Prop testing today

[harbormaster]

This afternoon I tested a couple of props that Julie of Throttle up Propellors was kind enough to send me for testing.

Here are the results...
1985 18 classic
350 Magnum (carbed)
Alpha 1 Gen II 1.50 gearing
2 people in the boat
Wind Speed: 22 mph
Wind Direction: SSE (163°)
Lake State: choppy
Water Temp: 85 F
Wave Height: 1.5 to 2 ft.
Wave Direction: SSE (157°)
Wave Period: 6 sec.
Saltwater

21 pitch Powertech 51 mph @ 5000 RPMs
21 pitch Mirage Plus 53 mph @ 5000 RPMS
21 pitch Vengence 52 mph @ 4800 RPMS (stock)

[Bryan Tuvell 33ZX]

Scot, POWER TECH says you get allot of bow lift, we sure did (mid range was impressive) when we tried one but it on occassion blew out, how was the ride in your classic compared to the other two props?
Just curious, I haven't read of any other classic guys trying this prop.
Thanks
Bryan

[harbormaster]

I noticed hardly any difference. If anything, the stock 21 pitch Vengence was the best performing prop.

I did notice that when trying to trim up the Mirage plus to gain more speed, I gained a loud vibration/buzz that was not heard with the other props.

I believe my engine is running a little rich.
I am going to tune it up and try again.

[oldLenny]

Scot. We were seeing the same numbers when I was in that thing with you and one MORE person. You, me and Gerry were getting 50 on E-Trex. I think you need an extra 100 ponies and start spinning something larger. If that doesn't makes sense to you, you should just sell that " 'ol thing " to me and get yourself a 22 with a big block. I can pick it up in Sept of 2003 while I'm in Possum... :D

Why not see if you can't get a 23" Mirage and spin it with a "slight tune up" at 4800-ish...it might be "slow out of the hole" wink but you might see some top end gains...theory says you'll see about 4600 RPM but hopefully you can "kick" that up a bit. (...a tune up...and then...STAINLESS MARINE... :D )

Drive it alone with low fuel and see if she can "spin" it...

[Cuda]

Scot, was that into or with that 22mph wind, or an average? That's a pretty stiff breeze.

[Tomahawk]

Scot - if you can, try a Turbo 14 1/4 X 23. If you don't get at least 54 mph, I'll eat my hat!

[BigGrizzly]

I can't beleive that T-up didn't includea Turbo. We have beaten the M-Plus every time on a clasic Donzi with a out of the box one. I also know a Vengence is a reqally good prop. Some people who know on this site swear by them. Scot, good real information for the board. Bring Kimmey to C-land I owe her a ride.

[harbormaster]

Lenny,

At PK we tried a 23 pitch Mirage plus and ran 50 at 4200 rpms.

[CDMA]

Harbormaster,

Not trying to step on your toes but have you looked at your tach or tried another GPS? Those numbers work out to alomst 20% slip and from past experience I think that power should result in closer to 60 mph.

Just trying to help you go faster...

Chris

[RickR]

If you're rated at 4600 to 4800 rpms you might be hitting the rev-limiter.
It is hard to hear it kick in at WOT but you might see the tach bounce.

[Barry Phillips]

Habormaster:
What is the rated HP on your 350mag, your top end seems low. I have a 1998 Classic 18 thats almost your boats twin, windshield and all. I run a bone stock 5.7L 250hp with a 23" Vengeance . I can manage a radar confirmed 65mph with a passenger and about 30 gallons of fuel at 4,400 rpm in cool weather. I have never seen below 60 in this boat under any conditions and with 3 passengers aboard. With my own testing in ideal conditions, by myself, and a light fuel load the boat has manged 67mph at 4,800 rpm. At 3,500 rpm it will run 50 mph all day. I tried a 21 " Mirarge Plus and lost about 3 mph and gained 200 rpm. Is the motor tired, how many hours are on it.

SO-SLO

[Barry Phillips]

Habormaster:
What is the rated HP on your 350mag, your top end seems low. I have a 1998 Classic 18 thats almost your boats twin, windshield and all. I run a bone stock 5.7L 250hp with a 23" Vengeance . I can manage a radar confirmed 65mph with a passenger and about 30 gallons of fuel at 4,400 rpm in cool weather. I have never seen below 60 in this boat under any conditions and with 3 passengers aboard. With my own testing in ideal conditions, by myself, and a light fuel load the boat has manged 67mph at 4,800 rpm. At 3,500 rpm it will run 50 mph all day. I tried a 21 " Mirarge Plus and lost about 3 mph and gained 200 rpm. Is the motor tired, how many hours are on it.

SO-SLO

[Rootsy]

I am a bit puzzled Scot,

i can't really comment fully since i am sure there are some details that i don't have or i'm missing BUT...

in the 16, trimmed out @ 5000 rpm with a 21P cleaver i WAS seeing just a tick under 65 mph... trimmed all of the way in with the nose buried i could get 4500 rpm and about 58 mph... i also have a 1.47 ratio Gen II...

in STOCK form (210 hp 5.7L) i could spin a 19P vengence about 4400 rpm and about 53 mph trimmed out...

just for comparison i ran heather's (for sale section) 87 18 with the tired ole 350 mag (270 pshp) & 1.5 ratio alpha w/ 21 cleaver on lake michigan in june... 4800 rpm and around 62ish with all the trim the boat had to offer...

although difficult to accept from a summer of running, if you trust the gps and the tach then maybe it is time to take a peek at the engine coupler...

also wanting you to go faster!

Jamie

[boldts]

Scot, Give a Turbo a try! You won't be sorry. Even with the 1.36 drive ratio in my drive, and the engine only turning 4600, I gained 4 MPH by going from a Mirage to a Turbo. Boat is also much more stable because of the smaller diameter of the Turbo. I haven't tried a Mirage + yet, but I've been told by those who have tried almost every prop out there that it won't beat the Turbo and the cost will be at least a $100 more. I only have a 22" pitch, but your welcome to try it if you like. Now, are they making that P-5 in a 21" yet? wink