Here is what we all have beeen waiting for.....
Got to the water at 8:30 am. 82 degrees
no breeze, Smooth water. And HOT

Ski was my 1200SS set up for racing not top speed.
Ski was riden in the normal position ,not the BS superman style ,and had a full tank of gas.

Prop was a box stock 14/20
base test result was 78mph @7640rpms

Removed the pump and prop . Installed the Set Back and guess what ....... The prop would hit the
pump HUB. It wouldnt spin. It also had the OEM spacer installed. Went to the local auto store and got a washer that was thicker than OEM . Bored the opening to fit and installed the washer. Installed the Riva Set Back Prop and tightened it. Used a Impros Billet Boot.
The prop now has alittle space between it and the pump. I am going to make a shim kit for this problem and allow the prop to be tune to the pump.

The first thing I noticed was the increase in RPMS
It was turning 7960. The bottom end pull was **** good and coming out of a hard corner was perfect.

This prop was night and day compared to a 14/20.

Best speed with the SET BACK was 76.6 @7960

It was alittle slower on top end but got to speed so **** fast it was incredible.

No back to the hitting the pump concern. The stock OEM washer comes in different thickness. Each one is different. I am machining different washers to get the prop as close as possible to the hub. This will reduce some RPMs and give more top Speed. I am going to tune the prop to the pump this week and test again next Saturday.

My overall opinion of this prop is with alittle prop/pump tuning it is the best prop out there period.

It is also faster than a box stock 13/19.The best I ran was 74 @7980.

14/20 78 @ 7640
13/19 washer removed 74 @ 7980
13/19 SET BACK 76.6 @ 7960.

RIVA FINALLY did a good job with this prop project.
If anyone wants to talk to me about the prop, call me. 301-788-3343

REMEMBER these are OUT OF THE BOX PROPS not "trued,modded or CUT"...



[ 08-04-2002: Message edited by: WppRacing ]

Thanks Brian If you had to guess how do you think this new prop compares speed and rpm wise to a 13/20?

IMO dont watse your time and money on a 13/20

Great info Brian. A quick question for you. On See-Ya's thread, someone said it looked like a 13/19 with the hub machined. Any opinion on how it compares to a "stock" 13/19 with the washer removed?.

I just got off the phone with him. There were alot of variables that werent taken into consideration. I did go faster with the set back than the standard prop.

Brian, any estimate on what someone (with a stage 2) would gain vs. a stock 13/19? Seems you picked up a little over 2 mph with your set up. Thanks for any info you can give.

Brian,how did it compare to one of Erics modded 14/20?

GPoweR

Brian............ditto what GPoweR asked. How does it or how would you anticipate it compares to Erics Speedcut on the 14/20.

Have a stock 2002 xlt 1200 and would like to install the set back impeller. Do I need any other mods to make this work or would it just work? Looking for a good low end power without doing mods to the engine.

With Eriks props you can dial your ski in.
If you are turning a box 13/19 around 7250 and are getting speeds of 67-69, then installing this prop will give you more performance and top end.
The prop is not for a stock ski, stage 2 or 3 .

Brian---You shouldnt have to shim the setback for clearance---your shaft is not seated correctly in your pump---see it all the time. the inner hub of the impeller seats against the washer stop on the shaft and if the shaft is seated too far forward the outer hub of the impeller is going to rub the pump.
Good job on the testing-----but to accurately test the 13/19setback -it would have to be compared to a standard 13/19 that is "trued" to the same exact pitch as the setback( which i bet is the same anyway) we'll know in a few days when we measure the "true pitch" of the setback. The standard 13/19 would have to be run without the washer which is exactly what the setback is.
those who already have a 13/19 will most likely get the exact same results by not running the washer and "truing" theirs to the setback specs--- for a lot cheaper also---after all it is the same impeller(root angle).

I got similar results today.

I took my ski for the first time and I turned 7910 RPM @76MPh with the 13/19 setback. My carbs were still rich....very rich.

Brian remove the grease cone and hammer the shaft down while placing a piece of wood on the end of the shaft and supporting the end vein housing on top of a vise if possible. This will bring your bearing to the lowest poing and allow more thread on the opposite end.

Carl we may have a problem here increasing the chances of blowing the seals if we do not run a washer.

Brian, you don't answer GPower and DMD question, what they realy whant to know (and i will have to include myself here also) is how this prop (the 13/19 set back) compare to the Speedfreek 14/20 "speed cut" prop on out of the hole (holeshot) midrange and top speed performance thanks, Ray

I DO NOT know how it compares to a speed cut or I prop, I am not using them .
The shaft was seated correctly.That was the first thing I checked. I even removed the cone and pressed it more. It is correct. The shaft will ONLY press as far as the inner sleeve will allow it to. I have done enough pumps to know whats correct. I use a 12 ton press to install the shafts and seat them .
The seals are installed the right way .

****Certain people are missing the main point here. It is all about testing an over the counter out of the box prop. NOT a "mod or trued or cut" prop.****

This is not a top end prop either. This is the last word I am going to say about this prop --- the prop is the best closed course prop yet. It ripps out of a corner and off the line and stays hooked up in rough water and has good top speed.I am going to fine tune it to my pump and it will stay on it. I might have lost 2 mph but It makes up for it every where else. Most of us ride in the REAL WORLD and in different water conditions daily and for a box prop you cant go wrong. Call me if you want to discuss the prop further

I will be in the mountains today riding my ATV and taking a break from the skis and water.

[ 08-04-2002: Message edited by: WppRacing ]

well Brian if you are that impressed with it im sold.

GPoweR

Put it in your wifes ski and you will never catch her........................bye

ive seen it rub the hub as well and some have done some modding on the stator section so it wont rub, the drive shafts were in correctly .jm2c

Brian........Rumor has it that if you would have tried the set back over in Long Island you would have been doing 80+.

Thanks for giving us your real world testing results as always. You and Fercho's real world #'s were almost identical........hat's off to both of ya.

Others are missing the point here too--the setback is a lot more $ than a regular 13/19----why spend extra $ for no reason when a 13/19 can be "trued" and made to perform exactly as a setback for much less. especially when almost everyone on the planet already has a 13/19 somewhere and doesnt feel like shelling out another 260$
Just saying to be a fair test---you must compare a setback to a 13/19 to IDENTICAL specs.
We all know about the inconsistencies of "out of the box" impellers.
For those who want to get the most out of their ski KNOW about the importance of at least starting with a trued impeller or knowing what the exact pitch is so "fine tuning can be made later on--
People want "out of the box performance" from there ski, just like the guy next to you---go with the "out of the box" impeller---bottom line.
Im sure many on this board would like to hear the results of the testing of a setback compared to an identical trued 13/19 -thats comparing apples to apples.

carl,
so your saying people should not buy rivas new prop, but should just send out a standard 13/19 to someone and have it trued and the results will be the same?