horseshoe, but 2nd gear is sluggish.

    I'm always in awe watching guys like JH4, Eslick, and a couple others rip through the chicane. I'm too much of a chicken to run over the rumble strip leaning to the right on exit the way these guys do, but it really straightens the exit out. And notice how they are NEVER past mid track, mid way through the chicane. Run wide as you enter the chicane, and your exit is fu***d.. But, Those top speeds you discuss are set up here. Then knowing how to work the banking out of nascar4 on the side of the tire, an d use 6th when needed. And to further complicate things, the wind can play a part in using 6th on front straight or not sometimes.

    One of the best vid's you can find on youtube, is Jason Farrell's vid from a couple seasons ago. It's on a kawi, but shows how you gear for 1st in I.H.S, and don't always use 6th on the front stretch ...

    my ss bike i hold 5th on the back straight heading to the chicane.. my SB will pull 6th down the back stretch, even with 1 less tooth on the back than the ss bike. It's a monster :) The front straight i was holding 5th on the SS bike all the way down FRONT straight, until i leaned over at the tri-oval. Then shifted to 6th to not beat on my motor (both motors were new that weekend).
     
    TurboBlew likes this.
  17. stangmx13

    stangmx13 Well-Known Member

    15.5k rpm in 5th might have less drive force than shifting to 6th. It all depends on your dyno numbers. Chances are improved with more midrange too.

    There are online calculators where u can input dyno numbers and your gearbox to get some good shift points.
     
  18. R1Racer99

    R1Racer99 Well-Known Member

    I guess we were wrong all along, even this guy can run up front with the help of a double bubble.
     
  19. Gino230

    Gino230 Well-Known Member

    Of course I realize that at my pace there's lots of work to be done everywhere but top speed at Daytona is one of those "freebies" because it doesn't require much extra work and an extra 5 MPH can pay big dividends. So it's definitely worth a BBS discussion (also a freebie)!

    In October I will try a taller gearing. At my pace, my gearing works pretty well in the infield, but I'm a little late getting to the throttle and down 2-3 MPH apex speed at some corners compared to the 1:53 pace riders (I have some AIM data to compare). Some of it is my poor choice in line. Some of it is, well, I'm just not that good (yet). A taller gear might force me to roll it in there a little faster.

    I'll also dig out my dyno chart and see where the power peaks are. Then I actually have to start looking at the tachometer.

    Greg you're right about the chicane- Danny lapped me there last year and I was like "how the FUK is he over there on that inside paint??" you can see his line pretty good on the Farrell video, which I use as a learning tool, also.

    You gotta love this place- ask and ye shall receive.

    @stangmx13 are you BBS'ing from a mountain bike in Vietnam?? Are you coming to Road Atlanta?
     
    MELK-MAN likes this.
  20. RM Racing

    RM Racing Tool user

    Try a different dyno. ;)
     

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