GPR-HO Conversion - Project-R

[Hurricane1000]

Be very careful using the R&D cam gears....

I had catastrophic engine failure using them.

[R3_killa]

GPR-HO Conversion - Project-R

Be very careful using the R&D cam gears....

I had catastrophic engine failure using them.

I used the R&D gears in my SHO and never had any issues.

I only used the the R&D gears as a template and drilled the holes in the OEM gears for the adjustment I wanted.

Just finished installing the gears and all is in order [emoji1362]

Was your catastrophic failure due to not setting timing properly?

[R3_killa]

GPR-HO Conversion - Project-R

Got some testing done this weekend after doing the cam gear mods and safe to say that some power was gained.

All tests were done the same and was best out of 3 runs:



As you can see, I gained 3mph and 370rpm! I am now experiencing some porpoising so I've done some grinding to my pump and removed all the shims:



Will give this a go next and post results. After I've tuned the plate, I will be trying different pitches to find the sweet spot on this conversion setup. I'm currently running a 14/17 and have a 15/19 that I've just repitched on standby:

BEFORE



AFTER

[R3_killa]

GPR-HO Conversion - Project-R

The repitched 15/22 didn't go so well (67+mph @ 6800rpm) so ended up repitching the OEM FZR impeller to 13/19 and was able to bring rpm's down but maintain 69+mph meaning no speed was loss but was actually gained throughout the mid to top end range with more consistency.

I'm running the CanDoo GPS on the dash so it's fairly accurate. With better water conditions, I could see 70mph.



I will test this pitch again when the water conditions are better then continue to play with 2 more pitches before I come to a conclusion in what works best for my setup.

[davidescu_radu]

nice build - want to do something like it for buoy racing

[R3_killa]

GPR-HO Conversion - Project-R

Been trying to figure the best way to resolve the cavitation issue on my GPR-HO conversion and decided to remove the transom and try something I'm sure some have already tried or thought of:-

I removed the transom and bored it to 158mm to increase a bit more water flow entering the pump. I then had the 2inch spacers extension bored with a taper of 158mm > 155mm to maintain pressure going towards the wear ring/impeller. The impeller and wear ring remains 155mm. I'm using a Solas 13/19 repitched to 13/18.

The rpm's ranged 7900-8000rpm before this mod @ 69+mph so will update in the changes I've noticed if any.

[R3_killa]

GPR-HO Conversion - Project-R

Went for a test today and finally broke into the 70mph barrier [emoji1]

Best speed was [email protected] with 2010 oem FZR impeller which is essentially a 13/20 and 87mm nozzle.

Im going to play with the rideplate a bit now and see how that goes. Then try taking the trailing edge off by 1??.

[R3_killa]

nice build - want to do something like it for buoy racing

It's a great build once you can solve cavitation issue.