I can't post any numbers yet, only had it out 1 time for an hour and a half. I have a bad porpoising problem to cure before I can get any solid numbers. I also have a tach on order. I will say that since I added the Island modded carbs, the pro-tec head and the power core it runs real sweet! It's a rocket out of the hole and I'm betting on some good top end numbers when I get the porpoising settled down. I am amazed at how I sent Carl my carbs and just bolted them on and it runs better than it ever has! Instant acceleration and runs clean/smooth all the way thru the power band. I probably wont't have time to do back to back testing the the power core/cat con in and out. I'll leave that for the big boys, the wife is going to kill me if I spend much more time on this thing!

Thanks for the feedback VOODOO, is there any chance you may do comparison runs with the power core vs. the d-plate?....

I need a tiny tack as well, or all this is all for guessing...

Thanks again bro..
Dave

I don't have a D plate, so that's not a possibility. If I got real ambitious, I could put the cat back in and do a comparison but I just don't have the time right now. When I get the tach, I will get some rpm and speed numbers with my stock 13/19.

thx for this post, but is there anyone who can compare the power core to the d-plate? i guess take a stock boat and do it? i am really curious to see the results

Voodoo,

Did you step your sponsons? That made a huge difference on my ski.

Do you have the angle mod plate? If you do you may want to talk to Carl. He might recommend putting some washers between the plate and hull on the back two bolts on any type of rough water.

Thanks for posting about the power core. Looking forward to seeing your rpm's and speeds.

Jim

Spud, I havn't stepped them yet, although I did make that modification to my sponsons a while back. Carl recommended to try lowering them first, I will try it this way next time out. I'm sure I will find the right combination of lowering, stepping, or washers with some time spent. No, I don't have the angle mod, just the skegs machined off.

Just got back from spending an hour on the water. Porpoising is fixed by the sponsons being lowered. I will try stepping them next as I feel I am scrubbing a lot of speed by having them full down? It was windy and choppy today, best on GPS was 64.8. I could of had more if there would of been some flat water. I also feel the carbs are way rich, there is certainly more to be had when I get the tach and lean them down some.

voodoo, congrats on finally getting the heads.
i am currently running my sponsons fully up (and yes it does porpose) but with a little finesse and body position it goes away.... current best is 68 mph (gps). i just added the ride plate and can't believe how much i increased the acceleration and top end(1.5mph).
did you get base line #s before you added the power core? that would be extremely helpful to those of us with d-plates..

mxvet, I changed a lot of things before ever hitting the water this spring. Last year with the cat in I ran 64-65 with a best of 67.1 downwind on flat water. So my numbers really havn't been any better so far other than greatly improved acceleration. Why not? Well I changed too many things to know. Is the power core costing me some top end, don't know? I still need to do a lot of "dialing in" to get more speed out of this ski. I plan to step the sponsons instead of having them full down. There was no body positioning of finesse that could of fixed my porpoising, it was bad. At WOT, it was like riding a 60mph pogo stick and at slower speeds it almost made me sea sick. I don't see where I'm getting any more speed from the rideplate so far but as I said I changed so much it's hard to tell. When I get the tach I will lean the carbs down a little and see if I pick up some speed there also.

What is the inside diameter of the power core?

Salty

this thing is killing me!!!

Voodoo, I have an R&D D plate I can lend you to do some back to back tests if you want. You can send it back when your done.

Just got back from the lake and I've got some serious numbers guys and gals! I installed tiny tach so I can now give rpm readings along with my GPS numbers. I also stepped the sponsons and the handling is spot on now!!! Pretty much the same as with the sponsons down but less speed loss. I also leaned down the 125 main jets to
1 1/4 turns out. I still feel they may be rich? For the speed numbers I got 68.4 @7190 rpm's with 3/4 tank of fuel. The next day I recorded 69.8 with 2 bars of fuel @ 7190-7200 rpm's. This is with an OTB 13/19 and my listed mods. I'm very excited about these numbers! The best part is that I dusted that Ultra 150 that was taking me last year!!! Thanks, Carl

[ 05-26-2003, 09:22 PM: Message edited by: VOODOO ]

What exactly is the power core?

Power Core

http://www.rivayamaha.com/RivaStore/product_page.asp?Category=Riva%20GP1300R%20Power%20Core%20Exhaust%20Insert#

I should add that I have the washer in with that 13/19. Also that 69.8 was around noon, I'd like to think I would of broke 70 in the early morning cool air but who knows?

What were the temps?

Glad to see your ski is running good.

[ 05-26-2003, 10:56 PM: Message edited by: Spud ]

69.8 with a 13/19 is great!

Kind of goes to show you what reducing the wetted surface can do.

The best I got with a 13/19 washer out was 67.3@7280

I was running the Riva plate with no mods to it and the Riva 01 trim tabs.

Spud, the temp was in the 65-70 range.

CAn anyone tell me if these rpm's are about average or am I getting a little more out of the power core??? Spud, seems like you were getting a lot of rpm's for not a lot of speed, maybe your impeller was down on pitch? You even had the washer out, I havn't tried that yet.