Steve Zuckerman

Hey Bob,
Sounds great. I am bringing the Merc lab 32" that I ran 94.5 light (@ 5700) to the Jamboree if you want to test it. It's pretty sweet. Please bring the 29" P5X. I would like to test it.
Regards,
Steve

Rage

So with the 8.5:1 compression, head work and new cam but the same boost as before you made slightly more hp than before? Then you opened up the TB and increased the boost and got the final big jump in hp?

bobl

Yes that is basically correct. However, it hit a bottleneck and would not pull past 5600 with the 7 psi pulley before, so I couldn't really raise the boost in application. I just tried it on one dyno run. It made 800 HP at 6000 rpm with 5.5 psi boost before. After the rebuild it made less than 5 psi boost with the same pulley and made just slightly more power. Changing pulleys raised the boost to 6.5 and it would pull all the way to 6000. I talked to Dustin about raising the boost and he told me to port the throttle body because it was a restriction at that HP level. Doing so raised the boost 1 psi and picked up about 50 HP.

Bob

Rage

How big was the TB before and after you opened it up?

bobl

It's a huge 2000+ cfm throttle body. The problem is the way it is machined for the flame arrestor, which sits inside, causes a significant restriction when the FA is installed. By opening it up beneath the FA you gain a lot of surface area for air to pass through.

Steve Zuckerman

Bob,
I ran the boat before leaving Cumberland yesterday. It ran a quick 90 @ 5850 with my 28". Went straight back to the dock and put your 29P5-X on. Boat handled great, acelleration was very close to the 28". It took me a little farther to run it out, and every time I got to 90 I would get into rough water and have to back down. It ran 90 @ 5700, but felt like it was still pulling, maybe another mile and hour or 2.
I think it would be a good all round prop, keep my Rs down some, and be more efficient (fuel) in the mid range.
It was good to see you and the Texas crew.
Your 29" is going out via UPS this morning. Thanks for letting me borrow it.

39 Unlimited

Steve and Bob,

Has anyone tried the PX-5 on the 35 Nordic? I tried Mercury's Maximus offering with little success. From watching both of you last Saturday they certainly work for the 25 and 28.

Bob, that 25 is a rocket ship!

Steve Zuckerman

Gary,
I am not sure if anyone's tried them on a Flame? I would ask Matt and Julie at Throttle-Up www.throttle-up.com .
I agree on the Maximus. It's a big windmill. Matt tells me with a lot of work, they can be made to run, but it's a lot easier to start with a Hydromotive.
I have a friend who is running P5-Xs (stock 30s") on his 42' Fountain with modified 575s. It's running in the low 90s, so they are working on his step bottom with twins. Seems like they would also work on a Flame.
Regards,
Steve

Nordicflame

They were running 5 blades on the single engine (1200hp)Flame (IMCO) with the splitter but I don't remember which. If memory serves me it was running 100+. I'm sure the weighting difference would make it a non apples to apples comparison though. It does make me think that it likes transom lift which the single engine setup was creating. Just a thought

I'd be interested to know as well.

Dave