throttleup

Always a pleasure Bob!

Julie

raytart

iTrader: (1)

Hi Matt & Julie

This post goes back a few months but I took your advice and added a 1" spacer. Here are the results.

Gaffrig GPS speedo

At 2500rpm went from 25mph to 32mph
At 3000rpm went from 35mph to 41mph
At 4000 rpm went from 50mph to 60mph
At 5200 rpm went from 76mph to 78mph

At full throttle and trimmed way out I rarely hit the rev limiter. Prior to spacer I hit the rev limiter all the time.
So - It seems as if the low and mid range rpms had the most speed gains and only a minor speed gain at wide open. Not bad for only spending a few hundred $. Now I'm wondering if a prop swap is in need. What do you guys think. Keep in mind that todays conditions were a bit different than my original testing days conditions. Also keep in mind that I'm at sea level and salt water (Long Island).
(525efi 1.50 gears-its/xr drive-28 bravo with added cupping)

Any prop recommendations?
I'm thinking a stock bravo 30
or labbed 32

Ray

throttleup

Ray,

The first thing I would like to see is how the boat performs without the added cup. The cup was a band aid for an excessively high drive height. You don't need it now. After that analyze your results and go from there.

Matt

raytart

iTrader: (1)

I'll see if I can get my hands on a stock 28
But I know I'll be over the limiter again
I'll probably start with a stock 30

Thanks and I'll keep you posted

Steve Zuckerman

Ray,
In case you didn't see my results, my boat ran:
85.5 @ 5500 with the TU/Bravo 1 4 blade
86 @ 5600 with the TU/Hydromotive P5-X
excellent acelleration with both
both tested with my Imco case and a 1" spacer added
the Bravo definitely likes the spacer
the P5-X seems to be just as fast with the spacer, and it is carrying the boat better with a load
Oh yeah, modified 575SCi, est. HP 750 bobtail, 725 PSHP
Regards,
Steve

raytart

iTrader: (1)

If I go to the P5-X what pitch do you think I will need.
I tried the stock bravo 30 and couldn't spin it fast enough. (See Drive spacer results in the Nordic Forum)

Nordicflame

iTrader: (4)

27 P5X with a Nordic/TU tweek...

We have one currently running at high altitude (5000feet) with a 496HO/Whipple (740hp @ sea level/~590hp at 5000 ft) that spins 5100 and 75-78mph so if you can spin it a touch faster you should be near 80 on the salt.

Dave