2023 FX SVHO stage 1+ [tune RPM Limiter and impeller selection)

[Mr. GP1800]

I am picking up a 2023 FX Limited SVHO in a few weeks.

I would like to run with a stage 1+ setup on it, but keep my rpms limited at 8000 for Yamaha warranty preservation purposes.

I notice the stage 1+ kit uses the 13/18 impeller and claims to run at 8300 RPM.
Is it possible to go with the 13/20 on this setup to keep the RPMs down a little bit?

I'm not looking to make this ski a speed demon at all. I'd be happy if it was a 75 MPH ski. I just want it better than stock.

[Hurricane1000]

Riva tells me the OEM
rev-limter is actually
8300.

[Mr. GP1800]

Riva tells me the OEM
rev-limter is actually
8300.

That’s interesting. If that’s really the case maybe there wouldnt be an issue with turning it over 8000. Although any significant amount of run time over 8000 would surely raise a flag. I thought I saw somewhere is was around 7800 at top speed stock.

[Gilberjj]

Why are you choosing an arbitrary rpm limit of 8,000 RPM?
The SVHO motor has been around long enough that it seems clear that they hold up fine at 8,500+. It's an oversquare motor.

[seabrook]

Why are you choosing an arbitrary rpm limit of 8,000 RPM?
The SVHO motor has been around long enough that it seems clear that they hold up fine at 8,500+. It's an oversquare motor.

do you realize you are talking to 2 people that know their stuff?

[Mr. GP1800]

Why are you choosing an arbitrary rpm limit of 8,000 RPM?
The SVHO motor has been around long enough that it seems clear that they hold up fine at 8,500+. It's an oversquare motor.

Warranty. That’s why. I don’t want to mess up my warranty coverage in case of a catastrophic failure. I don’t need to go 85 MPH.

[Gilberjj]

Warranty. That's why. I don't want to mess up my warranty coverage in case of a catastrophic failure. I don't need to go 85 MPH.

I still don't understand. Why would turning over 8k rpm void your warranty?
Won't any tune will void your warranty?

[rephraim]

I still don’t understand. Why would turning over 8k rpm void your warranty?
Won’t any tune will void your warranty?

Yamaha ECU tracks RPM bands, 4-6k, 6-8k, 8-10k, etc. if you’re over 8k for 8% (example) of the time, they know a tune has been installed even if the ECU was reflashed with the bone stock tune prior to bringing it in for warranty work. And can deny an engine warranty claim if you say, drop a valve or something.

[Gilberjj]

Yamaha ECU tracks RPM bands, 4-6k, 6-8k, 8-10k, etc. if you’re over 8k for 8% (example) of the time, they know a tune has been installed even if the ECU was reflashed with the bone stock tune prior to bringing it in for warranty work. And can deny an engine warranty claim if you say, drop a valve or something.

ooohhhhh! That makes sense. Thanks for the knowledge drop.

[thomasdjames1]

Yamaha ECU tracks RPM bands, 4-6k, 6-8k, 8-10k, etc. if you're over 8k for 8% (example) of the time, they know a tune has been installed even if the ECU was reflashed with the bone stock tune prior to bringing it in for warranty work. And can deny an engine warranty claim if you say, drop a valve or something.

I cannot speak for an FX but a GP1800 SVHO will certainly spin over 8k with a full stage 1+ kit. Mine was ~8300 rpm with 50F and 60F air just after I installed the kit in the winter. In the summer I forgot what I am spinning but I think it is over 8k. When I was spinning 8300 rpm I think it was on a limiter or it may have gone faster.

[rephraim]

I cannot speak for an FX but a GP1800 SVHO will certainly spin over 8k with a full stage 1+ kit. Mine was ~8300 rpm with 50F and 60F air just after I installed the kit in the winter. In the summer I forgot what I am spinning but I think it is over 8k. When I was spinning 8300 rpm I think it was on a limiter or it may have gone faster.

Both my FX and GP spin 8,300 with Riva Stage 1+. Bone stock, my ‘21 FX would turn about 7400 full send, might have been a little higher but no where near 8k. Not sure what Riva was saying, maybe the limiter was set at 8,300 in the newer ‘22 hull but mine was no where near breaking the 8k mark even when the pump came unhooked.

[Wild Thing]

Standard 22 fx svho i never seen more than 7600 rpm on factory tune

[Mr. GP1800]

What I want to know is if the 13/20 impeller is a viable option over the 13/18. I don’t want to use the 13/18 and be spinning it over 8000 rpm. The 13/20 should drop rpm by 200-300 from the 13/18. But is the 13/20 ok to use with the new fx being bigger and heavier than a GP. I’m running a 13/20 on my GP now and I’m very happy with its performance.

[TXDroneRacer]

I don't have an answer to Mr. GP1800's question, but I do have an question. I assume there is a tradeoff going from the 13/18 to the 13/20.

Are these the tradeoffs? Please correct me if I am wrong:
13/18 - Less top speed for the same max RPM, More bottom end acceleration
13/20 - More top speed for the same max RPM, Less bottom end acceleration

[Hozzie]

What I want to know is if the 13/20 impeller is a viable option over the 13/18. I don't want to use the 13/18 and be spinning it over 8000 rpm. The 13/20 should drop rpm by 200-300 from the 13/18. But is the 13/20 ok to use with the new fx being bigger and heavier than a GP. I'm running a 13/20 on my GP now and I'm very happy with its performance.

I don't think the impeller itself has any bearing on the RPM's when using a tune. The tune will limit the RPM's to whatever you set it to, and that will have an impact on your speed based on which impeller, but I don't see how the impeller itself has any affect.

There will probably be some tradeoff, but if you potentially want a bit more speed at the lower RPM, then the 20 may do that, but you will probably give up a little something.

Or just go with the 13/18 and use the 8k tune and it is what it is.