Raise speed limiter vs eliminating it

[Btapppan]

Newbie here to tuning. I have a 2021 GP1800R SVHO and have ordered the Riva stage 1 kit. The factory speed limiter smoothly keeps it under 68.5MPH, and from my research thus far, it sounds like if I remove the speed limiter, I could face bouncing off of the rev limiter instead at higher speeds, is that correct? Is there a way to raise the speed limiter instead of removing it, for smooth WOT runs without fear of hitting the rev limiter? I've also read about adjusting impeller pitch to help limit RPM, is that my only option?

[Eric Kern]

Newbie here to tuning. I have a 2021 GP1800R SVHO and have ordered the Riva stage 1 kit. The factory speed limiter smoothly keeps it under 68.5MPH, and from my research thus far, it sounds like if I remove the speed limiter, I could face bouncing off of the rev limiter instead at higher speeds, is that correct? Is there a way to raise the speed limiter instead of removing it, for smooth WOT runs without fear of hitting the rev limiter? I've also read about adjusting impeller pitch to help limit RPM, is that my only option?

So I noticed your post was from a while ago and no one answered you (I see a lot of unanswered questions in this section of the forum), but I figured I'd answer. Anyways, I'm no pro, but I also have a '21 GP SVHO with a maptuner. Riva provides a pretty large selection of tunes for the skis, one (which I'm running now), is keeping everything the same, except removing the ÔÇ£speed limiterÔÇØ, which really just moves the rev limiter to 8000 RPM, the stock ski maxes out around 7800 RPM with this tune and I've had zero issues with hitting the rev limiter. Good for about 73-75mph (dash). Hope this helps.

[K447]

My experience with the rev limiter during WOT 'cruise' is that upon reaching the limiter target RPM the engine gently reduces RPM by a couple hundred, then walks the RPM back up, then glides down, and so on. If I was not watching the tachometer graph I might not even notice the RPM limiter.

'Bouncing off the limiter' is more about what happens when the jet pump unhooks from the water and the engine power zooms the RPM skyward almost instantly. The RPM limiter has to drastically curtail engine power and wait for the RPM to return to the operating range. When the ECU can again apply power, if the jet pump is still unloaded and the throttle is still squeezed, the RPM again rockets up and the limiter must again intervene. This is 'bouncing off the limiter'

I currently run the Riva Stage 1 Plus (8300 limiter?) 91 octane (the Riva Low Octane) tune on a pair of 2017 GP1800 SVHO. Previously I had the same tune but with 8000 limiter and during optimal conditions the engine could spin the impeller to a bit more than 8000. Hence my experience with the RPM limiter activating.

During the early phases of ownership I was concerned with warranty and ECU logging in the 'over 8000' RPM band. The Yamaha ECU * seems kinda sloppy about the exact RPM band threshold and even with the 8300 tune I have almost no accumulated minutes in the 8000-10,000 range.

I have not looked this year but as of May 2020? this was the CANDooPro reading from one of my ECU.



The chart makes it look like I spend a lot of time puttering around under 2000.
My guess is that the Yamaha RiDE system makes it so easy to just idle in neutral while chatting with others on the water that I do not shut the engine off as often as I would otherwise. We also transit slow speed zones on some of our rides


* Yamaha apparently has multiple versions/generations of the ECU firmware. I do not know if some of them are more 'accurate' than others in terms of noticing engine operation slightly beyond 8000. Mine doesn't seem to notice.

If I remember to check the current CANDooPro readings from my ECU RPM log for my GP1800 SVHO I will post an update.